JOURNAL OF MATERIALS SCIENCE
·
2021
·Vol. 56
·期 12
·7508-7519
·
IF 4.22
Yang Xu,Zhao Xiaofan,Wang Rui,Yang Zining,Song Changqing,Yuan Maohui,Han Kai,Lan Sheng,Wang Hongyan,Xu Xiaojun
Exploiting the optical/magnetic bifunctional upconversion nanoparticles (UCNPs) with small size has become a trend in the high-resolution biological imaging. Here, we report the simultaneous size manipulation and color tuning in Er 3+ -sensitized perovskite KZnF 3 UCNPs via Mn 2+ doping. It was found that the introduction of Mn 2+ into the KZnF 3 host matrix facilitates the reduction of the nanoparticle size (from 1 μm to 50 nm). Under the excitation of both 980 and 808 nm continuous wave (CW) laser, these KZnF 3 :Er 3+ /Mn 2+ (1/x mol%) UCNPs can efficiently generate tunable upconversion luminescence (UCL) and achieve pure red UCL as the Mn 2+ concentration reaches 30 mol%. It is suggested that the energy transfer (ET) processes between Er 3+ and Mn 2+ ions contribute to the single-band red UC emission, which was well supported by investigating the dependence of UCL intensity on the pump power and the decay lifetimes of 4 S 3/2 and 4 F 9/2 states of Er 3+ ions. In addition, the KZnF 3 :Er 3+ /Mn 2+ UCNPs have been used as the T 1 -weighted magnetic resonance imaging (MRI) agents, which exhibits a high optical contrast with the background. These features make the KZnF 3 :Er 3+ /Mn 2+ UCNPs promising for excellent dual-modal agents in UCL imaging and MRI.
研究领域:
生物医学工程
·
材料科学
·
光学成像
✓ 已验证
产品关联
DOI
高影响因子
Nanomaterials
·
2023
·Vol. 13
·期 16
·2337
·
IF 5.3
Kaiwang Chen,Dengliang Zhang,Qing Du,Wei Hong,Yue Liang,Xingxing Duan,Shangwei Feng,Linfeng Lan,Lei Wang,Jiangshan Chen,Dongge Ma
All-inorganic perovskite nanocrystals (NCs) of CsPbX3(X = Cl, Br, I) are promising for displays due to wide color gamut, narrow emission bandwidth, and high photoluminescence quantum yield (PLQY). However, pure red perovskite NCs prepared by mixing halide ions often result in defects and spectral instabilities. We demonstrate a method to prepare stable pure red emission and high-PLQY-mixed-halide perovskite NCs through simultaneous halide-exchange and ligand-exchange. CsPbBr3NCs with surface organic ligands are first synthesized using the ligand-assisted reprecipitation (LARP) method, and then ZnI2is introduced for anion exchange to transform CsPbBr3to CsPbBrxI3−xNCs. ZnI2not only provides iodine ions but also acts as an inorganic ligand to passivate surface defects and prevent ion migration, suppressing non-radiative losses and halide segregation. The luminescence properties of CsPbBrxI3−xNCs depend on the ZnI2content. By regulating the ZnI2exchange process, red CsPbBrxI3−xNCs with organic/inorganic hybrid ligands achieve near-unity PLQY with a stable emission peak at 640 nm. The CsPbBrxI3−xNCs can be combined with green CsPbBr3NCs to construct white light-emitting diodes with high-color gamut. Our work presents a facile ion exchange strategy for preparing spectrally stable mixed-halide perovskite NCs with high PLQY, approaching the efficiency limit for display or lighting applications.Keywords:perovskite nanocrystals;ligand assisted reprecipitation;halide-exchange;ligand-exchange;pure red emission
研究领域:
材料科学
·
纳米技术
·
光电
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Advanced Optical Materials
·
2023
·Vol. 11
·期 16
·2300306
·
IF 9
Wei Shen,Zhan Su,Shuo Chen,Yujun Dai,Yue Qiu,Yanfeng Chen,Jiayu Jiang,Jianbin Zhang,Yun Wang,Hao Cui,Yanxing He,Kun Cao,Bo Cai,Lihui Liu,Shufen Chen
Development of high-performance and stable pure red perovskite light-emitting devices (LEDs) promotes commercialization of perovskite. Benefiting from the quantum confinement effect, pure red CsPbI 3 quantum dots (QDs) can avoid the color drift issue for mixed halide systems. Herein, a facile temperature-dependent hot-injection method combined with low temperature gradient centrifugation is employed to prepare 5.60 ± 0.05 nm pure red QDs. The QDs exhibit 642 nm photoluminescence (PL) with 37 nm full width at half maximum, and their Commission Internationale de l'Eclairage (CIE) coordinates located at (0.708, 0.292) match well with standard pure red for Rec. 2020. The PL half-lifetime for pure red QDs solution is 210 days under ambient conditions, and both the X and Y coordinates of CIE only fluctuate within (0.002, 0.002). Finally, a simple NH 4 I post-treatment to decrease ligand length further boosts the QDs conductivity, and the pure red LED exhibits 9.4% maximum external quantum efficiency. The electroluminescence spectra exhibits a sharp peak at 645 nm, and their CIE coordinates are located at (0.707, 0.290). Furthermore, the pure red LED exhibits both good working and color stability. Its half-lifetime is 25.1 min and color drifts are only (0.002, 0.002) after 30.0 min of continuous working at 60 cd m −2 with a constant current density of 3.5 mA cm −2 .
研究领域:
材料科学
·
光电技术
·
纳米科技
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）