[20p-PA3-1~42] 12.3 Functional Materials and Novel Devices

▲ [20p-PA3-11] Performance Study of Near-Infrared Organic Photodetectors based on a Phthalocyanine Derivative and a Fullerene Derivative with Different Blend Ratios

〇(M2)Shahriar Kabir¹, Yukiko Takayashiki¹, Jun-ichi Hanna¹, Hiroaki Iino¹ (1.Tokyo Tech)

Keywords:organic photodetector, liquid crystalline semiconductor, near-infrared photodetector

In this work, we studied the static and dynamic performance of NIR organic photodetectors prepared with a binary blend of 1,4,8,11,15,18,22,25-octaocltyl-phthalocyanine (8H₂Pc) and a fullerene derivative, Phenyl-C61-butyric acid methyl ester (PC61BM). The materials were blended in weight ratios of 4:1 and 1:1 (8H₂Pc:PC61BM) and used as the active layer to prepare vertical OPDs with inverted architecture. We observed that OPDs prepared with the 4:1 blend ratio showed higher specific detectivity and responsivity. The best performing device showed very good maximum specific detectivity, D*_max = (J_ph/I_light)/(2qJ_d)^1/2 = 2.87×10¹³cmHz^1/2/W, maximum responsivity, R_max = 1.94A/W and maximum J_ph/J_d ratio = 1.35×10⁴ at -2V bias. We think that the OPDs prepared with 4:1 blend ratio perform better because of higher absorption in the NIR region by the blend material. Therefore, in this 8H₂Pc:PC61BM blend system, PC61BM is not necessarily acting as an acceptor but it is improving the thin film morphology of the active layer.