Analysis of organic photovoltaic devices with MoOx doped 4, 4′, 4"-tris(N-(3-methylphenyl)-N-phenylamin) triphenylamine as hole transport layer

MoOx doped 4,4', 4 ''-tris(N-(3-methylphenyl)-N-phenylamin) triphenylamine (m-MTDATA) is used as a hole transport layer to improve the efficiency of CuPc/C-60 small molecular organic photovoltaics. A series of devices is fabricated in a high vacuum system. One of the devices with the structure of indum tin oxides (ITO)/m-MTDATA:MoOx(3:1)(30 nm)/CuPc(20 nm)/C-60(40 nm)/Bphen (8 nm)/LiF(0.8 nm)/Al(100 nm) shows that the following parameters are achieved: the open circuit voltage V-oc = 0.40 V, short-circuit current J(sc) = 6.59 mA/cm(2), fill factor of 0.55, and power conversion efficiency n(p) = 1.46% under AM1.5 solar illumination. The efficiency of the device is improved by 38% compared with that of the device without hole transport layer ITO/CuPc(20 nm)/C-60(40 nm)/Bphen(8 nm)/LiF(0.8 nm)/Al(100 nm). The improvement of the device performance may be attributed to the addition of m-MTDATA:MoOx (3:1) (30 nm) hole transport layer that reduces the contact resistance between the ITO electrode and the organic layer, thus reducing the overall device series resistance and improving the efficiency of the device.