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Tanghe I, Molkens K, Vandekerckhove T, Respekta D, Waters A, Huang J, Beavon J, Harankahage D, Lin CY, Chen K, Van Thourhout D, Zamkov M, Geiregat P. Two-Dimensional Electron-Hole Plasma in Colloidal Quantum Shells Enables Integrated Lasing Continuously Tunable in the Red Spectrum. ACS NANO 2024; 18:14661-14671. [PMID: 38780137 DOI: 10.1021/acsnano.4c02907] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2024]
Abstract
Combining integrated optical platforms with solution-processable materials offers a clear path toward miniaturized and robust light sources, including lasers. A limiting aspect for red-emitting materials remains the drop in efficiency at high excitation density due to non-radiative quenching pathways, such as Auger recombination. Next to this, lasers based on such materials remain ill characterized, leaving questions about their ultimate performance. Here, we show that colloidal quantum shells (QSs) offer a viable solution for a processable material platform to circumvent these issues. We first show that optical gain in QSs is mediated by a 2D plasma state of unbound electron-hole pairs, opposed to bound excitons, which gives rise to broad-band and sizable gain across the full red spectrum with record gain lifetimes and a low threshold. Moreover, at high excitation density, the emission efficiency of the plasma state does not quench, a feat we can attribute to an increased radiative recombination rate. Finally, QSs are integrated on a silicon nitride platform, enabling high spectral contrast, surface emitting, and TE-polarized lasers with ultranarrow beam divergence across the entire red spectrum from a small surface area. Our results indicate QS materials are an excellent materials platform to realize highly performant and compact on-chip light sources.
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Affiliation(s)
- Ivo Tanghe
- Photonics Research Group, Ghent University, Gent 9000, Belgium
- Physics and Chemistry of Nanostructures, Ghent University, Gent 9000, Belgium
- NOLIMITS Core Facility for Non-Linear Microscopy and Spectroscopy, Ghent University, Gent 9000, Belgium
| | - Korneel Molkens
- Photonics Research Group, Ghent University, Gent 9000, Belgium
- Physics and Chemistry of Nanostructures, Ghent University, Gent 9000, Belgium
- NOLIMITS Core Facility for Non-Linear Microscopy and Spectroscopy, Ghent University, Gent 9000, Belgium
| | | | - Dobromił Respekta
- Physics and Chemistry of Nanostructures, Ghent University, Gent 9000, Belgium
- NOLIMITS Core Facility for Non-Linear Microscopy and Spectroscopy, Ghent University, Gent 9000, Belgium
| | - Amelia Waters
- Department of Physics, Bowling Green State University, Bowling Green, Ohio 43403, United States
| | - Jiamin Huang
- Department of Physics, Bowling Green State University, Bowling Green, Ohio 43403, United States
| | - Jacob Beavon
- Department of Physics, Bowling Green State University, Bowling Green, Ohio 43403, United States
| | - Dulanjan Harankahage
- Department of Chemistry, Bowling Green State University, Bowling Green, Ohio 43403, United States
- The Center for Photochemical Sciences, Bowling Green State University, Bowling Green, Ohio 43403, United States
| | - Chao Yang Lin
- Robinson Research Institute, Victoria University of Wellington, Wellington 6012, New Zealand
| | - Kai Chen
- MacDiarmid Institute for Advanced Materials and Nanotechnology, Wellington 6012, New Zealand
- Robinson Research Institute, Victoria University of Wellington, Wellington 6012, New Zealand
- The Dodd-Walls Centre for Photonic and Quantum Technologies, University of Otago, Dunedin 9016, New Zealand
| | | | - Mikhail Zamkov
- Department of Physics, Bowling Green State University, Bowling Green, Ohio 43403, United States
- The Center for Photochemical Sciences, Bowling Green State University, Bowling Green, Ohio 43403, United States
| | - Pieter Geiregat
- Physics and Chemistry of Nanostructures, Ghent University, Gent 9000, Belgium
- NOLIMITS Core Facility for Non-Linear Microscopy and Spectroscopy, Ghent University, Gent 9000, Belgium
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2
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Klepzig LF, Keppler NC, Rudolph DA, Schaate A, Behrens P, Lauth J. Highly Transparent, Yet Photoluminescent: 2D CdSe/CdS Nanoplatelet-Zeolitic Imidazolate Framework Composites Sensitive to Gas Adsorption. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2024; 20:e2309533. [PMID: 38078785 DOI: 10.1002/smll.202309533] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2023] [Indexed: 05/03/2024]
Abstract
In this work, thin composite films of zeolitic imidazolate frameworks (ZIFs) and colloidal two-dimensional (2D) core-crown CdSe/CdS nanoplatelet (NPL) emitters with minimal scattering are formed by a cycled growth method and yield highly transparent coatings with strong and narrow photoluminescence of the NPLs at 546 nm (FWHM: 25 nm) in a solid-state composite structure. The porous ZIF matrix acts as functional encapsulation for the emitters and enables the adsorption of the guest molecules water and ethanol. The adsorption and desorption of the guest molecules is then characterized by a reversable photoluminescence change of the embedded NPLs. The transmittance of the composite films exceeds the values of uncoated glass at visible wavelengths where the NPL emitters show no absorption (>540 nm) and renders them anti-reflective coatings. At NPL absorption wavelengths (440-540 nm), the transmittance of the thin composite film-coated glass lies close to the transmittance of uncoated glass. The fast formation of innovative, smooth NPL/ZIF composite films without pre-polymerizing the colloidal 2D nanostructures first provides a powerful tool toward application-oriented photoluminescence-based gas sensing.
