The prediction of carrier generation rate based on OTMM for perovskite solar cells based on different back electrodes

Abstract Perovskite Solar Cells (PSCs) have drawn tremendous attentions from scientific community due to their advantages of high efficiency and low-cost. However, the mechanism of photoelectron generation is unclear because the light field distribution is difficult to be quantitively characterized by conventional methods. The Optical Transfer Matrix Method (OTMM) has been applied in organic devices based on p-n structures. We have applied different materials as back electrode to examine the light propagation inside of planar p-i-n solar cells with regular structure (Glass/ITO/SnOx/CH3NH3PbI3/Spiro-OMeTAD/Back electrode). The simulations were performed by using OTMM to carry out the optical field modeling of simulated solar cells in visible-near infrared (NIR) range. Among the simulation models, it has been found that perovskite solar cells based on sliver electrode has highest light intensity oscillation and faster charge generation rate. But sliver electrode has lower stability because the iodine can diffuse to the interface and form AgI with the assist of NIR-induced thermal effect. By contrast, the independent graphene electrode has disadvantages of interlayer conductivity and transparency. Based on the simulation result, we recommend that the graphene can be applied as a buffer layer between perovskite and sliver electrode instead of being an independent electrode.