Nanoscale
·
2019
·Vol. 11
·期 17
·8475-8484
·
IF 6.97
Weishuo Xing,Xinsu Zhang,Chong Geng,Yangyang Xie,Yuchen Deng,Peng Li,Huanrong Li,Shu Xu,Wengang Bi
Multi-quantum-well quantum dots (MQW-QDs) with multiple emission peaks have been evaluated as promising single source emitters in the fabrication of high performance white LEDs. However, they still face a critical issue of color shift in practical applications, which is mainly attributed to the redistribution of the excitons between the adjacent wells under different excitation powers. Herein, we report sandwich structural MQW-QDs that provide highly stable dual emission. The study on the optical properties and exciton dynamics reveals that the thickness of the inner-barrier plays a crucial role in balancing the exciton distribution through regulating near-field energy transfer and light absorption between the adjacent wells. Meanwhile, the wells and the outer-barrier mainly influence the luminescence efficiency and the wavelength control of the dual emission peaks. The MQW-QDs with a minimum color shift versus excitation power are finally achieved by optimizing the structure parameters. A white LED based on the developed MQW-QDs exhibits a stable white light spectrum with high tolerance to the change of the excitation power, ensuring the advancement of the performance of MQW-QDs in lighting and display applications.
研究领域:
材料科学
·
光学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ACS Applied Materials & Interfaces
·
2020
·
IF 8.758
Guojun Zhou,Yan Xu,Zhiguo Xia
Quasi-two-dimensional perovskite multiple quantum wells (MQWs) have garnered attention on account of their good stability in comparison with three-dimensional analogs for light-emitting diode (LED) applications, but they exhibit a declined photoluminescence quantum yield (PLQY) for the backlight display technology. Herein, we report an in situ process by introducing layered materials as substrates to prepare the perovskite MQW powder and utilize hexagonal boron nitride (h-BN) as an example to investigate the luminescence characteristics and mechanism of h-BN@(PMA)2MAn–1PbnBr3n+1 (h-BN@PMPB). Remarkably, the deposition strategy enables an enhanced PLQY from 2.6 to 32.4%. A synergetic effect of low reabsorption, low defect concentration, and high absorptivity leads to high-efficiency cascade energy transfer and also an improvement in stability. Moreover, the h-BN@PMPB composite powder shows a narrow-band green emission band peaking at 532 nm with a full width at half maximum of 32 nm, and the white LED backlight reaches a wide color gamut 106.1% of the National Television Standards Committee (NTSC). This work reveals a general synthesis method for preparing perovskite powder and paves the way to achieve new solid-state luminescent materials with controlled size and morphology for backlight display applications.
研究领域:
材料科学
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光学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
INORGANIC CHEMISTRY
·
2024
·
IF 4.3
Kewei Gu,Tingting Wang,Guowei Yang,Nan Yu,Chengchao Du,Junli Wang
Two-dimensional inorganic–organic hybrid layered semiconductors are actively studied because of their naturally formed multiquantum well (MQW) structures and associated optical, photoelectric, and quantum optics characteristics. Silver benzeneselenolate (AgSePh, Ph = C6H5) is a new member of such hybrid layered materials, but has not fully been exploited. Herein, we present a quasi-solution method to prepare high quality free-standing AgSePh flake-like microcrystals by reacting diphenyl diselenide (Ph2Se2) with silver nanoparticles. The resultant AgSePh microflakes exhibit room-temperature (RT) resolvable MQW-induced quasi-particle quantization and interesting optical properties, such as three distinct excitonic resonance absorptions X1 (2.67 eV), X2 (2.71 eV), and X3 (2.83 eV) in the visible region, strong narrow-line width blue photoluminescence at ∼2.64 eV (470 nm) from the radiative recombination of the X1 exciton state, and a large exciton binding energy (∼0.35 eV). Furthermore, AgSePh microcrystals show high stability under water, oxygen, and heat environments, while above 220 °C, they will thermally decompose to silver and Ph2Se2 as evidenced by a combination of thermogravimetry and differential scanning calorimetry and pyrolysis-coupled gas chromatography–mass spectrometry studies. Finally, a comparison is extended between AgSePh and other metal benzeneselenolates, benzenethiolates, and alkanethiolates to clarify differences in their solubility, decomposition/melting temperature, and pyrolytic products.
研究领域:
材料科学
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光学
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产品关联
DOI
PubMed
高影响因子
Micromachines
·
2023
·Vol. 14
·期 3
·566
·
IF 3.4
Wenjun Huang,Xiangyu Miao,Zhaojun Liu
The optoelectronic effects of sidewall passivation on micro-light-emitting diodes (Micro-LEDs) were investigated using sol-gel chemical synthesis. Blue InGaN/GaN multi-quantum well (MQW) Micro-LEDs, ranging in size from 20 × 20 μm to 100 × 100 μm and with high EQE, were fabricated and distinguished by the passivation method used, including no passivation, sol-gel SiO2, and plasma-enhanced chemical vapor deposition (PECVD) SiO2. Impressively, the sol-gel method is advantageous in improving the optoelectronic performance of Micro-LEDs. The fabricated 20 × 20 μm Micro-LEDs showed an EQE of 27.7% with sol-gel passivation, which was a 14% improvement compared to devices without sidewall passivation. Sol-gel sidewall passivation allows Micro-LEDs to effectively achieve sharper edge emission, superior surface luminous uniformity, and intensity, providing the possibility for the fabrication of low-cost and high-efficiency Micro-LEDs.Keywords:sidewall passivation;sol-gel SiO2;GaN-based micro-light-emitting diodes (Micro-LEDs)
研究领域:
材料科学
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光电子学
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半导体器件
✓ 已验证
DOI
PubMed
高影响因子
ACS Applied Materials & Interfaces
·
2022
·
IF 10.383
Tong Wei,Kai Lian,Jiaqi Tao,Hu Zhang,Da Xu,Jiachen Han,Chao Fan,Zihui Zhang,Wengang Bi,Chun Sun
Luminescent solar concentrators (LSCs) can be used as large-area sunlight collectors, which show great potential in the application of building-integrated photovoltaic areas. Achieving highly efficient LSCs requires the suppression of reabsorption losses while maintaining a high photoluminescence quantum yield (PLQY) and broad absorption. Perovskites as the superstar fluorophores have recently emerged as candidates for large-area LSCs. However, highly emissive perovskites with a large Stokes shift and broad absorption have not been obtained up to now. Here, we devised a facile synthetic route to obtain Mn-doped multiple quantum well (MQW) Br-based perovskites. The Br-based perovskite host ensures broad absorption. Efficient energy transfer from the exciton to the Mn dopant produces a large Stokes shift and high PLQY simultaneously. By further coating the perovskites with Al2O3, the stability and PLQY are greatly elevated. A large area of liquid LSC (40 cm × 40 cm × 0.5 cm) is fabricated, which possesses an internal quantum efficiency (ηint) of 47% and an optical conversion efficiency (ηopt) reaching 11 ± 1%, which shows the highest value for large-area LSCs.
研究领域:
材料科学
·
可再生能源
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太阳能
·
光子学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）