Curvature-dependent strain-induced photoluminescence modulations in flexible Er-doped Pb0.98La0.02Zr0.95Ti0.05O3 antiferroelectric thin films prepared by the sol-gel method

Abstract

Tunable photoluminescence (PL) has wide applications in optical waveguides and communication. Since the PL intensity is strongly dependent on the crystal field symmetry, curvature-dependent strain-induced PL modulation is expected in flexible antiferroelectric (AFE) thin film materials. Here, flexible Er-doped Pb0.98La0.02Zr0.95Ti0.05O3 (PLZT) AFE thin films were prepared via the sol-gel method. A giant and reversible PL intensity modulation (482%) was achieved during the bending process. Based on density functional theory (DFT) calculations and Raman spectra measurements, the relationship amongst the curvature-dependent strains, crystal structure, and PL modulation was discussed. The induced strain leads to lattice distortion and even a phase transition, both of which contribute to the reduction in crystal symmetry and thus significantly enhance the PL intensity.