Nanoscale Advances
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2020
·Vol. 2
·期 5
·1973-1979
·
IF 0
Xin Liu,Zhao Luo,Wenxu Yin,Aleksandr P. Litvin,Alexander V. Baranov,Jiaqi Zhang,Wenyan Liu,Xiaoyu Zhang,Weitao Zheng
Formation of a non-emissive wide bandgap CsPb2Br5 component often accompanies the synthesis of CsPbBr3 perovskites, introducing undesired energy states and impeding the charge transport. Here, we demonstrate that a small amount of a methanol additive can promote the CsBr release rate, facilitating CsPbBr3 formation and suppressing CsPb2Br5 formation. Some of the methanol ionizes into CH5O+ and CH3O−, which act as surface ligands and change the crystallization environment, inducing shape evolution from spherical nanocrystals to rectangular nanoplatelets (NPLs), leading to monodispersed and phase-pure 8 unit-cell-thick CsPbBr3 NPLs. Meanwhile, nonradiative recombination processes are inhibited as a result of NPL surface passivation. Bright CsPbBr3 NPLs with a photoluminescence quantum yield reaching 90% were employed as emitters for electroluminescent light-emitting devices.
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CHEMISTRY OF MATERIALS
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2020
·
IF 9.567
Zhoujie Chen,Yangguang Hu,Jin Wang,Qing Shen,Yaohong Zhang,Chao Ding,Yu Bai,Guocan Jiang,Zhengquan Li,Nikolai Gaponik
Converting CO2 into chemical fuels with a photocatalyst and sunlight is an appealing approach to address climate deterioration and energy crisis. Metal complexes are superb candidates for CO2 reduction due to their tunable catalytic sites with high activity. The coupling of metal complexes with organic photosensitizers is regarded as a common strategy for establishing photocatalytic systems for visible-light-driven CO2 reduction. While most of the organic photosensitizers generally contain precious metals and are available through onerous synthetic routes, their large-scale application in the photocatalysis is limited. Halide perovskite nanocrystals (NCs) have been considered as one of the most promising light-harvesting materials to replace the organic photosensitizers due to their tunable light absorption range, low cost, abundant surface sites, and high molar extinction coefficient. Herein, we demonstrate a facile strategy to immobilize [Ni(terpy)2]2+ (Ni(tpy)) on inorganic ligand-capped CsPbBr3 NCs and to apply this hybrid as a catalyst for visible-light-driven CO2 reduction. In this hybrid photocatalytic system, the Ni(tpy) can provide specific catalytic sites and serve as electron sinks to suppress electron–hole recombination in the CsPbBr3 NCs. The CsPbBr3-Ni(tpy) catalytic system achieves a high yield (1724 μmol/g) in the reduction of CO2 to CO/CH4, which is approximately 26-fold higher than that achieved with the pristine CsPbBr3 NCs. This work has developed a method for enhancing the performance of photocatalytic CO2 reduction by immobilizing metal complexes on perovskite NCs. The methodology we present here provides a new platform for utilizing halide perovskite NCs for photocatalytic applications.
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Journal of Materials Chemistry A
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2020
·Vol. 8
·期 24
·11966-11975
·
IF 11.301
Guixiang Xie,Xiya Yang,Jialong Duan,Yanyan Duan,Qunwei Tang
Triboelectric nanogenerators (TENGs) have attracted growing attention because they are advanced energy conversion devices to efficiently harvest low-frequency mechanical energy from nature. How to increase the permittivity of electrode materials as well as the surface charge density is technically important to improve the output performances of a robust TENG. In this study, an all-inorganic cesium lead bromide (CsPbBr3) perovskite film with semiconducting characteristics is combined with metallic nano-platinum to build bulk Pt/CsPbBr3 Schottky junctions, which are used as triboelectric electrode materials in vertical contact-separation perovskite TENGs. The systematic characterization demonstrates that the electron binding energy and dielectric properties of bulk Pt/CsPbBr3 Schottky junction tailored perovskite films are maximized by optimizing the Pt dosage. An open-circuit voltage of 273 V, a short-circuit current density of 30.3 μA cm−2 and an instantaneous maximum power density of 1295.5 mW m−2 are achieved by the champion Pt/CsPbBr3 TENG at a Pt dosage of 0.5%. A maximum energy storage of 3.96 mJ is stored in a 1 μF capacitor within a 300 s charging period. This work provides new insights into Schottky junction TENGs for enriching the fundamental principles of both halide perovskites and TENGs.
