Photodielectric and Luminescence Properties of (K0.5Na0.5)NbO3-Based Ceramics Modified by (Sr0.5Sm0.5)(Mg0.5Nb0.5)O3

The photoinduced dielectric constant change can be used to develop light-controlled devices. (1 − x )(K 0.5 Na 0.5 )NbO 3 − x (Sr 0.5 Sm 0.5 )(Mg 0.5 Nb 0.5 )O 3 (KNN- x SSMN) ceramics were designed for investigating photoelectric and luminescent properties. The phase of the samples induced by SSMN changes from the orthogonal phase to the pseudo-cubic phase. The grain size shows a slight increase from 150 nm to 190 nm. The increase in the diffusion index from 1.48 to 1.86 indicates enhanced relaxation behavior. A pronounced photodielectric response with dielectric tunability of up to ~315% is obtained at x = 0.03, 80 Hz and 365 nm. Reversible capacitance switching at light-on and light-off states indicates the potential application in optical switches. Strong orange-red emission under 406 nm photoexcitation originating from Sm can be observed. These results help to explore new non-contact devices like light-controlled capacitive sensors and optical switches.