n型金属氧化物电子传输层在介观钙钛矿太阳能电池中的研究(英文)

mater.scichina.com link.springer.com Published online 27 September 2016 | doi: 10.1007/s40843-016-5121-1Sci China Mater 2016, 59(9): 757– 768SPECIAL ISSUE: Excitonic Solar Cells (I)N-type metal-oxide electron transport layer formesoscopic perovskite solar cellsYuli Xiong 1, Tongfa Liu 1, Xixi Jiang1,2, Yaoguang Rong1 and Hongwei Han 1*ABSTRACT To meet the challenge of continuously increas-ing global energy demands, organic-inorganic halide basedperovskite solar cells (PSCs) have garnered great attentionfrom the photovoltaic research community for their lowcost and high efficiency. The efficiency of perovskite-basedmesoscopic solar cells increases rapidly, from 3.8% in 2009 to22.1% in 2016. N-type metal-oxide electron transport layer,as one of the important components in mesoscopic PSCs(MPSCs), acts as not only a scaffold layer for the growthof perovskite crystals, but also a layer to supply transferpathways for electrons injected from perovskites. In thisreview, we discussed recent published reports of MPSCs withthe focus on n-type metal-oxide electron transport layer inMPSCs. The scaffold materials, scaffold nanostructure, andscaffold/perovskite interface engineering are considered,and the effects of these modifications of scaffolds on theperformance of MPSCs are summarized in this review.Keywords: n-type electron transport materials, mesoscopic,perovskite solar cells,electron transport, scaffold nanostructureINTRODUCTIONIn terms of the energy issues faced by global sustainableeconomy development, economically viable renewable en-ergy sources are very essential, in which solar energy is oneof the best candidates to satisfy the future global need forrenewable energy sources [1]. A great deal of attention hasbeen paid on solar cells, which possessdirect conversion ofsolar energy to electric energy. Dye-sensitized solar cells(DSSCs), known asthe Gr?tzel cell, were first fabricated byGr?tzel ’sgroup in 1991 [2] and perovskite solar cells (PSCs)were evolved from DSSC by using perovskite hybrid asthelight harvester [3]. The first use of perovskite in solar cellsdid not show a high efficiency. In 2009, Kojima et al. [3]employed CH 3NH 3PbI 3 and the analogue CH 3 NH 3 PbBr3 assensitizers in liquid-electrolyte-based DSSC, yielding a lowpower conversion efficiency (PCE) of only 3.81%. Due tothe solvation of perovskites in acetonitrile, the photocur-rent decayed under continuous irradiation. A key advancewas made in 2012 by replacing the liquid electrolyte with asolid hole transporting material (HTM), leading to a highPCE of 9.7% and enhanced cell stability [4]. Then, the cer-tificated PCE was boosted to 22.1%in 2016 [5], astremen-dous efforts have been devoted to the research of PSCs,in-cluding the primary mechanism, various materials fabrica-tion methods and architecture design.The general chemical formula of perovskite compoundsis ABX 3, where, for typical, X is a halogen ion (I- , Br- ,Cl - or their alloys) that bonds to the A and B cations, Ais typically CH 3NH 3+ (MA +), NH 2CHNH 3 + (FA +), Cs+ ortheir alloys, and B is typically Pb2+, Sn2+ or their alloys.They have a suitable direct band gap and an intense ab-sorption over the entire visible region, showing superiorphotovoltaic properties. The PSCs structure geometry isshown in Fig. 1, which is typically composed of transpar-ent electrode, counter electrode, light harvesting perovskitelayer, hole transport layer (HTL) and electron transportlayer (ETL). The perovskite layer is either adsorbed on thescaffold materials or prepared asa compact film, and thesetwo typical structures exist in mesoscopic PSC(MPSC) andplanar PSC. Two typical types of MPSC (A and B), corre-sponding to the two types of planar PSC (C and D), areshown in Fig. 1. Using perovskite with both high mobilityof electron and holes, PSC without HTL or ETL were alsofabricated. The HTL-free PSC shows a particular good in-dustrialization prospect due to the removal of expensive1 Michael Gr?tzel Center for Mesoscopic Solar Cells, Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology,Wuhan 430074, China2 Yunnan Key Laboratory for Micro/Nano Materials & Technology, School of Materials Science and Engineering, Yunnan University, Kunming 650091,China* Corresponding author (email: hongwei.han@hust.edu.cn)September 2016 | Vol.59 No.9 757? Science China Press and Springer-Verlag Berlin Heidelberg 2016SCIENCECHINA Materials REVIEWS