Giant Enhancement in Ferroelectric Polarization under Illumination

TL;DR

This study demonstrates a significant optical enhancement of ferroelectric polarization and dielectric properties in PLBZT ceramics under illumination, revealing potential for optoelectronic applications.

Contribution

It reports a novel large polarization increase in PLBZT ferroelectrics under light, a phenomenon not previously documented in similar materials.

Findings

200-300% increase in polarization under illumination

Large switchable open circuit voltage (~2 V)

Significant change in conduction current density

Abstract

We report optical enhancement in polarization and dielectric constant near room temperature in Pb0.6Li0.2Bi0.2Zr0.2Ti0.8O3 (PLBZT) electro-ceramics; these are doubly substituted members of the most important commercial ferroelectric PbZr0.2Ti0.8O3 (PZT:20/80). Partial (40%) substitution of equal amounts of Li+1 and Bi+3 in PZT: 20/80 retains the PZT tetragonal structure with space group P4mm. Under illumination of white light and weak 405-nm near-ultraviolet laser light (30 mW), an unexpectedly large (200-300%) change in polarization and displacement current was observed. Light also changes the dc conduction current density by one to two orders of magnitude with a large switchable open circuit voltage (Voc ~ 2 V) and short circuit current (Jsc ~ 5x10-8 A). The samples show a photo-current ON/OFF ratio of order 6:1 under illumination of weak light.