101
|
Huang Z, Xu Z, Mahboub M, Liang Z, Jaimes P, Xia P, Graham KR, Tang ML, Lian T. Enhanced Near-Infrared-to-Visible Upconversion by Synthetic Control of PbS Nanocrystal Triplet Photosensitizers. J Am Chem Soc 2019; 141:9769-9772. [PMID: 31180212 DOI: 10.1021/jacs.9b03385] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Photon upconversion employing semiconductor nanocrystals (NCs) makes use of their large and tunable absorption to harvest light in the near-infrared (NIR) wavelengths as well as their small gap between singlet and triplet excited states to reduce energy losses. Here, we report the highest QY (11.8%) thus far for the conversion of NIR to yellow photons by improving the quality of the PbS NC. This high QY was achieved by using highly purified lead and thiourea precursors. This QY is 2.6 times higher than from NCs prepared with commercially available lead and sulfide precursors. Transient absorption spectroscopy reveals two reasons for the enhanced QY: longer intrinsic exciton lifetimes of PbS NCs and the ability to support a longer triplet lifetime for the surface-bound transmitter molecule. Overall, this results in a higher efficiency of triplet exciton transfer from the PbS NC light absorber to the emitter and thus a higher photon upconversion QY.
Collapse
Affiliation(s)
- Zhiyuan Huang
- Department of Chemistry , University of California, Riverside , Riverside , California 92521 , United States
| | - Zihao Xu
- Department of Chemistry , Emory University , Atlanta , Georgia 30322 , United States
| | - Melika Mahboub
- Department of Materials Science & Engineering , University of California, Riverside , Riverside , California 92521 , United States
| | - Zhiming Liang
- Department of Chemistry , University of Kentucky , Lexington , Kentucky 40506 , United States
| | - Paulina Jaimes
- Department of Chemistry , University of California, Riverside , Riverside , California 92521 , United States
| | - Pan Xia
- Materials Science & Engineering Program , University of California, Riverside , Riverside , California 92521 , United States
| | - Kenneth R Graham
- Department of Chemistry , University of Kentucky , Lexington , Kentucky 40506 , United States
| | - Ming L Tang
- Department of Chemistry , University of California, Riverside , Riverside , California 92521 , United States.,Department of Materials Science & Engineering , University of California, Riverside , Riverside , California 92521 , United States
| | - Tianquan Lian
- Department of Chemistry , Emory University , Atlanta , Georgia 30322 , United States
| |
Collapse
|
102
|
The conversion of CuInS2/ZnS core/shell structure from type I to quasi-type II and the shell thickness-dependent solar cell performance. J Colloid Interface Sci 2019; 546:276-284. [DOI: 10.1016/j.jcis.2019.03.075] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2019] [Revised: 03/22/2019] [Accepted: 03/24/2019] [Indexed: 01/02/2023]
|
103
|
Davidson-Hall T, Aziz H. The role of excitons within the hole transporting layer in quantum dot light emitting device degradation. NANOSCALE 2019; 11:8310-8318. [PMID: 30982837 DOI: 10.1039/c8nr09560d] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
This work investigates the root causes of the limited stability of electroluminescent quantum dot light-emitting devices (QDLEDs). Studies using electrical measurements, continuous UV irradiation, and both steady-state and transient photoluminescence (PL) spectroscopy reveal that exciton-induced degradation of the hole transporting material (HTM) in QDLEDs plays a role in limiting their electroluminescence (EL) stability. The results indicate that there is a correlation between device EL stability and the susceptibility of the HTM to exciton-induced degradation. The presence of quenchers in the HTM layer can lead to a decrease in the luminescence quantum yield of QDs, suggesting that energy transfer between the QD and HTM films may play a role in this behavior. The results uncover a new degradation mechanism where excitons within the HTM limit the EL stability of QDLEDs.
Collapse
Affiliation(s)
- Tyler Davidson-Hall
- Department of Electrical and Computer Engineering and Waterloo Institute for Nanotechnology, University of Waterloo, 200 University Avenue West, Waterloo, Ontario N2L 3G1, Canada.
| | | |
Collapse
|
104
|
Moraitis P, Leeuwen GV, Sark WV. Visual Appearance of Nanocrystal-Based Luminescent Solar Concentrators. MATERIALS 2019; 12:ma12060885. [PMID: 30884811 PMCID: PMC6471105 DOI: 10.3390/ma12060885] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Revised: 03/05/2019] [Accepted: 03/06/2019] [Indexed: 11/25/2022]
Abstract
The luminescent solar concentrator (LSC) is a promising concept for the integration of photovoltaic (PV) generators into the building envelope. Having the form of semitransparent plates, LSCs offer a high degree of flexibility and can be used as windows or facades, as part of the of building-integrated photovoltaic (BIPV) industry. Existing performance characterizations of LSC devices focus almost exclusively on electric power generation. However, when used as window components, the transmitted spectrum can alter the color, potentially affecting the visual comfort of the occupants by altering the properties of the sunlight. In this study, eight different state-of-the-art nanocrystals are evaluated as potential candidates for LSC window luminophores, using Monte Carlo simulations. The transparency of each LSC window varies between 90% and 50%, and the color-rendering properties are assessed with respect to the color rendering index (CRI) and the correlated color temperature (CCT). It is found that luminophores with a wide absorption bandwidth in the visible spectrum can maintain a high CRI value (above 85) and CCT values close to the Planckian locus, even for high luminophore concentrations. In contrast, luminophores that only absorb partly in the visible spectrum suffer from color distortion, a situation characterized by low CCT and CRI values, even at high transmittance.
Collapse
Affiliation(s)
| | - Gijs van Leeuwen
- Copernicus Institute, Utrecht University, Utrecht 3584 CB, The Netherlands.
| | - Wilfried van Sark
- Copernicus Institute, Utrecht University, Utrecht 3584 CB, The Netherlands.
| |
Collapse
|
105
|
Long T, Cao J, Jiang ZJ. Predictable spectroscopic properties of type-II ZnTe/CdSe nanocrystals and electron/hole quenching. Phys Chem Chem Phys 2019; 21:5824-5833. [PMID: 30806432 DOI: 10.1039/c9cp00026g] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The spectroscopic properties of core/shell structured ZnTe/CdSe nanocrystals (NCs) have been systematically studied. By varying the ZnTe core diameter and the CdSe shell thickness, the absorption onset and the photoluminescence peak position of the ZnTe/CdSe NCs can be readily tuned over a wide range. The theoretical model based on an effective mass approximation demonstrates that the ZnTe/CdSe NCs have type II carrier localization in which the photoexcited electrons and holes are spatially separated and confined in the shell and core, respectively. The energetics of the conduction and valence bands and the bandgaps of the ZnTe/CdSe NCs are accurately predicted. The photoluminescent experiments show that electron quenchers having a large energy difference between their reduction potential and the lowest conduction band edge of the ZnTe/CdSe nanocrystals can completely quench the luminescence. Electron acceptors having a reduction potential only slightly below the conduction band edge partially quench the photoluminescence of the nanocrystals. In this case, the extent of quenching depends upon the thickness of the shell and the energy difference. Despite the confinement of photoexcited holes in the core, the photoluminescence could be still quenched by adsorbed hole quenchers. The extent of hole quenching depends upon the core size, the shell thickness and the oxidation potential of the quenchers. Basically, an increase in the core size and the shell thickness may lead to a decrease in the extent of hole quenching. The work presented here is of great interest since it can be extended to understand the spectroscopic properties and photoluminescence quenching behaviors of other core/shell semiconductor NCs.
Collapse
Affiliation(s)
- Tongqing Long
- Guangzhou Key Laboratory for Surface Chemistry of Energy Materials, New Energy Research Institute, College of Environment and Energy, South China University of Technology, Guangzhou 510006, China.
| | | | | |
Collapse
|
106
|
Park YS, Lim J, Klimov VI. Asymmetrically strained quantum dots with non-fluctuating single-dot emission spectra and subthermal room-temperature linewidths. NATURE MATERIALS 2019; 18:249-255. [PMID: 30617342 DOI: 10.1038/s41563-018-0254-7] [Citation(s) in RCA: 66] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Accepted: 11/16/2018] [Indexed: 05/21/2023]
Abstract
The application of colloidal semiconductor quantum dots as single-dot light sources still requires several challenges to be overcome. Recently, there has been considerable progress in suppressing intensity fluctuations (blinking) by encapsulating an emitting core in a thick protective shell. However, these nanostructures still show considerable fluctuations in both emission energy and linewidth. Here we demonstrate type-I core/shell heterostructures that overcome these deficiencies. They are made by combining wurtzite semiconductors with a large, directionally anisotropic lattice mismatch, which results in strong asymmetric compression of the emitting core. This modifies the structure of band-edge excitonic states and leads to accelerated radiative decay, reduced exciton-phonon interactions, and suppressed coupling to the fluctuating electrostatic environment. As a result, individual asymmetrically strained dots exhibit highly stable emission energy (<1 meV standard deviation) and a subthermal room-temperature linewidth (~20 meV), concurrent with nearly nonblinking behaviour, high emission quantum yields, and a widely tunable emission colour.
Collapse
Affiliation(s)
- Young-Shin Park
- Chemistry Division, Los Alamos National Laboratory, Los Alamos, NM, USA
- Centre for High Technology Materials, University of New Mexico, Albuquerque, NM, USA
| | - Jaehoon Lim
- Chemistry Division, Los Alamos National Laboratory, Los Alamos, NM, USA
- Department of Chemical Engineering & Department of Energy System Research, Ajou University, Suwon, Republic of Korea
| | - Victor I Klimov
- Chemistry Division, Los Alamos National Laboratory, Los Alamos, NM, USA.
| |
Collapse
|
107
|
Selopal GS, Mohammadnezhad M, Navarro-Pardo F, Vidal F, Zhao H, Wang ZM, Rosei F. A colloidal heterostructured quantum dot sensitized carbon nanotube-TiO 2 hybrid photoanode for high efficiency hydrogen generation. NANOSCALE HORIZONS 2019; 4:404-414. [PMID: 32254093 DOI: 10.1039/c8nh00227d] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Solar-driven photoelectrochemical (PEC) hydrogen (H2) generation is a promising approach to harvest solar energy for the production of a clean chemical fuel. However, the low photon-to-fuel conversion efficiency and long-term stability of PEC devices are major challenges to be addressed to enable large-scale commercialization. Here we report a simple, fast and cost-effective approach to fabricate high efficiency and stable PEC devices for H2 generation, by fabricating a hybrid photoanode obtained by incorporating small amounts of multiwall carbon nanotubes (MWCNTs) into a TiO2 mesoporous film and sensitizing with colloidal heterostructured CdSe/(CdSexS1-x)5/(CdS)2 quantum dots (QDs). The latter were specially designed to accelerate the exciton separation through a band engineering approach. The PEC devices based on the TiO2/QD-MWCNT (T/Q-M) hybrid photoanode with an optimized amount of MWCNTs (0.015 wt%) yield a saturated photocurrent density of 15.90 mA cm-2 (at 1.0 VRHE) under one sun illumination (AM 1.5G, 100 mW cm-2), which is 40% higher than that of the reference device based on TiO2/QD (T/Q) photoanodes. This is attributed to a synergistic effect of the promising optoelectronic properties of the colloidal heterostructured QDs and improved electron transport (reduced charge transfer resistance) within the TiO2-MWCNT hybrid anodes enabled by the directional path of MWCNTs for the photo-injected electrons towards FTO. Furthermore, the PEC device based on the T/Q-M hybrid photoanode is more stable (∼19% loss of its initial photocurrent density) when compared with the T/Q photoanode (∼35% loss) after two hours of continuous one sun illumination. Our results provide fundamental insights and a different approach to improve the efficiency and long-term stability of PEC devices and represent an essential step towards the commercialization of this emerging solar-to-fuel conversion technology.
