Transient and Flexible Photodetectors

With the rapid development of technology, electronic devices have become omnipresent in our daily life as they have brought much convenience in every aspect of human activity. Side-by-side, electronic waste (e-waste) has become a global environmental burden creating an ever-growing ecological problem. The transient device technology in which the devices can physically disappear completely in different environmental conditions has attracted widespread attention in recent years owing to its emerging application potential spanning from biomedical to military use. In this work, we demonstrated the first attempt for a dissolvable ecofriendly flexible photodetector using a hybrid of graphene and chlorophyll on a poly­(vinyl alcohol) substrate. The whole device can physically disappear in aqueous solutions in a time span of ∼30 min, while it shows a photoresponsivity of ∼200 A W^–1 under ambient conditions. The high carrier mobility of graphene and strong absorption strength of a green photon harvesting layer, chlorophyll, result in the photocurrent gain of the device as high as 10³ with subsecond response time under the illumination of red light. The newly designed photodetector shown here yields zero waste with a minimum impact on the environment, which is very useful for the development of the sustainability of our planet.