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Vonk SJW, Rabouw FT. Biexciton Blinking in CdSe-Based Quantum Dots. J Phys Chem Lett 2023:5353-5361. [PMID: 37276380 DOI: 10.1021/acs.jpclett.3c00437] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Experiments on single colloidal quantum dots (QDs) have revealed temporal fluctuations in the emission efficiency of the single-exciton state. These fluctuations, often termed "blinking", are caused by opening/closing of charge-carrier traps and/or charging/discharging of the QD. In the regime of strong optical excitation, multiexciton states are formed. The emission efficiencies of multiexcitons are lower because of Auger processes, but a quantitative characterization is challenging. Here, we quantify fluctuations of the biexciton efficiency for single CdSe/CdS/ZnS core-shell QDs. We find that the biexciton efficiency "blinks" significantly. The additional electron due to charging of a QD accelerates Auger recombination by a factor of 2 compared to the neutral biexciton, while opening/closing of a charge-carrier trap leads to an increase of the nonradiative recombination rate by a factor of 4. To understand the fast rate of trap-assisted recombination, we propose a revised model for trap-assisted recombination based on reversible trapping. Finally, we discuss the implications of biexciton blinking for lasing applications.
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Affiliation(s)
- Sander J W Vonk
- Debye Institute for Nanomaterials Science, Utrecht University, Princetonplein 1, 3584 CC Utrecht, The Netherlands
| | - Freddy T Rabouw
- Debye Institute for Nanomaterials Science, Utrecht University, Princetonplein 1, 3584 CC Utrecht, The Netherlands
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2
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Hong D, Zhang Y, Pan S, Liu H, Mao W, Lu Z, Tian Y. Moisture-Dependent Blinking of Individual CsPbBr 3 Nanocrystals Revealed by Single-Particle Spectroscopy. J Phys Chem Lett 2022; 13:10751-10758. [PMID: 36374491 DOI: 10.1021/acs.jpclett.2c03159] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
All-inorganic metal halide perovskite nanocrystals (NCs) have been exceptional candidates for high-performance solution-processed optoelectronic and photonic devices compared with organometal halide perovskite NCs due to their superior stability. However, the interactions between all-inorganic perovskite NCs and moisture, which is an acknowledged detrimental factor, are still under debate, and detailed investigations to uncover such fundamentals remain to be performed. Herein, with wide-field fluorescence microscopy, the burst photoluminescence blinking responses of CsPbBr3 NCs were observed in ambient air, and moisture rather than oxygen was verified to be the key factor that leads to the enhanced PL intensity and reduced OFF duration. This behavior is rationalized through an effective passivation effect of the adsorbed water molecules on the surface halide vacancies on CsPbBr3 NCs. This work validates that ∼40% humidity atmospheres are helpful for better utilizing the all-inorganic perovskites, which is evidence of their promising prospect for application.
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Affiliation(s)
- Daocheng Hong
- Key Laboratory for Advanced Technology in Environmental Protection of Jiangsu Province, Yancheng Institute of Technology, Yancheng, Jiangsu224051, China
- Laboratory of Mesoscopic Chemistry of MOE, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, Jiangsu210023, China
| | - Yuchen Zhang
- College of Engineering and Applied Sciences, Nanjing University, Nanjing, Jiangsu210023, China
| | - Shuhan Pan
- College of Engineering and Applied Sciences, Nanjing University, Nanjing, Jiangsu210023, China
| | - Hanyu Liu
- Laboratory of Mesoscopic Chemistry of MOE, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, Jiangsu210023, China
| | - Wei Mao
- College of Engineering and Applied Sciences, Nanjing University, Nanjing, Jiangsu210023, China
| | - Zhenda Lu
- College of Engineering and Applied Sciences, Nanjing University, Nanjing, Jiangsu210023, China
| | - Yuxi Tian
- Laboratory of Mesoscopic Chemistry of MOE, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, Jiangsu210023, China
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3
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Lu X, Hou X, Tang H, Yi X, Wang J. A High-Quality CdSe/CdS/ZnS Quantum-Dot-Based FRET Aptasensor for the Simultaneous Detection of Two Different Alzheimer's Disease Core Biomarkers. NANOMATERIALS (BASEL, SWITZERLAND) 2022; 12:nano12224031. [PMID: 36432316 PMCID: PMC9697525 DOI: 10.3390/nano12224031] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Revised: 11/06/2022] [Accepted: 11/12/2022] [Indexed: 05/31/2023]
Abstract
The simultaneous detection of two different biomarkers for the point-of-care diagnosis of major diseases, such as Alzheimer’s disease (AD), is greatly challenging. Due to the outstanding photoluminescence (PL) properties of quantum dots (QDs), a high-quality CdSe/CdS/ZnS QD-based fluorescence resonance energy transfer (FRET) aptasensor for simultaneously monitoring the amyloid-β oligomers (AβO) and tau protein was proposed. By engineering the interior inorganic structure and inorganic−organic interface, water-soluble dual-color CdSe/CdS/ZnS QDs with a near-unity PL quantum yield (>90%) and mono-exponential PL decay dynamics were generated. The π−π stacking and hydrogen bond interaction between the aptamer-functionalized dual-color QDs and gold nanorods@polydopamine (Au NRs@PDA) nanoparticles resulted in significant fluorescence quenching of the QDs through FRET. Upon the incorporation of the AβO and tau protein, the fluorescence recovery of the QDs-DNA/Au NRs@PDA assembly was attained, providing the possibility of simultaneously assaying the two types of AD core biomarkers. The lower detection limits of 50 pM for AβO and 20 pM for the tau protein could be ascribed to the distinguishable and robust fluorescence of QDs and broad spectral absorption of Au NRs@PDA. The sensing strategy serves as a viable platform for the simultaneously monitoring of the core biomarkers for AD and other major diseases.
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Affiliation(s)
- Xingchang Lu
- Hunan Provincial Key Laboratory of Micro & Nano Materials Interface Science, College of Chemistry and Chemical Engineering, Central South University, Changsha 410083, China
| | - Xiaoqi Hou
- School of Chemistry and Material Science, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, 1 Sub-lane Xiangshan, Hangzhou 310024, China
- Key Laboratory of Intelligent Sensing Materials and Chip Integration Technology of Zhejiang Province, Hangzhou Innovation Institute, Beihang University, Hangzhou 310052, China
| | - Hailin Tang
- SunYat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangzhou 510060, China
| | - Xinyao Yi
- Hunan Provincial Key Laboratory of Micro & Nano Materials Interface Science, College of Chemistry and Chemical Engineering, Central South University, Changsha 410083, China
| | - Jianxiu Wang
- Hunan Provincial Key Laboratory of Micro & Nano Materials Interface Science, College of Chemistry and Chemical Engineering, Central South University, Changsha 410083, China
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4
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Elkony Y, Ali M, Ebrahim S, Adel R. High Photoluminescence Polyindole/CuInS Quantum Dots for Pb Ions Sensor. J Inorg Organomet Polym Mater 2022. [DOI: 10.1007/s10904-022-02300-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
AbstractPolyindole is considered an excellent conducting polymer with interested properties for different applications. A novel polyindole (PIn)/CuInS (CIS)/ZnS quantum dots (QDs) nanocomposite was synthesized via in situ polymerization of PIn in presence of CIS/ZnS QDs. By investigating the effect of CIS/ZnS QDs on optical properties of PIn, it was found that the optical band gaps of PIn, CIS/ZnS QDs, and PIn/CIS/ZnS QDs nanocomposite were 3.24 eV, 4.68 eV and 3.44 eV, respectively. From the luminance spectra, it was observed that emission peaks of PIn at 442 and 468 nm are independent of the excitation wavelength with the highest intensity at excitation wavelength of 380 nm. However, the luminance spectrum of PIn/CIS/ZnS QDs nanocomposite exhibited a quenching peak for CIS/ZnS QDs while the intensity of PIn peak was enhanced. High resolution of transmission electron microscope image of CIS/ZnS QDs revealed nanocrystals with a size of 3–4.5 nm and lattice space of 0.2 nm. PIn/CIS/ZnS QDs nanocomposite as the fluorescent probe was employed for sensing different concentrations of Pb2+ from 5 to 50 ppb. The reaction between PIn/CIS/ZnS QDs and Pb2+ was slightly quenched and fixed after 90 min. The emission peak was reduced gradually with increasing concentration of lead via photo-induced electron transfer or ion exchange mechanism. The value of correlation coefficient (R2) was 0.99, the sensitivity was 0.0041 ppb−1 and limit of detection value was 4.48 ppb.
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5
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Xie M, Tao CL, Zhang Z, Liu H, Wan S, Nie Y, Yang W, Wang X, Wu XJ, Tian Y. Nonblinking Colloidal Quantum Dots via Efficient Multiexciton Emission. J Phys Chem Lett 2022; 13:2371-2378. [PMID: 35254074 DOI: 10.1021/acs.jpclett.2c00378] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Nonblinking colloidal quantum dots (QDs) are significant to their applications as single-photon sources or light-emitting materials. Herein, a simple heat-up method was developed to synthesize high-qualityWZ-CdSe/CdS core-shell colloidal QDs, which achieved a near-unity photoluminescence quantum yield (PLQY). It was found that the blinking behavior of such QDs was completely suppressed at high excitation intensities, and ultra-stable PL emission was observed. For this reason, a systematic investigation was conducted, revealing that the complete blinking suppression was attributed mainly to the efficient multiexciton emission at high excitation intensities. Such high-quality QDs with nonblinking behaviors and nearly ideal PL properties at high excitation intensities have massive potential applications in various robust conditions, including QD display screens, single-particle tracks, and single-photon sources.
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Affiliation(s)
- Mingcai Xie
- Key Laboratory of Mesoscopic Chemistry of MOE, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Chen-Lei Tao
- State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Zhen Zhang
- National Laboratory of Solid State Microstructures, School of Physics, and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210023, China
| | - Hanyu Liu
- Key Laboratory of Mesoscopic Chemistry of MOE, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Sushu Wan
- Key Laboratory of Mesoscopic Chemistry of MOE, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Yan Nie
- Key Laboratory of Mesoscopic Chemistry of MOE, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Weiqing Yang
- Key Laboratory of Mesoscopic Chemistry of MOE, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Xiaoyong Wang
- National Laboratory of Solid State Microstructures, School of Physics, and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210023, China
| | - Xue-Jun Wu
- State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Yuxi Tian
- Key Laboratory of Mesoscopic Chemistry of MOE, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
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6
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Hou L, Zhao C, Yuan X, Zhao J, Krieg F, Tamarat P, Kovalenko MV, Guo C, Lounis B. Memories in the photoluminescence intermittency of single cesium lead bromide nanocrystals. NANOSCALE 2020; 12:6795-6802. [PMID: 32181469 DOI: 10.1039/d0nr00633e] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Single cesium lead bromide (CsPbBr3) nanocrystals show strong photoluminescence intermittency, with on- and off- dwelling times following power-law distributions. We investigate the correlations for successive on-times and successive off-times, and find a memory effect in the photoluminescence intermittency of such inorganic perovskite nanocrystals. This memory effect is not sensitive to the nature of the surface capping ligand and the embedding polymer. These observations suggest that photoluminescence intermittency and its memory are mainly controlled by intrinsic traps in the nanocrystals. Our findings will help optimizing light-emitting devices based on these perovskite nanocrystals.
