JOURNAL OF PHYSICS D-APPLIED PHYSICS
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2024
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IF 3.1
Jinchan He,Cong Xie,Bo Wang,Ping Yang
Mn-doped perovskites have been extensively studied in optics, magnetism, and electronics due to their orange emission. However, successful Mn doping required a high Mn/Pb feed ratio. In this paper, Mn-doped CsPbBr3 nanoplatelets (NPLs) with bright orange emission were prepared by a two-step slow thermal injection synthesis. The slow injection of precursors effectively slow-down the crystal growth kinetic process and controls the growth of undoped CsPbBr3 NPLs. This process also significantly improves Mn doping efficiency. Mn doping induced the generation of numerous precursor clusters during the growth of CsPbBr3 NPLs, and the formation of these clusters was crucial for enhancing the doping efficiency. The maximum amount of Mn precursor in CsPb0.83Mn0.17Br3 was 50% of Pb precursors. The photoluminescence quantum yields (PLQYs) of CsPb0.94Mn0.06Br3 NPLs reached up to 80.6%, which was 3.1 times of that of CsPbBr3 NPLs. The PL properties of Mn-doped CsPbBr3 NPLs were significantly enhanced compared with pure CsPbBr3 NPLs. The growth process and luminescence mechanism of Mn-doped CsPbBr3 NPLs were discussed. High PLQYs and efficient Mn doping supplied an ideal approach for the preparation of various CsPbX3 (X = Cl, Br, and I) NCs for commercial applications.
研究领域:
材料科学
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光学
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纳米技术
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
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2021
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IF 13.273
Shuai Zhang,Yifei Zhao,Jiadong Zhou,Hong Ming,Chun-Hai Wang,Xiping Jing,Shi Ye,Qinyuan Zhang
Manganese (II) compounds are promising luminescent candidates for white light-emitting diodes (WLEDs) applications. However, the forbidden d - d transition of Mn 2+ ion makes the absorption of blue light and emission relatively weak without a sensitizer. The strategy of isolating MnX n (X is the ligand) with some ionic liquids is used to design two new hybrid compounds in this study, focusing on the orbital hybridization to relax the parity selection rule of the d - d transition. A large hindrance of the organic cations in the two new Manganese (II) hybrids enables a large Mn-Mn distance (up to ~ 10 Å) to form zero-dimensional (0D) structures, and the Mn sites in both compounds have a low site symmetry ( C 2 or C 1 ). The 0D structure of MnX n polyhedral is beneficial to isolatedly investigate the orbital hybridization of the ligand and Mn 2+ ion. A higher orbital hybridization extent for Mn-Br bond is evidenced by Density Functional Theory (DFT) simulation. This conclusion leads to the strong and stable green light emissions under preferable blue light (460 nm) excitations, giving photoluminescence quantum yields (PLQYs) as high as 76%. The WLEDs fabricated with these compounds have presented high luminous efficiency up to ~130 lm/W and survived multiple stability tests. The research favors the discovery of ideal Mn compounds for displays and lighting applications.
研究领域:
材料科学
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光电
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光子学
✓ 已验证
DOI
高影响因子
Journal of Materials Chemistry C
·
2019
·Vol. 7
·期 35
·10783-10788
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IF 6.641
Wenqiang Liu,Guodong Yuan,Yang Zhang,Qi Wang,Shuai Zhao,Zhiqiang Liu,Tongbo Wei,Junxi Wang,Jinmin Li
All-inorganic perovskite nanocrystals (NCs) have recently emerged as a new class of materials due to their tunable bandgaps and high photoluminescence quantum yields (PLQYs). The origin of the enhancement of PLQY of CsPbBr3 NCs is usually attributed to the efficient passivation of the surface halide vacancies creating nonradiative recombination sites. In this work, Br-rich CsPbBr3 NCs with a PLQY of 97% were prepared using an extreme excess of Br source with Br/Pb of 4.5/1 from the ligand itself at room temperature. Br-rich CsPbBr3 NC based light-emitting devices were fabricated under ambient conditions, exhibiting the maximum current efficiency of 1 cd A−1 at the luminance of 750 cd m−2. First principles calculations indicate that Br interstitials can form the strong localized states. Such localized effect can prevent photogenerated carriers from defusing to non-radiative recombination centers, thus being responsible for the high emission efficiency.
研究领域:
材料科学
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纳米技术
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光电
✓ 已验证
产品关联
DOI
高影响因子
ACS Applied Nano Materials
·
2025
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IF 5.5
Chasina Wang,Fengqing Jiao,Liyuan Zhang,Yishi Wu,Chuanlang Zhan
One of the key issues of lead-free halide double perovskite nanocrystals (DPNCs) is their low photoluminescence quantum yields (PLQYs), and the PLQYs of nondoped pristine DPNCs are currently below 2%, though they can be enhanced via strategies such as ion doping or surface passivation. Herein, we report an organic–inorganic hybrid approach to significantly increase the PLQYs of nondoped pristine DPNCs. With Cs2NaBiCl6 NCs as the model, we selected methylammonium (MA+) and formamidine (FA+) as organic A-site ions and for the first time successfully synthesized the organic–inorganic hybrid in-direct bandgap DPNCs, e.g., MA2NaBiCl6 and FA2NaBiCl6. The PLQYs of the prepared Cs2NaBiCl6, MA2NaBiCl6, and FA2NaBiCl6 are 1.9%, 6.2%, and 15.4%, respectively. The enhancement of PLQYs can be due to the lattice distortion on using the unsymmetric rod-like MA+ and V-like FA+ to replace the symmetric Cs+, which yields faster charge transfer, enhanced excitation, and reduced nonradiative recombination, which are combined to make the self-trapped excited state brighter with significantly enhanced PLQYs. Overall, our results clearly demonstrate that the organic–inorganic hybrid strategy is an effective way to tune the lattice distortion and significantly enhance the emission of nondoped DPNCs, which will open doors for designing functional optoelectronic materials.
