Open AccessOptoelectronic Properties of Tin–Lead Halide Perovskites
Author(s) -
Kimberley J. Savill,
Aleksander M. Ulatowski,
Laura M. Herz
Publication year - 2021
Publication title -
acs energy letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 8.632
H-Index - 105
ISSN - 2380-8195
DOI - 10.1021/acsenergylett.1c00776
Subject(s) - tin , materials science , optoelectronics , charge carrier , band gap , photovoltaic system , halide , absorption (acoustics) , nanotechnology , chemical physics , chemistry , inorganic chemistry , electrical engineering , metallurgy , composite material , engineering
Mixed tin-lead halide perovskites have recently emerged as highly promising materials for efficient single- and multi-junction photovoltaic devices. This Focus Review discusses the optoelectronic properties that underpin this performance, clearly differentiating between intrinsic and defect-mediated mechanisms. We show that from a fundamental perspective, increasing tin fraction may cause increases in attainable charge-carrier mobilities, decreases in exciton binding energies, and potentially a slowing of charge-carrier cooling, all beneficial for photovoltaic applications. We discuss the mechanisms leading to significant bandgap bowing along the tin-lead series, which enables attractive near-infrared bandgaps at intermediate tin content. However, tin-rich stoichiometries still suffer from tin oxidation and vacancy formation which often obscures the fundamentally achievable performance, causing high background hole densities, accelerating charge-carrier recombination, lowering charge-carrier mobilities, and blue-shifting absorption onsets through the Burstein-Moss effect. We evaluate impacts on photovoltaic device performance, and conclude with an outlook on remaining challenges and promising future directions in this area.