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Affiliation(s)
- Lars F Klepzig
- Institute of Physical Chemistry, Leibniz University Hannover, Callinstraße 3A, D-30167, Hannover, Germany
- Cluster of Excellence PhoenixD (Photonics, Optics and Engineering - Innovation Across Disciplines), Leibniz University Hannover, Welfengarten 1A, D-30167, Hannover, Germany
| | - Nils C Keppler
- Cluster of Excellence PhoenixD (Photonics, Optics and Engineering - Innovation Across Disciplines), Leibniz University Hannover, Welfengarten 1A, D-30167, Hannover, Germany
- Institute of Inorganic Chemistry, Leibniz University Hannover, Callinstraße 9, D-30167, Hannover, Germany
| | - Dominik A Rudolph
- Institute of Physical Chemistry, Leibniz University Hannover, Callinstraße 3A, D-30167, Hannover, Germany
| | - Andreas Schaate
- Cluster of Excellence PhoenixD (Photonics, Optics and Engineering - Innovation Across Disciplines), Leibniz University Hannover, Welfengarten 1A, D-30167, Hannover, Germany
- Institute of Inorganic Chemistry, Leibniz University Hannover, Callinstraße 9, D-30167, Hannover, Germany
- Laboratory of Nano and Quantum Engineering (LNQE), Leibniz University Hannover, Schneiderberg 39, D-30167, Hannover, Germany
| | - Peter Behrens
- Cluster of Excellence PhoenixD (Photonics, Optics and Engineering - Innovation Across Disciplines), Leibniz University Hannover, Welfengarten 1A, D-30167, Hannover, Germany
- Institute of Inorganic Chemistry, Leibniz University Hannover, Callinstraße 9, D-30167, Hannover, Germany
- Laboratory of Nano and Quantum Engineering (LNQE), Leibniz University Hannover, Schneiderberg 39, D-30167, Hannover, Germany
| | - Jannika Lauth
- Institute of Physical Chemistry, Leibniz University Hannover, Callinstraße 3A, D-30167, Hannover, Germany
- Cluster of Excellence PhoenixD (Photonics, Optics and Engineering - Innovation Across Disciplines), Leibniz University Hannover, Welfengarten 1A, D-30167, Hannover, Germany
- Laboratory of Nano and Quantum Engineering (LNQE), Leibniz University Hannover, Schneiderberg 39, D-30167, Hannover, Germany
- Institute of Physical Chemistry and Theoretical Chemistry, University of Tübingen, Auf der Morgenstelle 18, D-30167, Tübingen, Germany
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3
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Xiang W, Zhu B, Bai C, Gu B, Lv C, Zhang J. Thickness-modulated optical nonlinearity of colloidal CdSe-CdS core-shell nanoplatelets: large two-photon absorption and self-focusing effects. NANOSCALE 2023; 15:17996-18003. [PMID: 37906472 DOI: 10.1039/d3nr04532c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/02/2023]
Abstract
As a one-dimensional quantum confined material, colloidal semiconductor nanoplatelets have been widely studied as potential nonlinear materials due to their strong exciton effect and large two-photon absorption cross-section similar to that of two-dimensional materials. In this work, CdSe-CdS core-shell nanoplatelets were synthesized and third-order nonlinear optical properties related to shell thickness were measured using the Z-scan method. Measurement revealed a monotonic increase in the imaginary part of the third-order nonlinear susceptibility (Imχ(3)) of CdSe-CdS nanoplatelets, ranging from 0.62 × 10-13 esu to 2.43 × 10-13 esu, with the growth of shell thickness. The real part of the third-order nonlinear susceptibility (Reχ(3)) shows a non-monotonic change between 4.28 × 10-13 esu and 1.99 × 10-13 esu. The trends were further elucidated by analyzing the optical properties of the nanoplatelets, such as absorption, photoluminescence, and quantum yield, and understanding the variations in defect distribution, exciton binding energy, and quantum confinement effects. The results indicated that the appropriate passivation of the CdS shell effectively enhanced the luminescent performance and third-order nonlinearity of the nanoplatelets, while the induced defects and weakened quantum confinement effects due to the continued shell growth resulted in the opposite effect.
