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Your search keyword '"Xia, Ruidong"' showing total 293 results
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293 results on '"Xia, Ruidong"'

10. Azobenzene Sulphonic Dye Photoalignment as a Means to Fabricate Liquid Crystalline Conjugated Polymer Chain‐Orientation‐Based Optical Structures

Author

Zhang, Haoran, Ma, Lingling, Zhang, Qian, Shi, Yuping, Fang, Yueting, Xia, Ruidong, Hu, Wei, and Bradley, Donal DC

Subjects
chain orientation optical structures, F8BT and Red-F, liquid crystalline conjugated polymers, refractive index modulation, SD1 photoalignment, Optical Physics, Electrical and Electronic Engineering, Materials Engineering
Published
2020

39. Enhancing the Performance of Perovskite Solar Cells by Introducing 4-(Trifluoromethyl)-1 H -imidazole Passivation Agents.

Author

Hua, Wei, Niu, Qiaoli, Zhang, Ling, Chai, Baoxiang, Yang, Jun, Zeng, Wenjin, Xia, Ruidong, and Min, Yonggang

Subjects
SOLAR cells, PASSIVATION, PEROVSKITE, OPEN-circuit voltage, LEWIS bases, IMIDAZOLES, LEWIS acids
Abstract

Defects in perovskite films are one of the main factors that affect the efficiency and stability of halide perovskite solar cells (PSCs). Uncoordinated ions (such as Pb2+, I−) act as trap states, causing the undesirable non-radiative recombination of photogenerated carriers. The formation of Lewis acid–base adducts in perovskite directly involves the crystallization process, which can effectively passivate defects. In this work, 4-(trifluoromethyl)-1H-imidazole (THI) was introduced into the perovskite precursor solution as a passivation agent. THI is a typical amphoteric compound that exhibits a strong Lewis base property due to its lone pair electrons. It coordinates with Lewis acid Pb2+, leading to the reduction in defect density and increase in crystallinity of perovskite films. Finally, the power conversion efficiency (PCE) of PSC increased from 16.49% to 18.97% due to the simultaneous enhancement of open-circuit voltage (VOC), short circuit current density (JSC) and fill factor (FF). After 30 days of storage, the PCE of the 0.16 THI PSC was maintained at 61.9% of its initial value, which was 44.3% for the control device. The working mechanism of THI was investigated. This work provides an attractive alternative method to passivate the defects in perovskite. [ABSTRACT FROM AUTHOR]

Published
2023
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49. Rubbed PFN−Br as an Alignment Layer for Liquid Crystalline Conjugated Polymer Chain Orientation**.

Author

Wei, Xuanxuan, Zhang, Zhiyuan, Zhang, Qian, Fu, Shuai, and Xia, Ruidong

Subjects
POLYMER liquid crystals, CONJUGATED polymers, MOLECULAR weights, MONOMOLECULAR films, POLYFLUORENES, CHARGE transfer
Abstract

We report poly[(9,9‐bis(3'‐((N,N‐dimethyl)‐N‐ethylammonium)‐propyl)‐2,7‐fluorene)‐alt‐2,7‐(9,9‐dioctylfluorene)]dibromide (PFN−Br), a previously reported charge transfer interlayer for organic optoelectronic devices, as an orientation/alignment layer and rubbing as a means to achieve chain orientation for liquid crystalline conjugated polymers (LCCP). Polyfluorene and its derivatives, namely blue emission polymer poly(9,9‐dioctylfluorene) (PFO), green‐yellow emission polymer poly(9,9‐dioctylfluorene‐cobenzothiadiazole) (F8BT), and binary blend red emission polymer F8BT/Red F (Ref F=poly(triphenylamine‐co‐4,7‐di(thiophen‐2‐yl)benzo[c][1,2,5]thiadiazole‐co‐benzo[c]thiadiazole‐co‐9,9‐dioctyl‐9H‐fluorene)), demonstrated clear polarized absorption when PFN−Br was used as the orientation layer. We have studied the effects of rubbing times of a PFN−Br layer, and molecular weight, film thickness and annealing temperature of LCCP on the orientation degree. A high absorption anisotropy ratio of 12.22 was achieved for 106 nm thick F8BT film with a molecular weight of 55000 at the annealing temperature 265 °C, which is close to the theoretical limitation of the dichroic ratio of F8BT derived previously. Finally, we studied the amplified spontaneous emission (ASE) in chain oriented F8BT and PFO films. It showed that chain orientation made the ASE threshold anisotropic and lowers the threshold compared to the isotropic films if pumped under the favored configuration. This work provides a novel approach to reduce laser threshold and improve charge transfer simultaneously for electrically pumped devices when combined with the conductive property of PFN−Br. [ABSTRACT FROM AUTHOR]

Published
2022
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