Polarons and solitons in composite q-1-d systems: Vectorial separation of charges. Interchain molecular photocell

Abstract

The formation of “molecular heterojunction” (MJ) between two different q-1-d chains is analysed for both molecular and polymeric (Peierls) double chain systems. The behaviour of polarons (P)/ bipolarons (BP) is examined in MJs and at account of interchain electron hopping t ⦜, P/BP are shown to become inequal on both chains: lower P/BP is stabilised, while upper P becomes decaying due to favourable injection into adjacent chain. In MJ formed by conducting polymers like (CH) x neutral solitons S o transform into oppositely charged S + and S −. Lowest excitations of MJ are CT-excitons formed by P ±/BP ± pairs on adjacent chains. The energy of such interchain CTE may become negative indicating the instability to charging of chains similar to neutral-ionic transition known in CT crystals. Photogeneration in interchain molecular photocell based on vectorial photoseparation of P/BP in MJ is analysed and a possible interchain approach to molecular electronics is discussed.