Humidity-Induced Photoluminescence Hysteresis in Variable Cs/Br Ratio Hybrid Perovskites

Autor(es)

Howard, John M. ^{[1, 2]} ; Tennyson, Elizabeth M. ^{[1, 2]} ; Barik, Sabyasachi ^{[1, 3]} ; Szostak, Rodrigo ^[4] ; Waks, Edo ^{[1, 5]} ; Toney, Michael F. ^[6] ; Nogueira, Ana F. ^{[4, 6]} ; Neves, Bernardo R. A. ^{[7, 1]} ; Leite, Marina S. ^{[1, 2]}

Afiliação do(s) autor(es)

^[1] Univ Maryland, Inst Res Elect & Appl Phys, College Pk, MD 20740 - USA

^[2] Univ Maryland, Dept Mat Sci & Engn, College Pk, MD 20740 - USA

^[3] Univ Maryland, Dept Phys, College Pk, MD 20740 - USA

^[4] Univ Estadual Campinas, Inst Chem, BR-13083970 Campinas, SP - Brazil

^[5] Univ Maryland, Dept Elect & Comp Engn, College Pk, MD 20740 - USA

^[6] SLAC Natl Accelerator Lab, Stanford Synchrotron Radiat Lightsource, Menlo Pk, CA 94025 - USA

^[7] Univ Fed Minas Gerais, Dept Phys, BR-31270901 Belo Horizonte, MG - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Journal of Physical Chemistry Letters; v. 9, n. 12, p. 3463-3469, JUN 21 2018.
• Citações Web of Science: 4

Resumo

Hybrid organic inorganic perovskites containing Cs are a promising new material for light-absorbing and light-emitting optoelectronics. However, the impact of environmental conditions on their optical properties is not fully understood. Here, we elucidate and quantify the influence of distinct humidity levels on the charge carrier recombination in Cs(x)FA(1-x)Pb(IyBr1-y)(3) perovskites. Using in situ environmental photoluminescence (PL), we temporally and spectrally resolve light emission within a loop of critical relative humidity (rH) levels. Our measurements show that exposure up to 35% rH increases the PL emission for all Cs (10-17%) and Br (17-38%) concentrations investigated here. Spectrally, samples with larger Br concentrations exhibit PL redshift at higher humidity levels, revealing water-driven halide segregation. The compositions considered present hysteresis in their PL intensity upon returning to a low-moisture environment due to partially reversible hydration of the perovskites. Our findings demonstrate that the Cs/Br ratio strongly influences both the spectral stability and extent of light emission hysteresis. We expect our method to become standard when testing the stability of emerging perovskites, including lead-free options, and to be combined with other parameters known for affecting material degradation, e.g., oxygen and temperature. (AU)

• Processo FAPESP: 15/50450-8 - Mapping charge carrier recombination in perovskite solar cells with nanoscale spatial resolution
• Beneficiário: Ana Flávia Nogueira
• Linha de fomento: Auxílio à Pesquisa - Regular
• Processo FAPESP: 17/12582-5 - Perovskitas com cátions mistos: relação entre estrutura, composição, propriedades eletrônicas e eficiência das células solares
• Beneficiário: Rodrigo Szostak
• Linha de fomento: Bolsas no Brasil - Doutorado