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Affiliation(s)
- Lei Hou
- Université de Bordeaux, LP2N, Talence, France.
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7
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Ahmed T, Seth S, Samanta A. Mechanistic Investigation of the Defect Activity Contributing to the Photoluminescence Blinking of CsPbBr 3 Perovskite Nanocrystals. ACS NANO 2019; 13:13537-13544. [PMID: 31714741 DOI: 10.1021/acsnano.9b07471] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Exploration of the full potential of the perovskite nanocrystals (NCs) for different applications requires a thorough understanding of the pathways of recombination of the photogenerated charge carriers and associated dynamics. In this work, we have tracked the recombination routes of the charge carriers by probing photoluminescence (PL) intermittency of the immobilized and freely diffusing single CsPbBr3 NCs employing a time-tagged-time-resolved method. The immobilized single CsPbBr3 NCs show a complex PL time-trace, a careful analysis of which reveals that nonradiative band-edge recombination through trap states, trion recombination, and trapping of the hot carriers contribute to the blinking behavior of any given NC. A drastically suppressed PL blinking observed for the NCs treated with a tetrafluoroborate salt indicates elimination of most of the undesired recombination processes. A fluorescence correlation spectroscopy (FCS) study on the freely diffusing single NCs shows that enhanced PL and suppressed blinking of the treated particles are the outcome of an increase in per-particle brightness, not due to any increase in the number of particles undergoing "off"-"on" transition in the observation volume. The mechanistic details obtained from this study on the origin of blinking in CsPbBr3 NCs provide deep insight into the radiative and nonradiative charge carrier recombination pathways in these important materials, and this knowledge is expected to be useful for better design and development of bright photoluminescent samples of this class for optoelectronic applications.
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Affiliation(s)
- Tasnim Ahmed
- School of Chemistry , University of Hyderabad , Hyderabad 500046 , India
| | - Sudipta Seth
- School of Chemistry , University of Hyderabad , Hyderabad 500046 , India
| | - Anunay Samanta
- School of Chemistry , University of Hyderabad , Hyderabad 500046 , India
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8
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Affiliation(s)
- Yoshihiko Kanemitsu
- Institute for Chemical Research, Kyoto University Uji, Kyoto 611-0011, Japan
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9
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Mukherjee A, Ray KK, Phadnis C, Layek A, Bera S, Chowdhury A. Insights on heterogeneity in blinking mechanisms and non-ergodicity using sub-ensemble statistical analysis of single quantum-dots. J Chem Phys 2019; 151:084701. [PMID: 31470698 DOI: 10.1063/1.5095870] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Photo-luminescence (P-L) intermittency (or blinking) in semiconductor nanocrystals (NCs), a phenomenon ubiquitous to single-emitters, is generally considered to be temporally random intensity fluctuations between "bright" ("On") and "dark" ("Off") states. However, individual quantum-dots (QDs) rarely exhibit such telegraphic signals, and yet, a vast majority of single-NC blinking data are analyzed using a single fixed threshold which generates binary trajectories. Furthermore, while blinking dynamics can vary dramatically over NCs in the ensemble, the extent of diversity in the exponents (mOn/Off) of single-particle On-/Off-time distributions (P(tOn/Off)), often used to validate mechanistic models of blinking, remains unclear due to a lack of statistically relevant data sets. Here, we subclassify an ensemble of QDs based on the emissivity of each emitter and subsequently compare the (sub)ensembles' behaviors. To achieve this, we analyzed a large number (>1000) of blinking trajectories for a model system, Mn+2 doped ZnCdS QDs, which exhibits diverse blinking dynamics. An intensity histogram dependent thresholding method allowed us to construct distributions of relevant blinking parameters (such as mOn/Off). Interestingly, we find that single QD P(tOn/Off)s follow either truncated power law or power law, and their relative proportion varies over subpopulations. Our results reveal a remarkable variation in mOn/Off amongst as well as within subensembles, which implies multiple blinking mechanisms being operational amongst various QDs. We further show that the mOn/Off obtained via cumulative single-particle P(tOn/Off) is distinct from the weighted mean value of all single-particle mOn/Off, evidence for the lack of ergodicity. Thus, investigation and analyses of a large number of QDs, albeit for a limited time span of a few decades, are crucial to characterize the spatial heterogeneity in possible blinking mechanisms.
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Affiliation(s)
- Amitrajit Mukherjee
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai, India
| | - Korak Kumar Ray
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai, India
| | - Chinmay Phadnis
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai, India
| | - Arunasish Layek
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai, India
| | - Soumya Bera
- Department of Physics, Indian Institute of Technology Bombay, Powai, Mumbai, India
| | - Arindam Chowdhury
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai, India
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10
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Au TH, Buil S, Quélin X, Hermier JP, Lai ND. Photostability and long-term preservation of a colloidal semiconductor-based single photon emitter in polymeric photonic structures. NANOSCALE ADVANCES 2019; 1:3225-3231. [PMID: 36133591 PMCID: PMC9417270 DOI: 10.1039/c9na00411d] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Accepted: 07/03/2019] [Indexed: 05/27/2023]
Abstract
Colloidal semiconductor quantum dots (QDs) are promising candidates for various applications in electronics and quantum optics. However, they are sensitive and vulnerable to the chemical environment due to their highly dynamic surface with a large portion of exposed atoms. Hence, oxidation and detrimental defects on the nanocrystal (NC) interface dramatically deteriorate their optical as well as electrical properties. In this study, a simple strategy is proposed not only to obtain good preservation of colloidal semiconductor QDs by using a protective polymer matrix but also to provide excellent accessibility to micro-fabrication by optical lithography. A high-quality QD-polymer nanocomposite with mono-dispersion of the NCs is synthesized by incorporating the colloidal CdSe/CdS NCs into an SU-8 photoresist. Our approach shows that the oxidation of the core/shell QDs embedded in the SU-8 resist is completely avoidable. The deterministic insertion of multiple QDs or a single QD into photonic structures is demonstrated. Single photon generation is obtained and well-preserved in the nanocomposite and the polymeric structures.
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Affiliation(s)
- Thi Huong Au
- Laboratoire de Photonique Quantique et Moléculaire, UMR 8537, École Normale Supérieure de Cachan, Centrale Supélec, CNRS, Université Paris-Saclay 61 Avenue du Président Wilson 94235 Cachan Cedex France
- Groupe d'Étude de la Matière Condensée, Université de Versailles Saint-Quentin-en-Yvelines, CNRS UMR 8635, Université Paris-Saclay 45 Avenue des Etats-Unis 78035 Versailles Cedex France
| | - Stéphanie Buil
- Groupe d'Étude de la Matière Condensée, Université de Versailles Saint-Quentin-en-Yvelines, CNRS UMR 8635, Université Paris-Saclay 45 Avenue des Etats-Unis 78035 Versailles Cedex France
| | - Xavier Quélin
- Groupe d'Étude de la Matière Condensée, Université de Versailles Saint-Quentin-en-Yvelines, CNRS UMR 8635, Université Paris-Saclay 45 Avenue des Etats-Unis 78035 Versailles Cedex France
| | - Jean-Pierre Hermier
- Groupe d'Étude de la Matière Condensée, Université de Versailles Saint-Quentin-en-Yvelines, CNRS UMR 8635, Université Paris-Saclay 45 Avenue des Etats-Unis 78035 Versailles Cedex France
| | - Ngoc Diep Lai
- Laboratoire de Photonique Quantique et Moléculaire, UMR 8537, École Normale Supérieure de Cachan, Centrale Supélec, CNRS, Université Paris-Saclay 61 Avenue du Président Wilson 94235 Cachan Cedex France
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11
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Hu S, Ren Y, Wang Y, Li J, Qu J, Liu L, Ma H, Tang Y. Surface plasmon resonance enhancement of photoluminescence intensity and bioimaging application of gold nanorod@CdSe/ZnS quantum dots. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2019; 10:22-31. [PMID: 30680276 PMCID: PMC6334792 DOI: 10.3762/bjnano.10.3] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2018] [Accepted: 11/16/2018] [Indexed: 05/06/2023]
Abstract
Biological applications of core/shell near-infrared quantum dots (QDs) have attracted broad interest due to their unique optical and chemical properties. Additionally, the use of multifunctional nanomaterials with near-infrared QDs and plasmonic functional nanoparticles are promising for applications in electronics, bioimaging, energy, and environmental-related studies. In this work, we experimentally demonstrate how to construct a multifunctional nanoparticle comprised of CdSe/ZnS QDs and gold nanorods (GNRs) where the GNRs were applied to enhance the photoluminescence (PL) of the CdSe/ZnS QDs. In particular, we have obtained the scattering PL spectrum of a single CdSe/ZnS QD and GNR@CdSe/ZnS nanoparticle and comparison results show that the CdSe/ZnS QDs have an apparent PL enhancement of four-times after binding with GNRs. In addition, in vitro experimental results show that the biostability of the GNR@CdSe/ZnS nanoparticles can be improved by using folic acid. A bioimaging study has also been performed where GNR@CdSe/ZnS nanoparticles were used as an optical process for MCF-7 breast cancer cells.
