Self-Powered Photoelectrochemical Photodetectors Based on a CsPbBr₃/S‑<i>g</i>‑C₃N₄ Heterojunction-Sensitized 3D ZnO Nanostructured Thin Film

The production of photodetectors that can provide their own power needs and can be adapted to different application conditions is very important for next-generation optoelectronic devices. Three-dimensional (3D) ZnO in nanoflower (NF) morphology was synthesized to be sensitized with all-inorganic perovskite for the application of self-powered photodetector (PD) devices. Consequently, we report high-performance and air-/solvent-stable ZnO/CsPbBr3/S-g-C3N4-based PD devices in three different forms: as a solid-state form and photoelectrochemical (PEC)-type PDs in both liquid electrolyte systems and a quasi-solid-state (QSS) form. The solid-state configuration of the PD device generated a photocurrent density of 150 μA at 367 nm, while the detectivity and responsivity values were calculated as 3.4 × 1015 Jones and 0.25 AW–1, respectively. The device was confirmed to be air-stable upon stability tests for 90 days, retaining more than 65% of its initial current density. The self-power ability of ZnO/CsPbBr3/S-g-C3N4 PEC-type PDs was proven for both liquid electrolyte systems and QSS forms. Open cell voltage and sensitivity as high as 250 mV and 3.96 × 107%, respectively, were obtained for QSS ZnO/CsPbBr3/S-g-C3N4 PEC-type PDs. This study proved that the ZnO/CsPbBr3/S-g-C3N4-based PEC PD devices with high performance in the range of 367 to 460 nm can be adapted to meet different application requirements in a wide range from liquid electrolyte systems to solid- and QSS-type electrolyte systems

Impact on the Photocatalytic Dye Degradation of Morphology and Annealing-Induced Defects in Zinc Oxide Nanostructures

In this study, three different morphologies, nanoflower (NF), nano sponge (NS), and nano urchin (NU), of zinc oxide (ZnO) nanostructures were synthesized successfully via a mild hydrothermal method. After synthesis, the samples were annealed in the atmosphere at 300, 600, and 800 °C. Although annealing provides different degradation kinetics for different morphologies, ZnO NS performed significantly better than other morphologies for all annealing temperatures we used in the study. When the photoluminescence, electron paramagnetic resonance spectroscopy, BET surface, and X-ray diffraction analysis results are examined, it is revealed that the defect structure, pore diameter, and crystallinity cumulatively affect the photocatalytic activity of ZnO nanocatalysts. As a result, to obtain high photocatalytic activity in rhodamine B (RhB) degradation, it is necessary to develop a ZnO catalyst with fewer core defects, more oxygen vacancies, near band emission, large crystallite size, and large pore diameter. The ZnO NS-800 °C nanocatalyst studied here had a 35.6 × 10–3 min–1 rate constant and excellent stability after a 5-cycle photocatalytic degradation of RhB