P-Type Doping Using Formic Acid for Controlling Short Circuit Current and Fill Factor in Organic Solar Cells
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초록
내용
The introduction of the molecular doping process is necessary to enhance the optic and electronic properties of organic semiconductors for facilitating charge transport. Despite its advantages, doping technologies in organic solar cells (OSCs) are restricted to the development of n-type dopants used for balancing the electron and hole to increase electron mobility. Since the bulk-heterojunction (BHJ) microstructure in OSCs has randomly blended phases of the donor and acceptor, it is important to optimize charge extraction without loss by controlling the morphology. In this study, we report OSCs by p-type doping into a BHJ photoactive layer comprised of PM6 and Y6. The resulting device yields a significantly improved power conversion efficiency from 14.3% to 15.3% with a high fill factor of 71.7%. It is demonstrated that the p-doped photoactive layer exhibits enhanced conductivity, carrier mobilities, and suppressed charge recombination. Formic acid also acts as a film morphology modifier of the active layer with enhanced phase separation to transport the charge efficiently.