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ACS Applied Energy Materials
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2021
·
IF 6.024
Yuyao Zhang,Wen Chen,Min Zhou,Guobin Miao,Yueli Liu
Photoreduction of CO2 into useable hydrocarbon fuels has been widely used in the energy conversion field. However, the high carrier recombination rate and the low conversion efficiency of as-prepared catalysts greatly restrict their photocatalytic application. Herein, we synthesize Ti3C2/CsPbBr3 quantum dot (Ti3C2/CsPbBr3 QD) composites by the method of self-assembly, which are used in the photoreduction of CO2. As a result, Ti3C2/CsPbBr3 QD composites exhibit excellent photocatalytic activity and stability for the photocatalytic CO2 reduction. Especially, the generation rate of CO (17.98 μmol h–1 g–1) for Ti3C2/CsPbBr3 QD composites is 9.37 times higher than that of CsPbBr3 QDs (1.92 μmol h–1 g–1), and 97.35% of the activity is still retained after three consecutive cycles. The improved photocatalytic performance is mainly attributed to the construction of the type II-2 heterojunction as the built internal electric field (IEF) in the p–n junction could accelerate the separation for both photoinduced holes and electrons. Therefore, this work provides an insight into the construction of heterojunction photocatalysts with halide perovskite QD materials for photocatalytic applications.
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Small
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2021
·Vol. 17
·期 43
·2101359
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IF 13.281
Hao Lin,Qi Wei,Kar Wei Ng,Jia-Yi Dong,Jie-Lei Li,Wei-Wei Liu,Shan-Shan Yan,Shi Chen,Gui-Chuan Xing,Xiao-Sheng Tang,Zi-Kang Tang,Shuang-Peng Wang
Colloidal all-inorganic perovskites nanocrystals (NCs) have emerged as a promising material for display and lighting due to their excellent optical properties. However, blue emissive NCs usually suffer from low photoluminescence quantum yields (PLQYs) and poor stability, rendering them the bottleneck for full-color all-perovskite optoelectronic applications. Herein, a facile approach is reported to enhance the emission efficiency and stability of blue emissive perovskite nano-structures via surface passivation with potassium bromide. By adding potassium oleate and excess PbBr 2 to the perovskite precursor solutions, potassium bromide-passivated (KBr-passivated) blue-emitting (≈450 nm) CsPbBr 3 nanoplatelets (NPLs) is successfully synthesized with a respectably high PLQY of 87%. In sharp contrast to most reported perovskite NPLs, no shifting in emission wavelength is observed in these passivated NPLs even after prolonged exposures to intense irradiations and elevated temperature, clearly revealing their excellent photo- and thermal-stabilities. The enhancements are attributed to the formation of K-Br bonding on the surface which suppresses ion migration and formation of Br-vacancies, thus improving both the PL emission and stability of CsPbBr 3 NPLs. Furthermore, all-perovskite white light-emitting diodes (WLEDs) are successfully constructed, suggesting that the proposed KBr-passivated strategy can promote the development of the perovskite family for a wider range of optoelectronic applications.