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Affiliation(s)
- Wenbin Xiang
- Advanced Photonics Center, Southeast University, Nanjing 210096, China.
| | - Baohua Zhu
- Institute of Micro/Nano Photonic Materials and Applications, School of Physics and Electronics, Henan University, Kaifeng 475004, China
| | - Chunzheng Bai
- Advanced Photonics Center, Southeast University, Nanjing 210096, China.
| | - Bing Gu
- Advanced Photonics Center, Southeast University, Nanjing 210096, China.
| | - Changgui Lv
- Advanced Photonics Center, Southeast University, Nanjing 210096, China.
| | - Jiayu Zhang
- Advanced Photonics Center, Southeast University, Nanjing 210096, China.
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Abstract
Lasers and optical amplifiers based on solution-processable materials have been long-desired devices for their compatibility with virtually any substrate, scalability, and ease of integration with on-chip photonics and electronics. These devices have been pursued across a wide range of materials including polymers, small molecules, perovskites, and chemically prepared colloidal semiconductor nanocrystals, also commonly referred to as colloidal quantum dots. The latter materials are especially attractive for implementing optical-gain media as in addition to being compatible with inexpensive and easily scalable chemical techniques, they offer multiple advantages derived from a zero-dimensional character of their electronic states. These include a size-tunable emission wavelength, low optical gain thresholds, and weak sensitivity of lasing characteristics to variations in temperature. Here we review the status of colloidal nanocrystal lasing devices, most recent advances in this field, outstanding challenges, and the ongoing progress toward technological viable devices including colloidal quantum dot laser diodes.
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Affiliation(s)
- Namyoung Ahn
- Nanotechnology and Advanced Spectroscopy Team, C-PCS, Chemistry Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Clément Livache
- Nanotechnology and Advanced Spectroscopy Team, C-PCS, Chemistry Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Valerio Pinchetti
- Nanotechnology and Advanced Spectroscopy Team, C-PCS, Chemistry Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Victor I Klimov
- Nanotechnology and Advanced Spectroscopy Team, C-PCS, Chemistry Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
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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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Failla M, García Flórez F, Salzmann BBV, Vanmaekelbergh D, Stoof HTC, Siebbeles LDA. Effects of Pump Photon Energy on Generation and Ultrafast Relaxation of Excitons and Charge Carriers in CdSe Nanoplatelets. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2023; 127:1899-1907. [PMID: 36761230 PMCID: PMC9900632 DOI: 10.1021/acs.jpcc.2c07292] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Revised: 12/21/2022] [Indexed: 06/18/2023]
Abstract
We studied the initial nature and relaxation of photoexcited electronic states in CdSe nanoplatelets (NPLs). Ultrafast transient optical absorption (TA) measurements were combined with the theoretical analysis of the formation and decay of excitons, biexcitons, free charge carriers, and trions. In the latter, photons and excitons were treated as bosons and free charge carriers as fermions. The initial quantum yields of heavy-hole (HH) excitons, light-hole (LH) excitons, and charge carriers vary strongly with photon energy, while thermal relaxation occurs always within 1 ps. After that, the population of LH excitons is negligible due to relaxation to HH excitons or decay into free electrons and holes. Up to the highest average number of about four absorbed photons per NPL in our experiments, we found no signatures of the presence of biexcitons or larger complexes. Biexcitons were only observed due to the interaction of a probe-generated exciton with an exciton produced previously by the pump pulse. For higher pump photon energies, the initial presence of more free charge carriers leads to formation of trions by probe photons. On increasing the number of absorbed pump photons in an NPL, the yield of excitons becomes higher as compared to free charge carriers, since electron-hole recombination becomes more likely. In addition to a TA absorption feature at energy below the HH exciton peak, we also observed a TA signal at the high-energy side of this peak, which we attribute to formation of LH-HH biexcitons or trions consisting of a charge and LH exciton.
