| 초록 |
A new and facile photodiode fabrication strategy is suggested which includes genuine creation of anode buffer layer to achieve high quantum efficiency without sacrificing low noise current density. By adding small amount of cationic surfactant (CTAB) in the blend solution consisting of poly(3-hexylthiophene) and PCBM, we could simply generate preferentially oriented interface dipole layer of CTAB between ITO and active layer so that the workfunction of ITO could be tuned to be ~4.54 eV as studied by ultraviolet photoelectron spectroscopy, without the assistance of oxide buffer layer such as ZnO and TiO2. Moreover, we could observe synergetic contribution of addition of CTAB to the morphology of active layer, in terms of inter-miscibility between P3HT and PCBM. Thanks to such synergetic contribution of CTAB, the resulting photodiode with inverted diode geometry revealed high detectivity of ~ 2.5×1012 Jones based on low dark current of 0.13 n A/cm2 at -1V and low noise current of 4×10-1 pA/Hz0.5 as well as high EQE of 54.4%. This work opens the possibility of facile and simple photodiode fabrication in solution system. |
