In this work, we developed a very simple and novel approach for synthesizing TiO₂-ZnO nanocomposites via the urea-assisted thermal decomposition of titanium oxysulphate and zinc acetate at different weight ratios. The synthesized nanocomposite samples were studied by means of HR-TEM, XRD, STEM, UV–Vis DRS, PL and EDS. The observed results demonstrate that the TiO₂-ZnO nanocomposite consists of an anatase crystal phase of TiO₂ with a crystallite size of 10–15 nm. Combined characterization, including UV–Vis DRS, STEM, EDS and HR-TEM, revealed the successful formation of a heterojunction between TiO₂ and ZnO and an improvement in UV spectrum absorption. The photocatalytic activity was explored using MO degradation under ultraviolet light illumination. The results of the optimized TiO₂-ZnO nanocomposite show excellent photocatalytic activity and photostability over a number of degradation reaction cycles. In addition, the current approach has immense potential to be used as a proficient method for synthesizing mixed metal oxide nanocomposites.

This paper presents the fabrication of a copper tin sulfide (CTS) counter electrode for application in third-generation solar cells. The fabrication process involved modified chemical bath deposition (M-CBD) or a successive ionic layer adsorption reaction (SILAR). Initially, a ZnO seed layer was deposited onto a fluorine-doped tin oxide (FTO) substrate via CBD. Subsequently, a mesoporous layer of ZnO was deposited onto the FTO substrate using the doctor-blade method. The mesoporous ZnO layer was sensitized with CdS nanocrystals deposited using the SILAR method. Various characterization techniques, including UV–Vis spectroscopy, X-ray diffraction (XRD), and scanning electron microscopy (SEM), were employed to analyze the optical, structural, and morphological properties of the photoanode and CTS counter electrode. The results demonstrate the successful synthesis of a CTS counter electrode with desirable properties for solar-cell applications. The fabricated CTS counter electrode exhibited a conversion efficiency of 0.49%, which was significantly higher than that of carbon-based counter electrodes.

Due to increase of attention in energy and environmental concerns, there has been much interest developed in clean and renewable energy technologies. The utilization of green and eco-friendly sunlight through solar cells like photovoltaic cells, photo-electrochemical cells, and dye-sensitize and perovskite solar cells (DSSCs and PSCs) produces energy demand. Due to high electron mobility, suitable band alignment, and high optical transparency, the binary and ternary transition metal oxide materials such as TiO2, SnO2, ZnO, WO3, Bi2O3 and SrTiO3, Zn2SnO4, BaSnO3, etc. have attracted considerable attention as DSSC and PSC electrode materials. Highly efficient solar cells with sustainable performance under severe mechanical deformations are in great demand in forming wearable power supply devices, essential for space technologies. In this regard, myriads of studies have progressed in developing the said metal oxides by various means of nanostructure forms. The aim of this chapter is to highlight research background, basic concepts, operating parameters, working principles, theoretical aspects, and selection of materials with essential properties for DSSCs and PSCs applications.

The synthesis of Bi₂S₃ nanoparticles for sensitizing TiO₂ photoanodes were synthesized through a cost-effective and straightforward approach using modified chemical bath deposition (M-CBD) or successive ionic atomic layer adsorption reactions (SILAR) at room temperature. Initially, a TiO₂ seed layer was synthesized at room temperature via the chemical bath deposition method, followed by deposition of a mesoporous TiO₂ layer using the doctor blade method. This study investigated the influence of the number of SILAR cycles and the choice of counter electrodes on the performance of Bi₂S₃/TiO₂-based photoelectrodes. Characterization of the prepared Bi₂S₃/TiO₂ photoanode involved various techniques, including X-ray diffraction, UV–Vis spectroscopy, scanning electron microscopy, and Raman spectroscopy, enabling the analysis of its structural, optical, and morphological properties. The Bi₂S₃/TiO₂-based cell exhibits a maximum conversion efficiency of 0.8%, demonstrating the potential of this combination for photovoltaic applications. This study contributes to the field of solar cell technology by presenting a novel approach for sensitizing TiO₂ photoanodes with Bi₂S₃ nanoparticles, offering insights into the optimization of fabrication parameters and performance enhancement strategies for future device design and development.