Collapse
Affiliation(s)
- Gurpreet Singh Selopal
- Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, Chengdu 610054, P. R. China.
| | | | | | | | | | | | | |
Collapse
|
108
|
Counting growth factors in single cells with infrared quantum dots to measure discrete stimulation distributions. Nat Commun 2019; 10:909. [PMID: 30796217 PMCID: PMC6385258 DOI: 10.1038/s41467-019-08754-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2018] [Accepted: 01/29/2019] [Indexed: 12/20/2022] Open
Abstract
The distribution of single-cell properties across a population of cells can be measured using diverse tools, but no technology directly quantifies the biochemical stimulation events regulating these properties. Here we report digital counting of growth factors in single cells using fluorescent quantum dots and calibrated three-dimensional deconvolution microscopy (QDC-3DM) to reveal physiologically relevant cell stimulation distributions. We calibrate the fluorescence intensities of individual compact quantum dots labeled with epidermal growth factor (EGF) and demonstrate the necessity of near-infrared emission to overcome intrinsic cellular autofluoresence at the single-molecule level. When applied to human triple-negative breast cancer cells, we observe proportionality between stimulation and both receptor internalization and inhibitor response, reflecting stimulation heterogeneity contributions to intrinsic variability. We anticipate that QDC-3DM can be applied to analyze any peptidic ligand to reveal single-cell correlations between external stimulation and phenotypic variability, cell fate, and drug response. Measuring growth factors in single cells at physiologically relevant stimulation doses is challenging. Here the authors use fluorescent quantum dots and calibrated three-dimensional deconvolution microscopy to digitally count growth factors in single cells and reveal stimulation distributions in cancer cells.
Collapse
|
109
|
Lin ML, Miscuglio M, Polovitsyn A, Leng YC, Martín-García B, Moreels I, Tan PH, Krahne R. Giant-Shell CdSe/CdS Nanocrystals: Exciton Coupling to Shell Phonons Investigated by Resonant Raman Spectroscopy. J Phys Chem Lett 2019; 10:399-405. [PMID: 30626187 DOI: 10.1021/acs.jpclett.8b03211] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The interaction between excitons and phonons in semiconductor nanocrystals plays a crucial role in the exciton energy spectrum and dynamics, and thus in their optical properties. We investigate the exciton-phonon coupling in giant-shell CdSe/CdS core-shell nanocrystals via resonant Raman spectroscopy. The Huang-Rhys parameter is evaluated by the intensity ratio of the longitudinal-optical (LO) phonon of CdS with its first multiscattering (2LO) replica. We used four different excitation wavelengths in the range from the onset of the CdS shell absorption to well above the CdS shell band edge to get insight into resonance effects of the CdS LO phonon with high-energy excitonic transitions. The isotropic spherical giant-shell nanocrystals show consistently stronger exciton-phonon coupling as compared to the anisotropic rod-shaped dot-in-rod (DiR) architecture, and the 2LO/LO intensity ratio decreases for excitation wavelengths approaching the CdS band edge. The strong exciton-phonon coupling in the spherical giant-shell nanocrystals can be related to the delocalization of the electronic wave functions. Furthermore, we observe the radial breathing modes of the GS nanocrystals and their overtones by ultralow frequency Raman spectroscopy with nonresonant excitation, using laser energies well below the band gap of the heteronanocrystals, and highlight the differences between higher-order optical and acoustic phonon modes.
Collapse
Affiliation(s)
- Miao-Ling Lin
- State Key Laboratory of Superlattices and Microstructures , Institute of Semiconductors, Chinese Academy of Sciences , Beijing 100083 , China
- Center of Materials Science and Optoelectronics Engineering & CAS Center of Excellence in Topological Quantum Computation , University of Chinese Academy of Sciences , Beijing 100190 , China
| | - Mario Miscuglio
- Istituto Italiano di Tecnologia (IIT) , Via Morego 30 , 16163 Genoa , Italy
| | - Anatolii Polovitsyn
- Department of Chemistry , Ghent University , Krijgslaan 281-S3 , 9000 Gent , Belgium
| | - Yu-Chen Leng
- State Key Laboratory of Superlattices and Microstructures , Institute of Semiconductors, Chinese Academy of Sciences , Beijing 100083 , China
- Center of Materials Science and Optoelectronics Engineering & CAS Center of Excellence in Topological Quantum Computation , University of Chinese Academy of Sciences , Beijing 100190 , China
| | | | - Iwan Moreels
- Department of Chemistry , Ghent University , Krijgslaan 281-S3 , 9000 Gent , Belgium
| | - Ping-Heng Tan
- State Key Laboratory of Superlattices and Microstructures , Institute of Semiconductors, Chinese Academy of Sciences , Beijing 100083 , China
- Center of Materials Science and Optoelectronics Engineering & CAS Center of Excellence in Topological Quantum Computation , University of Chinese Academy of Sciences , Beijing 100190 , China
| | - Roman Krahne
- Istituto Italiano di Tecnologia (IIT) , Via Morego 30 , 16163 Genoa , Italy
| |
Collapse
|
110
|
Limiting the Spectral Diffusion of Nano-Scale Light Emitters using the Purcell effect in a Photonic-Confined Environment. Sci Rep 2019; 9:1195. [PMID: 30718590 PMCID: PMC6362058 DOI: 10.1038/s41598-018-37677-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2018] [Accepted: 12/10/2018] [Indexed: 12/03/2022] Open
Abstract
Partial suppression of the spectral diffusion of quantum dot (QD) excitons tuned to resonance of a nano-photonic cavity is reported. The suppression is caused by the Purcell enhancement of the QD-exciton recombination rate, which alters the rate of charging of the solid-state environment by the QD itself. The effect can be used to spectrally-stabilize solid-state emitters of single photons and other non-classical states of light.
Collapse
|
111
|
Milleville CC, Chen EY, Lennon KR, Cleveland JM, Kumar A, Zhang J, Bork JA, Tessier A, LeBeau JM, Chase DB, Zide JMO, Doty MF. Engineering Efficient Photon Upconversion in Semiconductor Heterostructures. ACS NANO 2019; 13:489-497. [PMID: 30576110 DOI: 10.1021/acsnano.8b07062] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Photon upconversion is a photophysical process in which two low-energy photons are converted into one high-energy photon. Photon upconversion has broad appeal for a range of applications from biomedical imaging and targeted drug release to solar energy harvesting. Current upconversion nanosystems, including lanthanide-doped nanocrystals and triplet-triplet annihilation molecules, have achieved upconversion quantum yields on the order of 10-30%. However, the performance of these materials is hampered by inherently narrow absorption cross sections and fixed energy levels originating in atomic, ionic, or molecular states. Semiconductors, on the other hand, have inherently wide absorption cross sections. Moreover, recent advances enable the synthesis of colloidal semiconductor nanoparticles with complex heterostructures that can control band alignments and tune optical properties. We synthesize and characterize a three-component heterostructure that successfully upconverts photons under continuous-wave illumination and solar-relevant photon fluxes. The heterostructure is composed of two cadmium selenide quantum dots (QDs), an absorber and emitter, spatially separated by a cadmium sulfide nanorod (NR). We demonstrate that the principles of semiconductor heterostructure engineering can be applied to engineer improved upconversion efficiency. We first eliminate electron trap states near the surface of the absorbing QD and then tailor the band gap of the NR such that charge carriers are funneled to the emitting QD. When combined, these two changes result in a 100-fold improvement in photon upconversion performance.
Collapse
Affiliation(s)
| | | | | | | | - Abinash Kumar
- Department of Materials Science and Engineering , North Carolina State University , Raleigh , North Carolina 27606 , United States
| | | | | | - Ansel Tessier
- The Tatnall School , Wilmington , Delaware 19807 , United States
| | - James M LeBeau
- Department of Materials Science and Engineering , North Carolina State University , Raleigh , North Carolina 27606 , United States
| | | | | | | |
Collapse
|
112
|
|
113
|
Kumagai K, Uematsu T, Torimoto T, Kuwabata S. Direct surface modification of semiconductor quantum dots with metal–organic frameworks. CrystEngComm 2019. [DOI: 10.1039/c9ce00769e] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Robust surface protective materials for luminescent semiconductor quantum dots (QDs) are demonstrated by using metal–organic frameworks (MOFs) through a direct link between them.
Collapse
Affiliation(s)
- Kohei Kumagai
- Department of Applied Chemistry
- Graduate School of Engineering
- Osaka University
- Suita
- Japan
| | - Taro Uematsu
- Department of Applied Chemistry
- Graduate School of Engineering
- Osaka University
- Suita
- Japan
| | - Tsukasa Torimoto
- Department of Crystalline Materials Science
- Graduate School of Engineering
- Nagoya University
- Chikusa-ku
- Japan
| | - Susumu Kuwabata
- Department of Applied Chemistry
- Graduate School of Engineering
- Osaka University
- Suita
- Japan
| |
Collapse
|
114
|
Gak VY, Spirin MG, Brichkin SB, Razumov VF. Influence of Dithiols on Fluorescence Blinking of Colloidal Quantum Dots InP@ZnS. HIGH ENERGY CHEMISTRY 2019. [DOI: 10.1134/s0018143919080010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
|
115
|
Madanayake NH, Rienzie R, Adassooriya NM. Nanoparticles in Nanotheranostics Applications. Nanotheranostics 2019. [DOI: 10.1007/978-3-030-29768-8_2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
|
116
|
Cheche TO, Chang YC. Efficient Modeling of Optical Excitations of Colloidal Core-Shell Semiconductor Quantum Dots by Using Symmetrized Orbitals. J Phys Chem A 2018; 122:9910-9921. [PMID: 30485085 DOI: 10.1021/acs.jpca.8b09758] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
An efficient method for the theoretical investigation of optical properties of semiconductor core-shell quantum dots (CSQDs) is introduced within the multiband k·p approach, which takes the advantage of the symmetry of the system. The heteroepitaxial strain and excitonic effect are included in the calculation of energy levels, envelope wave functions, exciton binding energy, and linear absorption coefficient. The adoption of symmetrized orbitals allows improvement of the computation time significantly. To avoid appearance of spurious solutions caused by imbalance of basis functions adopted, we consider an 8-band k·p model which is block-diagonalized into two conduction bands and six valence bands, that we call the 2 + 6-band model. The band nonparabolicity effect is modeled by an energy-dependent k·p term, such that the density of states obtained can mimic the actual density of states of a full-band model. The simulated absorption spectra of ZnTe/ZnSe CSQD are in good agreement with those observed experimentally, including the high rise of absorption at energies far above the absorption edge.
Collapse
Affiliation(s)
| | - Yia-Chung Chang
- Research Center for Applied Sciences , Academia Sinica , Taipei , Taiwan.,Department of Physics , National Cheng-Kung University , Tainan , Taiwan 70101
| |
Collapse
|
117
|
Guo X, Kuang Y, Wang S, Li Z, Shen H, Guo L. Shell-dependent blinking behavior and fluorescence dynamics of single ZnSe/CdS core/shell quantum dots. NANOSCALE 2018; 10:18696-18705. [PMID: 30270388 DOI: 10.1039/c8nr06749j] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
An understanding of blinking behavior and photodynamics is crucial for improving the optical properties of quantum dots (QDs). Here we report the emission blinking behavior and dynamical mechanisms of single ZnSe/CdS core/shell QDs with the shell thickness varying from 1 to 6 monolayers. We find that the emission blinking behavior can be efficiently suppressed in the single-exciton regime and that the photoluminescence (PL) quantum yields (QY) and the corresponding fraction-bright of ZnSe/CdS QDs can be optimized by regulating the shell thickness. Specifically, the PL QY reaches a maximum of 93% when the shell thickness is 4 monolayers. The intensity-resolved and time-resolved fluorescence dynamics of single QDs indicate that three exciton decay pathways via trion emission, band-edge emission and shallow surface trap-state emission contribute to the blinking behavior of ZnSe/CdS QDs. The competitive contribution ratios of these three decay components are responsible for the significant difference in emission properties of ZnSe/CdS QDs with different shell thicknesses. Our findings in this work demonstrate that an effective way to improve the quantum yields and fraction-bright of core/shell QDs is to enhance the band-edge emission while suppressing the trion emission and surface trap-state emission.
