Filterless Narrowband Photodetectors Based on Solution-Processed CH₃NH₃PbBr₃ Microcrystal/Indium Tin Oxide Heterojunctions

In this work, we have reported narrowband photodetectors based on solution-processed CH3NH3PbBr3 microcrystals/indium tin oxide bulk heterojunctions. Structural and optical studies showed that the CH3NH3PbBr3 microcrystals possessed high crystallinity with high-density surface defects. Accordingly, the excess carriers photoexcited near the surface of CH3NH3PbBr3 microcrystals owing to the absorption of high-energy photons mainly nonradiatively recombined. In contrast, the excess carriers photoexcited inside the CH3NH3PbBr3 microcrystals mostly generated the photocurrent due to the long charge carriers' diffusion length. Finally, narrowband photodetection with a response spectrum as narrow as 16 nm and a responsivity of 1.23 × 10–3 A/W·cm–2 has been demonstrated.