Unveiling Charge-Transfer Dynamics at Singlet Fission Layer/Hybrid Perovskite Interface

Singlet fission (SF) materials have been applied in varioustypesof solar cells to pursue higher power conversion efficiency (PCE)beyond the Shockley-Queisser (SQ) limit. SF implementationin perovskite solar cells has not been successfully realized yet dueto the insufficient understanding of the SF/perovskite heterojunctions.In this work, we attempt to elucidate the charge dynamics of an SF/perovskitesystem by incorporating a well-known SF molecule, TIPS-pentacene,and a triple-cation perovskite Cs-0.05(FA(0.85)MA(0.15))(0.95)PbI2.55Br0.45, owing to their well-matched energy structures. The transient absorptionspectra and kinetic fitting plots suggest an electron-transfer processfrom the triplet state of TIPS-pentacene to perovskite in the picosecondregime, which increases the carrier density by 20% in the perovskitelayer. This work confirms the existence of an electron-transfer processbetween the SF material and perovskite, providing a pathway to SF-enhancedperovskite solar cells.