Cyclic Voltammetry Investigation of Water-Stable Type II Nanoheterojunction Formation in CsPbBr₃-TiO₂

This study describes the synthesis of water-stable Type II nanoheterojunction formation in CsPbBr₃-TiO₂ and the investigation of its band structure parameters using cyclic voltammetry. CsPbBr₃ exhibits excellent photophysical properties, making it highly valuable for optoelectronic applications. However, the full potential of CsPbBr₃ in aqueous media is often compromised by its inherent instability in the presence of water. To address this issue, we developed a hybrid synthesis approach combining hot-injection and solvothermal methods to fabricate CsPbBr₃-TiO₂ NC. This strategy imports significant water stability to the NC. Structural and optical characterization, including HR-TEM, XRD, UV-PL spectroscopy, and XPS, confirmed the formation of the NC. The formation of a Type II nanoheterojunction was confirmed by CV, with band energy levels closely matching those data obtained from ultraviolet-photoelectron spectroscopy. The analysis reveals significant changes in the band structure, highlighting on charge transfer mechanisms in the heterostructure. The charge transfer properties were found to be strongly influenced by the conduction and valence band-edge energies, which are affected by surface ligands and solvation conditions. Additionally, CV conducted in an aqueous medium offers insights into the solvation effects and charge transfer mechanisms of NC in water, crucial for perovskite-based photocatalytic applications.