Optical Properties of Zinc Sulphide Thin Films Coated with Aqueous Organic Dye Extract for Solar and Optoelectronic Device Applications

Abstract

Optical properties of ZnS thin films coated with organic dye extract on different Zn 2+ concentrations from ZnSO 4 are presented in this study. The effects of concentration and post-deposition annealing temperatures on the optical properties of the films were investigated. Aqueous dye extract-coated ZnS nanocrystals, were prepared by a simple and low-cost chemical bath deposition method. Results obtained revealed that optical properties of the films were modified by concentration and post-deposition annealing temperature. Increasing concentration reduced the transparency of the films. Annealing increased the transparency of the films except for films deposited with 0.1M concentration of ZnSO 4 . In general, the heat-treated layers were found to transmit better than the as-deposited layers. The analysis of energy band gap showed a reduction in band gap with increasing Zn 2+ concentration of the asdeposited films. It also indicated that post-deposition annealing, increased energy band gap except for films deposited with 0.1M concentration of ZnSO 4 . The relationship between the energy band gap with both concentration and post-deposition annealing fit into the quadratic model with high R 2 values. The range of values of 3.889-3.981eV recorded for the band gaps is within the range for application in diverse solar architecture and optoelectronic devices.

Structural, Electrical and Optical Studies of ZnxCu1-xS (x = 0.8, 0.6, 0.4 and 0.2) Nanoparticles

“…ZnS is a wide bandgap semiconductor with a band gap energy of 3.68eV [1,2]. Due to wide band gap, it is useful in optoelectronics [3] and sensors [4]. Zinc Sulphide nanoparticles have potential for various applications in the field of solar cells [5], displays [6], lasers [7] and light emitting diodes, [8] ZnS exist in two phases, ie's cubic phase and hexagonal phase [9].…”