ACS Applied Materials & Interfaces
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2022
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IF 10.383
Meiqin Xiao,Ting Xiang,Dohyung Kim,Miaosheng Wang,Wei Zhang,Mahshid Ahmadi,Ting Li,Xiaoyan Wu,Long Xu,Ping Chen
The multiple quantum well structure of a quasi-two-dimensional (quasi-2D) perovskite leads to nonradiative Auger recombination (AR). This is due to high local carrier density in recombination centers, although the radiative recombination is improved by efficient energy transfer. In this study, we suppress the AR by introducing phenethylammonium acetate (PEAAc) into the quasi-2D PEA2Csn–1PbnBr3n+1 perovskite. The recombination centers of n ≥ 4 phases can be promoted because the COO– preferentially coordinates with Pb2+, inhibiting the fast formation of n = 1, 2, 3 phases with phenethylammonium anion (PEA+). Thus, the AR is suppressed due to the lower density of local charge carriers. To balance the AR suppression and decreasing binding energy in promoting the n ≥ 4 phases, the PEAAc:PEABr molar ratios are adjusted. At the optimal molar ratio, perovskite light-emitting diodes (PeLEDs) with a maximum luminescence of ∼29942 cd m–2 and a maximum external quantum efficiency of ∼20.2% are achieved. These results confirm the most efficient PeLEDs based on PEA2Csn–1PbnBr3n+1 without passivation. Moreover, the efficiency roll off is significantly mitigated with a high threshold of over 3.51 mA/cm2. This study develops high-efficiency PeLEDs with a low efficiency rolloff.
研究领域:
材料科学
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光电技术
✓ 已验证
产品关联
DOI
PubMed
高影响因子
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
·
2024
·Vol. 26
·期 15
·12179-12187
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IF 2.9
Jinwei Liu,Rong Lu,Anchi Yu
CsPbBr3 nanoplatelets (NPLs), as some of the two-dimensional lead halide perovskites, have been intensively investigated due to their outstanding photophysical and photoelectric properties. However, there remain unclear fundamental issues on their carrier kinetics and the low-energy tail in their photoluminescence (PL) spectrum. In this paper, we synthesized CsPbBr3 NPLs with five [PbBr6]4− monolayers and performed comprehensive studies by using steady-state absorption, PL, and femtosecond transient absorption (fs-TA) spectroscopic measurements. We determined both the biexciton Auger recombination time (7 ± 2 ps) and trapped exciton lifetime (110 ± 15 ps) of the five monolayer CsPbBr3 NPLs. We also investigated the origin of the low-energy tail emission in their PL spectrum. More importantly, we found that a negative ΔA feature in the energy range of 2.45–2.55 eV appears in their fs-TA spectrum at 2, 4 and 10 ps delay times, which could help them act as a laser gain medium. The low-energy tail emission in their PL spectrum overlaps well with the negative ΔA feature in the energy range of 2.45–2.55 eV in their fs-TA spectrum at 2, 4 and 10 ps delay times.
研究领域:
材料科学
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光学
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物理化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Advanced Optical Materials
·
2024
·Vol. 12
·期 18
·2400141
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IF 8
Hongyu Yang,Jingzhou Li,Zhanpeng Wang,Yichi Zhong,Hanhuai Yang,Hongxing Dong,Long Zhang
Lead halide perovskite quantum dots (LHP QDs) emerge as versatile photonic sources in electroluminescence and laser devices. Their applications in optoelectronic devices are hindered by surface distortion and ligand stripping during the purification process. In addition, the device performance roll-off suffers from the ultrafast non-radiative Auger recombination (AR). To address these issues, herein, CsPbBr 3 QDs are prepared with sizes ranging from 6.5 to 9.2 nm and the universal surface repairing strategy is proved to efficiently increase the biexciton lifetime and quantum yield up to 1.4 and 3 times, respectively. The strategy provides a PbBr x rich surface and strong binding didodecyldimethylammonium bromide (DDAB) ligands to achieve near-unity photoluminescence efficiency, which significantly improves their stability against anti-solvents and aging in ambient conditions. A single-mode laser device is realized by self-assembling the QDs into superlattice as optical microcavity, with low threshold of 9.45 µJ cm −2 , quality factor of 2187 and ultrafast lifetime of 3.22 ps. The superlattice laser is demonstrated as an optical encoder with large coding bandwidth of 0.133 THz. This work proposes new insight into the non-radiative AR process in these single-component CsPbBr 3 QDs, and will pave the way for optoelectronic devices working in intense conditions.
