Solution Processed CH ₃ NH ₃ SnI ₃ QDs/ZnO CQDs Heterojunction UV-Visible Broadband Photodetector

Solution-processed p-type, lead-free methylammonium tin iodide (MASI) perovskite quantum dots (PQDs) and n-type ZnO colloidal quantum dots (CQDs) were employed to fabricate an Ag/MASI PQDs/ZnO CQDs/ITO structured ultraviolet (UV)–visible broadband photodetector. The MASI PQDs were synthesized via a ligand-assisted reprecipitation (LARP) solution method, while the ZnO CQDs were prepared using a hot-injection solution process. The ZnO CQD layer acted as both an electron transport layer (ETL) and a UV absorption layer, whereas the MASI PQD thin film absorbed light across the UV–visible spectrum. The device exhibited a broadband photoresponse over 300–700nm, with maximum responsivity, external quantum efficiency (%EQE), and specific detectivity of 25.26 A/W (2.5 A/W), 8700.66% (516.66%), and$8.3\times 10^{{12}}$($8.22\times 10^{{11}}$) Jones, respectively, at 360nm (600nm) under incident light intensities of 1.04mW/cm2(5.8mW/cm2). Furthermore, the photodetector demonstrated rise ($\tau _{\text {r}}$) and fall ($\tau _{\text {f}}$) times of 0.207 (0.303s) and 0.368s (0.419s) at 360 (600nm), respectively.