Numerical studies of P3HT : PCBM organic solar cell with an additional polymer layer using drift diffusion model

Abstract

Solar energy can replace the conventional energy sources in the near future. Organic solar cells have been showing tremendous improvement in their device performance for the past few years. Organic materials with their semiconducting properties and mechanical aspects being similar to that of conventional plastic materials present an affordable alternative for new generation solar cells to wipe out the energy crisis. Among the various structures for organic solar cells, bulk heterojunction (BHJ)solar cells have attracted attention for their improved mechanism for electron-hole pair separation, mechanical flexibility etc. In this paper, organic solar cell based on P3HT : PCBM BHJ is studied and the influence of active layer thickness on the device performance is investigated using numerical simulations with the drift diffusion concept. We further analyse the variation of device parameters by adding an additional polymer active layer of donor material P3HT between the BHJ and PEDOT : PSS layer. The numerical simulations are performed using the general purpose photovoltaic device model. The device parameters are assigned with the intention of analysing a solar cell with high mobility and less recombination rate leading to high efficiency. The solar cell shows maximum power conversion efficiency (PCE)of 9.312% when the active layer thickness is 210nm. On adding additional P3HT layer, the optimized cell shows maximum PCE of 11.13% under AM 1.5G spectrum when the polymer active layer thickness is 15nm and BHJ is 195nm