Enantiospecificity in Organic Photoelectrochemical Transistors Enabled by Chirality-Induced Spin Selectivity Effects

Chirality, as an intrinsic feature of the living world, is associated with many significant biological processes. Although the chiral-induced spin selectivity (CISS) effects have been recognized and applied to provide spin control over chemical reactions, their implementation in the organic electrochemical transistor (OECT) remains a largely unexplored area. Herein, the OECT technology is combined with a photovoltaic gate electrode and the CISS effect, establishing a chiral organic photoelectrochemical transistor (OPECT) for enantiomer identification. The chiral Sn(II)-based metal-organic framework (SnMOF)/SnO₂ hybrid, serving as a spin filter to induce CISS properties, is coated on a TiO₂ nanotube array-based photosensitive gate. Using cystine enantiomers as proof-of-principle, a target recognition-induced electron donor (l-/d-cysteine) generation was further proposed. The CISS effect enables a more efficient transfer of spin-polarized electrons between the L-target and L-gate (or between the D-target and D-gate), inducing a greater channel current (I_D) variation. The comprehensive analysis of the I_D responses in the two chiral OPECT sensors further enables accurate and reliable determination of the concentration and composition of enantiomers in unknown mixtures. This study provides a straightforward methodology to apply the CISS effect for determining chiral targets in complex samples.