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Phase Transitions and Effect of Intermolecular Forces

Phase Transitions and Effect of Intermolecular Forces

Energética, estructuras y transiciones de fase de los polimorfos de yoduro de plomo de cesio cúbico y ortorrómbico

Bin Wang¹, Novendra Novendra¹, Alexandra Navrotsky¹

¹Peter A. Rock Thermochemistry Laboratory and NEAT ORU , University of California Davis , Davis , California 95616 , United States.

Journal of the American Chemical Society

|September 6, 2019

Resumen

Se estudió la estabilidad de la perovskita de yoduro de plomo de cesio mediante calorimetría. Los polimorfos CsPbI3 alfa y delta son estables, pero el alfa es metastable a temperatura ambiente.

Área de la Ciencia:

Ciencias de los materiales
Química del estado sólido
La termodinámica

Sus antecedentes:

Las perovskitas de yoduro de plomo de cesio (CsPbI3) son prometedoras para las células solares.
La estabilidad a largo plazo y el polimorfismo de CsPbI3 son desafíos críticos.
La comprensión termodinámica de los polimorfos CsPbI3 es limitada.

Objetivo del estudio:

Para determinar la estabilidad termodinámica de los polimorfos CsPbI3.
Investigar las vías de interconversión y descomposición de fases.
Para proporcionar información sobre la estabilidad de la perovskita halogenada.

Principales métodos:

Calorimetría de la solución a temperatura ambiente en el dimetilsulfóxido (DMSO).
Calorimetría por barrido diferencial (DSC).
Análisis termodinámico de las entalpías de formación.

Principales resultados:

Se midieron las entalpías de formación de CsPbI3 alfa y delta.
Ambos polimorfos son termodinámicamente estables frente a los haluros binarios.
Se confirma que el alfa-CsPbI3 es un polimorfo de alta temperatura, metastable en condiciones ambientales.

Conclusiones:

Los datos termodinámicos aclaran el polimorfismo y la estabilidad de CsPbI3.
La metestabilidad a temperatura ambiente puede ser común en las perovskitas funcionales.
Los hallazgos ayudan en el diseño de materiales de perovskita halogenada estable.

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