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Affiliation(s)
- Siyi Hu
- CAS Key Laboratory of Bio-Medical Diagnostics, Suzhou Institute of Biomedical Engineering and Technology, Chinese Academy of Sciences, Suzhou 215163, P. R. China
| | - Yu Ren
- School of Science, Changchun University of Science and Technology, Changchun 130022, P. R. China
| | - Yue Wang
- School of Science, Changchun University of Science and Technology, Changchun 130022, P. R. China
| | - Jinhua Li
- School of Science, Changchun University of Science and Technology, Changchun 130022, P. R. China
| | - Junle Qu
- College of Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, P. R. China
| | - Liwei Liu
- College of Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, P. R. China
| | - Hanbin Ma
- CAS Key Laboratory of Bio-Medical Diagnostics, Suzhou Institute of Biomedical Engineering and Technology, Chinese Academy of Sciences, Suzhou 215163, P. R. China
| | - Yuguo Tang
- CAS Key Laboratory of Bio-Medical Diagnostics, Suzhou Institute of Biomedical Engineering and Technology, Chinese Academy of Sciences, Suzhou 215163, P. R. China
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12
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Reid KR, McBride JR, La Croix AD, Freymeyer NJ, Click SM, Macdonald JE, Rosenthal SJ. Role of Surface Morphology on Exciton Recombination in Single Quantum Dot-in-Rods Revealed by Optical and Atomic Structure Correlation. ACS NANO 2018; 12:11434-11445. [PMID: 30403844 DOI: 10.1021/acsnano.8b06472] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The physical structure of colloidal quantum dot (QD) nanostructures strongly influences their optical and electronic behavior. A fundamental understanding of this interplay between structure and function is crucial to fully tailor the performance of QDs and their assemblies. Here, by directly correlating the atomic and chemical structure of single CdSe-CdS quantum dot-in-rods with time-resolved fluorescence measurements on the same structures, we identify morphological irregularities at their surfaces that moderate photoluminescence efficiencies. We find that two nonradiative exciton recombination mechanisms are triggered by these imperfections: charging and trap-assisted nonradiative processes. Furthermore, we show that the proximity of the surface defects to the CdSe core of the core-shell structures influences whether the charging or trap-assisted nonradiative channel dominates exciton recombination. Our results extend to other QD nanostructures and emphasize surface roughness as a crucial parameter when designing colloidal QDs with specific excitonic fates.
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13
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Wang X, Zhang G, Yang L, Sharman E, Jiang J. Material descriptors for photocatalyst/catalyst design. WILEY INTERDISCIPLINARY REVIEWS-COMPUTATIONAL MOLECULAR SCIENCE 2018. [DOI: 10.1002/wcms.1369] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Xijun Wang
- Hefei National Laboratory for Physical Sciences at the Microscale, iChEM (Collaborative Innovation Center of Chemistry for Energy Materials), CAS Center for Excellence in Nanoscience, School of Chemistry and Materials ScienceUniversity of Science and Technology of ChinaHefeiChina
| | - Guozhen Zhang
- Hefei National Laboratory for Physical Sciences at the Microscale, iChEM (Collaborative Innovation Center of Chemistry for Energy Materials), CAS Center for Excellence in Nanoscience, School of Chemistry and Materials ScienceUniversity of Science and Technology of ChinaHefeiChina
| | - Li Yang
- Hefei National Laboratory for Physical Sciences at the Microscale, iChEM (Collaborative Innovation Center of Chemistry for Energy Materials), CAS Center for Excellence in Nanoscience, School of Chemistry and Materials ScienceUniversity of Science and Technology of ChinaHefeiChina
| | - Edward Sharman
- Department of NeurologyUniversity of CaliforniaIrvineCalifornia
| | - Jun Jiang
- Hefei National Laboratory for Physical Sciences at the Microscale, iChEM (Collaborative Innovation Center of Chemistry for Energy Materials), CAS Center for Excellence in Nanoscience, School of Chemistry and Materials ScienceUniversity of Science and Technology of ChinaHefeiChina
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14
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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.
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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
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15
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Yarita N, Tahara H, Saruyama M, Kawawaki T, Sato R, Teranishi T, Kanemitsu Y. Impact of Postsynthetic Surface Modification on Photoluminescence Intermittency in Formamidinium Lead Bromide Perovskite Nanocrystals. J Phys Chem Lett 2017; 8:6041-6047. [PMID: 29189012 DOI: 10.1021/acs.jpclett.7b02840] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
We study the origin of photoluminescence (PL) intermittency in formamidinium lead bromide (FAPbBr3, FA = HC(NH2)2) nanocrystals and the impact of postsynthetic surface treatments on the PL intermittency. Single-dot spectroscopy revealed the existence of different individual nanocrystals exhibiting either a blinking (binary on-off switching) or flickering (gradual undulation) behavior of the PL intermittency. Although the PL lifetimes of blinking nanocrystals clearly correlate with the individual absorption cross sections, those of flickering nanocrystals show no correlation with the absorption cross sections. This indicates that flickering has an extrinsic origin, which is in contrast to blinking. We demonstrate that the postsynthetic surface treatment with sodium thiocyanate improves the PL quantum yields and completely suppresses the flickering, while it has no significant effect on the blinking behavior. We conclude that the blinking is caused by Auger recombination of charged excitons, and the flickering is due to a temporal drift of the exciton recombination rate induced by surface-trapped electrons.
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Affiliation(s)
- Naoki Yarita
- Institute for Chemical Research, Kyoto University , Uji, Kyoto 611-0011, Japan
| | - Hirokazu Tahara
- Institute for Chemical Research, Kyoto University , Uji, Kyoto 611-0011, Japan
| | - Masaki Saruyama
- Institute for Chemical Research, Kyoto University , Uji, Kyoto 611-0011, Japan
| | - Tokuhisa Kawawaki
- Institute for Chemical Research, Kyoto University , Uji, Kyoto 611-0011, Japan
| | - Ryota Sato
- Institute for Chemical Research, Kyoto University , Uji, Kyoto 611-0011, Japan
| | - Toshiharu Teranishi
- Institute for Chemical Research, Kyoto University , Uji, Kyoto 611-0011, Japan
| | - Yoshihiko Kanemitsu
- Institute for Chemical Research, Kyoto University , Uji, Kyoto 611-0011, Japan
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16
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Li B, Lu M, Liu W, Zhu X, He X, Yang Y, Yang Q. Reversible Electrochemical Control over Photoexcited Luminescence of Core/Shell CdSe/ZnS Quantum Dot Film. NANOSCALE RESEARCH LETTERS 2017; 12:626. [PMID: 29247304 PMCID: PMC5732114 DOI: 10.1186/s11671-017-2398-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/22/2017] [Accepted: 12/01/2017] [Indexed: 06/07/2023]
Abstract
Semiconductor quantum dots (QDs) are widely used in light-emitting diodes and solar cells. Electrochemical modulation is a good way to understand the electrical and optical properties of QDs. In this work, the effects of electrochemical control on photoluminescence (PL) spectra in core/shell CdSe/ZnS QD films are studied. The results show different spectral responses for surface emission and core emission when a negative electrochemical potential is applied: the core emission is redshifted while the surface emission is blueshifted. The former is attributed to the electrostatic expansion of the excitonic wave function, due to the asymmetric distribution of adsorbed cations on the surface of the dots. The latter is attributed to the occupation of lower surface states by the injected electrons, i.e., the photoexcited electrons are more likely to be trapped onto higher surface states, leading to a blueshift of the surface emission. Both the spectral shift and the accompanying PL-quenching processes are reversible by resetting the potential.
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Affiliation(s)
- Bo Li
- Department of Physics, Harbin Institute of Technology, Harbin, 150001, China
| | - Meilin Lu
- Department of Physics, Harbin Institute of Technology, Harbin, 150001, China
| | - Weilong Liu
- Department of Physics, Harbin Institute of Technology, Harbin, 150001, China
| | - Xiaojun Zhu
- Department of Physics, Harbin Institute of Technology, Harbin, 150001, China
| | - Xing He
- Department of Physics, Harbin Institute of Technology, Harbin, 150001, China
| | - Yanqiang Yang
- Department of Physics, Harbin Institute of Technology, Harbin, 150001, China
| | - Qingxin Yang
- Department of Physics, Harbin Institute of Technology, Harbin, 150001, China.
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17
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Guo T, Sampat S, Rupich SM, Hollingsworth JA, Buck M, Htoon H, Chabal YJ, Gartstein YN, Malko AV. Biexciton and trion energy transfer from CdSe/CdS giant nanocrystals to Si substrates. NANOSCALE 2017; 9:19398-19407. [PMID: 29210416 DOI: 10.1039/c7nr06272a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Observation of energy transfer (ET) from multiexcitonic (MX) complexes in nanocrystal quantum dots (NQDs) has been severely restricted due to efficient nonradiative Auger recombination leading to very low MX emission quantum yields. Here we employed "giant" CdSe/CdS NQDs with suppressed Auger recombination to study ET of biexcitons (BX) and charged excitons (trions) into Si substrate. Photoluminescence (PL) measurements of (sub)monolayers of gNQDs controllably assembled on various interacting surfaces and augmented by single gNQD's imaging reveal appearance of BX spectral signatures and progressive acceleration of PL lifetimes of all excitonic species on Si substrates. From statistical analysis of a large number of PL lifetime traces, representative exciton, trion and BX ET efficiencies are measured as ∼75%, 55% and 45% respectively. Detailed analysis of the MX's radiative rates demonstrate the crucial role of the radiative (waveguide) ET in maintaining high overall transfer efficiency despite the prevalent Auger recombination. Our observations point towards practical utilization of MX-bearing nanocrystals in future optoelectronics architectures.
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Affiliation(s)
- Tianle Guo
- Department of Physics, The University of Texas at Dallas, Richardson, TX 75080, USA.
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18
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Zhang L, Xu Q, Liu M, Kong L, Jiao M, Mu H, Wang D, Wang H, Chen J, Yang C. Temperature and Wavelength Dependence of Energy Transfer Process Between Quantized States and Surface States in CdSe Quantum Dots. NANOSCALE RESEARCH LETTERS 2017; 12:222. [PMID: 28347128 PMCID: PMC5366993 DOI: 10.1186/s11671-017-1971-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/04/2017] [Accepted: 03/01/2017] [Indexed: 06/06/2023]
Abstract
Temperature and wavelength dependence of energy transfer (ET) process between quantized states and surface trap states of CdSe quantum dots was investigated, respectively. The experimental results demonstrate that the photoluminescence (PL) intensity of the quantized states decreases with respect to the trap state emission, especially at lower temperatures. The observed ET process between quantized states and trap states which is influenced by the thermal population behavior. At the same temperature, the silver films can greatly enhance the energy transfer (ET) rate from the quantized states to trap states due to surface plasmonic coupling effect.
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Affiliation(s)
- Lei Zhang
- School of Physics and Optoelectronic Engineering, Ludong University, YanTai, 264025, China
| | - Qinfeng Xu
- School of Physics and Optoelectronic Engineering, Ludong University, YanTai, 264025, China.
| | - Mingliang Liu
- School of Physics and Optoelectronic Engineering, Ludong University, YanTai, 264025, China
| | - Lingbin Kong
- School of Physics and Optoelectronic Engineering, Ludong University, YanTai, 264025, China
| | - Mengmeng Jiao
- School of Physics and Optoelectronic Engineering, Ludong University, YanTai, 264025, China
| | - Haifeng Mu
- School of Physics and Optoelectronic Engineering, Ludong University, YanTai, 264025, China
| | - Dehua Wang
- School of Physics and Optoelectronic Engineering, Ludong University, YanTai, 264025, China
| | - Honggang Wang
- School of Physics and Optoelectronic Engineering, Ludong University, YanTai, 264025, China
- Ministerial Key Laboratory of JGMT, Nanjing University of Science and Technology, Nanjing, 210094, China
| | - Jiannong Chen
- School of Physics and Optoelectronic Engineering, Ludong University, YanTai, 264025, China
| | - Chuanlu Yang
- School of Physics and Optoelectronic Engineering, Ludong University, YanTai, 264025, China.
