Multilayer organic solar cells with wet-processed polymeric bulk heterojunction film and dry-processed small molecule films

Abstract

Here, we report multilayer organic solar cells fabricated using a mix of solution (wet) and thermal evaporation (dry) techniques, which consist of indium-tin oxide (ITO), poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS), poly(3-hexylthiophene) (P3HT):1-(3-methoxycarbonyl)-propyl-1-phenyl-(6,6)C61 (PCBM), C60, bathocuproine (BCP), and aluminum layers. Results show that the short circuit current density (JSC) of a ITO∕PEDOT:PSS∕C60/BCP/Al device was greatly improved by inserting a pristine P3HT light-absorbing layer between the PEDOT:PSS and C60 layers. Addition of PCBM to the P3HT layer lowered the JSC in the devices compared to the pristine P3HT layer and, in general, the JSC continued to decline with increasing PCBM content.