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高影响因子
Journal of Materials Chemistry C
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2021
·Vol. 9
·期 37
·12581-12589
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IF 7.393
Yixuan Liu,Lulu Zhang,Xuemi Long,PanPan Jiang,Chong Geng,Shu Xu
Perovskite nanocrystals (PNCs) are promising luminescent materials but suffer severe stability issues due to their ionic surface nature. SiO2 encapsulation is widely adopted for stabilizing PNCs in LED lighting and display applications. However, PNCs commonly lose ligands during the SiO2 encapsulation process, leading to fluorescence quenching and agglomeration. Here, CsPbBr3 PNCs with lead-carboxylate capping motif, which shows extraordinary ethanol and moisture resistance, were developed to facilitate fast and controlled growth of PNC–SiO2 nanocrystals using ethanol to accelerate the hydrolysis of tetramethoxysilane. Surface analysis revealed the preservation of the original carboxylate ligands after the reaction. Carboxylate and SiO2 form uniform dual-encapsulation that provides PNCs with superior air and water resistance, excellent photoluminescence maintenance, and high miscibility in silicone resin. Finally, saturated green LED and white-light LED with a wide color gamut were fabricated through on-chip packaging of the PNC–SiO2 on the blue LED chip. LEDs retained >85% of their light intensity after continuous illumination for 1000 h, demonstrating the high potential of the encapsulation method and the materials in light-emitting applications.
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JOURNAL OF ALLOYS AND COMPOUNDS
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2019
·
IF 4.175
Zhenghai Ou,Yongsheng Yi,Ziting Hu,Jiajie Zhu,Wenzhen Wang,Hua Meng,Xiaozheng Zhang,Shengqi Jing,Shanhu Xu,Feng Hong,Jian Huang,Juan Qin,Fei Xu,Run Xu,Yanyan Zhu,Linjun Wang
The optoelectrical properties of semiconductor devices are strongly related to the film morphology. Here, we found that, for CsPbBr 3 thin films prepared by spray coating, the addition of polymethyl methacrylate (PMMA) can completely eliminate voids and greatly reduce the surface roughness of the as-deposited films. As a consequence, the optoelectronic properties of the photodetectors fabricated as a simple vertical structure of Au/CsPbBr 3 (PMMA)/ITO can be improved. With the addition of PMMA, the dark current of the photodetector is reduced at least four times, and the photodetector exhibits a favourable optical response. With the illumination ranging from 400 to 510 nm, the calculated responsivity varies from 3.70 to 5.20 A/W. A good response speed with a rise time of 6.6 ms and a decay time of 11.3 ms can be achieved. Moreover, unlike the inorganic-organic hybrid perovskite detectors, this inorganic perovskite photodetector without encapsulation shows a favourable stability with a decay of 20% after 40 days under ambient air at 20% humidity.
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JOURNAL OF MOLECULAR LIQUIDS
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2019
·
IF 4.561
Xingyu Liu,Jinwei Gao,Guofu Zhou,Wanqiang Liu,Qianming Wang,Yuhui Zheng
The colloidal synthesis of nanoscale perovskites has generated intensive interests very recently and most of the preparation processes are performed in organic phases due to requirement of maintaining the stability. Since the exploration of CsPbX 3 assembly in aqueous medium is still rarely reported in recent years, we use the simple organic building block (2-methylimidazole, MEIM) for the first time to collect the mixture of two metal precursors (CsBr and PbBr 2 ) and CsPbBr 3 /MEIM nanocrystals have been perfectly formed with the aid of the effective organic layer in terms of coordination interactions with metal ions . Such lead halide perovskite material with diameters of 8–10 nm possesses stable and green-emitting feature in pure water. Extensive experimental conditions including reaction time, reagent ratio, addition sequence, pH/temperature dependence and solvent effect have been investigated in details. This study finds a new way to the controllable synthesis of perovskite nanoparticles in eco-friendly solvents and represents a next generation target material for utilization in opto-electronic fields.
