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Nonlinear Photocarrier Dynamics and the Role of Shallow Traps in Mixed-Halide Mixed-Cation Hybrid Perovskites

preprint
submitted on 31.03.2021, 20:38 and posted on 01.04.2021, 13:02 by David A. Valverde-Chávez, Esteban Rojas-Gatjens, Jacob Williamson, Sarthak Jariwala, Yangwei Shi, Declan P. McCarthy, Stephen Barlow, Seth R. Marder, David S. Ginger, Carlos Silva

We examine the role of surface passivation on carrier trapping and nonlinear recombination dynamics in hybrid metal-halide perovskites by means of excitation correlation photoluminescence (ECPL) spectroscopy. We find that carrier trapping occurs on subnanosecond timescales in both control (unpassivated) and passivated samples, which is consistent within a shallow-trap model. However, the impact of passivation has a direct effect on both shallow and deep traps. Our results reveal that the effect of passivation of deep traps is responsible for the increase of the carrier lifetimes, while the passivation of shallow traps reduces the excitation density required for shallow-trap saturation. Our work demonstrates how ECPL provides details about the passivation of shallow traps beyond those available via conventional time-resolved photoluminescence techniques.

Funding

U.S. Department of Energy's Office of Energy Efficiency and Renewable Energy (EERE) under the Solar Energy Technologies Office Award Number DE-EE0008747.

History

Email Address of Submitting Author

carlos.silva@gatech.edu

Institution

Georgia Institute of Technology

Country

United States

ORCID For Submitting Author

0000-0002-3969-5271

Declaration of Conflict of Interest

The authors declare no conflicts of interest.

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