Enhancing light scattering in low-temperature PDINO cathode interlayer of organic solar cells using plasmonic copper nanorods

• The incorporation of copper nanorods in the cathode interlayer of PDINO have significantly increased the performance of the fabricated organic solar cell. In summary, the 2% CuNRs device showed a Jsc of 14.92 mA/cm2, Voc of 0.63 V, FF of 67.91% and enhanced PCE of 6.36%, which was regarded as the optimal device. The high performance was attributed to the plasmonic resonance of CuNRs observed from the UV/Vis which increased the absorption at ∼525 nm. It was also observed that the Raman scattering of the 2% film was better than others, suggesting more molecular ordering. Consequently, this shows that CuNRs can play a significant role in improving the overall performance of organic solar cells. Organic solar cells (OSCs) are a potential alternative to photovoltaic devices due to affordability. However, the power conversion efficiency (PCE) of OSCs still suffers due to charge recombination, leading to limitations in their commercialisation. The application of cathode interlayers in OSCs has garnered much interest in renewable energy due to their low-temperature fabrication. In this study, various concentrations of colloidal copper nanorods (CuNRs) have been employed to enhance light scattering in perylene diimides functionalized with amino oxide (PDINO) cathode interlayer. The 56.13 nm long CuNRs have increased the absorbance of PDINO, showing enhancement in localised surface plasmonic resonance (LSPR) observed at ∼525 nm. Due to the LSPR, CuNRs have significantly improved the PCE of ITO/PEDOT:PSS/P3HT:PCBM/PDINO:CuNRs/Ag device by 36.28% compared to the pristine device, indicating a simple and low temperature method of fabricating efficient OSCs.