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Tuning the Fermi Level of TiO 2 Electron Transport Layer through Europium Doping for Highly Efficient Perovskite Solar Cells
Author(s) -
Xu Zhe,
Wu Jihuai,
Wu Tongyue,
Bao Quanlin,
He Xin,
Lan Zhang,
Lin Jianming,
Huang Miaoliang,
Huang Yunfang,
Fan Leqin
Publication year - 2017
Publication title -
energy technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.91
H-Index - 44
eISSN - 2194-4296
pISSN - 2194-4288
DOI - 10.1002/ente.201700377
Subject(s) - materials science , doping , europium , energy conversion efficiency , x ray photoelectron spectroscopy , perovskite (structure) , fermi level , crystallinity , ultraviolet photoelectron spectroscopy , optoelectronics , photoluminescence , mesoporous material , analytical chemistry (journal) , chemical engineering , electron , chemistry , luminescence , composite material , physics , biochemistry , catalysis , chromatography , quantum mechanics , engineering
The electron‐transport layer (ETL) plays an important role in the photovoltaic performance of perovskite solar cells (PSCs), and the energy level match of functional layers can appreciably improve the power conversion efficiency (PCE) of PSCs. Herein, we choose the rare‐earth europium ion Eu 3+ to dope a mesoporous TiO 2 ETL. X‐ray diffraction, field‐emission scanning electron microscopy, ultraviolet photoelectron spectroscopy, time‐resolved photoluminescence, and incident‐photo‐to‐current conversion efficiency experiments were performed to characterize the material. It is found that the Eu doping does not change the morphology, grain size, and crystallinity of TiO 2 . However, Eu doping upshifts the Fermi level of TiO 2 ETL by scavenging oxygen atoms and introducing oxygen vacancies on the surface of the layer, which results in low series resistance and fast charge transport in the ETLs, which in turn increases the power conversion efficiency of the device from 15.85 % (undoped PSC) to 17.90 % (Eu‐doped PSC). This work demonstrates an effective approach for enhancing the performance of PSCs by rare‐earth doping.