研究领域:
材料科学
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纳米技术
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光电子学
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无机化学
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无机-有机杂化材料
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半导体纳米晶体
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光物理
✓ 已验证
产品关联
DOI
高影响因子
Nanoscale
·
2021
·Vol. 13
·期 21
·9659-9667
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IF 7.79
Jingkun Xu,Shiming Guo,Junfeng Qu,Shuhong Xu,Chunlei Wang,Dayan Ban,Yiping Cui
All-inorganic cesium lead halide perovskite nanocrystals (NCs) are quite promising materials for emission-based applications. However, the intrinsic toxicity of lead, as well as the weak stability, remains to be resolved. Exploring more and more types of lead-free NCs with high photoluminescence quantum yields (PLQYs) and high stability is a fundamental task. This work gave the first example of copper doped cesium halide (Cu:CsX, X = Br, Cl/Br, Br/I) NCs with good stability and high PLQYs (∼31.2%), which could act as a new member of the lead-free NC family. A simple single-step ultrasonic method was applied for the synthesis of environmentally friendly Cu:CsX NCs. By varying the halide composition, the emission wavelength of Cu:CsX can be shifted within 450–505 nm. The as-prepared NCs show highly uniform size and excellent stability. Finally, UV pumped light-emitting diodes are demonstrated by using Cu:CsX NCs as a color conversion layer.
研究领域:
材料科学
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纳米技术
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光电技术
✓ 已验证
DOI
高影响因子
Materials Horizons
·
2023
·Vol. 11
·期 5
·1294-1304
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IF 13.3
Xu Li,Bibo Lou,Xu Chen,Meng Wang,Huifang Jiang,Shuailing Lin,Zhuangzhuang Ma,Mochen Jia,Yanbing Han,Yongtao Tian,Di Wu,Wen Xu,Xinjian Li,Chonggeng Ma,Zhifeng Shi
Lead halide perovskite nanocrystals (NCs) are highly promising for backlighting display applications due to their high photoluminescence quantum yields (PLQYs) and wide color gamut values. However, the practical applications of blue emitters are limited due to the toxicity of lead, unstable structure, and unsatisfactory PLQY. Herein, we report the successful synthesis of divalent europium-based perovskite CsEuBr3 NCs using a modified hot injection method. By optimizing the reaction conditions, the CsEuBr3 NCs display a deep-blue emission at 443 nm with a full width at half maximum (FWHM) of 28.5 nm, a color purity of 99.61%, and a record high PLQY of 93.51% for deep-blue narrow-band emissive lead-free perovskite NCs as far as we know. The emission mechanism of CsEuBr3 NCs is proved through first-principles calculations and spectral analysis. Notably, the CsEuBr3 NCs exhibit remarkable stability when exposed to high temperature, UV irradiation, and long-term sealed storage. The incorporation of CsEuBr3 NCs into polydimethylsiloxane (PDMS) serving as a converter is utilized for white light-emitting devices (WLEDs). WLEDs for backlight displays achieves a wide color gamut of 127.1% of the National Television System Committee standard (NTSC), 94.9% coverage of the ITU-R Recommendation BT.2020 (Rec.2020), and their half-lifetime is up to 1677 h, providing a promising pathway for highly efficient, environment-friendly and practical liquid crystal display backlights.
研究领域:
材料科学
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光电技术
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显示技术
✓ 已验证
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
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2023
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IF 6.2
Chenxu Wang,Lihe Yan,Jinhai Si,Tianyu Huo,Xun Hou
All-inorganic lead halide perovskites nanocrystals (NCs) have been demonstrated to be promising candidates for optoelectronic devices, but preparing perovskite NCs with high photoluminescence quantum yields (PLQYs) and excellent stability has been a challenge. In this work, CsPbBr 3 /Cs 4 PbBr 6 core/shell NCs with a PLQYs of 87.23% and long-term stability in ambient environments was prepared by room temperature inverse microemulsion method. The excellent stability of the sample was attributed to the protection of Cs 4 PbBr 6 , and higher PLQYs could be owing to the passivation effect of the core/shell structure. To illustrate the distribution of photogenerated carrier in the core/shell structure, a confined excitons model was proposed based on time-resolved PL and temperature dependent PL measurements. Femtosecond time-resolved transient absorption spectra measurements were performed upon different excitation wavelength to unveil the photogenerated carrier dynamics in core/shell NCs. Upon 300 nm excitation, a carrier transfer process with the time of 3.18 ps from shell to core layer was observed. Furthermore, both two- and three-photon absorption PL was discovered in core/shell NCs, further verifying the carrier transfer process.
研究领域:
材料科学
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光电
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纳米技术
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物理化学
✓ 已验证
DOI
高影响因子
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