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19
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Feng D, Yakovlev DR, Pavlov VV, Rodina AV, Shornikova EV, Mund J, Bayer M. Dynamic Evolution from Negative to Positive Photocharging in Colloidal CdS Quantum Dots. NANO LETTERS 2017; 17:2844-2851. [PMID: 28367630 DOI: 10.1021/acs.nanolett.6b05305] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The optical properties of colloidal semiconductor nanocrystals are largely influenced by the trapping of charge carriers on the nanocrystal surface. Different concentrations of electron and hole traps and different rates of their capture to the traps provide dynamical charging of otherwise neutral nanocrystals. We study the photocharging formation and evolution dynamics in CdS colloidal quantum dots with native oleic acid surface ligands. A time-resolved technique with three laser pulses (pump, orientation, and probe) is developed to monitor the photocharging dynamics with picosecond resolution on wide time scales ranging from picoseconds to milliseconds. The detection is based on measuring the coherent spin dynamics of electrons, allowing us to distinguish the type of carrier in the QD core (electron or hole). We find that although initially negative photocharging happens because of fast hole trapping, it eventually evolves to positive photocharging due to electron trapping and hole detrapping. The positive photocharging lasts up to hundreds of microseconds at room temperature. These findings give insight into the photocharging process and provide valuable information for understanding the mechanisms responsible for the emission blinking in colloidal nanostructures.
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Affiliation(s)
- Donghai Feng
- Experimentelle Physik 2, Technische Universität Dortmund , 44221 Dortmund, Germany
- State Key Laboratory of Precision Spectroscopy, East China Normal University , Shanghai 200062, China
| | - Dmitri R Yakovlev
- Experimentelle Physik 2, Technische Universität Dortmund , 44221 Dortmund, Germany
- Ioffe Institute, Russian Academy of Sciences , 194021 Saint Petersburg, Russia
| | - Victor V Pavlov
- Ioffe Institute, Russian Academy of Sciences , 194021 Saint Petersburg, Russia
| | - Anna V Rodina
- Ioffe Institute, Russian Academy of Sciences , 194021 Saint Petersburg, Russia
| | - Elena V Shornikova
- Experimentelle Physik 2, Technische Universität Dortmund , 44221 Dortmund, Germany
| | - Johannes Mund
- Experimentelle Physik 2, Technische Universität Dortmund , 44221 Dortmund, Germany
| | - Manfred Bayer
- Experimentelle Physik 2, Technische Universität Dortmund , 44221 Dortmund, Germany
- Ioffe Institute, Russian Academy of Sciences , 194021 Saint Petersburg, Russia
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20
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Pietryga JM, Park YS, Lim J, Fidler AF, Bae WK, Brovelli S, Klimov VI. Spectroscopic and Device Aspects of Nanocrystal Quantum Dots. Chem Rev 2017; 116:10513-622. [PMID: 27677521 DOI: 10.1021/acs.chemrev.6b00169] [Citation(s) in RCA: 395] [Impact Index Per Article: 56.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The field of nanocrystal quantum dots (QDs) is already more than 30 years old, and yet continuing interest in these structures is driven by both the fascinating physics emerging from strong quantum confinement of electronic excitations, as well as a large number of prospective applications that could benefit from the tunable properties and amenability toward solution-based processing of these materials. The focus of this review is on recent advances in nanocrystal research related to applications of QD materials in lasing, light-emitting diodes (LEDs), and solar energy conversion. A specific underlying theme is innovative concepts for tuning the properties of QDs beyond what is possible via traditional size manipulation, particularly through heterostructuring. Examples of such advanced control of nanocrystal functionalities include the following: interface engineering for suppressing Auger recombination in the context of QD LEDs and lasers; Stokes-shift engineering for applications in large-area luminescent solar concentrators; and control of intraband relaxation for enhanced carrier multiplication in advanced QD photovoltaics. We examine the considerable recent progress on these multiple fronts of nanocrystal research, which has resulted in the first commercialized QD technologies. These successes explain the continuing appeal of this field to a broad community of scientists and engineers, which in turn ensures even more exciting results to come from future exploration of this fascinating class of materials.
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Affiliation(s)
- Jeffrey M Pietryga
- Nanotechnology and Advanced Spectroscopy Team, Chemistry Division, Los Alamos National Laboratory , Los Alamos, New Mexico 87545, United States
| | - Young-Shin Park
- Nanotechnology and Advanced Spectroscopy Team, Chemistry Division, Los Alamos National Laboratory , Los Alamos, New Mexico 87545, United States.,Center for High Technology Materials, University of New Mexico , Albuquerque, New Mexico 87131, United States
| | - Jaehoon Lim
- Nanotechnology and Advanced Spectroscopy Team, Chemistry Division, Los Alamos National Laboratory , Los Alamos, New Mexico 87545, United States
| | - Andrew F Fidler
- Nanotechnology and Advanced Spectroscopy Team, Chemistry Division, Los Alamos National Laboratory , Los Alamos, New Mexico 87545, United States
| | - Wan Ki Bae
- Photo-Electronic Hybrids Research Center, Korea Institute of Science and Technology , Seoul 02792, Korea
| | - Sergio Brovelli
- Dipartimento di Scienza dei Materiali, Università degli Studi di Milano-Bicocca , I-20125 Milano, Italy
| | - Victor I Klimov
- Nanotechnology and Advanced Spectroscopy Team, Chemistry Division, Los Alamos National Laboratory , Los Alamos, New Mexico 87545, United States
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21
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Tsui EY, Carroll GM, Miller B, Marchioro A, Gamelin DR. Extremely Slow Spontaneous Electron Trapping in Photodoped n-Type CdSe Nanocrystals. CHEMISTRY OF MATERIALS : A PUBLICATION OF THE AMERICAN CHEMICAL SOCIETY 2017; 29:3754-3762. [PMID: 28989233 PMCID: PMC5628775 DOI: 10.1021/acs.chemmater.7b00839] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
The trapping dynamics of conduction-band electrons in colloidal degenerately doped n-CdSe nanocrystals prepared by photochemical reduction (photodoping) were measured by direct optical methods. The nanocrystals show spontaneous electron trapping with distributed kinetics that extend to remarkably long timescales. Shifts in nanocrystal band-edge potentials caused by quantum confinement and surface ion stoichiometry were also measured by spectroelectrochemical techniques, and their relationship to the slow electron trapping is discussed. The very long electron-trapping timescales observed in these measurements are more consistent with atomic rearrangement than with fundamental electron-transfer processes. Such slow and broadly distributed electron-trapping dynamics are reminiscent of the well-known distributed dynamics of nanocrystal photoluminescence blinking, and potential relationships between the two phenomena are discussed.
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Affiliation(s)
- Emily Y Tsui
- Department of Chemistry, University of Washington, Seattle, WA 98195-1700
| | - Gerard M Carroll
- Department of Chemistry, University of Washington, Seattle, WA 98195-1700
| | - Brigit Miller
- Department of Chemistry, University of Washington, Seattle, WA 98195-1700
| | - Arianna Marchioro
- Department of Chemistry, University of Washington, Seattle, WA 98195-1700
| | - Daniel R Gamelin
- Department of Chemistry, University of Washington, Seattle, WA 98195-1700
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22
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Qin H, Meng R, Wang N, Peng X. Photoluminescence Intermittency and Photo-Bleaching of Single Colloidal Quantum Dot. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2017; 29:1606923. [PMID: 28256776 DOI: 10.1002/adma.201606923] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Revised: 02/02/2017] [Indexed: 06/06/2023]
Abstract
Photoluminescence (PL) blinking of single colloidal quantum dot (QD)-PL intensity switching between different brightness states under constant excitation-and photo-bleaching are roadblocks for most applications of QDs. This progress report shall treat PL blinking and photo-bleaching both as photochemical events, namely, PL blinking as reversible and photo-bleaching being irreversible ones. Most studies on single-molecule spectroscopy of QDs in literature are related to PL blinking, which invites us to concentrate our discussions on the PL blinking, including its brief history in 20 years, analysis methods, competitive mechanisms and different strategies to battle it. In terms of suppression of the PL blinking, wavefunction confinement-confining photo-generated electron and hole within the core and inner portion of the shell of a core/shell QD-demonstrates significant advantages. This strategy yields nearly non-blinking QDs with their emission peaks covering most part of the visible window. As expected, the resulting QDs from this new strategy also show substantially improved anti-bleaching features.
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Affiliation(s)
- Haiyan Qin
- Center for Chemistry of Novel & High-Performance Materials, Department of Chemistry, Zhejiang University, Hangzhou, 310027, China
| | - Renyang Meng
- Center for Chemistry of Novel & High-Performance Materials, Department of Chemistry, Zhejiang University, Hangzhou, 310027, China
| | - Na Wang
- Center for Chemistry of Novel & High-Performance Materials, Department of Chemistry, Zhejiang University, Hangzhou, 310027, China
| | - Xiaogang Peng
- Center for Chemistry of Novel & High-Performance Materials, Department of Chemistry, Zhejiang University, Hangzhou, 310027, China
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23
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Meng R, Qin H, Niu Y, Fang W, Yang S, Lin X, Cao H, Ma J, Lin W, Tong L, Peng X. Charging and Discharging Channels in Photoluminescence Intermittency of Single Colloidal CdSe/CdS Core/Shell Quantum Dot. J Phys Chem Lett 2016; 7:5176-5182. [PMID: 27973911 DOI: 10.1021/acs.jpclett.6b02448] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Understanding photoluminescence (PL) intermittency of single quantum dots (QDs) (intensity blinking by randomly switching between distinguishable brightness states under continuous excitation) has been a long-standing fundamental challenge and potential roadblock for their applications. Here we introduce a new analysis method for single-molecule spectroscopy that treats the blinking as photochemical/chemical processes (switching between neutral/bright and charged/dim states). It uncovers the channels for charging (bright to dim) and discharging (dim to bright) involved in PL blinking of single CdSe/CdS core/shell QDs. Both charging and discharging of the single CdSe/CdS core/shell QD possess a photochemical channel (∼10-5 to 10-6 events/photon) that linearly depends on excitation in both single- and multi-exciton regime. These two linear channels coupled to a spontaneous discharging channel (∼2 events/s) to dictate the QDs from nonblinking to gradually blinking under increasing excitation. For high-quality CdSe/CdS core/shell QDs, Auger ionization of multiexciton for both charging and discharging is negligible.
