Photoinduced charge separation in Q1D heterojunction materials: Evidence for electron-hole pair separation in mixed-halide $MX$ solids

摘要

Resonance Raman experiments on doped and photoexcited single crystals ofmixed-halide $MX$ complexes ($M$=Pt; $X$=Cl,Br) clearly indicate chargeseparation: electron polarons preferentially locate on PtBr segments while holepolarons are trapped within PtCl segments. This polaron selectivity,potentially very useful for device applications, is demonstrated theoreticallyusing a discrete, 3/4-filled, two-band, tight-binding, extended Peierls-Hubbardmodel. Strong hybridization of the PtCl and PtBr electronic bands is thedriving force for separation.