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Small
·
2019
·Vol. 15
·期 34
·1901994
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IF 10.856
Meilin Xie,Huan Liu,Fengjun Chun,Wen Deng,Chao Luo,Zhihao Zhu,Min Yang,Yongmei Li,Wen Li,Wei Yan,Weiqing Yang
All-inorganic cesium lead halide perovskite nanocrystals (NCs) have emerged as attractive optoelectronic materials due to the excellent optical and electronic properties. However, their environmental stability, especially in the presence of water, is still a significant challenge for their further commercialization. Here, ultrahigh intrinsically water-stable all-inorganic quasi-2D CsPbBr 3 nanosheets (NSs) via aqueous phase exfoliation method are reported. Compared to conventional perovskite NCs, these unique quasi-2D CsPbBr 3 nanosheets present an outstanding long-term water stability with 87% photoluminescence (PL) intensity remaining after 168 h under water conditions. Moreover, the photoluminescence quantum yields (PLQY) of quasi-2D CsPbBr 3 NSs is up to 82.3%, and these quasi-2D CsPbBr 3 NSs also present good photostability of keeping 85% PL intensity after 2 h under 365 nm UV light. Evidently, such quasi-2D perovskite NSs will open up a new way to investigate the intrinsic stability of all-inorganic perovskites and further promote the commercial development of perovskite-based optoelectronic and photovoltaic devices.
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ACS Applied Materials & Interfaces
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2018
·
IF 8.097
Bo Wang,Congyang Zhang,Shouqiang Huang,Zhichun Li,Long Kong,Ling Jin,Junhui Wang,Kaifeng Wu,Liang Li
Lead halide perovskite nanocrystals (NCs) as promising optoelectronic materials are intensively researched. However, instability is one of the biggest challenges needed to overcome before fulfill their practical applications. To improve their stability, we present a postsynthetic controlled phase transformation of CsPbBr3 toward CsPbBr3/Rb4PbBr6 core/shell structure triggered by rubidium oleate treatment. The resulting core/shell NCs show exceptional photostability both in solution and on-chip. The solution of CsPbBr3/Rb4PbBr6 NCs can remain over 90% of the initial emission photoluminescence quantum yields after 42 h of intense light-emitting diodes illumination (450 nm, 175 mW/cm2), which is even better than the conventional CdSe/CdS quantum dots whose emission drop to 50% after 18 h under the same condition. We believe that the exceptional photostability should be resulted from the protection of the robust Rb4PbBr6 shell on CsPbBr3 NCs.
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高影响因子
ADVANCED FUNCTIONAL MATERIALS
·
2018
·Vol. 28
·期 22
·1801193
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IF 13.325
Yuequn Shang,Gang Li,Weimin Liu,Zhijun Ning
Metal halide perovskites are rising as a competitive material for next-generation light-emitting diodes (LEDs). However, the development of perovskite LEDs is impeded by their fast carriers diffusion and poor stability in bias condition. Herein, quasi-2D CsPbBr 3 quantum wells homogeneously surrounded by inorganic crystalline Cs 4 PbBr 6 of large bandgap are grown. The centralization of carriers in nanoregion facilitates radiative recombination and brings much enhanced luminescence quantum yield. The external quantum efficiency and luminescence intensity of the LEDs based on this nanocomposite are one order of magnitude higher than the conventional low-dimensional perovskite. Meanwhile, the use of inorganic nanocomposite materials brings much improved device operation lifetime under constant electrical field.
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Photonics Research
·
2019
·Vol. 7
·期 8
·837-846
·
IF 5.522
Ying Zhang,Haiou Zhu,Taiwu Huang,Zongpeng Song,Shuangchen Ruan
Perovskite quantum dots (QDs) are of great interest due to their outstanding optoelectronic properties and tremendous application potential. Improving photoluminescence (PL) spectra in all-inorganic perovskite QDs is of great importance for performance enhancement. In this work, the PL quantum yield of the CsPbBr3 perovskite QDs is enhanced from 70% to 95% with increasing radiation pressure. Such enhancement is attributed to the increased binding energy of self-trapped excitons (STEs) upon radiation pressure, which is consistent with its blue-shifted PL and other characterization results. Furthermore, we study ultrafast absorption spectroscopy and find that the dynamics of relaxation from free excitons to STEs in radiation pressure CsPbBr3 QDs is ascribed to stronger electron–phonon coupling in the contracted octahedral structure. It is further demonstrated that radiation pressure can boost the PL efficiency and explore effectively the relationship between the structure and optical properties.
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