Highly Responsive Photochromic Ceramics for High-Contrast Rewritable Information Displays

Inspired by their excellent thermal stability and strong fatigue resistance, inorganic photochromic materials have been highlighted as promising candidates in various photonic applications ranging from photoswitches, anti-counterfeiting, and encryption to information storage. However, the lack of suitable inorganic materials with both fast photoresponse and strong coloration contrast heavily restricts their applications. Herein, a new strategy is proposed to achieve high photochromic performance via constructing deep-lying traps in ferroelectric ceramics. The obtained K0.5Na0.5NbO3-Eu (KNN-Eu) ceramic exhibits a reversible yellow-gray color change with high fatigue resistance upon alternating illumination (420 nm) and thermal stimulus (450 degrees C). A fast response time of around 1 s and a large reflectivity difference of 39.2% between the colored and bleached states are simultaneously achieved in KNN-Eu ceramic, which is by far the best performance ever reported in inorganic photochromic materials. Benefiting from these excellent properties, KNN-Eu is the first ferroelectric photochromic ceramic to support an instant and hand-(re)writable information display. The enhanced photochromic performance is expected to facilitate the application of photochromic materials in numerous optical devices and provides a significant guidance to design other inorganic photochromic materials.

Automated summary

This study proposes a new strategy to achieve high photochromic performance by constructing deep-lying traps in ferroelectric ceramics. The obtained K0.5Na0.5NbO3-Eu (KNN-Eu) ceramic shows a reversible yellow-gray color change with high fatigue resistance and achieves a fast response time and large reflectivity difference, making it the best performing inorganic photochromic material to date.