A study on structural, optical, and electrical characteristics of perovskite CsPbBr 3 QD/2D-TiSe 2 nanosheet based nanocomposites for optoelectronic applications.

Lead halide perovskite (CsPbBr 3 ) quantum dots (QDs) and two-dimensional (2D) layered transition metal dichalcogenides have a significant application in solution-processed optoelectronic devices. Here, we report the oleylamine-assisted exfoliation of TiSe 2 nanosheets (NSs) in dichlorobenzene with high concentration and stable dispersion. The functionalized TiSe 2 NSs were used to synthesize the solution-processed perovskite CsPbBr 3 QD/TiSe 2 NS-based nanocomposite. The perovskite QDs and TiSe 2 NSs were characterized by different techniques. The strong photoluminescence (PL) quenching and decreased lifetime decay of the nanocomposite indicates efficient charge transfer from photo-excited CsPbBr 3 to TiSe 2 NSs. The calculated charge-transfer rate constant ( K ET ) from photo-excited CsPbBr 3 to TiSe 2 NSs increased from 1.50 × 10 8 to 2.79 × 10 8 s -1 in different concentrations of TiSe 2 NSs (5 to 20 μg mL -1 ), respectively. Furthermore, the photo-currents of CsPbBr 3 QD/TiSe 2 NS nanocomposite devices were dramatically enhanced ∼2 times compared to pristine CsPbBr 3 QD based devices, which supports the charge transfer and charge separation in nanocomposite devices.