Photoinduced Persistent Polarization Change in a Spin Transition Crystal. Issue 39 (18th August 2022)

• Record Type: Journal Article
• Authors: Su, Sheng‐Qun; Wu, Shu‐Qi; Huang, Yu‐Bo; Xu, Wen‐Huang; Gao, Kai‐Ge; Okazawa, Atsushi; Okajima, Hajime; Sakamoto, Akira; Kanegawa, Shinji; Sato, Osamu
• Is Part Of: Angewandte Chemie international edition. Volume 61:Issue 39(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-08-18
• Subjects: Ion Displacement -- Photoexcitation -- Polarization Change -- Pyroelectric Current -- Spin Transition; Chemistry -- Periodicals; 540
• DOI: 10.1002/anie.202208771
• Languages: English
• ISSNs: 1433-7851

Abstract

Abstract: Using light as a local heat source to induce a temporary pyroelectric current is widely recognized as an effective way to control the polarization of crystalline materials. In contrast, harnessing light directly to modulate the polarization of a crystal via excitation of the electronic bands remains less explored. In this study, we report an Fe II spin crossover crystal that exhibits photoinduced macroscopic polarization change upon excitation by green light. When the excited crystal relaxes to the ground state, the corresponding pyroelectric current can be detected. An analysis of the structures, magnetic properties and the Mössbauer and infrared spectra of the complex, supported by calculations, revealed that the polarization change is dictated by the directional relative movement of ions during the spin transition process. The spin transition and polarization change occur simultaneously in response to light stimulus, which demonstrates the enormous potential of polar spin crossover systems in the field of optoelectronic materials. Abstract : A photoinduced persistent polarization change was achieved in an ionic Fe II spin‐crossover complex by combining the light‐induced excited spin‐state trapping effect (LIESST) and macroscopic polarization. The pyroelectric current is detected at a crystal level when the light‐induced metastable state returns to the ground state. This study provides a platform for the development of optoelectric materials.