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Affiliation(s)
- Michele Failla
- Chemical
Engineering Department, Delft University
of Technology, Van der Maasweg 9, 2629 HZDelft, The Netherlands
| | - Fransisco García Flórez
- Institute
for Theoretical Physics and Center for Extreme Matter and Emergent
Phenomena, Utrecht University, Princetonplein 5, 3584 CCUtrecht, The Netherlands
| | - Bastiaan B. V. Salzmann
- Condensed
Matter and Interfaces, Debye Institute, Utrecht University, Princetonplein 1, 3584 CCUtrecht, The Netherlands
| | - Daniel Vanmaekelbergh
- Condensed
Matter and Interfaces, Debye Institute, Utrecht University, Princetonplein 1, 3584 CCUtrecht, The Netherlands
| | - Henk T. C. Stoof
- Institute
for Theoretical Physics and Center for Extreme Matter and Emergent
Phenomena, Utrecht University, Princetonplein 5, 3584 CCUtrecht, The Netherlands
| | - Laurens D. A. Siebbeles
- Chemical
Engineering Department, Delft University
of Technology, Van der Maasweg 9, 2629 HZDelft, The Netherlands
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Ashokan A, Han J, Hutchison JA, Mulvaney P. Spectroelectrochemistry of CdSe/Cd xZn 1-xS Nanoplatelets. ACS NANO 2023; 17:1247-1254. [PMID: 36629376 DOI: 10.1021/acsnano.2c09298] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
We report an unexpected enhancement of photoluminescence (PL) in CdSe-based core/shell nanoplatelets (NPLs) upon electrochemical hole injection. Moderate hole doping densities induce an enhancement of more than 50% in PL intensity. This is accompanied by a narrowing and blue-shift of the PL spectrum. Simultaneous, time-resolved PL experiments reveal a slower luminescence decay. Such hole-induced PL brightening in NPLs is in stark contrast to the usual observation of PL quenching of CdSe-based quantum dots following hole injection. We propose that hole injection removes surface traps responsible for the formation of negative trions, thereby blocking nonradiative Auger processes. Continuous photoexcitation causes the enhanced PL intensity to decrease back to its initial level, indicating that photocharging is a key step leading to loss of PL luminescence during normal aging. Modulating the potential can be used to reversibly enhance or quench the PL, which enables electro-optical switching.
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Affiliation(s)
- Arun Ashokan
- ARC Centre of Excellence in Exciton Science, School of Chemistry, University of Melbourne, Parkville, Victoria3010, Australia
| | - Jiho Han
- ARC Centre of Excellence in Exciton Science, School of Chemistry, University of Melbourne, Parkville, Victoria3010, Australia
| | - James A Hutchison
- ARC Centre of Excellence in Exciton Science, School of Chemistry, University of Melbourne, Parkville, Victoria3010, Australia
| | - Paul Mulvaney
- ARC Centre of Excellence in Exciton Science, School of Chemistry, University of Melbourne, Parkville, Victoria3010, Australia
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Schiettecatte P, Hens Z, Geiregat P. A roadmap to decipher ultrafast photophysics in two-dimensional nanomaterials. J Chem Phys 2023; 158:014202. [PMID: 36610952 DOI: 10.1063/5.0134962] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Atomically thin two-dimensional (2D) semiconductors are extensively investigated for optoelectronic applications that require strong light-matter interactions. In view of such applications, it is essential to understand how (photo)excitation alters the non-linear optical response of these materials under high carrier density conditions. Broadband transient absorption (TA) spectroscopy is by now a widely used tool to study the semiconductor physics in such highly excited systems. However, the complex interplay between different many-body interactions in 2D materials produces highly congested spectral information and an ensuing non-trivial non-linear photo-response, thereby masking the desired intrinsic photophysics. Herein, we outline a concise roadmap for analyzing such congested datasets based on examples of TA analysis of various 2D materials. In particular, we emphasize the synergy between an initial qualitative understanding of the transient photo-response based on line shapes and their derivatives and a consequent quantitative spectral deconvolution backed by such insights.
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Affiliation(s)
- Pieter Schiettecatte
- Physics and Chemistry of Nanostructures, Department of Chemistry, Ghent University, 9000 Ghent, Belgium
| | - Zeger Hens
- Physics and Chemistry of Nanostructures, Department of Chemistry, Ghent University, 9000 Ghent, Belgium
| | - Pieter Geiregat
- Physics and Chemistry of Nanostructures, Department of Chemistry, Ghent University, 9000 Ghent, Belgium
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