Enhancing Efficiency and Stability in Perovskite Solar Cells Through Blended Hole Transporting Materials Incorporating Benzo[g]quinoxaline-Conjugated Small Molecules

In this work, two electron-deficient polycyclic aromatics-based organic small materials, BQX-1 and BQX-2, with a benzo[ g ]quinoxaline moiety connected with arylamine donors are synthesized via simple procedures for potential application in perovskite solar cells (PSCs). Both hole transporting materials (HTMs) exhibit promising optical, electrochemical, thermal, and charge transport properties, with potential for PSC applications. Utilizing a hybrid HTM consisting of a blend of spiro-OMeTAD and a newly synthesized organic small molecule is a straightforward and effective approach to enhancing the efficiency and stability of PSCs. When blended with spiro-OMeTAD, these compounds enhance PSC performance, film morphology, and charge transport. The addition of BQX-1 or BQX-2 to spiro-OMeTAD significantly improves the properties of spiro-OMeTAD. As a result, the mixed BQX-1 /spiro-OMeTAD HTM-based device achieves a remarkable efficiency of 19.40%, surpassing the efficiency of single-component HTM-based devices (17.6%) under the same conditions. Importantly, long-term stability tests reveal that PSCs utilizing blended HTMs maintain notably higher power conversion efficiencies compared with spiro-OMeTAD-based devices. These results indicate that spiro-OMeTAD/ BQX-1 or BQX-2 mixed HTMs in advancing PSC technology toward greater efficiency and broader commercial viability.