Photochromic Response and Steady‐State Photoconductivity of Fibrous‐Reticulated α‐MoO3 Thin Films Prepared by Modified Spray Pyrolysis Technique

Abstract

AbstractA modified spray pyrolysis technique is used for preparing α‐MoO3 thin films after subsequent heat treatment at a relatively low temperature. The spray parameters are selected through a wide variety of elaboration conditions for best photochromic features. Different numbers of spraying and drying cycles are performed to investigate the thickness effect on the structural, morphological, optical, electrical, and photo‐electrical properties of the nanostructured α‐MoO3 films. These film samples are characterized by X‐ray diffraction (XRD) and scanning electron microscopy (SEM), and thus the film thickness effect is elucidated and correlated to the crystallite shape and size. The SEM micrographs show fibrous‐reticulated morphology for all the film samples investigated here. The photochromic properties of α‐MoO3 sprayed thin films are investigated by measuring the transmission spectra before and after UV‐light exposure. The changes in the optical transmission of these film samples are monitored for different exposure times. The UV exposure time effect as well as the thickness effect on the photochromic response of the film samples is investigated and discussed based on the particle size analysis. The photosensitivity is evaluated in various illumination levels to elucidate the carrier transport in the α‐MoO3 films and to determine the type of the recombination processes in these films.