Superhalide substituted perovskites for high performance photodetection

Varun Sridhar^1*, Surojit Chattopadhyay¹

¹Biomedical science and engineering, Institute of Biophotonics, Beitou, Taiwan

* Presenter:Varun Sridhar, email:varunsimha123@gmail.com

Perovskites are promising materials for photodetection due to their excellent and tunable optoelectronic properties. However, FAPbI₃ perovskites suffers from environmental degradation that limits its application. In addition to other ways reported to control the degradation, we have used hexafluorophosphate (PF₆) substitution of the iodine. We show from various study, including electron microscopy and synchrotron based X-ray characterization, that at low levels of substitution with PF₆ results in better crystallinity and stability of the FAPbI_3-x(PF₆)_x film. To prove the enhancement in crystalline quality and stability, we have fabricated perovskite@graphene photodetector (PD) devices with and without PF₆ substitution. The pure perovskite@graphene device showed an unstable, and a weak photoresponse. However, minimally PF₆ substitution, combined with graphene, enhanced the photoresponsivity and detectivity to ~ 10⁶ AW^-1, and ~10¹⁴ Jones, respectively, under an illumination of ~ 30 nW/cm² of 405 nm laser, under 1 V bias. This result opens up a route to stabilize the perovskites and study its beneficial effect in high performance optoelectronic devices.

Keywords: Perovskites, Superhalogen, Photodetector, Graphene, Ultrahigh responsivity