Effect of Organic Solar Cells by Inserting Pentacene Layer

This work have demonstrated the effect of small molecule organic solar cells based on a planer heterojunction of phthalocyanine (CuPc) and fullerene (C₆₀) by inserting pentacene layer between MoO₃ and CuPc. The performance of device with structure indium tin oxide (ITO)/MoO₃ (5 nm)/pentacene (0~10 nm)/CuPc (20 nm)/C₆₀ (30 nm)/ 2, 9-dimethyl-4, 7-diphenyl-1, 10-phenanthroline BCP (10 nm)/aluminum (Al, 100 nm) was enhanced by inserting optimized thickness pentacene layer. The power conversion efficiency (PCE) of device compared to reference information was improved from 0.564% to 0.782%. This achievement of efficiency is not only attributed to the properties of pentacene, which is more suitable in hole transporting ability of high carrier mobility (~1.5 cm²/Vs) and field-effect mobility (~3.0 cm²/Vs), but also the thin MoO₃ layer blocks the transfer of electrons into anode and therefore reduces electron leakage current, which leads to the increase of open circuit voltage (V_OC), short circuit current (J_SC), and PCE. As a result, the pentacene interlayer is also served as a hole transport layer to improve transport of charge carriers and reduce dissociation of excitons.