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Ajuste de la vida polarizada por espín en perovskita de haluro metálico bidimensional a través de la energía de
Xihan Chen1,2, Haipeng Lu1,3, Kang Wang1,4
1National Renewable Energy Laboratory, Golden, Colorado 80401, United States.
Journal of the American Chemical Society
|November 12, 2021
Resumen
Los investigadores exploraron la relajación del espín en perovskitas 2D para opto-spintrónica. Lograron largas vidas de espín de excitón de ~ 26 ps a temperatura ambiente, identificando mecanismos clave de relajación de espín para el diseño de dispositivos futuros.
Área de la Ciencia:
- Ciencias de los materiales
- Física de la materia condensada
- La óptica cuántica
Sus antecedentes:
- Las perovskitas de haluro metálico son prometedoras para los dispositivos opto-espintrónicos debido a la manipulación de carga y espín.
- Las perovskitas de menor dimensión ofrecen una simetría única y un acoplamiento de órbita de espín para el levantamiento de degeneración de espín.
- El logro de largas vidas polarizadas por espín es crucial para realizar el potencial de aplicación de estos materiales.
Objetivo del estudio:
- Para investigar la excitación selectiva de espín de los excitones en cristales únicos de perovskita de yoduro de plomo en 2D.
- Comprender los mecanismos de relajación de espín en estos materiales.
- Establecer principios de diseño para lograr una larga vida útil de los semiconductores de perovskita.
Principales métodos:
- Se utilizó la espectroscopia de reflexión transitoria con resolución de tiempo y polarización.
- Estudió una serie de cristales simples de perovskita yodurada de plomo en 2D (n = 1).
- Densidad de excitación variada y energía de unión de excitones.
Principales resultados:
- Tiempos de relajación de espín de excitón alcanzados de ~ 26 ps a temperatura ambiente y bajas densidades de excitación.
- Se han observado largas vidas de espín en 2D EOA2PbI4 (EOA = etanolamina) con poca energía de unión.
- Identificó el mecanismo de D'yakonov-Perel (DP) en densidades bajas y el mecanismo de Bir-Aronov-Pikus (BAP) en densidades altas.
Conclusiones:
- La excitación selectiva de espín de los excitones se demuestra en perovskitas 2D.
- Los mecanismos de relajación de la espina (DP y BAP) se identifican en función de la densidad de excitación.
- Estos hallazgos proporcionan principios de diseño para mejorar la vida útil del espín en perovskitas de haluro metálico para aplicaciones optoespintrónicas.
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