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Affiliation(s)
- Renyang Meng
- Center for Chemistry of Novel & High-Performance Materials, Department of Chemistry, Zhejiang University , Hangzhou 310027, China
| | - Haiyan Qin
- Center for Chemistry of Novel & High-Performance Materials, Department of Chemistry, Zhejiang University , Hangzhou 310027, China
| | - Yuan Niu
- Center for Chemistry of Novel & High-Performance Materials, Department of Chemistry, Zhejiang University , Hangzhou 310027, China
- State Key Laboratory of Modern Optical Instrumentation, College of Optical Science and Engineering, Zhejiang University , Hangzhou 310027, China
| | - Wei Fang
- State Key Laboratory of Modern Optical Instrumentation, College of Optical Science and Engineering, Zhejiang University , Hangzhou 310027, China
| | - Sen Yang
- State Key Laboratory of Modern Optical Instrumentation, College of Optical Science and Engineering, Zhejiang University , Hangzhou 310027, China
| | - Xing Lin
- State Key Laboratory of Modern Optical Instrumentation, College of Optical Science and Engineering, Zhejiang University , Hangzhou 310027, China
| | - Hujia Cao
- Center for Chemistry of Novel & High-Performance Materials, Department of Chemistry, Zhejiang University , Hangzhou 310027, China
| | - Junliang Ma
- Center for Chemistry of Novel & High-Performance Materials, Department of Chemistry, Zhejiang University , Hangzhou 310027, China
| | - Wanzhen Lin
- Center for Chemistry of Novel & High-Performance Materials, Department of Chemistry, Zhejiang University , Hangzhou 310027, China
| | - Limin Tong
- State Key Laboratory of Modern Optical Instrumentation, College of Optical Science and Engineering, Zhejiang University , Hangzhou 310027, China
| | - Xiaogang Peng
- Center for Chemistry of Novel & High-Performance Materials, Department of Chemistry, Zhejiang University , Hangzhou 310027, China
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24
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Xu W, Liu W, Schmidt JF, Zhao W, Lu X, Raab T, Diederichs C, Gao W, Seletskiy DV, Xiong Q. Correlated fluorescence blinking in two-dimensional semiconductor heterostructures. Nature 2016; 541:62-67. [DOI: 10.1038/nature20601] [Citation(s) in RCA: 129] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Accepted: 10/28/2016] [Indexed: 01/14/2023]
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25
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Cao H, Ma J, Huang L, Qin H, Meng R, Li Y, Peng X. Design and Synthesis of Antiblinking and Antibleaching Quantum Dots in Multiple Colors via Wave Function Confinement. J Am Chem Soc 2016; 138:15727-15735. [DOI: 10.1021/jacs.6b10102] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Hujia Cao
- Center for Chemistry of Novel & High-Performance Materials, Department of Chemistry, Zhejiang University, Hangzhou 310027, China
| | - Junliang Ma
- Center for Chemistry of Novel & High-Performance Materials, Department of Chemistry, Zhejiang University, Hangzhou 310027, China
| | - Lin Huang
- Center for Chemistry of Novel & High-Performance Materials, Department of Chemistry, Zhejiang University, Hangzhou 310027, China
| | - Haiyan Qin
- Center for Chemistry of Novel & High-Performance Materials, Department of Chemistry, Zhejiang University, Hangzhou 310027, China
| | - Renyang Meng
- Center for Chemistry of Novel & High-Performance Materials, Department of Chemistry, Zhejiang University, Hangzhou 310027, China
| | - Yang Li
- Center for Chemistry of Novel & High-Performance Materials, Department of Chemistry, Zhejiang University, Hangzhou 310027, China
| | - Xiaogang Peng
- Center for Chemistry of Novel & High-Performance Materials, Department of Chemistry, Zhejiang University, Hangzhou 310027, China
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26
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Abstract
Organic (opto)electronic materials have received considerable attention due to their applications in thin-film-transistors, light-emitting diodes, solar cells, sensors, photorefractive devices, and many others. The technological promises include low cost of these materials and the possibility of their room-temperature deposition from solution on large-area and/or flexible substrates. The article reviews the current understanding of the physical mechanisms that determine the (opto)electronic properties of high-performance organic materials. The focus of the review is on photoinduced processes and on electronic properties important for optoelectronic applications relying on charge carrier photogeneration. Additionally, it highlights the capabilities of various experimental techniques for characterization of these materials, summarizes top-of-the-line device performance, and outlines recent trends in the further development of the field. The properties of materials based both on small molecules and on conjugated polymers are considered, and their applications in organic solar cells, photodetectors, and photorefractive devices are discussed.
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Affiliation(s)
- Oksana Ostroverkhova
- Department of Physics, Oregon State University , Corvallis, Oregon 97331, United States
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27
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Efros AL, Nesbitt DJ. Origin and control of blinking in quantum dots. NATURE NANOTECHNOLOGY 2016; 11:661-71. [PMID: 27485584 DOI: 10.1038/nnano.2016.140] [Citation(s) in RCA: 215] [Impact Index Per Article: 26.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Accepted: 06/29/2016] [Indexed: 05/24/2023]
Abstract
Semiconductor nanocrystals offer an enormous diversity of potential device applications, based on their size-tunable photoluminescence, high optical stability and 'bottom-up' chemical approaches to self-assembly. However, the promise of such applications can be seriously limited by photoluminescence intermittency in nanocrystal emission, that is, 'blinking', arising from the escape of either one or both of the photoexcited carriers to the nanocrystal surface. In the first scenario, the remaining nanocrystal charge quenches photoluminescence via non-radiative Auger recombination, whereas for the other, the exciton is thought to be intercepted before thermalization and does not contribute to the photoluminescence. This Review summarizes the current understanding of the mechanisms responsible for nanocrystal blinking kinetics as well as core-shell engineering efforts to control such phenomena. In particular, 'softening' of the core-shell confinement potential strongly suppresses non-radiative Auger processes in charged nanocrystals, with successful non-blinking implementations demonstrated in CdSe-CdS core-thick-shell nanocrystals and their modifications.
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Affiliation(s)
- Alexander L Efros
- Naval Research Laboratory, Center for Computational Material Science, Washington DC 20375, USA
| | - David J Nesbitt
- JILA, University of Colorado and National Institute of Standards and Technology, and Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309-0440, USA
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28
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Yuan H, Debroye E, Caliandro G, Janssen KP, van Loon J, Kirschhock CEA, Martens JA, Hofkens J, Roeffaers MBJ. Photoluminescence Blinking of Single-Crystal Methylammonium Lead Iodide Perovskite Nanorods Induced by Surface Traps. ACS OMEGA 2016; 1:148-159. [PMID: 27617323 PMCID: PMC5013672 DOI: 10.1021/acsomega.6b00107] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2016] [Accepted: 07/14/2016] [Indexed: 05/25/2023]
Abstract
Photoluminescence (PL) of organometal halide perovskite materials reflects the charge dynamics inside of the material and thus contains important information for understanding the electro-optical properties of the material. Interpretation of PL blinking of methylammonium lead iodide (MAPbI3) nanostructures observed on polycrystalline samples remains puzzling owing to their intrinsic disordered nature. Here, we report a novel method for the synthesis of high-quality single-crystal MAPbI3 nanorods and demonstrate a single-crystal study on MAPbI3 PL blinking. At low excitation power densities, two-state blinking was found on individual nanorods with dimensions of several hundred nanometers. A super-resolution localization study on the blinking of individual nanorods showed that single crystals of several hundred nanometers emit and blink as a whole, without showing changes in the localization center over the crystal. Moreover, both the blinking ON and OFF times showed power-law distributions, indicating trapping-detrapping processes. This is further supported by the PL decay times of the individual nanorods, which were found to correlate with the ON/OFF states. Furthermore, a strong environmental dependence of the nanorod PL blinking was revealed by comparing the measurements in vacuum, nitrogen, and air, implying that traps locate close to crystal surfaces. We explain our observations by proposing surface charge traps that are likely related to under-coordinated lead ions and methylammonium vacancies to result in the PL blinking observed here.
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Affiliation(s)
- Haifeng Yuan
- Department
of Chemistry, KU Leuven, Celestijnenlaan 200F, B-3001 Leuven, Belgium
| | - Elke Debroye
- Department
of Chemistry, KU Leuven, Celestijnenlaan 200F, B-3001 Leuven, Belgium
| | - Giorgio Caliandro
- Department
of Chemistry, KU Leuven, Celestijnenlaan 200F, B-3001 Leuven, Belgium
| | - Kris P.
F. Janssen
- Department
of Chemistry, KU Leuven, Celestijnenlaan 200F, B-3001 Leuven, Belgium
| | - Jordi van Loon
- Centre
for Surface Chemistry and Catalysis, KU
Leuven, Kasteelpark Arenberg
23, 3001 Heverlee, Belgium
| | | | - Johan A. Martens
- Centre
for Surface Chemistry and Catalysis, KU
Leuven, Kasteelpark Arenberg
23, 3001 Heverlee, Belgium
| | - Johan Hofkens
- Department
of Chemistry, KU Leuven, Celestijnenlaan 200F, B-3001 Leuven, Belgium
- RIES, Hokkaido
University,
N20W10, Kita-Ward, Sapporo 001-0020, Japan
| | - Maarten B. J. Roeffaers
- Centre
for Surface Chemistry and Catalysis, KU
Leuven, Kasteelpark Arenberg
23, 3001 Heverlee, Belgium
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29
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Hu F, Lv B, Yin C, Zhang C, Wang X, Lounis B, Xiao M. Carrier Multiplication in a Single Semiconductor Nanocrystal. PHYSICAL REVIEW LETTERS 2016; 116:106404. [PMID: 27015498 DOI: 10.1103/physrevlett.116.106404] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2015] [Indexed: 06/05/2023]
Abstract
To confirm the existence of the carrier multiplication (CM) effect and estimate its generation efficiency of multiple excitons in semiconductor nanocrystals (NCs), it is imperative to completely exclude the false contribution of charged excitons from the measured CM signal. Here we place single CdSe NCs above an aluminum film and successfully resolve their UV-excited photoluminescence (PL) time trajectories where the true and false CM signals are contained in the blinking "on" and "off" levels, respectively. By analyzing the PL dynamics of the on-level photons, an average CM efficiency of ∼20.2% can be reliably estimated when the UV photon energy is ∼2.46 times the NC energy gap.
