The role of annealing in optimizing the electrical, linear, and nonlinear optical properties ZIf-8@TiO2 films for possible use in photonic and optoelectronic devices

Abstract

Abstract Here, we fabricate zeolitic imidazolate framework-8 (ZIF-8)–doped 5 wt. % nanosized TiO2 (ZIf-8@TiO2) thin films using a vapor coating unit. The effects of annealing up to 473 K on the physical characteristics of fabricated ZIf-8@TiO2 thin films were studied. XRD, FTIR, and UV-Vis spectroscopy were utilized to investigate the structural properties of the as-deposited and annealed samples. An increase of approximately 18% was observed in the electrical conductivity. As the annealing temperature increased, the light transmission decreased. This could be due to the growth or aggregation of TiO2 particles during annealing. Raising the annealing temperature by 100 K enhanced the refractive index (n) and energy gap (Eg) by approximately 33% and 8%, respectively. The decrease in ε1 and ε2 in response to the annealing temperature increase was due to the evaporation of MOF organic linkers. The nonlinear optical results indicated a dependence on the annealing temperatures that improved charge carrier mobility and coherent light-matter interactions. Our thesis findings can improve the overall performance and efficiency of optoelectronic devices.