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La inyección de agujeros electroquímicos expulsa selectivamente el yodo de las películas mixtas de perovskita
Gergely F Samu1,2,3, Ádám Balog1, Filippo De Angelis4,5,6
1Department of Physical Chemistry and Materials Science, Interdisciplinary Excellence Centre , University of Szeged , Rerrich Square 1 , Szeged , H-6720 , Hungary.
Journal of the American Chemical Society
|July 2, 2019
Resumen
La captura de agujeros en las perovskitas de halogenuros metálicos provoca la expulsión de yoduro, formando dominios ricos en bromuro. Esta movilidad de iones halogenados afecta la estabilidad y el rendimiento de las células solares de perovskita.
Área de la Ciencia:
- Ciencias de los materiales
- Química del estado sólido
- Las instalaciones fotovoltaicas
Sus antecedentes:
- La movilidad de iones halogenados es crucial para las propiedades de la perovskita de halogenados metálicos.
- Comprender el movimiento de iones es clave para mejorar el rendimiento y la estabilidad del dispositivo.
Objetivo del estudio:
- Investigar el efecto del atrapamiento de agujeros en la movilidad de iones halogenados en perovskitas halogenadas mixtas.
- Para sondear el mecanismo de expulsión de yoduro y sus consecuencias.
Principales métodos:
- Bias electroquímico anódico para inyección selectiva de agujeros.
- Espectroscopia de absorción transitoria para el seguimiento de procesos dinámicos.
Principales resultados:
- La captura de agujeros en los sitios de yodo conduce a la expulsión de yodo (como I2 o I3-) de las películas CH3NH3PbBr1.5I1.5.
- La expulsión da como resultado la formación de dominios CH3NH3PbBr3 y un enlace Pb-I debilitado.
- La expulsión de yoduro crea una red rica en defectos, acelerando la recombinación del portador de carga.
Conclusiones:
- La movilidad selectiva del yoduro impulsa la segregación de fase inducida por la luz en las películas de perovskita.
- Este fenómeno tiene implicaciones significativas para la estabilidad operativa de las células solares de perovskita.
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