Collapse
Affiliation(s)
- Xing Guo
- Institute of Micro/Nano Photonic Materials and Application, School of Physics and Electronics, Henan University, Kaifeng, 475004, People's Republic of China.
| | | | | | | | | | | |
Collapse
|
118
|
Chen Y, Ryou A, Friedfeld MR, Fryett T, Whitehead J, Cossairt BM, Majumdar A. Deterministic Positioning of Colloidal Quantum Dots on Silicon Nitride Nanobeam Cavities. NANO LETTERS 2018; 18:6404-6410. [PMID: 30251868 DOI: 10.1021/acs.nanolett.8b02764] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Engineering an array of precisely located cavity-coupled active media poses a major experimental challenge in the field of hybrid integrated photonics. We deterministically position solution-processed colloidal quantum dots (QDs) on high quality (Q)-factor silicon nitride nanobeam cavities and demonstrate light-matter coupling. By lithographically defining a window on top of an encapsulated cavity that is cladded in a polymer resist, and spin coating the QD solution, we can precisely control the placement of the QDs, which subsequently couple to the cavity. We show rudimentary control of the number of QDs coupled to the cavity by modifying the size of the window. Furthermore, we demonstrate Purcell enhancement and saturable photoluminescence in this QD-cavity platform. Finally, we deterministically position QDs on a photonic molecule and observe QD-coupled cavity supermodes. Our results pave the way for precisely controlling the number of QDs coupled to a cavity by engineering the window size, the QD dimension, and the solution chemistry and will allow advanced studies in cavity enhanced single photon emission, ultralow power nonlinear optics, and quantum many-body simulations with interacting photons.
Collapse
Affiliation(s)
- Yueyang Chen
- Electrical Engineering , University of Washington , Seattle , Washington 98189 , United States
| | - Albert Ryou
- Electrical Engineering , University of Washington , Seattle , Washington 98189 , United States
| | - Max R Friedfeld
- Department of Chemistry , University of Washington , Seattle , Washington 98189 , United States
| | - Taylor Fryett
- Electrical Engineering , University of Washington , Seattle , Washington 98189 , United States
| | - James Whitehead
- Electrical Engineering , University of Washington , Seattle , Washington 98189 , United States
| | - Brandi M Cossairt
- Department of Chemistry , University of Washington , Seattle , Washington 98189 , United States
| | - Arka Majumdar
- Electrical Engineering , University of Washington , Seattle , Washington 98189 , United States
- Department of Physics , University of Washington , Seattle , Washington 98189 , United States
| |
Collapse
|
119
|
Manceau M, Vezzoli S, Glorieux Q, Giacobino E, Carbone L, De Vittorio M, Hermier JP, Bramati A. CdSe/CdS Dot-in-Rods Nanocrystals Fast Blinking Dynamics. Chemphyschem 2018; 19:3288-3295. [PMID: 30281885 DOI: 10.1002/cphc.201800694] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2018] [Indexed: 11/07/2022]
Abstract
Analyzing the autocorrelation function of the fluorescence intensity, we demonstrate that these nanoemitters are characterized by a short value of the mean duration of bright periods (ten to a few hundreds of microseconds). The comparison of the results obtained for samples with different geometries shows that not only the shell thickness is crucial but also the shape of the dot-in-rods. Increasing the shell aspect ratio results in shorter bright periods suggesting that surface traps impact the stability of the fluorescence intensity.
Collapse
Affiliation(s)
- M Manceau
- Laboratoire Kastler Brossel, Sorbonne Université, CNRS, ENS-PSL Research University, Collège de France, 4, place Jussieu Case 74, F-75005, Paris, France
- Université Paris 13, Sorbonne Paris Cité, Laboratoire de Physique des Lasers, F-93430, Villetaneuse, France
| | - S Vezzoli
- The Blackett Laboratory, Department of Physics, Imperial College London, London, SW72AZ, United Kingdom
| | - Q Glorieux
- Laboratoire Kastler Brossel, Sorbonne Université, CNRS, ENS-PSL Research University, Collège de France, 4, place Jussieu Case 74, F-75005, Paris, France
| | - E Giacobino
- Laboratoire Kastler Brossel, Sorbonne Université, CNRS, ENS-PSL Research, University, Collège de France, 4, place Jussieu Case 74, F-75005, Paris, France
| | - L Carbone
- CNR NANOTEC-Institute of Nanotechnology c/o Campus Ecotekne, University of Salento, Via Monteroni -, 73100, Lecce, Italy
| | - M De Vittorio
- Istituto Italiano di Tecnologia (IIT) Center for Bio-Molecular Nanotechnologies Via Barsanti sn, 73010 Arnesano (Lecce), Italy, CNR NANOTEC-Institute of Nanotechnology c/o Campus Ecotekne, University of Salento, Via Monteroni -, 73100, Lecce, Italy
| | - J-P Hermier
- Groupe d'Etude de la Matière Condensée (GEMaC), Université de Versailles Saint-Quentin-en-Yvelines, CNRS UMR 8635, Université Paris-Saclay, 45 Avenue des Etats-Unis, 78035, Versailles Cedex, France
| | - A Bramati
- Laboratoire Kastler Brossel, Sorbonne Université, CNRS, ENS-PSL Research University, Collège de France, 4, place Jussieu Case 74, F-75005, Paris, France
| |
Collapse
|
120
|
Barak Y, Meir I, Shapiro A, Jang Y, Lifshitz E. Fundamental Properties in Colloidal Quantum Dots. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2018; 30:e1801442. [PMID: 29923230 DOI: 10.1002/adma.201801442] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2018] [Revised: 04/22/2018] [Indexed: 06/08/2023]
Abstract
A multidisciplinary approach for the production and characterization of colloidal quantum dots, which show great promise for implementation in modern optoelectronic applications, is described. The approach includes the design and formation of unique core/shell structures with alloy-composed layers between the core and the shell. Such structures eliminate interfacial defects and suppress the Auger process, thus reducing the known fluorescence blinking and endowing the quantum dots with robust chemical and spectral stability. The unique design enables the generation and sustained existence of single and multiple excitons with a defined spin-polarized emission recombination. The studies described herein implement the use of single-dot magneto-optical measurements and optically detected magnetic resonance spectroscopy, for direct identification of interfacial defects and for resolving exciton fine structure. The results are of paramount importance for a fundamental understanding of optical transitions in colloidal quantum dots, with an impact on appropriate materials design for practical applications.
Collapse
Affiliation(s)
- Yahel Barak
- Schulich Faculty of Chemistry, Solid State Institute, Russell Berrie Nanotechnology Institute, Grand Technion Energy Program, Technion, Haifa, 3200003, Israel
| | - Itay Meir
- Schulich Faculty of Chemistry, Solid State Institute, Russell Berrie Nanotechnology Institute, Grand Technion Energy Program, Technion, Haifa, 3200003, Israel
| | - Arthur Shapiro
- Schulich Faculty of Chemistry, Solid State Institute, Russell Berrie Nanotechnology Institute, Grand Technion Energy Program, Technion, Haifa, 3200003, Israel
| | - Youngjin Jang
- Schulich Faculty of Chemistry, Solid State Institute, Russell Berrie Nanotechnology Institute, Grand Technion Energy Program, Technion, Haifa, 3200003, Israel
| | - Efrat Lifshitz
- Schulich Faculty of Chemistry, Solid State Institute, Russell Berrie Nanotechnology Institute, Grand Technion Energy Program, Technion, Haifa, 3200003, Israel
| |
Collapse
|
121
|
Zhao H, Liu J, Vidal F, Vomiero A, Rosei F. Tailoring the interfacial structure of colloidal "giant" quantum dots for optoelectronic applications. NANOSCALE 2018; 10:17189-17197. [PMID: 30191225 DOI: 10.1039/c8nr04313b] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Colloidal semiconductor quantum dots (QDs) are promising building blocks for the realization of future optoelectronic technologies, thanks to their size-tunable electronic and optical properties. Among various types of QDs, colloidal "giant" QDs (g-QDs, core/thick-shell) have been widely used in different applications, such as solar cells, light emitting devices, luminescent solar concentrators and photoelectrochemical (PEC) hydrogen production. However, g-QDs have a thick-shell which serves as a physical barrier for electron and hole transfer, leading to a slow charge transfer rate. In this work, we synthesized CdSe/CdSexS1-x/CdS core/shell/shell g-QDs with an intermediate CdSexS1-x alloyed layer. The presence of this interfacial layer largely improves the absorption of CdSe/CdS QDs, particularly in the 300-650 nm range. By engineering the interfacial layer, the holes can leak more into the CdS shell region compared to that of CdSe/CdS QDs. PEC devices based on alloyed g-QDs exhibit a 20% higher saturated photocurrent density (11 ± 0.5 mA cm-2) compared to CdSe/CdS QDs. In addition, after one-hour illumination (100 mW cm-2), the PEC cell based on alloyed g-QDs still exhibits a photocurrent density of 7.5 mA cm-2, maintaining 70% of its initial value. Such alloyed g-QDs are very promising for several emerging optoelectronic applications, where charge separation, transfer and transport play a critical role for the realization of high performance devices.
Collapse
Affiliation(s)
- Haiguang Zhao
- State Key Laboratory & College of Physics, Qingdao University, No. 308 Ningxia Road, Qingdao 266071, PR China.
| | | | | | | | | |
Collapse
|
122
|
Basu K, Zhang H, Zhao H, Bhattacharya S, Navarro-Pardo F, Datta PK, Jin L, Sun S, Vetrone F, Rosei F. Highly stable photoelectrochemical cells for hydrogen production using a SnO 2-TiO 2/quantum dot heterostructured photoanode. NANOSCALE 2018; 10:15273-15284. [PMID: 30067257 DOI: 10.1039/c8nr02286k] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Photoelectrochemical (PEC) water splitting implementing colloidal quantum dots (QDs) as sensitizers is a promising approach for hydrogen (H2) generation, due to the QD's size-tunable optical properties. However, the challenge of long-term stability of the QDs is still unresolved. Here, we introduce a highly stable QD-based PEC device for H2 generation using a photoanode based on a SnO2-TiO2 heterostructure, sensitized by CdSe/CdS core/thick-shell "giant" QDs. This hybrid photoanode architecture leads to an appreciable saturated photocurrent density of ∼4.7 mA cm-2, retaining an unprecedented ∼96% of its initial current density after two hours, and sustaining ∼93% after five hours of continuous irradiation under an AM 1.5G (100 mW cm-2) simulated solar spectrum. Transient photoluminescence (PL) measurements demonstrate that the heterostructured SnO2-TiO2 photoanode exhibits faster electron transfer compared with the bare TiO2 photoanode. The lower electron transfer rate in the TiO2 photoanode can be attributed to slow electron kinetics in the ultraviolet regime, revealed by ultrafast transient absorption spectroscopy. Graphene microplatelets were further introduced into the heterostructured photoanode, which boosted the photocurrent density to ∼5.6 mA cm-2. Our results demonstrate that the SnO2-TiO2 heterostructured photoanode holds significant potential for developing highly stable PEC cells.
Collapse
Affiliation(s)
- Kaustubh Basu
- Institut National de la Recherche Scientifique, Centre Énergie, Matériaux et Télécommunications, Université du Québec, 1650 Boulevard Lionel-Boulet, Varennes, Québec J3X 1S2, Canada.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
123
|
Tong X, Kong X, Wang C, Zhou Y, Navarro‐Pardo F, Barba D, Ma D, Sun S, Govorov AO, Zhao H, Wang ZM, Rosei F. Optoelectronic Properties in Near-Infrared Colloidal Heterostructured Pyramidal "Giant" Core/Shell Quantum Dots. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2018; 5:1800656. [PMID: 30128262 PMCID: PMC6097093 DOI: 10.1002/advs.201800656] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2018] [Revised: 06/01/2018] [Indexed: 05/29/2023]
Abstract
Colloidal heterostructured quantum dots (QDs) are promising candidates for next-generation optoelectronic devices. In particular, "giant" core/shell QDs (g-QDs) can be engineered to exhibit outstanding optical properties and high chemical/photostability for the fabrication of high-performance optoelectronic devices. Here, the synthesis of heterostructured CuInSe x S2-x (CISeS)/CdSeS/CdS g-QDs with pyramidal shape by using a facile two-step method is reported. The CdSeS/CdS shell is demonstrated to have a pure zinc blend phase other than typical wurtzite phase. The as-obtained heterostructured g-QDs exhibit near-infrared photoluminescence (PL) emission (≈830 nm) and very long PL lifetime (in the microsecond range). The pyramidal g-QDs exhibit a quasi-type II band structure with spatial separation of electron-hole wave function, suggesting an efficient exciton extraction and transport, which is consistent with theoretical calculations. These heterostructured g-QDs are used as light harvesters to fabricate a photoelectrochemical cell, exhibiting a saturated photocurrent density as high as ≈5.5 mA cm-2 and good stability under 1 sun illumination (AM 1.5 G, 100 mW cm-2). These results are an important step toward using heterostructured pyramidal g-QDs for prospective applications in solar technologies.
