arXiv subjects

L. G. Occhipinti

Publications and source records attributed to L. G. Occhipinti.

2 recordsLinked to original sources

arXiv2023

Spray-Coated Graphene/Quantum Dots Paper-Based Photodetectors

Paper is an ideal substrate for the development of flexible and environmentally sustainable ubiquitous electronic systems. When combined with nanomaterials, it can be harnessed for various Internet-of-Things applications, ranging from wearable electronics to smart packaging. In this study, we present a non-vacuum spray deposition of arrays of hybrid single layer graphene (SLG)-CsPbBr3 perovskite quantum dots (QDs) photodetectors on a paper substrate. This approach combines the advantages of two large-area techniques: chemical vapor deposition (CVD) and spray-coating. The first technique allows for the pre-deposition of CVD SLG, while the second enables the spray coating of a mask to pattern CVD SLG, electrode contacts, and photoactive QDs layers. The prepared paper-based photodetectors achieved an external responsivity of 520 A/W under 405 nm illumination at <1V operating voltage. By fabricating arrays of photodetectors on a paper substrate in the air, this work highlights the potential of this scalable approach for enabling ubiquitous electronics on paper.

physics.app-ph↗

arXiv2023

Graphene-perovskite fibre photodetectors

The integration of optoelectronic devices, such as transistors and photodetectors (PDs), into wearables and textiles is of great interest for applications such as healthcare and physiological monitoring. These require flexible/wearable systems adaptable to body motions, thus materials conformable to non-planar surfaces, and able to maintain performance under mechanical distortions. Here, we prepare fibre PDs combining rolled graphene layers and photoactive perovskites. Conductive fibres ($\sim$500$Ω$/cm) are made by rolling single layer graphene (SLG) around silica fibres, followed by deposition of a dielectric layer (Al$_{2}$O$_{3}$ and parylene C), another rolled SLG as channel, and perovskite as photoactive component. The resulting gate-tunable PDs have response time$\sim$5ms, with an external responsivity$\sim$22kA/W at 488nm for 1V bias. The external responsivity is two orders of magnitude higher and the response time one order of magnitude faster than state-of-the-art wearable fibre based PDs. Under bending at 4mm radius, up to$\sim$80\% photocurrent is maintained. Washability tests show$\sim$72\% of initial photocurrent after 30 cycles, promising for wearable applications.

physics.app-ph↗