Photo-induced macro/mesoscopic scale ion displacement in mixed-halide perovskites:ring structures and ionic plasma oscillations  

作　　者：Xiaoxiao Sun Yong Zhang Weikun Ge 

机构地区：[1]Laboratory for Thin Films and Photovoltaics,Empa-Swiss Federal Laboratories for Materials Science and Technology,8600 Duebendorf,Switzerland [2]Department of Information Technology and Electrical Engineering,ETH Zurich,8093 Zurich,Switzerland [3]Institute of Ion Beam Physics and Materials Research,Helmholtz-Zentrum Dresden-Rossendorf,Dresden 01328,Germany [4]Department of Electrical and Computer Engineering,The University of North Carolina at Charlotte,Charlotte,NC 28223,USA [5]Department of Physics,Tsinghua University,Beijing 10084,People's Republic of China

出　　处：《Light(Science & Applications)》2022年第10期2388-2398,共11页光（科学与应用)（英文版）

摘　　要：Contrary to the common belief that the light-induced halide ion segregation in a mixed halide alloy occurs within the illuminated area,we find that the Br ions released by light are expelled from the illuminated area,which generates a macro/mesoscopic size anion ring surrounding the illuminated area,exhibiting a photoluminescence ring.This intriguing phenomenon can be explained as resulting from two counter-balancing effects:the outward diffusion of the light-induced free Br ions and the Coulombic force between the anion deficit and surplus region.Right after removing the illumination,the macro/mesoscopic scale ion displacement results in a built-in voltage of about 0.4 V between the ring and the center.Then,the displaced anions return to the illuminated area,and the restoring force leads to a damped ultra-low-frequency oscillatory ion motion,with a period of about 20-30 h and lasting over 100 h.This finding may be the first observation of an ionic plasma oscillation in solids.Our understanding and controlling the"ion segregation"demonstrate that it is possible to turn this commonly viewed"adverse phenomenon"into novel electronic applications,such as ionic patterning,self-destructive memory,and energy storage.

关 键 词：MIXED removing RETURN 

分 类 号：O53[理学—等离子体物理]