Collapse
Affiliation(s)
- Xin Tong
- Institute of Fundamental and Frontier SciencesUniversity of Electronic Science and Technology of ChinaChengdu610054P. R. China
- Institut National de la Recherche ScientifiqueCentre Énergie Matériaux et Télécommunications1650 Boul. Lionel BouletVarennesQCJ3X 1S2Canada
| | - Xiang‐Tian Kong
- Institute of Fundamental and Frontier SciencesUniversity of Electronic Science and Technology of ChinaChengdu610054P. R. China
- Department of Physics and AstronomyOhio UniversityAthensOH45701USA
| | - Chao Wang
- Institut National de la Recherche ScientifiqueCentre Énergie Matériaux et Télécommunications1650 Boul. Lionel BouletVarennesQCJ3X 1S2Canada
| | - Yufeng Zhou
- Institut National de la Recherche ScientifiqueCentre Énergie Matériaux et Télécommunications1650 Boul. Lionel BouletVarennesQCJ3X 1S2Canada
| | - Fabiola Navarro‐Pardo
- Institute of Fundamental and Frontier SciencesUniversity of Electronic Science and Technology of ChinaChengdu610054P. R. China
- Institut National de la Recherche ScientifiqueCentre Énergie Matériaux et Télécommunications1650 Boul. Lionel BouletVarennesQCJ3X 1S2Canada
| | - David Barba
- Institut National de la Recherche ScientifiqueCentre Énergie Matériaux et Télécommunications1650 Boul. Lionel BouletVarennesQCJ3X 1S2Canada
| | - Dongling Ma
- Institut National de la Recherche ScientifiqueCentre Énergie Matériaux et Télécommunications1650 Boul. Lionel BouletVarennesQCJ3X 1S2Canada
| | - Shuhui Sun
- Institute of Fundamental and Frontier SciencesUniversity of Electronic Science and Technology of ChinaChengdu610054P. R. China
- Institut National de la Recherche ScientifiqueCentre Énergie Matériaux et Télécommunications1650 Boul. Lionel BouletVarennesQCJ3X 1S2Canada
| | | | - Haiguang Zhao
- State Key Laboratory and College of PhysicsQingdao UniversityQingdao266071P. R. China
| | - Zhiming M. Wang
- Institute of Fundamental and Frontier SciencesUniversity of Electronic Science and Technology of ChinaChengdu610054P. R. China
| | - Federico Rosei
- Institute of Fundamental and Frontier SciencesUniversity of Electronic Science and Technology of ChinaChengdu610054P. R. China
- Institut National de la Recherche ScientifiqueCentre Énergie Matériaux et Télécommunications1650 Boul. Lionel BouletVarennesQCJ3X 1S2Canada
| |
Collapse
|
124
|
Kim HM, Cho S, Kim J, Shin H, Jang J. Li and Mg Co-Doped Zinc Oxide Electron Transporting Layer for Highly Efficient Quantum Dot Light-Emitting Diodes. ACS APPLIED MATERIALS & INTERFACES 2018; 10:24028-24036. [PMID: 29952540 DOI: 10.1021/acsami.8b04721] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Zinc-oxide (ZnO) is widely used as an n-type electron transporting layer (ETL) for quantum dot (QD) light-emitting diode (QLED) because various metal doping can be possible and ZnO nanoparticle can be processed at low temperatures. We report here a Li- and Mg-doped ZnO, MLZO, which is used for ETL of highly efficient and long lifetime QLEDs. Co-doping, Mg and Li, in ZnO increases its band gap and electrical resistivity and thus can enhance charge balance in emission layer (EML). It is found also that the O-H concentration at the oxide surface decreases and exciton decay time of QDs on the metal oxide increases by co-doping in ZnO. The inverted green QLEDs with MLZO ETL exhibits the maximum current efficiency (CEmax) of 69.1 cd/A, power efficiency (PEmax) of 73.8 lm/W, and external quantum efficiency (EQEmax) of 18.4%. This is at least two times higher compared with the efficiencies of the QLEDs with Mg-doped ZnO ETL. The optimum Li and Mg concentrations are found to be 10% each. The deep-red, red, light-blue, and deep-blue QLEDs with MLZO ETLs exhibit the CEmax of 6.0, 22.3, 1.9, and 0.5 cd/A, respectively. The MLZO introduced here can be widely used as ETL of highly efficient QLEDs.
Collapse
Affiliation(s)
- Hyo-Min Kim
- Advanced Display Research Center (ADRC), Department of Information Display , Kyung Hee University , Dongdaemoon-ku, Seoul 130-701 , Korea
| | - Sinyoung Cho
- Advanced Display Research Center (ADRC), Department of Information Display , Kyung Hee University , Dongdaemoon-ku, Seoul 130-701 , Korea
| | - Jeonggi Kim
- Advanced Display Research Center (ADRC), Department of Information Display , Kyung Hee University , Dongdaemoon-ku, Seoul 130-701 , Korea
| | - Hyeonjeong Shin
- Advanced Display Research Center (ADRC), Department of Information Display , Kyung Hee University , Dongdaemoon-ku, Seoul 130-701 , Korea
| | - Jin Jang
- Advanced Display Research Center (ADRC), Department of Information Display , Kyung Hee University , Dongdaemoon-ku, Seoul 130-701 , Korea
| |
Collapse
|
125
|
Lai R, Pu C, Peng X. On-Surface Reactions in the Growth of High-Quality CdSe Nanocrystals in Nonpolar Solutions. J Am Chem Soc 2018; 140:9174-9183. [DOI: 10.1021/jacs.8b04743] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Runchen Lai
- Center for Chemistry of High-Performance & Novel Materials, Department of Chemistry, Zhejiang University, Hangzhou 310027, China
| | - Chaodan Pu
- Center for Chemistry of High-Performance & Novel Materials, Department of Chemistry, Zhejiang University, Hangzhou 310027, China
| | - Xiaogang Peng
- Center for Chemistry of High-Performance & Novel Materials, Department of Chemistry, Zhejiang University, Hangzhou 310027, China
| |
Collapse
|
126
|
Dawood F, Wang J, Schulze PA, Sheehan CJ, Buck MR, Dennis AM, Majumder S, Krishnamurthy S, Ticknor M, Staude I, Brener I, Goodwin PM, Amro NA, Hollingsworth JA. The Role of Liquid Ink Transport in the Direct Placement of Quantum Dot Emitters onto Sub-Micrometer Antennas by Dip-Pen Nanolithography. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2018; 14:e1801503. [PMID: 29952107 DOI: 10.1002/smll.201801503] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2018] [Revised: 05/14/2018] [Indexed: 06/08/2023]
Abstract
Dip-pen nanolithography (DPN) is used to precisely position core/thick-shell ("giant") quantum dots (gQDs; ≥10 nm in diameter) exclusively on top of silicon nanodisk antennas (≈500 nm diameter pillars with a height of ≈200 nm), resulting in periodic arrays of hybrid nanostructures and demonstrating a facile integration strategy toward next-generation quantum light sources. A three-step reading-inking-writing approach is employed, where atomic force microscopy (AFM) images of the pre-patterned substrate topography are used as maps to direct accurate placement of nanocrystals. The DPN "ink" comprises gQDs suspended in a non-aqueous carrier solvent, o-dichlorobenzene. Systematic analyses of factors influencing deposition rate for this non-conventional DPN ink are described for flat substrates and used to establish the conditions required to achieve small (sub-500 nm) feature sizes, namely: dwell time, ink-substrate contact angle and ink volume. Finally, it is shown that the rate of solvent transport controls the feature size in which gQDs are found on the substrate, but also that the number and consistency of nanocrystals deposited depends on the stability of the gQD suspension. Overall, the results lay the groundwork for expanded use of nanocrystal liquid inks and DPN for fabrication of multi-component nanostructures that are challenging to create using traditional lithographic techniques.
Collapse
Affiliation(s)
- Farah Dawood
- Materials Physics and Applications Division, Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA
| | - Jun Wang
- Materials Physics and Applications Division, Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA
| | - Peter A Schulze
- Materials Physics and Applications Division, Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA
| | - Chris J Sheehan
- Materials Physics and Applications Division, Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA
| | - Matthew R Buck
- Materials Physics and Applications Division, Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA
| | - Allison M Dennis
- Materials Physics and Applications Division, Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA
| | - Somak Majumder
- Materials Physics and Applications Division, Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA
| | - Sachi Krishnamurthy
- Materials Physics and Applications Division, Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA
| | - Matthew Ticknor
- Materials Physics and Applications Division, Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA
| | - Isabelle Staude
- Nonlinear Physics Centre, Research School of Physics and Engineering, The Australian National University, Canberra, Australian Capital Territory, 0200, Australia
| | - Igal Brener
- Center for Integrated Nanotechnologies, Sandia National Laboratories, Albuquerque, NM, 87185, USA
| | - Peter M Goodwin
- Materials Physics and Applications Division, Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA
| | - Nabil A Amro
- Advanced Creative Solutions Technology, Carlsbad, CA, 92008, USA
| | - Jennifer A Hollingsworth
- Materials Physics and Applications Division, Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA
| |
Collapse
|
127
|
Orfield NJ, Majumder S, McBride JR, Yik-Ching Koh F, Singh A, Bouquin SJ, Casson JL, Johnson AD, Sun L, Li X, Shih CK, Rosenthal SJ, Hollingsworth JA, Htoon H. Photophysics of Thermally-Assisted Photobleaching in "Giant" Quantum Dots Revealed in Single Nanocrystals. ACS NANO 2018; 12:4206-4217. [PMID: 29709173 DOI: 10.1021/acsnano.7b07450] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Quantum dots (QDs) are steadily being implemented as down-conversion phosphors in market-ready display products to enhance color rendering, brightness, and energy efficiency. However, for adequate longevity, QDs must be encased in a protective barrier that separates them from ambient oxygen and humidity, and device architectures are designed to avoid significant heating of the QDs as well as direct contact between the QDs and the excitation source. In order to increase the utility of QDs in display technologies and to extend their usefulness to more demanding applications as, for example, alternative phosphors for solid-state lighting (SSL), QDs must retain their photoluminescence emission properties over extended periods of time under conditions of high temperature and high light flux. Doing so would simplify the fabrication costs for QD display technologies and enable QDs to be used as down-conversion materials in light-emitting diodes for SSL, where direct-on-chip configurations expose the emitters to temperatures approaching 100 °C and to photon fluxes from 0.1 W/mm2 to potentially 10 W/mm2. Here, we investigate the photobleaching processes of single QDs exposed to controlled temperature and photon flux. In particular, we investigate two types of room-temperature-stable core/thick-shell QDs, known as "giant" QDs for which shell growth is conducted using either a standard layer-by-layer technique or by a continuous injection method. We determine the mechanistic pathways responsible for thermally-assisted photodegradation, distinguishing effects of hot-carrier trapping and QD charging. The findings presented here will assist in the further development of advanced QD heterostructures for maximum device lifetime stability.
