Research on heterojunction semiconductor photodetectors based on CsPbBr3 QDs/CsPbBrxI3–x QDs

• A heterojunction photodetector based on CsPbBr3 QDs/CsPbBrxI3–x QDs was fabricated, achieving a type II band alignment that enhances carrier extraction and reduces non-radiative recombination. • By tuning the Br:I ratio, the band gap of CsPbBrxI3–x QDs was adjusted from 2.284 to 2.394 eV, enabling optimized energy level matching with the carbon electrode. • The optimized device with CsPbBr3 QDs/CsPbBr2I QDs heterostructure showed a 73% increase in responsivity and a specific detectivity improvement from 6.98 × 10^12 to 3.19 × 10^13 Jones. • The on/off ratio of the heterojunction photodetector reached 10^6, demonstrating significant performance enhancement over the pristine CsPbBr3 QDs device.