High-performance broadband photodetector based on perovskite quantum dot with an ITO/CH₃NH₃SnI₃ QD/Ag structure

This study reports the synthesis and application of lead-free CH₃NH₃SnI₃ perovskite quantum dots (PQDs) for broadband photodetection. The PQDs were synthesised using the ligand-assisted reprecipitation (LARP) method and characterized using Transmission Electron Microscopy (TEM) and Selected Area Electron Diffraction (SAED). The TEM and SAED analysis confirmed the presence of quantum dots with an average particle size of ~2.58 nm. An ITO/CH₃NH₃SnI₃ QD/Ag photodetector was fabricated using spin-coating, forming a metal–semiconductor–metal (MSM) structure. The device exhibited strong photoresponse under both UV (385 nm, 9.9 mW/cm²) and visible (600 nm, 5.8 mW/cm²) illumination. The responsivity reached ~2.38 A /W at 385 nm and ~2.23 A/W at 600 nm, with corresponding Specific Detectivity (D*) values of 1.18 × 10¹² Jones and 1.10 × 10¹² Jones at –1 V bias. These results demonstrate the suitability of CH₃NH₃SnI₃ PQDs for high-performance, environmentally friendly broadband optoelectronic applications.