Efficiency and stability improvement of organic solar cells based on PTB7: PCBM through hot-substrate coating

Abstract

Despite the relatively high efficiency of the organic solar cells (OSCs), their stability issues have not yet been fully resolved. Various approaches have been reported in the literature to improve the overall performance and stability of OSCs. In this work, the approach of hot-substrate coating was carried out to enhance the performance and stability of OSCs based on the PTB7:PC71BM active layer. The approach involves maintaining the substrate temperature at 150°C, while depositing the active layers with a spin coater. The results demonstrate that OSCs fabricated via hot-substrate coating achieved a power conversion efficiency (PCE) of 7.94%, whereas devices with active layers deposited at room temperature (RT) achieved an average efficiency of 5.6%. According to the stability study of the devices, it was observed that the hot-substrate coated devices maintained 94% of their initial PCE after 72 h of operation. This is where the RT-coated devices retained 53% of their efficiency. In conclusion, the proposed approach can be applied to improve the efficiency and stability of organic solar cells.