Study of Charge Transfer Characteristics in Hybrid Polymer Solar Cells Using Intensity Modulated Spectroscopy

Polymer solar cells are widely investigated for their low-cost fabrication process and promising power conversion efficiency (PCE). The highest PCE reported in these cells is 12.6%, which is barely enough to make it a commercially successful product. These solar cells also suffer from stability problems. To improve the PCE further, it is imperative to understand the dynamics of charge transfer in these cells and identify the challenges. We recently developed a simple setup for performing intensity modulated photovoltage and photocurrent spectroscopies (IMVS and IMPS respectively) on solar cells to investigate the transport properties of photo-generated carriers. We fabricated bulk heterojunction type polymer solar cells, which consists of a light absorbing layer made of an electron donor polymer mixed with an electron acceptor polymer and studied the carrier transport and recombination characteristics. In this presentation, we will discuss the results of our studies on these solar cells in the hybrid inverted configuration.