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Affiliation(s)
- Fengrui Hu
- National Laboratory of Solid State Microstructures, School of Physics, and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Bihu Lv
- National Laboratory of Solid State Microstructures, School of Physics, and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Chunyang Yin
- National Laboratory of Solid State Microstructures, School of Physics, and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Chunfeng Zhang
- National Laboratory of Solid State Microstructures, School of Physics, and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Xiaoyong Wang
- National Laboratory of Solid State Microstructures, School of Physics, and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Brahim Lounis
- Laboratoire Photonique Numérique et Nanosciences, Université de Bordeaux, Institut d'Optique Graduate School and CNRS, Talence 33405, France
| | - 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
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30
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Lee DU, Kim DH, Choi DH, Kim SW, Lee HS, Yoo KH, Kim TW. Microstructural and optical properties of CdSe/CdS/ZnS core-shell-shell quantum dots. OPTICS EXPRESS 2016; 24:A350-A357. [PMID: 26832587 DOI: 10.1364/oe.24.00a350] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
CdSe/CdS/ZnS core-shell-shell quantum dots (QDs) were synthesized by using a solution process. High-resolution transmission electron microscopy images and energy dispersive spectroscopy profiles confirmed that stoichiometric CdSe/CdS/ZnS core-shell-shell QDs were formed. Ultraviolet-visible absorption and photoluminescence (PL) spectra of CdSe/CdS/ZnS core-shell-shell QDs showed the dominant excitonic transitions from the ground electronic subband to the ground hole subband (1S(e)-1S(3/2)(h)). The PL mechanism is suggested; the carriers generated by the exciting high-energy photons in the shell region are relaxed to the band-edge states of the core region and recombined to emit lower-energy photons. The activation energy of the carriers confined in the CdSe/CdS/ZnS core-shell-shell QDs, as obtained from temperature-dependent PL spectra, was 200 meV. The quantum efficiency of the CdSe/CdS/ZnS core-shell-shell QDs at 300 K was estimated to be approximately 57%.
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31
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Rabouw FT, Kamp M, van Dijk-Moes RJA, Gamelin DR, Koenderink AF, Meijerink A, Vanmaekelbergh D. Delayed Exciton Emission and Its Relation to Blinking in CdSe Quantum Dots. NANO LETTERS 2015; 15:7718-25. [PMID: 26496661 DOI: 10.1021/acs.nanolett.5b03818] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
The efficiency and stability of emission from semiconductor nanocrystal quantum dots (QDs) is negatively affected by "blinking" on the single-nanocrystal level, that is, random alternation of bright and dark periods. The time scales of these fluctuations can be as long as many seconds, orders of magnitude longer than typical lifetimes of exciton states in QDs. In this work, we investigate photoluminescence from QDs delayed over microseconds to milliseconds. Our results prove the existence of long-lived charge-separated states in QDs. We study the properties of delayed emission as a direct way to learn about charge carrier separation and recovery of the exciton state. A new microscopic model is developed to connect delayed emission to exciton recombination and blinking from which we conclude that bright periods in blinking are in fact not characterized by uninterrupted optical cycling as often assumed.
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Affiliation(s)
- Freddy T Rabouw
- Condensed Matter and Interfaces, Debye Institute for Nanomaterials Science , Princetonplein 1, 3584 CC Utrecht, The Netherlands
| | - Marko Kamp
- Center for Nanophotonics, FOM Institute AMOLF , Science Park 104, 1098 XG Amsterdam, The Netherlands
| | - Relinde J A van Dijk-Moes
- Condensed Matter and Interfaces, Debye Institute for Nanomaterials Science , Princetonplein 1, 3584 CC Utrecht, The Netherlands
| | - Daniel R Gamelin
- Department of Chemistry, University of Washington , Seattle, Washington 98195-1700, United States
| | - A Femius Koenderink
- Center for Nanophotonics, FOM Institute AMOLF , Science Park 104, 1098 XG Amsterdam, The Netherlands
| | - Andries Meijerink
- Condensed Matter and Interfaces, Debye Institute for Nanomaterials Science , Princetonplein 1, 3584 CC Utrecht, The Netherlands
| | - Daniël Vanmaekelbergh
- Condensed Matter and Interfaces, Debye Institute for Nanomaterials Science , Princetonplein 1, 3584 CC Utrecht, The Netherlands
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32
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Zbydniewska E, Duzynska A, Popoff M, Hourlier D, Lenfant S, Judek J, Zdrojek M, Mélin T. Charge Blinking Statistics of Semiconductor Nanocrystals Revealed by Carbon Nanotube Single Charge Sensors. NANO LETTERS 2015; 15:6349-6356. [PMID: 26418364 DOI: 10.1021/acs.nanolett.5b01338] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
We demonstrate the relation between the optical blinking of colloidal semiconductor nanocrystals (NCs) and their electrical charge blinking for which we provide the first experimental observation of power-law statistics. To show this, we harness the performance of CdSe/ZnS NCs coupled with carbon nanotube field-effect transistors (CNTFETs), which act as single charge-sensitive electrometers with submillisecond time resolution, at room temperature. A random telegraph signal (RTS) associated with the NC single-trap charging is observed and exhibits power-law temporal statistics (τ(-α), with α in the range of ∼1-3), and a Lorentzian current noise power spectrum with a well-defined 1/f(2) corner. The spectroscopic analysis of the NC-CNTFET devices is consistent with the charging of NC defect states with a charging energy of Ec ≥ 200 meV. These results pave the way for a deeper understanding of the physics and technology of nanocrystal-based optoelectronic devices.
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Affiliation(s)
- Ewa Zbydniewska
- Institute of Electronics Microelectronics and Nanotechnology, IEMN-CNRS UMR 8520 , Avenue Poincaré CS60069, 59652 Villeneuve d'Ascq France
- Faculty of Physics, Warsaw University of Technology , Koszykowa 75, 00-662 Warsaw, Poland
| | - Anna Duzynska
- Faculty of Physics, Warsaw University of Technology , Koszykowa 75, 00-662 Warsaw, Poland
| | - Michka Popoff
- Institute of Electronics Microelectronics and Nanotechnology, IEMN-CNRS UMR 8520 , Avenue Poincaré CS60069, 59652 Villeneuve d'Ascq France
- Lille Centre for Infection and Immunity, Cellular Microbiology of Infectious Pathogens, CNRS UMR8204, INSERM U1019, University of Lille Nord-de-France, Institut Pasteur de Lille , F-59019 Lille, France
| | - Djamila Hourlier
- Institute of Electronics Microelectronics and Nanotechnology, IEMN-CNRS UMR 8520 , Avenue Poincaré CS60069, 59652 Villeneuve d'Ascq France
| | - Stéphane Lenfant
- Institute of Electronics Microelectronics and Nanotechnology, IEMN-CNRS UMR 8520 , Avenue Poincaré CS60069, 59652 Villeneuve d'Ascq France
| | - Jaroslaw Judek
- Faculty of Physics, Warsaw University of Technology , Koszykowa 75, 00-662 Warsaw, Poland
| | - Mariusz Zdrojek
- Faculty of Physics, Warsaw University of Technology , Koszykowa 75, 00-662 Warsaw, Poland
| | - Thierry Mélin
- Institute of Electronics Microelectronics and Nanotechnology, IEMN-CNRS UMR 8520 , Avenue Poincaré CS60069, 59652 Villeneuve d'Ascq France
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33
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Non-blinking (Zn)CuInS/ZnS Quantum Dots Prepared by In Situ Interfacial Alloying Approach. Sci Rep 2015; 5:15227. [PMID: 26458511 PMCID: PMC4602315 DOI: 10.1038/srep15227] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2015] [Accepted: 09/15/2015] [Indexed: 11/09/2022] Open
Abstract
Semiconductor quantum dots (QDs) are very important optical nanomaterials with a wide range of potential applications. However, blinking behavior of single QD is an intrinsic drawback for some biological and photoelectric applications based on single-particle emission. Herein we present a rational strategy for fabrication of non-blinking (Zn)CuInS/ZnS QDs in organic phase through in situ interfacial alloying approach. This new strategy includes three steps: synthesis of CuInS QDs, eliminating the interior traps of QDs by forming graded (Zn)CuInS alloyed QDs, modifying the surface traps of QDs by introducing ZnS shells onto (Zn)CuInS QDs using alkylthiols as sulfur source and surface ligands. The suppressed blinking mechanism was mainly attributed to modifying QDs traps from interior to exterior via a step-by-step modification. Non-blinking QDs show high quantum yield, symmetric emission spectra and excellent crystallinity, and will enable applications from biology to optoelectronics that were previously hindered by blinking behavior of traditional QDs.
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34
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Whitcomb KJ, Geisenhoff JQ, Ryan DP, Gelfand MP, Van Orden A. Photon Antibunching in Small Clusters of CdSe/ZnS Core/Shell Quantum Dots. J Phys Chem B 2015; 119:9020-8. [PMID: 25232642 DOI: 10.1021/jp5083856] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Coincident photon histogram measurements of fluorescence antibunching via confocal microscopy correlated with atomic force microscopy were carried out on (i) individual CdSe/ZnS core/shell quantum dots (QDs), (ii) several well separated QDs, and (iii) clusters of QDs. Individual QDs and well separated QDs showed the expected degree of antibunching for a single emitter and several independent emitters, respectively. The degree of antibunching in small, compact clusters was more characteristic of a single emitter than multiple emitters. The antibunching in clusters provides strong evidence of nonradiative energy transfer between QDs in a cluster. A minimal phenomenological model of energy transfer gives reasonable quantitative agreement with the experimental results.
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Affiliation(s)
- Kevin J Whitcomb
- †Department of Chemistry and ‡Department of Physics, Colorado State University, Fort Collins, Colorado 80523, United States
| | - Jessica Q Geisenhoff
- †Department of Chemistry and ‡Department of Physics, Colorado State University, Fort Collins, Colorado 80523, United States
| | - Duncan P Ryan
- †Department of Chemistry and ‡Department of Physics, Colorado State University, Fort Collins, Colorado 80523, United States
| | - Martin P Gelfand
- †Department of Chemistry and ‡Department of Physics, Colorado State University, Fort Collins, Colorado 80523, United States
| | - Alan Van Orden
- †Department of Chemistry and ‡Department of Physics, Colorado State University, Fort Collins, Colorado 80523, United States
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35
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Wen X, Ho-Baillie A, Huang S, Sheng R, Chen S, Ko HC, Green MA. Mobile Charge-Induced Fluorescence Intermittency in Methylammonium Lead Bromide Perovskite. NANO LETTERS 2015; 15:4644-9. [PMID: 26086568 DOI: 10.1021/acs.nanolett.5b01405] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Organic-inorganic halide perovskite has emerged as a very promising material for solar cells due to its excellent photovoltaic enabling properties resulting in rapid increase in device efficiency over the last 3 years. Extensive knowledge and in-depth physical understanding in the excited state carrier dynamics are urgently required. Here we investigate the fluorescence intermittency (also known as blinking) in vapor-assisted fabricated CH3NH3PbBr3 perovskite. The evident fluorescence blinking is observed in a dense CH3NH3PbBr3 perovskite film that is composed of nanoparticles in close contact with each other. In the case of an isolated nanoparticle no fluorescence blinking is observed. The "ON" probability of fluorescence is dependent on the excitation intensity and exhibits a similar power rule to semiconductor quantum dots at higher excitation intensity. As the vapor-assisted fabricated CH3NH3PbBr3 perovskite film is a cluster of nanoparticles forming a dense film, it facilitates mobile charge migration between the nanoparticles and charge accumulation at the surface or at the boundary of the nanoparticles. This leads to enhanced Auger-like nonradiative recombination contributing to the fluorescence intermittency observed. This finding provides unique insight into the charge accumulation and migration and thus is of crucial importance for device design and improvement.
