[23p-D114-1~12] 12.3 Functional Materials and Novel Devices

▲ [23p-D114-4] Solution Processed Bulk-Heterojunction Organic Photodetectors with an Alkoxy-Phthalocyanine Derivative for Near-Infrared Sensing

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

Keywords:Organic semiconductor, Near-infrared light, Organic photodetector

We fabricated and characterized bulk-heterojunction (BHJ) organic photodetectors with 1,4,8,11,15,18,22,25-octaalkoxy-phthalocyanine (8OH₂Pc), and Phenyl-C61-butyric acid methyl ester (PC₆₁BM) with blend ratios of 4:1 and 1:4 w/w. Under 810 nm light (60 mW/cm²) at -1 V, the 1:4 and 4:1 w/w samples showed shot noise limited specific detectivity (D*_sh) of 9.3×10¹⁰ and 3.9×10⁸ Jones, responsivity (R) of 9.2 and 2.7×10^-2 mA/W, and external quantum efficiency (EQE) of 1.4×10^-2 and 4.1×10^-5 %, respectively. X-ray diffraction measurement showed that active layer of 1:4 w/w sample was amorphous-like while that of 4:1 w/w was crystalline similar to 8OH₂Pc. The surface roughness of 1:4 w/w sample was also remarkably low. These effects were attributed to the higher concentration of amorphous PC₆₁BM in the blend which resulted in a highly intermixed BHJ with small grain size and large interface area. These conditions enhanced the exciton dissociation in 1:4 w/w sample and improved performance.