Optoelectronic Duple Bistable Switches: A Bulk Molecular Single Crystal and Unidirectional Ultraflexible Thin Film Based on Imidazolium Fluorochromate

Optical‐electrical duple bistable switches are those that enable simultaneous conversion of both optical and electrical signals in one device to realize seamless integration. Herein, imidazolium‐FCrO3 can be prepared into a large‐size single crystal and ultraflexible thin film with ultrahigh unidirectionality of (0 0 4) and is characterized through scanning electron microscopy (SEM), atomic force microscopy (AFM), powder X‐ray diffraction, etc. Both the thin film and crystal display synchronously eximious optoelectronic duple characteristics (dielectric and nonlinear optical second harmonic generation (SHG) bistable switching ON/OFF), with a record‐high SHG contrast of ≈250 (2.0 times that of KDP, potassium dihydrogen phosphate, exceeding all the known molecular materials/crystalline switches, revealing its potential to obtain high‐efficiency signal‐to‐noise ratio), sensitive dielectric bistability, and remarkable switching antifatigue. These attributes make imidazolium‐FCrO3 a potential candidate in photoelectric seamless integration devices and flexible multifunctional devices. Imidazolium‐FCrO3 is a novel optoelectronic duple bistable switch, which can be prepared into bulk single crystal and highly flexible thin film, exhibiting supereminent ON–OFF dielectric and nonlinear optical switching with obvious antifatigue in several cycles. The thin film has a preferred (0 0 4) orientation in accordance with the c‐axis of the crystal.