Nanoscale
·
2019
·Vol. 11
·期 36
·16907-16918
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IF 6.97
Hong Lin,Jian Mao,Minchao Qin,Zhilong Song,Wanjian Yin,Xinhui Lu,Wallace C. H. Choy
While red is one of the primary colors for display applications, the investigation of visible red emitting perovskites, particularly 2D perovskites, is relatively limited. In this work, we demonstrate a single-phase Ruddlesden–Popper quasi-2D (C3H7NH3)2CsPb2I7 perovskite for red color LEDs. Through increasing the annealing temperature of (C3H7NH3)2CsPb2I7 perovskite thin films, we have successfully achieved tunable emission wavelengths from 654 to 691 nm. Equally important, for all the quasi-2D perovskite LEDs, once the annealing temperature is fixed, the emission spectrum is independent of bias voltages, which is very important for their use in lighting and displays. With the analysis of the crystallinity, morphology, and thermodynamic stability of the quasi-2D perovskite, we find that the obtained (C3H7NH3)2CsPb2I7 perovskite is a single-phase quasi-2D perovskite with only n = 2 phase. Besides, we found that the red shifting of emission wavelength is caused by the increase of perovskite crystal size while increasing the annealing temperature. Our results also show that the temperature-induced color tunability can be applied to a series of quasi-2D perovskites with different alkylammonium cations. Importantly, we find that short alkylammonium spacers offer better electrical properties for efficient current transport and high performance in LED applications. This work contributes to controlling the optoelectronic properties of quasi-2D perovskites via controlling their crystal growth as well as paves the way to realize practical lighting and display applications of perovskite LEDs.
研究领域:
材料科学
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光电功能材料
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半导体器件
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纳米结构材料
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固态照明
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DOI
高影响因子
Journal of Materials Chemistry A
·
2018
·Vol. 6
·期 46
·23773-23779
·
IF 9.931
Zhiyuan Wang,Ruqin Zhang,Min Zhao,Zhongqiang Wang,Bingwei Wei,Xuefeng Zhang,Shuai Feng,Hailiang Cao,Peizhi Liu,Yuying Hao,Hua Wang,Bingshe Xu,Stephen J. Pennycook,Junjie Guo
High-performance organic photovoltaics (OPVs) are of great scientific and technological importance due to their potential large-scale industrial applications. Introducing semiconductor quantum dots has been proven to be an effective way to improve the power conversion efficiency (PCE) of OPVs. In this paper, we report a novel approach to fabricate atomically thin antimonene quantum sheets (AMQSs) possessing a uniform size (≈2.2 nm) via imidazolium ionic liquid-assisted exfoliation. In this method, the yield of AMQSs (1.1 mg mL−1) has been increased by nearly two orders of magnitude compared with that of previously reported methods. Furthermore, upon adding AMQSs into the light absorber in OPVs, the optimal device with 1.0 mg mL−1 AMQSs shows the highest PCE of 9.75%, resulting in over 25% enhancement in PCE compared to that of the reference device. It also leads to a noticeable enhancement in the short-circuit current density (Jsc) of 16.7% and the fill factor (FF) of 8.4%. The increased PCE is mainly due to the two-dimensional electronic structure of AMQSs that can enhance the light absorption, assist exciton dissociation and reduce charge recombination of OPVs. This work provides a new avenue toward mass production of two-dimensional quantum sheets and points to a new strategy for highly efficient OPVs.
研究领域:
材料科学
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纳米科技
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光伏技术
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半导体物理
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能源材料
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DOI
高影响因子
NEW JOURNAL OF CHEMISTRY
·
2020
·Vol. 44
·期 33
·14103-14107
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IF 3.288
Chanchan Xu,Le Lv,Dawei Luo,Wei Liu
By using pyrazine derivatives, three different types of copper(I) iodide based inorganic–organic hybrid structures, 1D-CuI(2-mo-pz) (1, 2-mo-pz = 2-methoxy-pyrazine), 2D-CuI(2,3-dm-pz)0.5 (2, 2,3-dm-pz = 2,3-dimethyl-pyrazine), and 2D-Cu2I2(2,5-dm-pz)2 (3, 2,5-dm-pz = 2,5-dimethyl-pyrazine), have been obtained by using a slow-diffusion method. Single crystal and powder X-ray diffraction analyses reveal that these hybrid structures are a one-dimensional (1D) staircase chain based structure, two-dimensional (2D) staircase-chain based structure, and 2D rhomboid dimer based structure, respectively. All of the three compounds show photoluminescence, with the internal quantum yield (IQY) as high as 88.2% for 1. This work provides evidence that for this type of hybrid materials, the structure of the inorganic module could be determined by the selection of the organic ligands and that the substituted group on the organic ligands can influence the luminescence efficiency of the hybrid structures.
