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Interface Engineering of Perovskite Solar Cells with Air Plasma Treatment for Improved Performance
Author(s) -
Ma Xiao,
Tang Peng,
Liu Dong,
Zhang Jingquan,
Feng Lianghuan,
Wu Lili
Publication year - 2017
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.201700536
Subject(s) - x ray photoelectron spectroscopy , perovskite (structure) , materials science , photoluminescence , mesoporous material , energy conversion efficiency , perovskite solar cell , chemical engineering , electron transfer , fermi level , analytical chemistry (journal) , plasma , electron , optoelectronics , chemistry , photochemistry , catalysis , biochemistry , physics , chromatography , quantum mechanics , engineering
For high‐efficiency perovskite solar cells (PSCs), interface engineering becomes critical for carrier collection from the active perovskite material to the transport layer. To enhance the power conversion efficiency (PCE), herein we demonstrate a novel method named surface plasma treatment on a mesoporous TiO 2 electron‐transport layer (ETL) to improve electron extraction and transport properties at the perovskite/TiO 2 interface. According to the XPS results, the plasma treatment induced a partial reduction of Ti 4+ to Ti 3+ within the TiO 2 lattice and increased the concentration of oxygen vacancies on the TiO 2 surface. Ultraviolet photoelectron spectra (UPS) show that the Fermi level of TiO 2 upshifts about 0.2 eV which may effectively promote carrier separation and transfer at the perovskite/TiO 2 interface. In addition, these created donor levels of Ti 3+ and oxygen vacancies donate extra electrons, increasing the conductivities of TiO 2 films and which could further promote transport. The time‐resolved photoluminescence spectra (TRPL) confirm that the decay time decreases dramatically from 656 ns to 235 ns after 90 s plasma treatment, which indicates a more efficient electron‐transfer process. Based on all the above‐mentioned results, a remarkable enhancement in cell efficiency was obtained, such that the average efficiency was improved from 11.5 % to 14.3 % under AM 1.5G irradiation (100 mW cm −2 ).