Solution-dispersed copper iodide anode buffer layer gives P3HT:PCBM-based organic solar cells an efficiency boost

In this work, we proposed solution-dispersion of copper iodide (CuI) anode buffer layer (ABL) for inverted organic solar cell (I-OSC) application. It was found that device coated with CuI ABL achieved a higher power conversion efficiency of 3.20%, which can be attributed to the significant improvement of the photovoltaic properties such as short circuit current density (J_sc) and fill factor. The electrical characterizations (i.e. series resistance (R_series), shunt resistance (R_shunt) and impedance measurement) have revealed that the free holes can be extracted to the anode electrode more effectively through CuI ABL compared to that of standard device (without CuI). As a result, CuI suppressed holes to recombine with electrons residing at the lowest unoccupied molecular orbital of PCBM. The obtained results indicate that CuI is an effective ABL and solution dispersion method can be used to apply for I-OSC application. We believe that this work is suitable to apply in low-temperature processed flexible-based optoelectronic devices.