High-Performance Colloidal ZnO Quantum Dots/TIPS-Pentacene Heterojunction- Based Ultraviolet Photodetectors

This article reports a p-type TIPS-pentacene and n-type colloidal ZnO quantum dots (QDs) organic/ inorganic heterojunction-based ultraviolet (UV) photodetector. The colloidal ZnO QDs of average sizes of ~1.77 nm are synthesized using a hot injection route. A thin film of ZnO colloidal QDs (CQDs) is first grown on an indium-doped tin oxide (ITO)-coated glass substrate using the spin coating method. The TIPS-pentacene organic thin film is then grown on the ZnO CQDs layer by the spin coating method. The photoresponse of the proposed structure is measured for monochromatic light of wavelengths in the range of 300–700 nm. Under 1-V reverse bias operation, the proposed UV-photodetector shows the maximum responsivity, detectivity, and external quantum efficiency (EQE) of ~59.15 A/W, ~ $7.01\times 10$ ¹³ cmHz ^1/2 /W, and ~19877% respectively, at 370-nm wavelength of the incident UV light of 43- ${\mu }\text{W}$ /cm ² intensity.