Collapse
Affiliation(s)
- Noah J Orfield
- Materials Physics and Applications Division: Center for Integrated Nanotechnologies , Los Alamos National Laboratory , Los Alamos , New Mexico 87545 , United States
| | - Somak Majumder
- Materials Physics and Applications Division: Center for Integrated Nanotechnologies , Los Alamos National Laboratory , Los Alamos , New Mexico 87545 , United States
| | - James R McBride
- Department of Chemistry , Vanderbilt University , Nashville , Tennessee 37235 , United States
| | - Faith Yik-Ching Koh
- Materials Physics and Applications Division: Center for Integrated Nanotechnologies , Los Alamos National Laboratory , Los Alamos , New Mexico 87545 , United States
| | - Ajay Singh
- Materials Physics and Applications Division: Center for Integrated Nanotechnologies , Los Alamos National Laboratory , Los Alamos , New Mexico 87545 , United States
| | - Sarah J Bouquin
- Materials Physics and Applications Division: Center for Integrated Nanotechnologies , Los Alamos National Laboratory , Los Alamos , New Mexico 87545 , United States
| | - Joanna L Casson
- Chemistry Division , Los Alamos National Laboratory , Los Alamos , New Mexico 87545 , United States
| | - Alex D Johnson
- Physics Department and Center for Complex Quantum Systems , University of Texas at Austin , Austin , Texas 78712 , United States
| | - Liuyang Sun
- Physics Department and Center for Complex Quantum Systems , University of Texas at Austin , Austin , Texas 78712 , United States
| | - Xiaoqin Li
- Physics Department and Center for Complex Quantum Systems , University of Texas at Austin , Austin , Texas 78712 , United States
| | - Chih-Kang Shih
- Physics Department and Center for Complex Quantum Systems , University of Texas at Austin , Austin , Texas 78712 , United States
| | - Sandra J Rosenthal
- Department of Chemistry , Vanderbilt University , Nashville , Tennessee 37235 , United States
| | - Jennifer A Hollingsworth
- Materials Physics and Applications Division: Center for Integrated Nanotechnologies , Los Alamos National Laboratory , Los Alamos , New Mexico 87545 , United States
| | - Han Htoon
- Materials Physics and Applications Division: Center for Integrated Nanotechnologies , Los Alamos National Laboratory , Los Alamos , New Mexico 87545 , United States
| |
Collapse
|
128
|
Yang Z, Zhang Y, Liu J, Ai J, Lai S, Zhao Z, Ye B, Ruan Y, Guo T, Yu X, Chen G, Lin Y, Xu S. Ultrastable Quantum Dot Composite Films under Severe Environments. ACS APPLIED MATERIALS & INTERFACES 2018; 10:15880-15887. [PMID: 29652475 DOI: 10.1021/acsami.8b02790] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Semiconductor quantum dots (QDs) have attracted extensive attention because of their remarkable optical and electrical characteristics. However, the practical application of QDs and further the QD composite films have greatly been hindered mainly owing to their essential drawbacks of extreme unstability under oxygen and water environments. Herein, one simple method has been employed to enhance enormously the stability of Cd xZn1- xSe yS1- y QD composite films by a combination of Cd xZn1- xSe yS1- y QDs and poly(vinylidene) fluoride (PVDF), which is characteristic of closely arranged molecular chains and strong hydrogen bonds. There are many particular advantages in using QD/PVDF composite films such as easy processing, low cost, large-area fabrication, and especially extreme stability even in the boiling water for more than 240 min. By employing K2SiF6:Mn4+ as a red phosphor, a prototype white light-emitting diode (WLED) with color coordinates of (0.3307, 0.3387), Tc of 5568 K, and color gamut 112.1NTSC(1931)% at 20 mA has been fabricated, and there is little variation under different excitation currents, indicating that the QD/PVDF composite films fabricated by this simple blade-coating process make them ideal candidates for liquid-crystal display backlight utilization via assembling a WLED on a large scale owing to its ultrahigh stability under severe environments.
Collapse
Affiliation(s)
- Zunxian Yang
- National & Local United Engineering Laboratory of Flat Panel Display Technology , Fuzhou University , Fuzhou 350116 , P. R. China
| | - Yuxiang Zhang
- National & Local United Engineering Laboratory of Flat Panel Display Technology , Fuzhou University , Fuzhou 350116 , P. R. China
| | - Jiahui Liu
- National & Local United Engineering Laboratory of Flat Panel Display Technology , Fuzhou University , Fuzhou 350116 , P. R. China
| | - Jingwei Ai
- National & Local United Engineering Laboratory of Flat Panel Display Technology , Fuzhou University , Fuzhou 350116 , P. R. China
| | - Shouqiang Lai
- National & Local United Engineering Laboratory of Flat Panel Display Technology , Fuzhou University , Fuzhou 350116 , P. R. China
| | - Zhiwei Zhao
- National & Local United Engineering Laboratory of Flat Panel Display Technology , Fuzhou University , Fuzhou 350116 , P. R. China
| | - Bingqing Ye
- National & Local United Engineering Laboratory of Flat Panel Display Technology , Fuzhou University , Fuzhou 350116 , P. R. China
| | - Yushuai Ruan
- National & Local United Engineering Laboratory of Flat Panel Display Technology , Fuzhou University , Fuzhou 350116 , P. R. China
| | - Tailiang Guo
- National & Local United Engineering Laboratory of Flat Panel Display Technology , Fuzhou University , Fuzhou 350116 , P. R. China
| | - Xuebin Yu
- Department of Materials Science , Fudan University , Shanghai 200433 , P. R. China
| | - Gengxu Chen
- National & Local United Engineering Laboratory of Flat Panel Display Technology , Fuzhou University , Fuzhou 350116 , P. R. China
| | - Yuanyuan Lin
- National & Local United Engineering Laboratory of Flat Panel Display Technology , Fuzhou University , Fuzhou 350116 , P. R. China
| | - Sheng Xu
- National & Local United Engineering Laboratory of Flat Panel Display Technology , Fuzhou University , Fuzhou 350116 , P. R. China
| |
Collapse
|
129
|
Pramanik S, Bhandari S, Pan UN, Roy S, Chattopadhyay A. A White Light-Emitting Quantum Dot Complex for Single Particle Level Interaction with Dopamine Leading to Changes in Color and Blinking Profile. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2018; 14:e1800323. [PMID: 29665212 DOI: 10.1002/smll.201800323] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Revised: 02/19/2018] [Indexed: 06/08/2023]
Abstract
The interaction of the neurotransmitter dopamine is reported with a single particle white light-emitting (WLE) quantum dot complex (QDC). The QDC is composed of yellow emitting ZnO quantum dots (Qdots) and blue emitting Zn(MSA)2 complex (MSA = N-methylsalicylaldimine) synthesized on their surfaces. Sensing is achieved by the combined changes in the visual luminescence color from white to blue, chromaticity color coordinates from (0.31, 0.33) to (0.24, 0.23) and the ratio of the exponents (αon /αoff ) of on/off probability distribution (from 0.24 to 3.21) in the blinking statistics of WLE QDC. The selectivity of dopamine toward ZnO Qdots, present in WLE QDC, helps detect ≈13 dopamine molecules per Qdot. Additionally, the WLE QDC exhibits high sensitivity, with a limit of detection of 3.3 × 10-9 m (in the linear range of 1-100 × 10-9 m) and high selectivity in presence of interfering biological species. Moreover, the single particle on-off bilking statistics based detection strategy may provide an innovative way for ultrasensitive detection of analytes.
Collapse
Affiliation(s)
- Sabyasachi Pramanik
- Department of Chemistry, Indian Institute of Technology Guwahati, Guwahati, 781039, Assam, India
| | - Satyapriya Bhandari
- Centre for Nanotechnology, Indian Institute of Technology Guwahati, Guwahati, 781039, Assam, India
| | - Uday Narayan Pan
- Department of Chemistry, Indian Institute of Technology Guwahati, Guwahati, 781039, Assam, India
| | - Shilaj Roy
- Department of Chemistry, Indian Institute of Technology Guwahati, Guwahati, 781039, Assam, India
| | - Arun Chattopadhyay
- Department of Chemistry, Indian Institute of Technology Guwahati, Guwahati, 781039, Assam, India
- Centre for Nanotechnology, Indian Institute of Technology Guwahati, Guwahati, 781039, Assam, India
| |
Collapse
|
130
|
Yuan G, Gómez DE, Kirkwood N, Boldt K, Mulvaney P. Two Mechanisms Determine Quantum Dot Blinking. ACS NANO 2018; 12:3397-3405. [PMID: 29579376 DOI: 10.1021/acsnano.7b09052] [Citation(s) in RCA: 73] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Many potential applications of quantum dots (QDs) can only be realized once the luminescence from single nanocrystals (NCs) is understood. These applications include the development of quantum logic devices, single-photon sources, long-life LEDs, and single-molecule biolabels. At the single-nanocrystal level, random fluctuations in the QD photoluminescence occur, a phenomenon termed blinking. There are two competing models to explain this blinking: Auger recombination and surface trap induced recombination. Here we use lifetime scaling on core-shell chalcogenide NCs to demonstrate that both types of blinking occur in the same QDs. We prove that Auger-blinking can yield single-exponential on/off times in contrast to earlier work. The surface passivation strategy determines which blinking mechanism dominates. This study summarizes earlier studies on blinking mechanisms and provides some clues that stable single QDs can be engineered for optoelectronic applications.
Collapse
Affiliation(s)
- Gangcheng Yuan
- ARC Centre of Excellence in Exciton Science, School of Chemistry , University of Melbourne , Parkville , Victoria 3010 , Australia
| | | | - Nicholas Kirkwood
- ARC Centre of Excellence in Exciton Science, School of Chemistry , University of Melbourne , Parkville , Victoria 3010 , Australia
| | - Klaus Boldt
- ARC Centre of Excellence in Exciton Science, School of Chemistry , University of Melbourne , Parkville , Victoria 3010 , Australia
| | - Paul Mulvaney
- ARC Centre of Excellence in Exciton Science, School of Chemistry , University of Melbourne , Parkville , Victoria 3010 , Australia
| |
Collapse
|
131
|
Califano M. Suppression of Auger Recombination in Nanocrystals via Ligand-Assisted Wave Function Engineering in Reciprocal Space. J Phys Chem Lett 2018; 9:2098-2104. [PMID: 29589440 DOI: 10.1021/acs.jpclett.8b00248] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
A limiting factor to the technological application of conventional semiconductor nanostructures is their fast Auger recombination time. Strategies to increase it have so far mostly focused on decreasing the electron-hole wave function overlap in real space through structural modifications involving either elongation or shell growth. Here we propose an alternative mechanism for Auger recombination suppression: a decrease in the overlap of electron and hole wave functions in reciprocal space.
Collapse
Affiliation(s)
- Marco Califano
- Pollard Institute, School of Electronic and Electrical Engineering , University of Leeds , Leeds LS2 9JT , United Kingdom
| |
Collapse
|
132
|
Photon antibunching in a cluster of giant CdSe/CdS nanocrystals. Nat Commun 2018; 9:1536. [PMID: 29670113 PMCID: PMC5906464 DOI: 10.1038/s41467-018-03971-w] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2017] [Accepted: 03/24/2018] [Indexed: 01/12/2023] Open
Abstract
When closely packed into a high-density film, semiconductor nanocrystals (NCs) can interact with each other to yield collective optical behaviours, which are normally difficult to characterize due to the ensemble average effect. Here we synthesized semiconductor NC clusters and performed single-particle spectroscopic measurements to probe the electronic couplings of several giant CdSe/CdS NCs contained in one cluster with nanometer-scale separations. Such a single cluster exhibits multiple emission peaks at the cryogenic temperature with nearly identical photoluminescence decay dynamics, suggesting that the Förster-type energy transfer does not occur among the composing NCs. Surprisingly, strong photon antibunching is still observed from a single cluster, which can be attributed to the Auger annihilation of photo-excited excitons from different NCs. The isolation of several nearby NCs interacting with the above novel mechanism has marked a solid progress towards a full understanding and an efficient control of the operation parameters in NC-based optoelectronic devices.