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Affiliation(s)
- Xiaoming Wen
- †Australian Centre for Advanced Photovoltaics (ACAP), School of Photovoltaic and Renewable Energy Engineering, University of New South Wales, Sydney 2052, Australia
| | - Anita Ho-Baillie
- †Australian Centre for Advanced Photovoltaics (ACAP), School of Photovoltaic and Renewable Energy Engineering, University of New South Wales, Sydney 2052, Australia
| | - Shujuan Huang
- †Australian Centre for Advanced Photovoltaics (ACAP), School of Photovoltaic and Renewable Energy Engineering, University of New South Wales, Sydney 2052, Australia
| | - Rui Sheng
- †Australian Centre for Advanced Photovoltaics (ACAP), School of Photovoltaic and Renewable Energy Engineering, University of New South Wales, Sydney 2052, Australia
| | - Sheng Chen
- †Australian Centre for Advanced Photovoltaics (ACAP), School of Photovoltaic and Renewable Energy Engineering, University of New South Wales, Sydney 2052, Australia
| | - Hsien-chen Ko
- ‡Institute of Physics, Academia Sinica, Nankang, Taipei, 105, Taiwan
| | - Martin A Green
- †Australian Centre for Advanced Photovoltaics (ACAP), School of Photovoltaic and Renewable Energy Engineering, University of New South Wales, Sydney 2052, Australia
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36
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Whitham PJ, Knowles KE, Reid PJ, Gamelin DR. Photoluminescence Blinking and Reversible Electron Trapping in Copper-Doped CdSe Nanocrystals. NANO LETTERS 2015; 15:4045-51. [PMID: 26007328 DOI: 10.1021/acs.nanolett.5b01046] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Single-particle photoluminescence blinking is observed in the copper-centered deep-trap luminescence of copper-doped CdSe (Cu(+):CdSe) nanocrystals. Blinking dynamics for Cu(+):CdSe and undoped CdSe nanocrystals are analyzed to identify the effect of Cu(+), which selectively traps photogenerated holes. Analysis of the blinking data reveals that the Cu(+):CdSe and CdSe nanocrystal "off"-state dynamics are statistically identical, but the Cu(+):CdSe nanocrystal "on" state is shorter lived. Additionally, a new and pronounced temperature-dependent delayed luminescence is observed in the Cu(+):CdSe nanocrystals that persists long beyond the radiative lifetime of the luminescent excited state. This delayed luminescence is analogous to the well-known donor-acceptor pair luminescence of bulk copper-doped phosphors and is interpreted as revealing metastable charge-separated excited states formed by reversible electron trapping at the nanocrystal surfaces. A mechanistic link between this delayed luminescence and the luminescence blinking is proposed. Collectively, these data suggest that electron (rather than hole) trapping/detrapping is responsible for photoluminescence intermittency in these nanocrystals.
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Affiliation(s)
- Patrick J Whitham
- Department of Chemistry, University of Washington, Seattle, Washington 98195-1700, United States
| | - Kathryn E Knowles
- Department of Chemistry, University of Washington, Seattle, Washington 98195-1700, United States
| | - Philip J Reid
- Department of Chemistry, University of Washington, Seattle, Washington 98195-1700, United States
| | - Daniel R Gamelin
- Department of Chemistry, University of Washington, Seattle, Washington 98195-1700, United States
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37
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Osad'ko IS. Two types of the relation between the intensity and the life time of photoluminescence of core/shell semiconductor quantum dots: important role of Coulomb field and tunneling transitions. J Chem Phys 2015; 141:164312. [PMID: 25362304 DOI: 10.1063/1.4898381] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
It has been recently found [Gh. Galland, Y. Ghosh, A. Steinbrück, M. Sykora, J. A. Hollingsworth, and V. I. Klimov, Nature (London) 479, 203 (2011)] that semiconductor core/shell nanocrystals (NCs) with blinking photoluminescence (PL) can be of "A" or "B" type. NCs of A-type exhibit correlation between the intensity of PL and the life time. In NCs of B-type such correlation is absent. Simple model based on combination of the charging model and the two-level system model is proposed for describing emissive properties of NCs of both types. The model invokes fluctuations of emission ability γ(em) of NC to explain the emissive properties of NCs of B-type. Our combined model is also in agreement with anticorrelation between the duration τ(off) of off intervals and PL life time t(off) in off intervals found recently for NCs of A-type in the experiment [A. A. Cordones, T. J. Bixby, and S. R. Leone, Nano Lett. 11, 3366 (2011)].
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Affiliation(s)
- I S Osad'ko
- Institute for spectroscopy RAS, Troitsk, 142190 Moscow, Russia
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38
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Volkán-Kacsó S. Two-state theory of binned photon statistics for a large class of waiting time distributions and its application to quantum dot blinking. J Chem Phys 2015; 140:224110. [PMID: 24929377 DOI: 10.1063/1.4881460] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
A theoretical method is proposed for the calculation of the photon counting probability distribution during a bin time. Two-state fluorescence and steady excitation are assumed. A key feature is a kinetic scheme that allows for an extensive class of stochastic waiting time distribution functions, including power laws, expanded as a sum of weighted decaying exponentials. The solution is analytic in certain conditions, and an exact and simple expression is found for the integral contribution of "bright" and "dark" states. As an application for power law kinetics, theoretical results are compared with experimental intensity histograms from a number of blinking CdSe/ZnS quantum dots. The histograms are consistent with distributions of intensity states around a "bright" and a "dark" maximum. A gap of states is also revealed in the more-or-less flat inter-peak region. The slope and to some extent the flatness of the inter-peak feature are found to be sensitive to the power-law exponents. Possible models consistent with these findings are discussed, such as the combination of multiple charging and fluctuating non-radiative channels or the multiple recombination center model. A fitting of the latter to experiment provides constraints on the interaction parameter between the recombination centers. Further extensions and applications of the photon counting theory are also discussed.
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Affiliation(s)
- Sándor Volkán-Kacsó
- Noyes Laboratory of Chemical Physics, California Institute of Technology, 1200 East California Boulevard, Pasadena, California 91125, USA
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39
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Abualnaja KM, Šiller L, Horrocks BR. Metal-enhanced luminescence of silicon quantum dots: effects of nanoparticles and molecular electron donors and acceptors on the photofading kinetics. NANOTECHNOLOGY 2015; 26:145704. [PMID: 25785514 DOI: 10.1088/0957-4484/26/14/145704] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Alkyl-capped silicon quantum dots (SiQDs) show enhanced luminescence when drop cast as films on glass slides in mixtures with Ag or Au nanoparticles or the electron donor ferrocene (Fc). Metal enhancement of quantum dot photoluminescence (PL) is known to arise from a combination of the intense near-field associated with the surface plasmon of the metal on the rate of absorption and the decrease in the lifetime of the excited state. Here we present evidence that an additional factor is also involved: electron transfer from the metal to the quantum dot. Under CW irradiation with an argon ion laser at 488 nm, SiQDs undergo a reversible photofading of the PL as the particles photoionize. A steady-state condition is established by the competition between photoionization and electron-hole recombination. The fading of the initial PL I0 to the steady-state value I∞ can be modelled by a simple first order decay with a lognormal distribution of rates, which reflects the heterogeneity of the sample. In the presence of Ag and Au nanoparticles, the modal rate constants of photofading increase by factors of up to 4-fold and the ratio I0/I∞ decreases by factors up to 5-fold; this is consistent with an increase in the rate of electron-hole recombination facilitated by the metal nanoparticles acting as sources of electrons. Further support for this interpretation comes from the enhancement in PL observed in photofading experiments with films of SiQDs mixed with Fc; this compound is a well-known one-electron donor, but shows no plasmon band which complicates the estimation of PL enhancement with Ag NPs.
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Affiliation(s)
- Khamael M Abualnaja
- School of Chemical Engineering and Advanced Materials, Herschel Building, Newcastle University, NE1 7RU, UK
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40
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Hu F, Cao Z, Zhang C, Wang X, Xiao M. Defect-induced photoluminescence blinking of single epitaxial InGaAs quantum dots. Sci Rep 2015; 5:8898. [PMID: 25754220 PMCID: PMC4354043 DOI: 10.1038/srep08898] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Accepted: 02/06/2015] [Indexed: 11/09/2022] Open
Abstract
Here we report two types of defect-induced photoluminescence (PL) blinking behaviors observed in single epitaxial InGaAs quantum dots (QDs). In the first type of PL blinking, the "off" period is caused by the trapping of hot electrons from the higher-lying excited state (absorption state) to the defect site so that its PL rise lifetime is shorter than that of the "on" period. For the "off" period in the second type of PL blinking, the electrons relax from the first excited state (emission state) into the defect site, leading to a shortened PL decay lifetime compared to that of the "on" period. This defect-induced exciton quenching in epitaxial QDs, previously demonstrated also in colloidal nanocrystals, confirms that these two important semiconductor nanostructures could share the same PL blinking mechanism.
