ELECTRICAL CHARACTERIZATION OF P3HT/PCBM BULK HETEROJUNCTION ORGANIC SOLAR CELL

Abstract

Photovoltaic performance of bulk heterojunction organic solar cell based on poly (3-hexylthiophene) (P3HT) and [6,6]-phenyl C61-butyric acid methyl ester (PCBM) were investigated. The active layer is a spin coated organic blend of a p material (P3HT) and an n-material from the fullerene derivative PCBM; it is sandwiched between electrodes ITO-PEDOT/PSS and Al/LiF as back-contact. Modeling of organic bulk heterojunction solar cells is complicated because of various internal mechanisms involved. Two models have been suggested, namely an effective medium model and a network model. We applied an effective medium model where the main assumption is the p–n nanostructure is treated as one single effective semiconductor layer, and parameters in this configuration are fed into a standard solar cell device simulator, called SCAPS. In this model, other non-carrier related properties, such as the refractive index n, the dielectric constant ε and the absorption constant α are influenced by both p–n materials and used as input parameters. The power conversion efficiency of 3.88% with short circuit current density of 20.61 mA/cm 2 , open circuit voltage of 0.39 V and fill factor of 48% were obtained. Finally, factors which could limit cell conversion efficiency are discussed.