Low‐Power Photodetectors Based on PVA Modified Reduced Graphene Oxide Hybrid Solutions

A low-cost broadband photodetector based on CsPbBr3quantum dots/transfer-free eco-friendly graphene heterostructures for fast photoresponse

We have successfully demonstrated CsPbBr3perovskite quantum dots (QDs)/transfer-free eco-friendly (TFEF) graphene heterostructures with broadband and fast photoresponse. At first, the TFEF graphene is grown directly on the SiO2/Si substrates in an atmospheric pressure chemical vapor deposition (APCVD) system with the copper-foil wrapping methods and camphor precursors. Raman mapping image (15 × 15μm2) showed TFEF graphene with high coverage across the surface (∼65% single-layer graphene, ∼15% bilayer graphene, and ∼20% multilayer graphene). After that, CsPbBr3QDs were synthesized and then spin-coated on the TFEF graphene surface to form heterostructures. Compared to pure CsPbBr3QD-based photodetectors (PDs), CsPbBr3QDs/TFEF graphene-based PDs show a higher photo-to-dark current ratio of ∼7.2 at 2 V white light illumination (112 mW cm-2). Furthermore, the CsPbBr3QDs/TFEF graphene-based PDs show a broadband photoresponse range from ultraviolet to near-infrared with a peak responsivity reaching up to 32 mA W-1, a high detectivity (2.2 × 1010cm·Hz1/2/W) and fast operation speed (rise/fall time: ∼7/∼ 14 ms). This study opens avenues to develop low-cost and rapid fabrication processes of perovskite/2D nanomaterial-based PDs for fast optical communication, image capture, and flame detection applications.

Development and characterization of self-powered, highly sensitive optoelectronic device based on PVA-rGO nanofibers/n-Si

This study provided a promising way to fabricate low-cost and high-performance Poly (vinyl alcohol)-reduced graphene oxide (PVA-RGO) nanofibers/n-Si heterojunction photodetector. For this purpose, the hybrid heterojunction with a very-high rectification ratio (2.4 × 106) was achieved by successfully coating PVA-RGO nanofibers on n-Si wafer by electrospinning method. When the electro-optical analysis of the fabricated heterojunction photodetector under visible light depending on the light intensity, ultraviolet (UV) and infrared (IR) lights was examined in detail, it was observed that the photodetector exhibited both self-powered behavior and very high photo-response under each light sources. However, the highest optical performance was obtained under UV (365 nm) originated from PVA-RGO layer and IR (850 nm) light from both interfacial states between PVA-RGO nanofibers and Si and from Si layer. Under 365 nm UV light, the maximum performance values of R, D, ON/OFF ratio, normalized photo-dark-current ratio and external quantum efficiency (%) were obtained as 688 mA W-1, 1.15 × 1015Jones, 2.49 × 106, 8.28 × 1010W-1and 234%, respectively.