Twin-Perovskite Structured Ba8Ti3Nb4O24: Pr3+: A Fast Photochromics with Millisecond-Level Response Speed for Optical Storage

Photochromism (PC) involves profound and complex optoelectronic processes and the interplay of color centers and the host matrix. To date, achieving a fast PC response speed remains a challenge. Here, a new fast PC "twin-perovskite" niobate ceramic, Ba8Ti3Nb4O24: Pr3+ (BTN:Pr3+), exhibiting a remarkable PC response time down to 20 ms and a record PC contrast of 42.3% among niobate-based PC materials, is identified. Experimental and theoretical approaches reveal the key role of the oxygen vacancy in the PC reaction. It is proposed that the fast PC response is related to the short time spent redistributing charge carriers due to a single type of color center and the quick transport of charge carriers within the densely packed crystal framework featuring a face-sharing twin-plane structure. Finally, we present demo experiments of real-time write-display of information in a repeatable manner and demonstrate bit-by-bit information optical storage at high write speeds that could be read in dual modes.