Electrically Detectable Photoinduced Polarization Switching in a Molecular Prussian Blue Analogue
Yu‐Bo Huang, Junqiu Li, Wen‐Huang Xu, Wenwei Zheng, Xiaopeng Zhang, Kaige Gao, Tianchi Ji, Taisuke Ikeda, Takumi Nakanishi, Shinji Kanegawa, Shu‐Qi Wu, Shengqun Su, Osamu Sato
Abstract
Light, a nondestructive and remotely controllable external stimulus, effectively triggers a variety of electron-transfer phenomena in metal complexes. One prime example includes using light in molecular cyanide-bridged [FeCo] bimetallic Prussian blue analogues, where it switches the system between the electron-transferred metastable state and the system’s ground state. If this process is coupled to a ferroelectric-type phase transition, the generation and disappearance of macroscopic polarization, entirely under light control, become possible. In this research, we successfully executed a nonpolar-to-polar phase transition in a trinuclear cyanide-bridged [Fe 2 Co] complex crystal via directional electron transfer. Intriguingly, by exposing the crystal to the wavelength of light─785 nm─without any electric field─we can drive this ferroelectric phase transition to completely depolarize the crystal, during which a measurable electric current response can be detected. These discoveries signify an important step toward the realization of fully light-controlled ferroelectric memory devices.