Simulation and Experimental Device Performance Analysis of TiO₂Based Inverted Organic Solar Cells

Simulation and experimental analysis of TiO₂ based organic solar cells (OSCs) using the Solar Cell Capacitance Simulator is presented herein. The OSCs were simulated in two different device configurations, i.e., with TiO₂ (inverted device) and without a TiO₂ interlayer (reference device). Secondly, the simulation analysis of OSCs was compared with experimental device characteristics. The efficiency levels of the OSCs were well matched, and good agreement was found between the simulated and experimental results. The role of the TiO₂ layer between the indium tin oxide substrate and device active layer (AL) was shown to be quite significant when comparing the efficiency of the reference and inverted devices. Thermal annealing played a crucial role in enhancing the efficiency of the inverted OSCs. The performance parameters of both computational and experimental OSCs were quite consistent with increasing annealing temperature ranging from room temperature (RT) to 110°C. However, at higher temperature, the OSCs started to deteriorate due to the diffusion of silver (Ag) into molybdenum oxide (MoO₃) and into the device AL, which transformed the MoO₃ layer into a MoO₃-Ag alloy, resulting in the loss of its hole extraction properties.