Photocatalytic Deposition of Nanostructured CsPbBr₃ Perovskite Quantum Dot Films on Mesoporous TiO₂ and Their Enhanced Visible-Light Photodegradation Properties

Abstract

Herein, we report the in situ photocatalytic deposition of cesium lead bromide (CsPbBr 3 ) perovskite quantum dots on mesoporous TiO 2 -coated fluorine-doped tin oxide (FTO/TiO 2 ) electrodes. The mesoporous TiO 2 layer is used as a photocatalyst to promote the following: (1) the Pb deposition from a Pb 2+ aqueous solution and (2) the in situ Pb conversion into CsPbBr 3 perovskite in the presence of a CsBr methanolic solution without any organic capping agent. Both steps are carried out under ultraviolet light irradiation under ambient conditions without any post-treatment. The obtained FTO/TiO 2 /CsPbBr 3 film was characterized by UV–vis diffuse reflectance spectroscopy, X-ray diffraction, photoluminescence spectroscopy, scanning electron microscopy, and transmission electron microscopy. The FTO/TiO 2 /CsPbBr 3 heterojunction exhibited enhanced visible-light photodegradation activity demonstrated for the oxidation of curcumin organic dye as a model system. The novel and simple approach to fabricating a supported photocatalyst represents a scalable general method to use semiconductors as a platform to incorporate different perovskites, either all-inorganic or hybrid, for optoelectronic applications. The perovskite deposition method mediated by the UV light at room temperature could be further applied to flexible and wearable solar power electronics.

Probing the cw-Laser-Induced Fluorescence Enhancement in CsPbBr3 Nanocrystal Thin Films: An Interplay between Photo and Thermal Activation

“…The data are depicted in Figure . For laser powers higher than 150 μW, we have observed that fluorescence photobleaching takes place on the sample (fluorescence intensity reduction), as observed in other studies. − …”

Perovskite Nanostructure Films for Optoelectronics and Photovoltaics

“…Unlike the postsynthesis deposition of the NCs that results in lower compactness of the films, the in situ deposition of the NCs can be carried out by the two-step photocatalytic deposition of the NCs on mesoporous TiO 2 , where metallic Pb was first photocatalytically deposited on the FTO/TiO 2 substrate followed by photocatalytic reduction of Cs + to form the CsPbBr 3 NC films (Figure e) . Although lower quality MHP NC films with excess pinholes are obtained by different deposition methods, the film quality can be improved by annealing or mild heating in the presence of polar solvent vapors (Figure d,f) .…”

Defect-Passivated Photosensor Based on Cesium Lead Bromide (CsPbBr3) Perovskite Quantum Dots for Microbial Detection

“…Cesium lead bromide (CsPbBr 3 ) perovskite quantum dots (QD) have been used in various applications, including lightemitting devices, 1−3 photosensors, 4,5 and so on because of their high charge carrier mobility, high photoluminescence quantum yield (PLQY), and long carrier lifetime. 6 However, perovskite QDs have intrinsic chemical instability in the presence of moisture, heat, and ultraviolet (UV) radiation. 7 To overcome such instability, various kinds of passivation methods have been developed using polymers and crystal cross-linking materials like 2-aminoterephtahalic acid, phenyl ammonium iodide, and so on.…”

“…Cesium lead bromide (CsPbBr 3 ) perovskite quantum dots (QD) have been used in various applications, including light-emitting devices, − photosensors, , and so on because of their high charge carrier mobility, high photoluminescence quantum yield (PLQY), and long carrier lifetime . However, perovskite QDs have intrinsic chemical instability in the presence of moisture, heat, and ultraviolet (UV) radiation .…”