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Affiliation(s)
- Fengrui Hu
- National Laboratory of Solid State Microstructures and School of Physics, Nanjing University, Nanjing 210093, China
| | - Zengle Cao
- National Laboratory of Solid State Microstructures and School of Physics, Nanjing University, Nanjing 210093, China
| | - Chunfeng Zhang
- National Laboratory of Solid State Microstructures and School of Physics, Nanjing University, Nanjing 210093, China
| | - Xiaoyong Wang
- National Laboratory of Solid State Microstructures and School of Physics, Nanjing University, Nanjing 210093, China
| | - Min Xiao
- 1] National Laboratory of Solid State Microstructures and School of Physics, Nanjing University, Nanjing 210093, China [2] Department of Physics, University of Arkansas, Fayetteville, AR 72701, USA
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41
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Brawand NP, Vörös M, Galli G. Surface dangling bonds are a cause of B-type blinking in Si nanoparticles. NANOSCALE 2015; 7:3737-3744. [PMID: 25644225 DOI: 10.1039/c4nr06376g] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Exponential blinking statistics was reported in oxidized Si nanoparticles and the switching mechanism was attributed to the activation and deactivation of unidentified nonradiative recombination centers. Using ab initio calculations we predicted that Si dangling bonds at the surface of oxidized nanoparticles introduce defect states which, depending on their charge and local stress conditions, may give rise to ON and OFF states responsible for exponential blinking statistics. Our results are based on first principles calculations of charge transition levels, single particle energies, and radiative and nonradiative lifetimes of dangling bond defects at the surface of oxidized silicon nanoparticles under stress.
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42
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Kambhampati P. On the kinetics and thermodynamics of excitons at the surface of semiconductor nanocrystals: Are there surface excitons? Chem Phys 2015. [DOI: 10.1016/j.chemphys.2014.11.008] [Citation(s) in RCA: 69] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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43
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Guzelturk B, Erdem O, Olutas M, Kelestemur Y, Demir HV. Stacking in colloidal nanoplatelets: tuning excitonic properties. ACS NANO 2014; 8:12524-33. [PMID: 25469555 DOI: 10.1021/nn5053734] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Colloidal semiconductor quantum wells, also commonly known as nanoplatelets (NPLs), have arisen among the most promising materials for light generation and harvesting applications. Recently, NPLs have been found to assemble in stacks. However, their emerging characteristics essential to these applications have not been previously controlled or understood. In this report, we systematically investigate and present excitonic properties of controlled column-like NPL assemblies. Here, by a controlled gradual process, we show that stacking in colloidal quantum wells substantially increases exciton transfer and trapping. As NPLs form into stacks, surprisingly we find an order of magnitude decrease in their photoluminescence quantum yield, while the transient fluorescence decay is considerably accelerated. These observations are corroborated by ultraefficient Förster resonance energy transfer (FRET) in the stacked NPLs, in which exciton migration is estimated to be in the ultralong range (>100 nm). Homo-FRET (i.e., FRET among the same emitters) is found to be ultraefficient, reaching levels as high as 99.9% at room temperature owing to the close-packed collinear orientation of the NPLs along with their large extinction coefficient and small Stokes shift, resulting in a large Förster radius of ∼13.5 nm. Consequently, the strong and long-range homo-FRET boosts exciton trapping in nonemissive NPLs, acting as exciton sink centers, quenching photoluminescence from the stacked NPLs due to rapid nonradiative recombination of the trapped excitons. The rate-equation-based model, which considers the exciton transfer and the radiative and nonradiative recombination within the stacks, shows an excellent match with the experimental data. These results show the critical significance of stacking control in NPL solids, which exhibit completely different signatures of homo-FRET as compared to that in colloidal nanocrystals due to the absence of inhomogeneous broadening.
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Affiliation(s)
- Burak Guzelturk
- Department of Electrical and Electronics Engineering, Department of Physics, UNAM - Institute of Materials Science and Nanotechnology, Bilkent University , Ankara 06800, Turkey
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44
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Dong C, Liu H, Ren J. Assessing the blinking state of fluorescent quantum dots in free solution by combining fluorescence correlation spectroscopy with ensemble spectroscopic methods. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2014; 30:12969-12976. [PMID: 25290853 DOI: 10.1021/la503055v] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The current method for investigating the blinking behavior is to immobilize quantum dots (QDs) in the matrix and then apply a fluorescent technique to monitor the fluorescent trajectories of individual QDs. So far, no method can be used to directly assess the blinking state of ensemble QDs in free solution. In this study, a new method was described to characterize the blinking state of the QDs in free solution by combining single molecule fluorescence correlation spectroscopy (FCS) with ensemble spectroscopic methods. Its principle is based on the observation that the apparent concentration of bright QDs obtained by FCS is less than its actual concentration measured by ensemble spectroscopic method due to the QDs blinking. We proposed a blinking index (Kblink) for characterizing the blinking state of QDs, and Kblink is defined as the ratio of the actual concentration (Cb,actual) measured by the ensemble spectroscopic method to the apparent concentration (Cb,app) of QDs obtained by FCS. The effects of certain factors such as laser intensity, growth process, and ligands on blinking of QDs were investigated. The Kblink data of QDs obtained were successfully used to characterize the blinking state of QDs and explain certain experimental results.
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Affiliation(s)
- Chaoqing Dong
- School of Chemistry & Chemical Engineering, State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University , 800 Dongchuan Road, Shanghai 200240, P. R. China
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van Schooten KJ, Boehme C, Lupton JM. Coherent magnetic resonance of nanocrystal quantum-dot luminescence as a window to blinking mechanisms. Chemphyschem 2014; 15:1737-46. [PMID: 24756986 DOI: 10.1002/cphc.201400081] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2014] [Revised: 03/04/2014] [Indexed: 11/08/2022]
Abstract
Blinking of colloidal nanocrystal quantum dots, random intermittency in the stream of photons emitted by single particles, has long commanded the curiosity of researchers. Why does the particle suddenly shut off, and what are the pathways to quench emission? Single-particle microscopy is not the only way to approach these fundamental questions on the interaction of light and matter: time-domain sub-ensemble spectroscopies can also yield relevant information on microscopic electronic processes. We illustrate recent advances in pulsed optically detected magnetic resonance and highlight the conceptual relevance to unravelling mechanisms controlling intermittency on the single-particle level. Magnetic resonance reveals two distinct luminescence quenching channels, which appear to be related to those previously surmised from single-particle studies: a trapped charge-separated state in which the exciton is quenched by dissociation and the particle remains neutral; and a charged state of the particle in which spin-dependent Auger recombination quenches luminescence.
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Affiliation(s)
- Kipp J van Schooten
- Department of Physics and Astronomy, University of Utah, 115 South 1400 East, Salt Lake City, UT 84112-0830 (USA)
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Schmidt R, Krasselt C, Göhler C, von Borczyskowski C. The fluorescence intermittency for quantum dots is not power-law distributed: a luminescence intensity resolved approach. ACS NANO 2014; 8:3506-3521. [PMID: 24580107 DOI: 10.1021/nn406562a] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The photoluminescence (PL) of single emitters like semiconductor quantum dots (QDs) shows PL intermittency, often called blinking. We explore the PL intensities of single CdSe/ZnS QDs in polystyrene (PS), on polyvenylalcohol (PVA), and on silicon oxide (SiOx) by the change-point analysis (CPA). By this, we relate results from the macrotime (sub-ms to 1000 s) and the microtime (0.1-100 ns) range to discrete PL intensities. We conclude that the intensity selected "on"-times in the ms range correspond to only a few (discrete) switching times, while the PL decays in the ns range are multiexponential even with respect to the same selected PL intensity. Both types of relaxation processes depend systematically on the PL intensity in course of a blinking time trace. The overall distribution of on-times does not follow a power law contrary to what has often been reported but can be compiled into 3-4 characteristic on-times. The results can be explained by the recently suggested multiple recombination centers model. Additionally, we can identify a well-defined QD state with a very low PL intensity above the noise level, which we assign to the strongly quenched exciton state. We describe our findings by a model of a hierarchical sequence of hole and electron trapping. Blinking events are the consequence of slow switching processes among these states and depend on the physicochemical properties of the heterogeneous nanointerface of the QDs.
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Affiliation(s)
- Robert Schmidt
- Institute of Physics, Optical Spectroscopy and Molecular Physics, Centre for Nanostructured Materials and Analytics (nanoMA), Technische Universität Chemnitz , 09107 Chemnitz, Germany
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Voznyy O, Sargent EH. Atomistic model of fluorescence intermittency of colloidal quantum dots. PHYSICAL REVIEW LETTERS 2014; 112:157401. [PMID: 24785069 DOI: 10.1103/physrevlett.112.157401] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2013] [Indexed: 06/03/2023]
Abstract
Optoelectronic applications of colloidal quantum dots demand a high emission efficiency, stability in time, and narrow spectral bandwidth. Electronic trap states interfere with the above properties but understanding of their origin remains lacking, inhibiting the development of robust passivation techniques. Here we show that surface vacancies improve the fluorescence yield compared to vacancy-free surfaces, while dynamic vacancy aggregation can temporarily turn fluorescence off. We find that infilling with foreign cations can stabilize the vacancies, inhibiting intermittency and improving quantum yield, providing an explanation of recent experimental observations.
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Affiliation(s)
- O Voznyy
- Department of Electrical and Computer Engineering, University of Toronto, 10 King's College Road, Toronto, Ontario M5S 3G4, Canada
| | - E H Sargent
- Department of Electrical and Computer Engineering, University of Toronto, 10 King's College Road, Toronto, Ontario M5S 3G4, Canada
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Mangum BD, Sampat S, Ghosh Y, Hollingsworth JA, Htoon H, Malko AV. Influence of the core size on biexciton quantum yield of giant CdSe/CdS nanocrystals. NANOSCALE 2014; 6:3712-3720. [PMID: 24569861 DOI: 10.1039/c3nr06558h] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
We present a systematic study of photoluminescence (PL) emission intensity and biexciton (BX) quantum yields (QYBX) in individual "giant" CdSe/CdS nanocrystals (g-NCs) as a function of g-NC core size and shell thickness. We show that g-NC core size significantly affects QYBX and can be utilized as an effective tuning parameter towards higher QYBX while keeping the total volume of the g-NC constant. Specifically, we observe that small-core (2.2 nm diameter) CdSe/CdS NCs with a volume of ∼200 nm(3) (shell comprises 4 CdS monolayers) show very low average and maximum QYBX's of ∼3 and 7%, respectively. In contrast, same-volume medium-core (3 nm diameter) NCs afford higher average values of ∼10%, while QYBX's of ∼30% are achieved for same-volume large-core (5.5 nm diameter) CdSe/CdS NCs, with some approaching ∼80%. These observations underline the influence of the g-NC core size on the evolution of PL emissive states in multi-shell NCs. Moreover, our study also reveals that the use of long anneal times in the growth of CdS shells plays a critical role in achieving high QYBX.
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Affiliation(s)
- Benjamin D Mangum
- Materials Physics and Applications Division, Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.
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Amecke N, Heber A, Cichos F. Distortion of power law blinking with binning and thresholding. J Chem Phys 2014; 140:114306. [DOI: 10.1063/1.4868252] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
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Hollingsworth JA. Nanoscale engineering facilitated by controlled synthesis: From structure to function. Coord Chem Rev 2014. [DOI: 10.1016/j.ccr.2013.09.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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