Switchable Bulk Photovoltaic Effect in Intrinsically Ferroelectric 3D All-Inorganic CsPbBr3 Perovskite Nanocrystals

• Published in: ACS nano 2024-08, Vol.18 (34), p.23310
• Main Authors: Ghosh, Anashmita, Paul, Susmita, Das, Mrinmay, Sarkar, Piyush Kanti, Bhardwaj, Pooja, Sheet, Goutam, Das, Surajit, Kalimuddin, Sk, Datta, Anuja, Acharya, Somobrata
• Format: Article
• Language: English
• ISSN: 1936-086X; 1936-086X
• DOI: 10.1021/acsnano.4c06297

Ferroelectric all-inorganic halide perovskite nanocrystals with both spontaneous polarization and visible light absorption are promising candidates for designing ferroelectric photovoltaic applications. It remains a challenge to realize ferroelectric photovoltaic devices with all-inorganic halide perovskites that can be operated in the absence of an external electric field. Here we report that a popular all-inorganic halide perovskite nanocrystal, CsPbBr3, exhibits a ferroelectricity-driven photovoltaic effect under visible light in the absence of an external electric field. Pristine CsPbBr3 nanocrystals exhibit intrinsic ferroelectric key properties with a notable saturated polarization of ∼0.15 μC/cm2 and a high Curie temperature of 462 K, driven by the stereochemical activity of the Pb(II) lone pair. Furthermore, application of an external electric field allows the photovoltaic effect to be enhanced and the spontaneous polarization to be switched with the direction of the electric field. CsPbBr3 nanocrystals exhibit a robust fatigue performance and a prolonged photoresponse under continuous illumination in the absence of an external electric field. These findings establish all-inorganic halide perovskite nanocrystals as potential candidates for designing photoferroelectric devices by coupling optical functionalities and ferroelectric responses.Ferroelectric all-inorganic halide perovskite nanocrystals with both spontaneous polarization and visible light absorption are promising candidates for designing ferroelectric photovoltaic applications. It remains a challenge to realize ferroelectric photovoltaic devices with all-inorganic halide perovskites that can be operated in the absence of an external electric field. Here we report that a popular all-inorganic halide perovskite nanocrystal, CsPbBr3, exhibits a ferroelectricity-driven photovoltaic effect under visible light in the absence of an external electric field. Pristine CsPbBr3 nanocrystals exhibit intrinsic ferroelectric key properties with a notable saturated polarization of ∼0.15 μC/cm2 and a high Curie temperature of 462 K, driven by the stereochemical activity of the Pb(II) lone pair. Furthermore, application of an external electric field allows the photovoltaic effect to be enhanced and the spontaneous polarization to be switched with the direction of the electric field. CsPbBr3 nanocrystals exhibit a robust fatigue performance and a prolonged photoresponse under continuous illumination in the