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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

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

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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]
Total Authors: 9
[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
Total Affiliations: 7
Document type: Journal article
Source: Journal of Physical Chemistry Letters; v. 9, n. 12, p. 3463-3469, JUN 21 2018.
Web of Science Citations: 8

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)

FAPESP's process: 15/50450-8 - Mapping charge carrier recombination in perovskite solar cells with nanoscale spatial resolution
Grantee:Ana Flávia Nogueira
Support type: Regular Research Grants
FAPESP's process: 17/12582-5 - Perovskites with mixed cations: relationship between structure, composition, electronic properties and efficiency of solar cells
Grantee:Rodrigo Szostak
Support type: Scholarships in Brazil - Doctorate