Recent Progress on Photomultiplication Type Organic Photodetectors

Photodetectors as a significant unit of intelligent optoelectronic systems have stimulated immense attention from multidisciplinary areas. Photomultiplication (PM) is desirable for sensitive photodetectors with strong detection capability of weak light, which can further simplify the photo-detection systems without pre-amplifier circuit. For organic photodetectors (OPDs), PM phenomenon cannot be realized by utilizing the principle of avalanche effect or impact ionization as in inorganic materials, stemming from organic semiconductor materials with large exciton binding energy and disordered structure. In this review, the recent progress on PM type OPDs is comprehensively summarized from the perspective of device physics and material science. Charge tunneling injection induced by interfacial traps becomes the mainstream working mechanism for obtaining PM phenomenon. A series of PM type OPDs was achieved by utilizing interfacial blocking layer and introducing trap states into active layer or interfacial layer. The filter-free PM type narrowband OPDs are realized by combining the concept of charge injection narrowing with the mechanism of PM. Meanwhile, further development on this hot topic is proposed and fully discussed, including multifunctional OPDs, organic-inorganic hybrid photodetectors, and photodetector systems.