Quantitative Phase-Change Thermodynamics and Metastability of Perovskite-Phase Cesium Lead Iodide.

Author(s) Dastidar, S.; Hawley, C.J.; Dillon, A.D.; Gutierrez-Perez, A.D.; Spanier, J.E.; Fafarman, A.T.
Journal J Phys Chem Lett
Date Published 2017 Mar 16
Abstract

The perovskite phase of cesium lead iodide (α-CsPbI3 or "black" phase) possesses favorable optoelectronic properties for photovoltaic applications. However, the stable phase at room temperature is a nonfunctional "yellow" phase (δ-CsPbI3). Black-phase polycrystalline thin films are synthesized above 330 °C and rapidly quenched to room temperature, retaining their phase in a metastable state. Using differential scanning calorimetry, it is shown herein that the metastable state is maintained in the absence of moisture, up to a temperature of 100 °C, and a reversible phase-change enthalpy of 14.2 (±0.5) kJ/mol is observed. The presence of atmospheric moisture hastens the black-to-yellow conversion kinetics without significantly changing the enthalpy of the transition, indicating a catalytic effect, rather than a change in equilibrium due to water adduct formation. These results delineate the conditions for trapping the desired phase and highlight the significant magnitude of the entropic stabilization of this phase.

DOI 10.1021/acs.jpclett.7b00134
ISSN 1948-7185
Citation Dastidar S, Hawley CJ, Dillon AD, Gutierrez-Perez AD, Spanier JE, Fafarman AT. Quantitative Phase-Change Thermodynamics and Metastability of Perovskite-Phase Cesium Lead Iodide. J Phys Chem Lett. 2017;8(6):1278-1282.

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