Enhancement of CsPbBr3 nanocrystal photodetector by plasmonic effect and their angle dependence study

In-organic perovskite nanocrystals (CsPbBr_3) show great potential for optical sensing applications that have excellent optic properties such as high carrier mobility, long carrier diffusion length, excellent visible light absorption. The absorption spectrum well overlaps with localized surface plasma resonance (LSPR) of noble Au nanocrystals (Au NCs). Currently, the state-of-art photocurrent of CsPbBr_3 is within the nanoampere range, limiting further practical application. Therefore, we would like to enhance the photocurrent of CsPbBr_3 nanocrystals and improve the device's stability. With the nature of energy level alignment between Au nanoparticle and CsPbBr_3 nanocrystals , significant photocurrent enhancement was demonstrated. In this study, CsPbBr_3 perovskite nanocrystals have been synthesized and used to fabricate the photodetector onto the gold finger electrode. Under laser excitement with wavelength at 520 nm, it has been observed that CsPbBr_3 nanocrystals alone could obtain the photocurrent to 100 nA. By introducing with the Au Nanoparticles, the net photocurrent has been increased nearly 1µA. Therefore, it could be said that Au nanoparticles can assist the photocurrent generation of CsPbBr_3 nanocrystals more sufficiently with better stability. This allows the further device system integration of such CsPbBr_3 nanocrystals with Au nanoparticles.