Project R-8516

Unraveling and stretching the fundamental limits of near-infrared photodetection based on organic semiconductors (Research)

Due to their application in night and thermal vision systems, infrared image sensors are truly imaginative. To date, the detector and the electronic readout are prepared separately and then interconnected at the pixel level. Obviously, this is a time-consuming process, resulting in low throughput and thus high cost, limiting widespread use. A monolithic approach with direct deposition of the detectors on top of the electronic readout can provide a solution. However, attempts to apply this technology to the current inorganic low bandgap absorbers were not very successful because of compatibility issues. In this respect, organic semiconductors are much more attractive as they can be processed from solution at low temperature on virtually every substrate, with additional advantages in terms of flexibility, robustness, and sustainability. For UV-visible light detection, organic photodetectors (OPDs) can already match and even surpass the performance of state of the art inorganic photodetectors. Unfortunately, organic materials generally show limited absorption in the near-infrared (NIR) part of the spectrum. In the present project, we target novel NIR-absorbing materials for regular bulk heterojunction NIR-OPDs as well as organic cavity enhanced photodetectors with the main aim to elucidate the fundamental limitations of NIR photodetection based on organic semiconductors, with a strong emphasis on revealing the relations between charge transfer states and OPD performance metrics

01 January 2018 - 31 December 2021