Enhanced Photoluminescence and Solar Cell Performance via Lewis Base Passivation of Organic鈥揑norganic Lead Halide Perovskites

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• 作者：Nakita K. Noel ; Antonio Abate ; Samuel D. Stranks ; Elizabeth S. Parrott ; Victor M. Burlakov ; Alain Goriely ; Henry J. Snaith
• 刊名：ACS Nano
• 出版年：2014
• 出版时间：October 28, 2014
• 年：2014
• 卷：8
• 期：10
• 页码：9815-9821
• 全文大小：468K
• ISSN：1936-086X

文摘

Organic鈥搃norganic metal halide perovskites have recently emerged as a top contender to be used as an absorber material in highly efficient, low-cost photovoltaic devices. Solution-processed semiconductors tend to have a high density of defect states and exhibit a large degree of electronic disorder. Perovskites appear to go against this trend, and despite relatively little knowledge of the impact of electronic defects, certified solar-to-electrical power conversion efficiencies of up to 17.9% have been achieved. Here, through treatment of the crystal surfaces with the Lewis bases thiophene and pyridine, we demonstrate significantly reduced nonradiative electron鈥揾ole recombination within the CH₃NH₃PbI_3鈥?i>xCl_x perovskite, achieving photoluminescence lifetimes which are enhanced by nearly an order of magnitude, up to 2 渭s. We propose that this is due to the electronic passivation of under-coordinated Pb atoms within the crystal. Through this method of Lewis base passivation, we achieve power conversion efficiencies for solution-processed planar heterojunction solar cells enhanced from 13% for the untreated solar cells to 15.3% and 16.5% for the thiophene and pyridine-treated solar cells, respectively.

Keywords:

organic鈭抜norganic perovskite; coordinate bonding; perovskite solar cells; surface passivation; under-coordinated atoms; photoluminescence; defect sites