Chiral Bifacial Indacenodithiophene-Based Hole-Transport Materials With Chirality-Induced Spin Selectivity:...

Chirality-induced spin selectivity (CISS) is emerging as a key element for spin-dependent functions in organic electronics. We previously developed a chiral bifacial indacenodithiophene (IDT) backbone that shows strong CISS in both π-conjugated polymers and non-fullerene acceptors (NFAs). Building on this platform, here we report triarylamine-functionalized, chiral bifacial IDT-based hole-transport materials (HTMs). Spin-coated films of (R,R)-1 and (S,S)-1 exhibit pronounced CISS with spin polarization (SP) ≈ 60%. Across our chiral-bifacial IDT series, π-conjugated polymers, NFAs, and these HTMs, we observe a consistent chirality-spin polarity correspondence: (S,S) chirality yields negative SP, whereas (R,R) yields positive SP, representing a platform-level demonstration across three material classes. In perovskite solar cells, these HTMs also act as effective surface passivators; devices passivated with homochiral (R,R)-1 gave higher efficiencies than meso- or racemic counterparts. Space-charge-limited current measurements likewise indicate approximately threefold higher hole mobility for the homochiral film relative to the racemate. While a direct causal connection to the CISS effect remains to be demonstrated, these observations are consistent with a CISS-assisted, efficient spin-selective transport mechanism. Taken together, this work establishes a chirality-spin polarity correspondence and demonstrates effective perovskite passivation, with higher hole mobility correlating with homochirality, highlighting new opportunities for homochiral materials in device science.