Defect Engineering by Annealing: Managing the Trade-Off Relationship between Photochromic and Electrical Properties in Knn-Based Translucent Ceramics

Abstract

Rare-earth-doped transparent ferroelectrics exhibit outstanding optical transparency, photoluminescence, photochromic and electrical properties, showing potential for use in optoelectronic applications. However, there is an inevitable trade-off relationship between optical and electrical coupling during the integration of multifunctionality. In this work, Ba2+, Ho3+ and Yb3+ were codoped in KNN ceramics (as a model material) to overcome the contradiction between optical and electrical properties.The defects (mainly oxygen vacancies) within the ceramics can be effectively regulated through annealing under different atmospheres. At the cost of a slight decrease in PC performance, the electrical properties significantly improved; i.e., for the optimal ceramic annealed in an oxygen atmosphere, both the maximum and remnant polarizations nearly doubled, and the resistivity significantly decreased compared to that of the original sample. A mechanism for regulating these properties was proposed. This research serves as a valuable example for adjusting the optical and electrical properties of other ferroelectrics through annealing.

Keywords: KNN, translucent ceramics, annealing, photoluminescence, photochromism