Enhanced photocatalysis and photodetection using highly crystalline CZTS thin films optimized using stabilizers

In this work, high crystalline copper zinc tin sulfide (CZTS) thin films optimized using various stabilizers were fabricated using a low-cost non-vacuum-based spin coating method. The structural and optical properties of these films were characterized by XRD, FESEM, Raman spectroscopy, XRF and PL. Kesterite CZTS structure and its composition were confirmed by XRD and XRF, respectively. Trace secondary phase peaks were found using Raman spectroscopy and an optical band gap of 1.53 eV was obtained using photoluminescence measurements. In addition, density functional theory calculations were performed to understand the role of stabilizers in the formation of thin films. The results indicated variation in the crystallinity of the films upon changing the stabilizers. Photocatalytic degradation performance and photocurrent response were estimated to assess the crystallinity-property relationship. The thin film obtained using cyclohexylamine (CHA) stabilizer showed the highest methylene blue (MB) degradation i.e. 97% in 180 min with a reaction rate constant of 0.019 min−1 which is 73% greater than the thin films without stabilizers. The photocurrent response of this film was found to be 29 μA/cm2, which was twice that of CZTS thin films without stabilizers. It was found the use of a cyclohexylamine stabilizer in CZTS thin film preparation improved the structural and optical characteristics of thin films. This study is significant in the context of obtaining high-quality CZTS thin films for efficient solar photovoltaic, photocatalysis and other optoelectronic devices.