研究领域:
无机化学
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材料化学
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配位化学
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光物理
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功能材料
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DOI
高影响因子
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
·
2015
·Vol. 17
·期 38
·25525-25535
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IF 4.493
Yuanyuan Zhou,Hui Tang,Peiyi Wu
Thermo-dynamic volume phase transition mechanisms of poly[oligo(ethylene glycol)methacrylate] (POEGMA) based microgels with poly(ionic liquid) (PIL) cross-linking moieties are investigated in detail on the basis of temperature-dependent Fourier transform infrared (FTIR) spectroscopy. The original FTIR data are further analysed by two-dimensional correlation spectroscopy (2Dcos) with the perturbation correlation moving window (PCMW) technique. It is observed that the content of hydrophilic PIL cross-linking structure strongly affects the temperature induced volume phase transition mechanism of microgels in which the less cross-linked microgel exhibits a sharp volume phase transition process while the highly cross-linked microgel presents a broad transition behavior. Peculiarly, the dehydration of C–H groups acts as the driving force for the whole phase transition process within the less cross-linked microgel network and cooperative response of chemical groups is identified. It is deduced that the hydrophilic PIL moieties develop polymer–water–polymer interactions with CO groups as CO⋯D2O–PIL hydrogen bonds emerge in the less cross-linked system. As regards the highly cross-linked microgel system, the phase transition process is driven by the disruption of hydrogen bonds between CO groups and water molecules while the response of C–H groups becomes insensitive. PIL moieties passively dehydrate following the dehydration of C–H groups on oligo(ethylene glycol) side chains and no hydrogen bond between CO group and IL–D2O association appears during the phase transition process.
研究领域:
高分子科学
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软物质物理
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生物材料
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药物递送
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智能响应材料
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DOI
高影响因子
Small
·
2024
·Vol. 21
·期 4
·2410657
·
IF 13
Jia Wang,De Wang,Zelin Zhao,Ganggang Chang,Wei Guo,Jun Xu,Yinyu Xiang,Junrui Li,Junsheng Li
Developing cost-effective ruthenium (Ru)-based HER electrocatalysts as alternatives to commercial Pt/C is crucial for the advancement of proton exchange membrane water electrolysis (PEMWE). However, the strong hydrogen adsorption of Ru-based catalysts restricts its activity. Herein, a strategy is reported to tune the electronic structure and improve mass transfer by implanting Ru atoms onto the (002) facet of two-dimensional zeolitic imidazolate framework-67 (Ru@ L ZIF (002) ) to optimize the d -band center ( ε d ) of Ru and the hydrogen spillover behavior. Benefiting from the ultrathin nanosheet structure and optimized ε d of Ru, the over-strong H adsorption energy is weakened and the electron/mass transfer is facilitated. Ru@ L ZIF (002) exhibits an overpotential of 9.2 mV at 10 mA cm −2 and a long-lasting stability of 35 days at 100 mA cm −2 . The mass activity and price activity of Ru@ L ZIF (002) is 2.9 and 14.7 times higher than Pt/C, respectively. More impressively, Ru@ L ZIF (002) delivers a cell voltage of 2.01 V at a high current density of 4 A cm −2 in PEMWE. The excellent long-term durability of 1200 hours operating at 4 A cm −2 with an ultralow decay rate of 7.5 × 10 −3 mV h −1 has been achieved, making it promising as a cost-effective alternative to Pt/C catalyst for PEMWE applications.
研究领域:
电催化
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材料科学
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能源化学
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纳米材料
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电化学工程
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可持续能源技术
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DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
·
2023
·Vol. 34
·期 9
·794
·
IF 2.8
Li Ji,Xiang Peng,Tan Xinyu,Li Bowen,Zhang Kai,Zhu Ying,Ren Yanqi,Chen Xiaobo
Organic–inorganic lead halide peroxides (OIHPs) have attracted much interest due to their excellent photovoltaic properties, but practical applications are limited by long-term stability and further performance enhancement. Two-dimensional/three-dimensional (2D/3D) heterojunction is a promising strategy to address these issues. Here, short-chain 3,5-dichlorobenzylamine (DBA) with halogen functional groups is introduced to react with excess PbI 2 to form the 2D perovskite layer in mixed perovskite films of Cs 0.05 (FA 0.85 MA 0.15 ) 0.95 Pb(I 0.85 Br 0.15 ) 3 , which passivates surface defects, favours energy band alignment of functional layers and suppresses non-radiative recombination of carriers. As a result, DBA-treated 2D/3D PSCs obtained a champion PCE of 21.54% with an improved open circuit voltage ( V oc ) of 1.171 V. More importantly, the 2D/3D heterojunction can effectively protect the underlying 3D perovskite from moisture ingress. The unencapsulated 2D/3D devices retain 90% of their initial efficiency even after aging at 40 ± 5% RH for 1000 h, while the 3D device retains only 40%.
研究领域:
材料科学
·
光伏技术
·
纳米结构材料
·
表面化学
·
能源材料
✓ 已验证
DOI
高影响因子
Physica Status Solidi-Rapid Research Letters
·
2023
·Vol. 18
·期 7
·2300102
·
IF 2.8
Wenlong Chu,Ruifeng Xin,Luwei Zou,Xiulian Fan,Xilong Zhou,Cheng Li,Yu Zhou
2D nonlayered materials have attracted more and more attention due to their novel properties and special surface structures. However, due to isotropic chemical bonds within the crystal, the synthesis of ultrathin 2D nonlayered materials is an urgent challenge. Herein, α -Fe 2 O 3 2D nanosheets as thin as ≈8.2 nm on different substrates using self-designed ultralow concentration precursors combined with Gibbs free energy and Se catalysts design are successfully synthesized. The thickness-dependent growth mechanism is systematically studied, demonstrating the thermodynamic and kinetic controlling factors. The as-grown α -Fe 2 O 3 nanosheets are demonstrated with single-crystal structures without any other elements doping. The α -Fe 2 O 3 nanosheets photodetectors show the reasonable response performance with the positive photoconductive mechanism. This improved chemical vapor deposition method provides a promising idea for the synthesis of ultrathin 2D nonlayered materials.
研究领域:
材料科学
·
纳米科技
·
表面科学
·
凝聚态物理
·
光电子学
✓ 已验证
DOI
高影响因子
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