Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
6534366 | Solar Energy Materials and Solar Cells | 2018 | 7 Pages |
Abstract
Electrochromic(EC), nonstoichiometric NiOx thin films were made by reactive magnetron sputtering at low oxygen flow ratio(i.e., P=O2/Ar+O2â¤10%). The results of optical spectral, x-ray diffraction spectrum, and x-ray photoelectron spectroscopy analyses indicate that the samples are oxygen(nickel)-deficient as Pâ¤%4(â¥%6), resulting in sub(over)-stoichiometry films. Spectroelectrochemical measurements show that the EC effect of NiOx in nonaqueous PCâLiClO4 electrolyte is direct correlation with the nickel vacancy concentration in films, while that in the aqueous KOH solution is nearly uninfluenced upon the change in stoichiometry as Pâ¥%4. The films deposited at P=6% exhibit higher coloration efficiency of â25.3cm2Câ1, larger ionic diffusion coefficient of â2.84Ã10â14m2sâ1, and broader EC modulation span of 24% in PCâLiClO4 than the other ones. Based upon these values, EC devices featuring a WO3/PMMAâPCâLiClO4/NiOx structure and excellent performances were fabricated. We demonstrated that the nickel anodization should be responsible for the initial “activation” phenomena, which decreases(increases) the number of oxygen(nickel) vacancies. Moreover, the cause of degradation resulting from Li+-ion trapping in the IS layer was also clarified. This work provides a general framework for studying and designing superior EC devices, experimentally as well as theoretically.
Related Topics
Physical Sciences and Engineering
Chemical Engineering
Catalysis
Authors
Junji Guo, Mei Wang, Zhi-Bin Zhang, Guobo Dong, Famin Liu, Hao Wang, Hang Yu, Yu Xiao, Jiang Liu, Xungang Diao,