Investigation of Impacts of Annealing on the Properties of Poly (3,4-ethylene dioxythiophene)/poly (styrene sulfonate) (PEDOT:PSS) Films

Abstract

Poly(3,4-ethylene dioxythiophene)/poly(styrene sulfonic acid) (PEDOT:PSS) holds a promise in the electronics and optoelectronics world owing to its promising electrical conductivity, exciting optical transparency, and improved structural network. It has found diverse applications in various technological fields and electronics devices, such as photovoltaics devices, light-emitting diodes, and photodiodes. However, the optical, surface morphology and structural properties of PEDOT:PSS films are significantly influenced by post-treatment processes, among which annealing plays a vital role. Annealing influences the surface property, phase separation, and molecular orderliness of PEDOT:PSS films, which invariably impacts their charge transport and optical behaviours. In this study, we evaluate the effects of thermal treatment on the optical, structural, and surface morphology properties of poly(3,4-ethylenedioxythiophene/poly styrene sulfonate) (PEDOT:PSS) thin film particularly for solar energy conversion application. The optical, structural, and surface morphology properties of PEDOT:PSS films as a function of annealing temperatures were studied by UV - Visible spectroscopy, X-ray diffraction, and scanning electron microscopy techniques respectively. An increase in annealing temperature improves the photons transmittance characteristic of the films. The X-ray diffraction pattern of the annealed film exhibits slight markedly improvement in the peak intensity suggesting improvement in the order of molecular structure and the SEM images reveals an increase in surface roughness of the annealed films improving the pathway for charge carrier mobility. These results highlight the significance of annealing treatments on the characteristic performance of PEDOT:PSS films for diverse electronic applications.