Organic-inorganic hybrid inverted photodiode with planar heterojunction for achieving low dark current and high detectivity

Abstract

In this study, the strategy of using an organic-inorganic hybrid planar heterojunction consisting of polymeric semiconductors and inorganic nanocrystals is introduced to realize a high-performance hybrid photodiode (HPD) with low dark current and high detectivity. To prevent undesired charge injection under the reverse bias condition, which is the major dark current source of the photodiode, a well-defined planar heterojunction is strategically constructed via smart solution process techniques. The optimized HPD renders a low dark current of similar to 10(-5) mA cm(-2) at -5V and similar to 10(-6) mA cm(-2) at -1V, as well as a high detectivity similar to 10(12) Jones across the entire visible wavelength range. Furthermore, excellent photocurrent stability is demonstrated under continuous light exposure. We believe that the solution-processed planar heterojunction with inverted structure can be an attractive alternative diode structure for fabricating high-performance HPDs, which usually suffer from high dark current issues.