研究领域:
材料科学
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光学工程
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纳米技术
✓ 已验证
产品关联
DOI
高影响因子
Journal of Physical Chemistry C
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2022
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IF 4.177
Kseniia A. Sergeeva,Kezhou Fan,Aleksandr A. Sergeev,Sile Hu,Haochen Liu,Christopher C. Chan,Stephen V. Kershaw,Kam Sing Wong,Andrey L. Rogach
We investigate the charge carrier dynamics in HgTe quantum dots emitting in the second near-infrared window (1000–2500 nm). To provide a link between fundamental physics and practical application, we made consistent studies of the charge carrier dynamics evolution for quantum dots in different states: colloidal solutions of quantum dots capped with a long-chain ligand; thin films made from them; and finally, exchanged to short-chain ligand films suitable for field effect transistor based devices. Ultrafast transient absorption spectroscopy reveals an ultralow Auger-related nonradiative relaxation threshold at 0.1 exciton per quantum dot, both in colloidal solutions and solid films, with a rate of 30 ns–1. The exchange from long- to short-chain ligands causing closer packing of the HgTe quantum dots leads to a strong increase of the Auger recombination rate of up to 100 ns–1. The competition between the Auger process and excitonic recombination significantly affects the performance of HgTe-based thin film photodetectors operating at room temperature, resulting in a 2 orders of magnitude drop in responsivity when the excitation flux was increased from 0.01 to 5 W·cm–2.
研究领域:
材料科学
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光子学
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纳米技术
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光电子学
✓ 已验证
产品关联
DOI
高影响因子
Journal of Physical Chemistry Letters
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2024
·
IF 4.8
Jialin Bai,Xing Liu,Xiaochun Chi,Aiwei Tang,Hanzhuang Zhang,Wenyu Ji
Distinguishing and understanding the nonradiative recombination of charges are crucial for optimizing quantum-dot light-emitting diodes (QLEDs). Auger recombination (AR), a well-known nonradiative process, is widely recognized to occur in QLEDs. However, it has not yet been directly observed in a real working QLED. Here, the AR effect is verified in the QLED at temperatures of <150 K. At low temperatures, the QLED exhibits a unique S-shaped external quantum efficiency (EQE) evolution as the driving current density increases. Experimental and modeling results indicate that this S-shaped EQE results from the asynchronous changes in the behavior of injection of electrons and holes into the quantum-dot emission layer. At low driving voltages, both electron and hole currents are limited by the Fowler–Nordheim (F–N) tunneling behavior. The relatively low barrier for electrons leads to overwhelming electron injection and seriously imbalanced charges in the quantum dots, triggering the AR process. As the voltage increases, the electron current within the emission layer is no longer governed by F–N tunneling but limited by space charges. Then, charge injection becomes balanced, and the EQE increases. These results offer valuable insights into the charge injection and recombination processes within QLEDs, as well as implications for device design.
研究领域:
光电子学
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纳米技术
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固体物理
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材料科学
✓ 已验证
DOI
高影响因子
Journal of Physical Chemistry Letters
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2020
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IF 6.71
Minghuan Cui,Chaochao Qin,Yuanzhi Jiang,Mingjian Yuan,Liuhong Xu,Didi Song,Yuhai Jiang,Yufang Liu
Quasi-two-dimensional (quasi-2D) Ruddlesden–Popper perovskites (RPPs) have been reported recently as laser media. The carrier dynamics of lasing in quasi-2D RPP films is still controversial. This work presents the amplified spontaneous emission (ASE) at room temperature based on the solution-processed quasi-2D (PEA)2Csn–1PbnBr3n+1 (⟨n⟩ = 3–5) thin films. Transient absorption spectroscopy was conducted to demonstrate the accumulation of excitons and population inversion for ASE caused by the energy transfer process along cascade quantum wells. The competition between the ASE and Auger recombination processes was observed via systematic and quantitative studies on the carrier dynamics. It is found that the contribution of Auger recombination is reduced by decreasing the temperature or adjusting the domain distribution of the quasi-2D RPP films, in order to achieve lower thresholds. This work re-emphasizes the importance of Auger recombination control for achieving low-threshold electrically or continuous-wave driven lasers and deepens the fundamental understanding of charge carrier dynamics of lasing in quasi-2D perovskite films.
