Ultrabroadband photodetection with quantum dot/graphene hybrids on flexible substrate.*

X-ray and visible-light detection are vital to advances in medical imaging, nuclear security, astrophysics, wearable electronics, and many other sensing needs. Quantum dot and graphene nanohybrids utilize quantum confinement and enhanced light-matter interaction to achieve responsivities up to 10^7 A/W. Where previous photodetectors (PDs) are limited around visible and near-IR detection, we report on hybrids using lead-sulfide QDs, coated in polymethyl methacrylate (PMMA) to self-scintillate and achieve ultrabroadband detection. These PDs boast a spectrum stretching from near-IR to x-ray, a span of 4 orders of magnitude. Furthermore, these devices are developed on polyethylene terephthalate (PET) substrate to augment the strength already provided by graphene, allowing flexibility and enhancing durability. Our work shows the PMMA coatings of these devices and their PET substrate do not hinder performance in the visible-IR range. These detectors perform while bent to radii of curvature as small as 6 mm and retain said performance over time. This work demonstrates that not only are ultrabroadband PDs achievable with PbS QDs and graphene, but flexible sensors are achievable using PET substrate, creating opportunities for imaging and sensing applications in diverse environments.