Transparent, Wearable, Broadband, and Highly Sensitive Upconversion Nanoparticles and Graphene-Based Hybrid Photodetectors

Numerous investigations of photon upconversion in lanthanide-doped upconversion nanoparticles (UCNPs) have led to its application in the fields of bioimaging, biodetection, cancer therapy, displays, and energy conversion. Herein, we demonstrate a new approach toward lanthanide doped UCNPs and a graphene hybrid planar and rippled structure photodetector. The multi-energy sublevels from the 4f' electronic configuration of lanthanides results in longer excited state lifetime for photogenerated charge carriers. This opens up a new regime for ultra-high-sensitivity and broadband photodetection. Under 808 nm infrared light illumination, the planar hybrid photodetector shows a photoresponsivity of 190 AW(-1), which is higher than the currently reported responsivities of the same class of devices. Also, the rippled graphene and UCNPs hybrid photodetector on a poly(dimethylsiloxane) substrate exhibits an excellent stretchability, wearability, and durability with high photoresponsivity. This design makes a significant contribution to the ongoing research in the field of wearable and stretchable optoelectronic devices.