研究领域:
材料科学
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光电子学
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光子学
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凝聚态物理
✓ 已验证
DOI
高影响因子
ACS Nano
·
2025
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IF 16
Xueyang Li,Jun Du,Yuxi Jia,Shu Hu,Gang Li,Boyu Zhang,Jingyi Zhu,Jingwei Guo,Kaifeng Wu
Liquid-state optical gain media are desired for high-power lasing applications due to their easier heat management than solid-state media, as well as for the emerging field of optofluidics. Colloidal quantum dots (QDs) are solution-processed materials that carry many attractive properties suitable for liquid lasing. To date, however, their lasing action is often achieved in close-packed films, as a high volume fraction of QDs is required for stimulated emission to outpace the ultrafast Auger decay of gain-active multiexciton states. Here we report liquid lasing from color-tunable (red, orange, and green) alloyed core/shell QDs with impeded Auger recombination. Lasing action is achieved by loading the QD-solutions into cavities under quasi-continuous-wave excitation. The light amplification behaviors of QD-solutions under ambient conditions are much more stable compared to those of both solid-state QD-films and dye solutions. Compatibility with aqueous solvents and ease of scalability are also demonstrated. An optimized optical power efficiency of 17.2% has been achieved. These results indicate that liquid lasing from colloidal QDs holds strong promise for real-world implementation.
研究领域:
光子学
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纳米技术
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材料科学
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光学
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量子电子学
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化学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ADVANCED MATERIALS
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2025
·
IF 26.8
Changjiang Shi,Haihua Zhang,Haolun Li,Hongbing Fu
Blue-green lasers are essential for next-generation optoelectronics. While GaN-InGaN lasers offer excellent performance, their complex fabrication and challenges in precise bandgap tuning remain significant limitations. Hybrid lead halide perovskites present a promising alternative, with tunable bandgaps and cost-effective solution processing. However, halide migration in these materials causes spectral instability and luminescence shifts under operational conditions. Here, a novel class of Rb-Cs alloyed quasi-2D perovskites is introduced that achieve both low amplified spontaneous emission (ASE) thresholds and exceptional spectral stability. By precisely tuning the Rb-Cs ratio, it realizes ASE across the blue-green spectrum (481–532 nm). Rb-Cs alloying critically modulates the quantum well distribution, optimizes the energy landscape, and suppresses Auger recombination, resulting in a record-low ASE threshold of 1.94 µJ·cm −2 —over 50% lower than that of mixed-halide perovskites. These materials exhibit remarkable spectral robustness, with ASE spectra remaining stable even after prolonged thermal annealing, thereby overcoming halide migration-induced degradation. Furthermore, micro-ring laser arrays fabricated from these Rb-Cs alloyed perovskites demonstrate superior lasing characteristics, including high-quality whispering-gallery-mode resonances and low lasing thresholds, underscoring their potential for advanced laser technologies.
研究领域:
光电子学
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材料科学
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光子学
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半导体激光器
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钙钛矿光电器件
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激光技术
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Nature Photonics
·
2022
·Vol. 16
·期 7
·485-490
·
IF 39.728
Chen Yifan,Yin Jun,Wei Qi,Wang Chenhao,Wang Xiaoting,Ren Hui,Yu Siu Fung,Bakr Osman M.,Mohammed Omar F.,Li Mingjie
Multiple exciton generation (MEG), the generation of multiple electron–hole pairs from a single high-energy photon, can enhance the photoconversion efficiency in several technologies including photovoltaics, photon detection and solar-fuel production 1 , 2 , 3 , 4 , 5 , 6 . However, low efficiency, high photon-energy threshold and fast Auger recombination impede its practical application 1 , 7 . Here we achieve enhanced MEG with an efficiency of up to 87% and photon-energy threshold of two times the bandgap in highly stable, weakly confined formamidinium tin–lead iodide perovskite nanocrystals (FAPb 1– x Sn x I 3 NCs; x ≤ 0.11). Importantly, an MEG-driven increment in the internal photocurrent quantum efficiency exceeding 100% with a low threshold is observed in such NC-sensitized photoconductors under ultraviolet-light illumination. The MEG enhancement mechanism is found to be mediated by the slower cooling and reduced trapping of hot carriers above the MEG threshold after the partial substitution of Pb by Sn. Our findings corroborate the potential importance of narrow-bandgap perovskite NCs for the development of optoelectronics that could benefit from MEG.
研究领域:
光伏技术
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光子检测
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太阳能燃料生产
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纳米技术
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材料科学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）