Collapse
|
133
|
Panfil YE, Oded M, Banin U. Colloidal Quantum Nanostructures: Emerging Materials for Display Applications. Angew Chem Int Ed Engl 2018; 57:4274-4295. [PMID: 28975692 PMCID: PMC6001641 DOI: 10.1002/anie.201708510] [Citation(s) in RCA: 133] [Impact Index Per Article: 22.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2017] [Indexed: 11/11/2022]
Abstract
Colloidal semiconductor nanocrystals (SCNCs) or, more broadly, colloidal quantum nanostructures constitute outstanding model systems for investigating size and dimensionality effects. Their nanoscale dimensions lead to quantum confinement effects that enable tuning of their optical and electronic properties. Thus, emission color control with narrow photoluminescence spectra, wide absorbance spectra, and outstanding photostability, combined with their chemical processability through control of their surface chemistry leads to the emergence of SCNCs as outstanding materials for present and next-generation displays. In this Review, we present the fundamental chemical and physical properties of SCNCs, followed by a description of the advantages of different colloidal quantum nanostructures for display applications. The open challenges with respect to their optical activity are addressed. Both photoluminescent and electroluminescent display scenarios utilizing SCNCs are described.
Collapse
Affiliation(s)
- Yossef E. Panfil
- Institute of Chemistry and the Center for Nanoscience and NanotechnologyThe Hebrew University of JerusalemJerusalem9190401Israel
| | - Meirav Oded
- Institute of Chemistry and the Center for Nanoscience and NanotechnologyThe Hebrew University of JerusalemJerusalem9190401Israel
| | - Uri Banin
- Institute of Chemistry and the Center for Nanoscience and NanotechnologyThe Hebrew University of JerusalemJerusalem9190401Israel
| |
Collapse
|
134
|
Cui Y, Cui X, Zhang L, Xie Y, Yang M. Theoretical characterization on the size-dependent electron and hole trapping activity of chloride-passivated CdSe nanoclusters. J Chem Phys 2018; 148:134308. [DOI: 10.1063/1.5023408] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Affiliation(s)
- Yingqi Cui
- Institute of Atomic and Molecular Physics, Sichuan University, Chengdu 610065, People’s Republic of China
| | - Xianhui Cui
- Institute of Atomic and Molecular Physics, Sichuan University, Chengdu 610065, People’s Republic of China
| | - Li Zhang
- Institute of Atomic and Molecular Physics, Sichuan University, Chengdu 610065, People’s Republic of China
| | - Yujuan Xie
- Institute of Atomic and Molecular Physics, Sichuan University, Chengdu 610065, People’s Republic of China
| | - Mingli Yang
- Institute of Atomic and Molecular Physics, Sichuan University, Chengdu 610065, People’s Republic of China
| |
Collapse
|
135
|
Efros AL, Delehanty JB, Huston AL, Medintz IL, Barbic M, Harris TD. Evaluating the potential of using quantum dots for monitoring electrical signals in neurons. NATURE NANOTECHNOLOGY 2018; 13:278-288. [PMID: 29636589 DOI: 10.1038/s41565-018-0107-1] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2017] [Accepted: 02/26/2018] [Indexed: 06/08/2023]
Abstract
Success in the projects aimed at providing an advanced understanding of the brain is directly predicated on making critical advances in nanotechnology. This Perspective addresses the unique interface of neuroscience and nanomaterials by considering the foundational problem of sensing neuron membrane voltage and offers a potential solution that may be facilitated by a prototypical nanomaterial. Despite substantial improvements, the visualization of instantaneous voltage changes within individual neurons, whether in cell culture or in vivo, at both the single-cell and network level at high speed remains complex and problematic. The unique properties of semiconductor quantum dots (QDs) have made them powerful fluorophores for bioimaging. What is not widely appreciated, however, is that QD photoluminescence is exquisitely sensitive to proximal electric fields. This property should be suitable for sensing voltage changes that occur in the active neuronal membrane. Here, we examine the potential role of QDs in addressing the important challenge of real-time optical voltage imaging.
Collapse
Affiliation(s)
- Alexander L Efros
- Center for Computational Materials Science (6390), US Naval Research Laboratory, Washington, DC, USA.
| | - James B Delehanty
- Center for Bio/Molecular Science and Engineering (6900), US Naval Research Laboratory, Washington, DC, USA
| | - Alan L Huston
- Optical Sciences Division (5611), US Naval Research Laboratory, Washington, DC, USA
| | - Igor L Medintz
- Center for Bio/Molecular Science and Engineering (6900), US Naval Research Laboratory, Washington, DC, USA
| | - Mladen Barbic
- Applied Physics and Instrumentation Group, Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - Timothy D Harris
- Applied Physics and Instrumentation Group, Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA.
| |
Collapse
|
136
|
Navarro-Pardo F, Zhao H, Wang ZM, Rosei F. Structure/Property Relations in "Giant" Semiconductor Nanocrystals: Opportunities in Photonics and Electronics. Acc Chem Res 2018; 51:609-618. [PMID: 29260851 DOI: 10.1021/acs.accounts.7b00467] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Semiconductor nanocrystals exhibit size-tunable absorption and emission ranging from the ultraviolet (UV) to the near-infrared (NIR) spectral range, high absorption coefficient, and high photoluminescence quantum yield. Effective surface passivation of these so-called quantum dots (QDs) may be achieved by growing a shell of another semiconductor material. The resulting core/shell QDs can be considered as a model system to study and optimize structure/property relations. A special case consists in growing thick shells (1.5 up to few tens of nanometers) to produce "giant" QDs (g-QDs). Tailoring the chemical composition and structure of CdSe/CdS and PbS/CdS g-QDs is a promising approach to widen the spectral separation of absorption and emission spectra (i.e., the Stokes shift), improve the isolation of photogenerated carriers from surface defects and enhance charge carrier lifetime and mobility. However, most stable systems are limited by a thick CdS shell, which strongly absorbs radiation below 500 nm, covering the UV and part of the visible range. Modification of the interfacial region between the core and shell of g-QDs or tuning their doping with narrow band gap semiconductors are effective approaches to circumvent this challenge. In addition, the synthesis of g-QDs composed of environmentally friendly elements (e.g., CuInSe2/CuInS2) represents an alternative to extend their absorption into the NIR range. Additionally, the band gap and band alignment of g-QDs can be engineered by proper selection of the constituents according to their band edge positions and by tuning their stoichiometry during wet chemical synthesis. In most cases, the quasi-type II localization regime of electrons and holes is achieved. In this type of g-QDs, electrons can leak into the shell region, while the holes remain confined within the core region. This electron-hole spatial distribution is advantageous for optoelectronic devices, resulting in efficient electron-hole separation while maintaining good stability. This Account provides an overview of emerging engineering strategies that can be adopted to optimize structure/property relations in colloidal g-QDs for efficient photon management or charge separation/transfer. In particular, we focus on our recent contributions to this rapidly expanding field of research. We summarize the design and synthesis of a variety of colloidal g-QDs with the aim of tuning the optical properties, such as absorption/emission in a wide region of the solar spectrum, which allows enlargement of their Stokes shift. We also describe the band alignment within these systems, charge carrier dynamics, and charge transfer from g-QDs into semiconducting oxides. We show how these tailored g-QDs may be used as active components in luminescent solar concentrators, photoelectrochemical cells for hydrogen generation, QD-sensitized solar cells and optical nanothermometers. In each case, we aim at providing insights on structure/property relationships and on how to optimize them toward improving device performance. Finally, we describe perspectives for future work, sketching new directions and opportunities in this field of research at the intersection between chemistry, physics, materials science and engineering.
Collapse
Affiliation(s)
- Fabiola Navarro-Pardo
- Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, Chengdu 610054, P.R. China
- Centre for Energy, Materials and Telecommunications, Institut National de la Recherche Scientifique, 1650 Boulevard Lionel-Boulet, Varennes, Québec J3X 1S2, Canada
| | - Haiguang Zhao
- College of Physics and The Cultivation Base for State Key Laboratory, Qingdao University, No. 308 Ningxia Road, Qingdao 266071, P.R. China
| | - Zhiming M. Wang
- Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, Chengdu 610054, P.R. China
| | - Federico Rosei
- Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, Chengdu 610054, P.R. China
- Centre for Energy, Materials and Telecommunications, Institut National de la Recherche Scientifique, 1650 Boulevard Lionel-Boulet, Varennes, Québec J3X 1S2, Canada
| |
Collapse
|
137
|
Ghimire S, Biju V. Relations of exciton dynamics in quantum dots to photoluminescence, lasing, and energy harvesting. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY C-PHOTOCHEMISTRY REVIEWS 2018. [DOI: 10.1016/j.jphotochemrev.2018.01.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
|
138
|
Panfil YE, Oded M, Banin U. Kolloidale Quantennanostrukturen: neue Materialien für Displayanwendungen. Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201708510] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Yossef E. Panfil
- Institute of Chemistry and the Center for Nanoscience and Nanotechnology; The Hebrew University of Jerusalem; Jerusalem 9190401 Israel
| | - Meirav Oded
- Institute of Chemistry and the Center for Nanoscience and Nanotechnology; The Hebrew University of Jerusalem; Jerusalem 9190401 Israel
| | - Uri Banin
- Institute of Chemistry and the Center for Nanoscience and Nanotechnology; The Hebrew University of Jerusalem; Jerusalem 9190401 Israel
| |
Collapse
|
139
|
Reid KR, McBride JR, Freymeyer NJ, Thal LB, Rosenthal SJ. Chemical Structure, Ensemble and Single-Particle Spectroscopy of Thick-Shell InP-ZnSe Quantum Dots. NANO LETTERS 2018; 18:709-716. [PMID: 29282985 PMCID: PMC6163126 DOI: 10.1021/acs.nanolett.7b03703] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Thick-shell (>5 nm) InP-ZnSe colloidal quantum dots (QDs) grown by a continuous-injection shell growth process are reported. The growth of a thick crystalline shell is attributed to the high temperature of the growth process and the relatively low lattice mismatch between the InP core and ZnSe shell. In addition to a narrow ensemble photoluminescence (PL) line-width (∼40 nm), ensemble and single-particle emission dynamics measurements indicate that blinking and Auger recombination are reduced in these heterostructures. More specifically, high single-dot ON-times (>95%) were obtained for the core-shell QDs, and measured ensemble biexciton lifetimes, τ2x ∼ 540 ps, represent a 7-fold increase compared to InP-ZnS QDs. Further, high-resolution energy dispersive X-ray (EDX) chemical maps directly show for the first time significant incorporation of indium into the shell of the InP-ZnSe QDs. Examination of the atomic structure of the thick-shell QDs by high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) reveals structural defects in subpopulations of particles that may mitigate PL efficiencies (∼40% in ensemble), providing insight toward further synthetic refinement. These InP-ZnSe heterostructures represent progress toward fully cadmium-free QDs with superior photophysical properties important in biological labeling and other emission-based technologies.
