Asymmetrically Substituted 10H,10′H-9,9′-Spirobi[acridine] Derivatives as Hole-Transporting Materials for Perovskite Solar Cells

Hole-transporting materials (HTMs) based on the 10H, 10 ' H-9,9 '-spirobi [acridine] core (BSA50 and BSA51) were synthesized, and their electronic properties were explored. Experimental and theoretical studies show that the presence of rigid 3,6-dimethoxy-9H-carbazole moieties in BSA 50 brings about improved hole mobility and higher work function compared to bis(4-methoxyphenyl)amine units in BSA51, which increase interfacial hole transportation from perovskite to HTM. As a result, perovskite solar cells (PSCs) based on BSA50 boost power conversion efficiency (PCE) to 22.65 %, and a PSC module using BSA50 HTM exhibits a PCE of 21.35 % (6.5x7 cm) with a V-oc of 8.761 V and FF of 79.1 %. The unencapsulated PSCs exhibit superior stability to devices employing spiro-OMeTAD, retaining nearly 90 % of their initial efficiency after 1000 h operation output. This work demonstrates the high potential of molecularly engineered spirobi[acridine] derivatives as HTMs as replacements for spiro-OMeTAD.

Automated summary

Hole-transporting materials based on the 10H, 10 'H-9,9' -spirobi[acridine] core were synthesized and their electronic properties were explored. The presence of specific structural elements in these materials resulted in improved hole mobility and higher work function, leading to enhanced performance of perovskite solar cells.