ZnO-based inverted organic solar cells: a comparative analysis of simulation and experimental devices

ZnO-based Inverted Organic Solar Cells (OSCs) were simulated using the Solar Cell Capacitance Simulator (SCAPS-1D) software. Two different device architectures were employed: single-layer (SL) and trilayer (TL) configurations. In the SL-OSCs, the structure consisted of a P3HT/PCBM blend between ZnO and molybdenum oxide (MoO₃) layers. The P3HT/PCBM blend layers were combined with thin layers from donor (P3HT) and acceptor (PCBM) materials for the TL-OSCs. Electrospray deposition (ESD) was utilized to fabricate the OSCs for comparison. The analysis of the results showed that the TL-OSCs exhibited improved device performance and operational stability compared to the SL devices. Simulated efficiencies were 2.85% for TL and 2.25% for SL, whereas experimental OSCs yielded 1.47% (TL) and 0.84% (SL) efficiencies. This increasing trend in TL-OSCs’ performance aligns with existing literature. Furthermore, the TL OSC structures demonstrated good stability at optimum annealing temperatures up to 130 °C. Additionally, the ZnO-based TL devices displayed enhanced ambient stability under continuous 8h illumination compared to SL-OSCs. This improvement can be attributed to the interfacial layer, which aids in separating charge carriers and reducing recombination rates, consequently enhancing overall device efficiency. The stacked layers in TL OSCs may also function as a barrier, inhibiting diffusion and protecting against moisture and oxygen exposure, thereby contributing to improved device stability.