Collapse
Affiliation(s)
- Kemar R. Reid
- Department of Interdisciplinary Materials Science, Vanderbilt University, Nashville, Tennessee 37235, United States
- Vanderbilt Institute for Nanoscale Science and Engineering, Vanderbilt University, Nashville, Tennessee 37235, United States
| | - James R. McBride
- Vanderbilt Institute for Nanoscale Science and Engineering, Vanderbilt University, Nashville, Tennessee 37235, United States
- Department of Chemistry, Vanderbilt University, Nashville, Tennessee 37235, United States
- correspondence: ,
| | - Nathaniel J. Freymeyer
- Vanderbilt Institute for Nanoscale Science and Engineering, Vanderbilt University, Nashville, Tennessee 37235, United States
- Department of Chemistry, Vanderbilt University, Nashville, Tennessee 37235, United States
| | - Lucas B. Thal
- Department of Chemistry, Vanderbilt University, Nashville, Tennessee 37235, United States
| | - Sandra J. Rosenthal
- Department of Interdisciplinary Materials Science, Vanderbilt University, Nashville, Tennessee 37235, United States
- Vanderbilt Institute for Nanoscale Science and Engineering, Vanderbilt University, Nashville, Tennessee 37235, United States
- Department of Chemistry, Vanderbilt University, Nashville, Tennessee 37235, United States
- Department of Physics and Astronomy, Vanderbilt University, Nashville, Tennessee 37235, United States
- Department of Pharmacology, Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, Tennessee 37235, United States
- correspondence: ,
| |
Collapse
|
140
|
le Feber B, Prins F, De Leo E, Rabouw FT, Norris DJ. Colloidal-Quantum-Dot Ring Lasers with Active Color Control. NANO LETTERS 2018; 18:1028-1034. [PMID: 29283266 PMCID: PMC5817622 DOI: 10.1021/acs.nanolett.7b04495] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2017] [Revised: 12/15/2017] [Indexed: 05/03/2023]
Abstract
To improve the photophysical performance of colloidal quantum dots for laser applications, sophisticated core/shell geometries have been developed. Typically, a wider bandgap semiconductor is added as a shell to enhance the gain from the quantum-dot core. This shell is designed to electronically isolate the core, funnel excitons to it, and reduce nonradiative Auger recombination. However, the shell could also potentially provide a secondary source of gain, leading to further versatility in these materials. Here we develop high-quality quantum-dot ring lasers that not only exhibit lasing from both the core and the shell but also the ability to switch between them. We fabricate ring resonators (with quality factors up to ∼2500) consisting only of CdSe/CdS/ZnS core/shell/shell quantum dots using a simple template-stripping process. We then examine lasing as a function of the optical excitation power and ring radius. In resonators with quality factors >1000, excitons in the CdSe cores lead to red lasing with thresholds at ∼25 μJ/cm2. With increasing power, green lasing from the CdS shell emerges (>100 μJ/cm2) and then the red lasing begins to disappear (>250 μJ/cm2). We present a rate-equation model that can explain this color switching as a competition between exciton localization into the core and stimulated emission from excitons in the shell. Moreover, by lowering the quality factor of the cavity we can engineer the device to exhibit only green lasing. The mechanism demonstrated here provides a potential route toward color-switchable quantum-dot lasers.
Collapse
Affiliation(s)
- Boris le Feber
- Optical Materials Engineering Laboratory,
Department of Mechanical and Process Engineering, ETH Zurich, 8092 Zurich, Switzerland
| | | | - Eva De Leo
- Optical Materials Engineering Laboratory,
Department of Mechanical and Process Engineering, ETH Zurich, 8092 Zurich, Switzerland
| | - Freddy T. Rabouw
- Optical Materials Engineering Laboratory,
Department of Mechanical and Process Engineering, ETH Zurich, 8092 Zurich, Switzerland
| | - David J. Norris
- Optical Materials Engineering Laboratory,
Department of Mechanical and Process Engineering, ETH Zurich, 8092 Zurich, Switzerland
| |
Collapse
|
141
|
Davidson-Hall T, Aziz H. The role of polyethylenimine in enhancing the efficiency of quantum dot light-emitting devices. NANOSCALE 2018; 10:2623-2631. [PMID: 29354848 DOI: 10.1039/c7nr07683e] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Although the use of polyethylenimine (PEI) in quantum dot light-emitting devices (QDLEDs) has recently been found to improve efficiency, the mechanism behind this increase has been disputed in the literature. In this work, we conduct investigations to elucidate the role of PEI in enhancing QDLED efficiency. Spectroscopic studies of devices with a phosphorescent marking layer reveal that the PEI layer increases, rather than decreases, the generation of excitons within the hole transporting layer indicative of increased electron injection. Delayed electroluminescence measurements corroborate these findings as devices with a PEI interlayer exhibit a greater concentration of excess mobile and trapped electrons. We attribute the improvement in efficiency despite the ensuing increased charge imbalance within the devices to the passivation of exciton quenching at the ZnO/QD interface. The increase in efficiency predominantly occurs over low driving currents which is particularly attractive for the brightness targets of display applications. Furthermore, despite the increased charge imbalance, the PEI passivation layer appears to have little effect on QDLED stability. This shows that excess electrons and Auger quenching by unneutralized electrons are not detrimental to QDLED stability.
Collapse
Affiliation(s)
- Tyler Davidson-Hall
- Department of Electrical and Computer Engineering and Waterloo Institute for Nanotechnology, University of Waterloo, 200 University Avenue West, Waterloo, Ontario N2L 3G1, Canada.
| | | |
Collapse
|
142
|
Ren F, Lindley SA, Zhao H, Tan L, Gonfa BA, Pu YC, Yang F, Liu X, Vidal F, Zhang JZ, Vetrone F, Ma D. Towards understanding the unusual photoluminescence intensity variation of ultrasmall colloidal PbS quantum dots with the formation of a thin CdS shell. Phys Chem Chem Phys 2018; 18:31828-31835. [PMID: 27841403 DOI: 10.1039/c6cp05786a] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
In this study, we report anomalous size-dependent photoluminescence (PL) intensity variation of PbS quantum dots (QDs) with the formation of a thin CdS shell via a microwave-assisted cation exchange approach. Thin shell formation has been established as an effective strategy for increasing the PL of QDs. Nonetheless, herein we observed an unusual PL decrease in ultrasmall QDs upon shell formation. We attempted to understand this abnormal phenomenon from the perspective of trap density variation and the probability of electrons and holes reaching surface defects. To this end, the quantum yield (QY) and PL lifetime (on the ns-μs time scales) of pristine PbS QDs and PbS/CdS core/shell QDs were measured and the radiative and non-radiative recombination rates were derived and compared. Moreover, transient absorption (TA) analysis (on the fs-ns time scale) was performed to better understand exciton dynamics at early times that lead to and affect longer time dynamics and optical properties such as PL. These experimental results, in conjunction with theoretical calculations of electron and hole wave functions, provide a complete picture of the photophysics governing the core/shell system. A model was proposed to explain the size-dependent optical and dynamic properties observed.
Collapse
Affiliation(s)
- Fuqiang Ren
- Institut National de la Recherche Scientifique - Énergie, Matériaux et Télécommunications, Univerisité du Québec, 1650 Boul. Lionel-Boulet, Varennes, Québec J3X 1S2, Canada.
| | - Sarah A Lindley
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, CA 95064, USA.
| | - Haiguang Zhao
- Institut National de la Recherche Scientifique - Énergie, Matériaux et Télécommunications, Univerisité du Québec, 1650 Boul. Lionel-Boulet, Varennes, Québec J3X 1S2, Canada.
| | - Long Tan
- Institut National de la Recherche Scientifique - Énergie, Matériaux et Télécommunications, Univerisité du Québec, 1650 Boul. Lionel-Boulet, Varennes, Québec J3X 1S2, Canada.
| | - Belete Atomsa Gonfa
- Institut National de la Recherche Scientifique - Énergie, Matériaux et Télécommunications, Univerisité du Québec, 1650 Boul. Lionel-Boulet, Varennes, Québec J3X 1S2, Canada.
| | - Ying-Chih Pu
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, CA 95064, USA.
| | - Fan Yang
- Institut National de la Recherche Scientifique - Énergie, Matériaux et Télécommunications, Univerisité du Québec, 1650 Boul. Lionel-Boulet, Varennes, Québec J3X 1S2, Canada.
| | - Xinyu Liu
- Department of Mechanical Engineering, McGill University, 817 Sherbrooke Street West, Montreal, Quebec H3A 0C3, Canada
| | - François Vidal
- Institut National de la Recherche Scientifique - Énergie, Matériaux et Télécommunications, Univerisité du Québec, 1650 Boul. Lionel-Boulet, Varennes, Québec J3X 1S2, Canada.
| | - Jin Z Zhang
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, CA 95064, USA.
| | - Fiorenzo Vetrone
- Institut National de la Recherche Scientifique - Énergie, Matériaux et Télécommunications, Univerisité du Québec, 1650 Boul. Lionel-Boulet, Varennes, Québec J3X 1S2, Canada. and Centre for Self-Assembled Chemical Structures, McGill University, Montreal, Quebec H3A 2K6, Canada
| | - Dongling Ma
- Institut National de la Recherche Scientifique - Énergie, Matériaux et Télécommunications, Univerisité du Québec, 1650 Boul. Lionel-Boulet, Varennes, Québec J3X 1S2, Canada.
| |
Collapse
|
143
|
Saniepay M, Mi C, Liu Z, Abel EP, Beaulac R. Insights into the Structural Complexity of Colloidal CdSe Nanocrystal Surfaces: Correlating the Efficiency of Nonradiative Excited-State Processes to Specific Defects. J Am Chem Soc 2018; 140:1725-1736. [PMID: 29293359 DOI: 10.1021/jacs.7b10649] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
II-VI colloidal semiconductor nanocrystals (NCs), such as CdSe NCs, are often plagued by efficient nonradiative recombination processes that severely limit their use in energy-conversion schemes. While these processes are now well-known to occur at the surface, a full understanding of the exact nature of surface defects and of their role in deactivating the excited states of NCs has yet to be established, which is partly due to challenges associated with the direct probing of the complex and dynamic surface of colloidal NCs. Here, we report a detailed study of the surface of cadmium-rich zinc-blende CdSe NCs. The surfaces of these cadmium-rich species are characterized by the presence of cadmium carboxylate complexes (CdX2) that act as Lewis acid (Z-type) ligands that passivate undercoordinated selenide surface species. The systematic displacement of CdX2 from the surface by N,N,N',N'-tetramethylethylene-1,2-diamine (TMEDA) has been studied using a combination of 1H NMR and photoluminescence spectroscopies. We demonstrate the existence of two independent surface sites that differ strikingly in the binding affinity for CdX2 and that are under dynamic equilibrium with each other. A model involving coupled dual equilibria allows a full characterization of the thermodynamics of surface binding (free energy, as well as enthalpic and entropic terms), showing that entropic contributions are responsible for the difference between the two surface sites. Importantly, we demonstrate that cadmium vacancies only lead to important photoluminescence quenching when created on one of the two sites, allowing a complete picture of the surface composition to be drawn where each site is assigned to specific NC facet locale, with CdX2 binding affinity and nonradiative recombination efficiencies that differ by up to two orders of magnitude.
Collapse
Affiliation(s)
- Mersedeh Saniepay
- Department of Chemistry, Michigan State University , East Lansing, Michigan 48824-1322, United States
| | - Chenjia Mi
- Department of Chemistry, Michigan State University , East Lansing, Michigan 48824-1322, United States
| | - Zhihui Liu
- Department of Chemistry, Michigan State University , East Lansing, Michigan 48824-1322, United States
| | - E Paige Abel
- Department of Chemistry, Michigan State University , East Lansing, Michigan 48824-1322, United States
| | - Rémi Beaulac
- Department of Chemistry, Michigan State University , East Lansing, Michigan 48824-1322, United States
| |
Collapse
|
144
|
Shornikova EV, Biadala L, Yakovlev DR, Feng D, Sapega VF, Flipo N, Golovatenko AA, Semina MA, Rodina AV, Mitioglu AA, Ballottin MV, Christianen PCM, Kusrayev YG, Nasilowski M, Dubertret B, Bayer M. Electron and Hole g-Factors and Spin Dynamics of Negatively Charged Excitons in CdSe/CdS Colloidal Nanoplatelets with Thick Shells. NANO LETTERS 2018; 18:373-380. [PMID: 29160075 DOI: 10.1021/acs.nanolett.7b04203] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
We address spin properties and spin dynamics of carriers and charged excitons in CdSe/CdS colloidal nanoplatelets with thick shells. Magneto-optical studies are performed by time-resolved and polarization-resolved photoluminescence, spin-flip Raman scattering and picosecond pump-probe Faraday rotation in magnetic fields up to 30 T. We show that at low temperatures the nanoplatelets are negatively charged so that their photoluminescence is dominated by radiative recombination of negatively charged excitons (trions). Electron g-factor of 1.68 is measured, and heavy-hole g-factor varying with increasing magnetic field from -0.4 to -0.7 is evaluated. Hole g-factors for two-dimensional structures are calculated for various hole confining potentials for cubic- and wurtzite lattice in CdSe core. These calculations are extended for various quantum dots and nanoplatelets based on II-VI semiconductors. We developed a magneto-optical technique for the quantitative evaluation of the nanoplatelets orientation in ensemble.
