Modelling and Performance Analysis of CuPc and C60 Based Bilayer Organic Photodetector

Abstract

An optoelectronic device model for organic photodetector based on bilayer structure has been presented. Drift-diffusion and optical-generation model from Synopsys tool have been incorporated and its optoelectronics behavior has been discussed. The model shows an outstanding rectifying behavior under dark condition due to the different work function of the electrodes. Photocurrent density of 6.64 mA/cm2 is found under the illumination of 3 W/cm2. To analyze rectifying behavior of current density-voltage characteristics of the organic photodetector, the curve has been fitted with the Shockley equation. The enhancement of ideality factor of diode current under illumination from that of dark current at forward bias is attributed to enhancement of recombination loss due to generation of photo-carrier and injection of carriers from electrodes. Almost equal probability of photocurrent spectra in the entire spectral region indicates equal probability of exciton generated and dissociated at the interface between CuPc and C60 layers. The detectivity of the proposed photodetector is calculated and it is in order of 1010 Jones at 650 nm due to high dark current density and recombination loss. The presence of interface trap density and large transport distance give evidence of low response speed in the device.