Porphyrinoid materials for near-infrared organic photodetectors (R-10011)

Near-infrared (NIR) photodetection is highly valuable for numerous scientific, industrial and recreational applications like night vision, thermal imaging and chemical sensing. To date, the so-called hybrid technology is used for these image sensors, in which both the photodetector (PD) 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. A monolithic approach is hence more attractive. Attempts to apply this technology to the state-of-the-art inorganic low bandgap absorbers are, however, not very successful because of compatibility issues. In this respect, organic semiconductors are much more appealing. As nature itself has developed porphyrins as light-harvesting chromophores, it feels natural to pursue PD systems based on similar molecules. Moreover, molecular engineering of the porphyrinoid material allows to extend their absorption to the NIR. Besides, device engineering allows to optimize the PD performance in terms of dark current density (Jd), external quantum efficiency (EQE) and specific detectivity (D*). In this project I will prepare advanced push-pull type porphyrinoid materials with very low bandgaps with a particular emphasis on corroles, contracted porphyrin derivatives with a specific coordination behavior and distinct photophysical features by optimized synthetic sequences and I will evaluate them in NIR organic PDs, with the specific aim to prepare devices competitive with their inorganic counterparts.

Keywords:near-infrared light, Organic photodetectors, porphyrinoid materials

Disciplines:Organic chemical synthesis, Physical organic chemistry, Molecular and organic electronics