Achieving direct electrophoretically deposited highly stable polymer induced CsPbBr₃ colloidal nanocrystal films for high-performance optoelectronics

Synthesizing colloidal nanocrystals (NCs) with long-term stable under ambient conditions via appropriate ligands capping is highly challenging. Herein, the rapid synthesis of CsPbBr₃ colloidal NCs at room temperature using polyvinylpyrrolidone as the primary ligand is demonstrated. The addition of ethylene glycol stabilizes the colloidal NCs and enhance their photoluminescence by ∼ 5-fold. Colloidal NCs have a net negative surface charge, which enables the direct electrophoretic deposition of a polymer-induced all-inorganic CsPbBr₃ NC film with ultra-high stability under ambient conditions at relative humidity of 55% for 240 days. As an example of the application of the CsPbBr₃ NC film in an optoelectronic device, a hybrid MoS₂/CsPbBr₃ field-effect phototransistor is fabricated, which exhibits a detectivity of 9 × 10¹² Jones and an ultra-high responsivity of 1.2 × 10⁷ A W⁻¹ under the illumination of 450-nm laser at 4.4 pW. The noble and practical methods applied in our CsPbBr₃ NC films could be extended to produce various types of uniform NC films over a large geometrical area with outstanding long-term environmental stability, holding significant promise for use in a broad range of advanced optoelectronic devices.