| 초록 |
Looking at the trends of organic photodiode (OPD) research, the optimized thickness of the active layer is saturated at ~0.5μm, which is actually not very thinner compared to that of Si-photodiode. This is due to the issue of dark current in thin film OPDs. Here we decrease the thickness of active layer by trap-assisted photomultiplication mechanism with the optimized chemical composition. Although high dark current issue still presents, however, we can dramatically increase external quantum efficiency via photomultiplication, so that high detectivity of 1012 comparable to conventional Si can be obtained with significantly reduced thickness of 70 nm. A nonfullerene acceptor, IDIC was introduced strategically between hole transport active layer and cathode, turned out to be much more efficient sensitizer than the conventional fullerene-based acceptors, as confirmed by the effective lowering of the Schottky barrier under illumination, as well as the highest EQE exceeding 130,000%. |
