Low-Dimensional Nanostructure Based Flexible Photodetectors: Device Configuration, Functional Design, Integration, and Applications

CONSPECTUS:A flexible photodetector that extends unique capabilities such as deformation,adaptivity to a soft surface,mechanical stability,and high photoresponsivity compared to the rigid devices has come to prominence in telecommunication,remote sensing,medical diagnostics,image sensing,optical communication,and the biomimetic human visual system.Low-dimensional nanomaterials consisting of one-dimensional(1D)nanowires(NWs),2D nanoplates,and heterojunctions such as quantum dot modified NWs,hierarchical 1D hybrid nanomaterials,1D/2D composites,2D/2D heterostructures,etc.are considered as promising photosensitive materials in designing a flexible photodetector owing to the large surface to volume ratio and mechanical suppleness along the growth direction of the 1D NWs,excellent mechanical strength,superior structural stability,fast electron mobility,and low power dissipation of 2D nanoplates,and the synergistic effect of the heterojunctions.In this Account,we present our recent progress on low-dimensional nanostructure based flexible photodetectors.First,the three components,including the soft substrate,conductive electrodes,and representative lowdimensional nanomaterials(1D NWs,2D nanoplates,and various types of heterojunctions)required for achieving flexible photodetector are summarized.Then,the design strategies toward functional photodetectors are presented in terms of their flexibility,stretchability,transparency,and photodetector with tunable photoresponse properties.The integration concepts of the photodetector with flexible energy storage to realize independent detectivity and the field effect transistor to amplify the responsivity are also provided.Furthermore,the application examples of the flexible photodetector in the artificial visual memory system and the biomimetic eye are reviewed.Finally,we discuss the future prospects of the low-dimensional nanostructure based flexible photodetector in the field of flexible image sensing and integrated electronics.