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Pseudohalide‐Exchanged Quantum Dot Solids Achieve Record Quantum Efficiency in Infrared Photovoltaics
Author(s) -
Sun Bin,
Voznyy Oleksandr,
Tan Hairen,
Stadler Philipp,
Liu Mengxia,
Walters Grant,
Proppe Andrew H.,
Liu Min,
Fan James,
Zhuang Taotao,
Li Jie,
Wei Mingyang,
Xu Jixian,
Kim Younghoon,
Hoogland Sjoerd,
Sargent Edward H.
Publication year - 2017
Publication title -
advanced materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.707
H-Index - 527
eISSN - 1521-4095
pISSN - 0935-9648
DOI - 10.1002/adma.201700749
Subject(s) - materials science , passivation , quantum dot , photovoltaics , solar cell , nanotechnology , halogen , infrared , active layer , chemical engineering , optoelectronics , layer (electronics) , photovoltaic system , thin film transistor , chemistry , organic chemistry , ecology , alkyl , engineering , biology , physics , optics
Application of pseudohalogens in colloidal quantum dot (CQD) solar‐cell active layers increases the solar‐cell performance by reducing the trap densities and implementing thick CQD films. Pseudohalogens are polyatomic analogs of halogens, whose chemistry allows them to substitute halogen atoms by strong chemical interactions with the CQD surfaces. The pseudohalide thiocyanate anion is used to achieve a hybrid surface passivation. A fourfold reduced trap state density than in a control is observed by using a suite of field‐effect transistor studies. This translates directly into the thickest CQD active layer ever reported, enabled by enhanced transport lengths in this new class of materials, and leads to the highest external quantum efficiency, 80% at the excitonic peak, compared with previous reports of CQD solar cells.