Two-Dimensional Perovskite Nanoplatelets-Based Photodetectors for UV Light Detection

Perovskite nanocrystals have an added advantage as promising materials for optoelectronic applications due to their peculiar photoluminescence (PL) properties. Here, we report the preparation of perovskite nanoplatelets (NPLs) by using the vacuum-assisted low-temperature (VALT) method. The perovskite NPLs offer the advantage of cutting off the longer wavelength photons and are highly sensitive due to their large surface-to-volume ratio. The PL quantum yield (PLQY) of the synthesized perovskite NPLs is boosted up to 80% by the postsynthesis passivation and is stable for 20 days. These NPLs can absorb the UV light and re-emit in the visible region, i.e., 460 nm. Furthermore, we have fabricated the photodetector using perovskite NPLs as the active layer, and the device exhibits a maximum responsivity of 2.72 A/W, an ON/ OFF ratio of
$2\times 10^{{3}}$
, a specific detectivity of
$2.4\times 10^{{11}}$
Jones, and an external quantum efficiency (EQE) of 887%. The rise and fall times of the fabricated devices are estimated as 200 and 270 ms, respectively. The longer rise and fall times are due to the enormous number of traps at the interface between the randomly oriented NPLs and the interface between the CsPbBr3 NPLs and the Al electrode.