Collapse
Affiliation(s)
- Elena V Shornikova
- Experimentelle Physik 2, Technische Universität Dortmund , 44221 Dortmund, Germany
- Rzhanov Institute of Semiconductor Physics, Siberian Branch of Russian Academy of Sciences , 630090 Novosibirsk, Russia
| | - Louis Biadala
- Institut d'Electronique, de Microélectronique et de Nanotechnologie, CNRS , 59652 Villeneuve-d'Ascq, France
| | - Dmitri R Yakovlev
- Experimentelle Physik 2, Technische Universität Dortmund , 44221 Dortmund, Germany
- Ioffe Institute, Russian Academy of Sciences , 194021 St. Petersburg, Russia
| | - Donghai Feng
- Experimentelle Physik 2, Technische Universität Dortmund , 44221 Dortmund, Germany
- State Key Laboratory of Precision Spectroscopy, East China Normal University , 200062 Shanghai, China
| | - Victor F Sapega
- Ioffe Institute, Russian Academy of Sciences , 194021 St. Petersburg, Russia
| | - Nathan Flipo
- Experimentelle Physik 2, Technische Universität Dortmund , 44221 Dortmund, Germany
| | | | - Marina A Semina
- Ioffe Institute, Russian Academy of Sciences , 194021 St. Petersburg, Russia
| | - Anna V Rodina
- Ioffe Institute, Russian Academy of Sciences , 194021 St. Petersburg, Russia
| | - Anatolie A Mitioglu
- High Field Magnet Laboratory (HFML-EMFL), Radboud University , 6525 ED Nijmegen, The Netherlands
| | - Mariana V Ballottin
- High Field Magnet Laboratory (HFML-EMFL), Radboud University , 6525 ED Nijmegen, The Netherlands
| | - Peter C M Christianen
- High Field Magnet Laboratory (HFML-EMFL), Radboud University , 6525 ED Nijmegen, The Netherlands
| | - Yuri G Kusrayev
- Ioffe Institute, Russian Academy of Sciences , 194021 St. Petersburg, Russia
| | - Michel Nasilowski
- Laboratoire de Physique et d'Etude des Matériaux, ESPCI, CNRS , 75231 Paris, France
| | - Benoit Dubertret
- Laboratoire de Physique et d'Etude des Matériaux, ESPCI, CNRS , 75231 Paris, France
| | - Manfred Bayer
- Experimentelle Physik 2, Technische Universität Dortmund , 44221 Dortmund, Germany
- Ioffe Institute, Russian Academy of Sciences , 194021 St. Petersburg, Russia
| |
Collapse
|
145
|
Song HJ, Jeong BG, Lim J, Lee DC, Bae WK, Klimov VI. Performance Limits of Luminescent Solar Concentrators Tested with Seed/Quantum-Well Quantum Dots in a Selective-Reflector-Based Optical Cavity. NANO LETTERS 2018; 18:395-404. [PMID: 29226688 DOI: 10.1021/acs.nanolett.7b04263] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Luminescent solar concentrators (LSCs) can serve as large-area sunlight collectors for photovoltaic devices. An important LSC characteristic is a concentration factor (C), which is defined as the ratio of the output and the input photon flux densities. This parameter can be also thought of as an effective enlargement factor of a solar cell active area. On the basis of thermodynamic considerations, the C-factor can reach extremely high values that exceed those accessible with traditional concentrating optics. In reality, however, the best reported values of C are around 30. Here we demonstrate that using a new type of high-emissivity quantum dots (QDs) incorporated into a specially designed cavity, we are able to achieve the C of ∼62 for spectrally integrated emission and ∼120 for the red portion of the photoluminescence spectrum. The key feature of these QDs is a seed/quantum-well/thick-shell design, which allows for obtaining a high emission quantum yield (>95%) simultaneously with a large LSC quality factor (QLSC of ∼100) defined as the ratio of absorption coefficients at the wavelengths of incident and reemitted light. By incorporating the QDs into a specially designed cavity equipped with a top selective reflector (a Bragg mirror or a thin silver film), we are able to effectively recycle reemitted light achieving light trapping coefficients of ∼85%. The observed performance of these devices is in remarkable agreement with analytical modeling, which allows us to project that the applied approach should allow one to boost the spectrally integrated concentration factors to more than 100 by further improving light trapping and/or increasing QLSC.
Collapse
Affiliation(s)
- Hyung-Jun Song
- Center for Advanced Solar Photophysics, Chemistry Division, Los Alamos National Laboratory , Los Alamos, New Mexico 87545, United States
| | - Byeong Guk Jeong
- Center for Advanced Solar Photophysics, Chemistry Division, Los Alamos National Laboratory , Los Alamos, New Mexico 87545, United States
- Photoelectronic Hybrids Research Center, Korea Institute of Science and Technology , Seoul 02792, Republic of Korea
- Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology , Daejeon 34141, Republic of Korea
| | - Jaehoon Lim
- Center for Advanced Solar Photophysics, Chemistry Division, Los Alamos National Laboratory , Los Alamos, New Mexico 87545, United States
| | - Doh C Lee
- Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology , Daejeon 34141, Republic of Korea
| | - Wan Ki Bae
- Photoelectronic Hybrids Research Center, Korea Institute of Science and Technology , Seoul 02792, Republic of Korea
| | - Victor I Klimov
- Center for Advanced Solar Photophysics, Chemistry Division, Los Alamos National Laboratory , Los Alamos, New Mexico 87545, United States
| |
Collapse
|
146
|
Enright MJ, Cossairt BM. Synthesis of tailor-made colloidal semiconductor heterostructures. Chem Commun (Camb) 2018; 54:7109-7122. [DOI: 10.1039/c8cc03498b] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
This feature article provides an account of the various bottom-up and top-down methods that have been developed to prepare colloidal heterostructures and highlights the benefits of a seeded assembly approach for greater control and customizability.
Collapse
|
147
|
Zhou Y, Zhao H, Ma D, Rosei F. Harnessing the properties of colloidal quantum dots in luminescent solar concentrators. Chem Soc Rev 2018; 47:5866-5890. [DOI: 10.1039/c7cs00701a] [Citation(s) in RCA: 126] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
This review summarizes the recent progress, challenges and perspectives of luminescent solar concentrators based on colloidal quantum dots via harnessing their properties.
Collapse
Affiliation(s)
- Yufeng Zhou
- Énergie Matériaux Télécommunications Research Centre
- Institut National de la Recherche Scientifique
- Varennes
- Canada
| | - Haiguang Zhao
- College of Physics & The Cultivation Base for State Key Laboratory
- Qingdao University
- P. R. China
| | - Dongling Ma
- Énergie Matériaux Télécommunications Research Centre
- Institut National de la Recherche Scientifique
- Varennes
- Canada
| | - Federico Rosei
- Énergie Matériaux Télécommunications Research Centre
- Institut National de la Recherche Scientifique
- Varennes
- Canada
- Institute of Fundamental and Frontier Sciences
| |
Collapse
|
148
|
Roy D, Mandal S, De CK, Kumar K, Mandal PK. Nearly suppressed photoluminescence blinking of small-sized, blue–green–orange–red emitting single CdSe-based core/gradient alloy shell/shell quantum dots: correlation between truncation time and photoluminescence quantum yield. Phys Chem Chem Phys 2018; 20:10332-10344. [DOI: 10.1039/c8cp00952j] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Nearly suppressed PL blinking of small sized CdSe based CGASS QDs.
Collapse
Affiliation(s)
- Debjit Roy
- Department of Chemical Sciences
- Indian Institute of Science Education and Research (IISER) Kolkata
- Mohanpur
- India
| | - Saptarshi Mandal
- Department of Chemical Sciences
- Indian Institute of Science Education and Research (IISER) Kolkata
- Mohanpur
- India
| | - Chayan K. De
- Department of Chemical Sciences
- Indian Institute of Science Education and Research (IISER) Kolkata
- Mohanpur
- India
| | - Kaushalendra Kumar
- Department of Chemical Sciences
- Indian Institute of Science Education and Research (IISER) Kolkata
- Mohanpur
- India
| | - Prasun K. Mandal
- Department of Chemical Sciences
- Indian Institute of Science Education and Research (IISER) Kolkata
- Mohanpur
- India
- Centre for Advanced Functional Materials
| |
Collapse
|
149
|
Jang EP, Jo JH, Kim MS, Yoon SY, Lim SW, Kim J, Yang H. Near-complete photoluminescence retention and improved stability of InP quantum dots after silica embedding for their application to on-chip-packaged light-emitting diodes. RSC Adv 2018; 8:10057-10063. [PMID: 35540847 PMCID: PMC9078749 DOI: 10.1039/c8ra00119g] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2018] [Accepted: 03/05/2018] [Indexed: 12/23/2022] Open
Abstract
Silica is the most commonly used oxide encapsulant for passivating fluorescent quantum dots (QDs) against degradable conditions. Such a silica encapsulation has been conventionally implemented via a Stöber or reverse microemulsion process, mostly targeting CdSe-based QDs to date. However, both routes encounter a critical issue of considerable loss in photoluminescence (PL) quantum yield (QY) compared to pristine QDs after silica growth. In this work, we explore the embedment of multishelled InP/ZnSeS/ZnS QDs, whose stability is quite inferior to CdSe counterparts, in a silica matrix by means of a tetramethyl orthosilicate-based, waterless, catalyst-free synthesis. It is revealed that the original QY (80%) of QDs is nearly completely retained in the course of the present silica embedding reaction. The resulting QD–silica composites are then placed in degradable conditions such UV irradiation, high temperature/high humidity, and operation of an on-chip-packaged light-emitting diode (LED) to attest to the efficacy of silica passivation on QD stability. Particularly, the promising results with regard to device efficiency and stability of the on-chip-packaged QD-LED firmly suggest the effectiveness of the present silica embedding strategy in not only maximally retaining QY of QDs but effectively passivating QDs, paving the way for the realization of a highly efficient, robust QD-LED platform. Silica embedding strategy enabling a nearly full PL retention of the original QY of InP QDs is proposed for the realization of a highly efficient, robust QD-LED platform.![]()
Collapse
Affiliation(s)
- Eun-Pyo Jang
- Department of Materials Science and Engineering
- Hongik University
- Seoul 04066
- Republic of Korea
| | - Jung-Ho Jo
- Department of Materials Science and Engineering
- Hongik University
- Seoul 04066
- Republic of Korea
| | - Min-Seok Kim
- Department of Materials Science and Engineering
- Hongik University
- Seoul 04066
- Republic of Korea
| | - Suk-Young Yoon
- Department of Materials Science and Engineering
- Hongik University
- Seoul 04066
- Republic of Korea
| | - Seung-Won Lim
- Department of Materials Science and Engineering
- Hongik University
- Seoul 04066
- Republic of Korea
| | - Jiwan Kim
- Department of Advanced Materials Engineering
- Kyonggi University
- Suwon 16227
- Republic of Korea
| | - Heesun Yang
- Department of Materials Science and Engineering
- Hongik University
- Seoul 04066
- Republic of Korea
| |
Collapse
|
150
|
Wang R, Huang XY, Zhang CF, Wang XY, Xiao M. Coherent Exciton-Phonon Coupling in CdSe/ZnS Nanocrystals Studied by Two-Dimensional Electronic Spectroscopy. CHINESE J CHEM PHYS 2017. [DOI: 10.1063/1674-0068/30/cjcp1711222] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Affiliation(s)
- Rui Wang
- National Laboratory of Solid State Microstructures, School of Physics, and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Xin-yu Huang
- National Laboratory of Solid State Microstructures, School of Physics, and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Chun-feng Zhang
- National Laboratory of Solid State Microstructures, School of Physics, and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Xiao-yong Wang
- National Laboratory of Solid State Microstructures, School of Physics, and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Min Xiao
- National Laboratory of Solid State Microstructures, School of Physics, and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
- Department of Physics, University of Arkansas, Fayetteville, Arkansas 72701, USA
| |
Collapse
|