All-spin-coating vacuum-free processed semi-transparent inverted polymer solar cells with PEDOT:PSS anode and PAH-D interfacial layer

Semi-transparent inverted polymer solar cells (PSCs) were fabricated by all-spin-coating vacuum-free process. An interfacial layer of poly(allylamine hydrochloride) and dextran (PAH-D) was introduced to modify the surface wettability of poly(3-hexylthiophene) (P3HT):[6,6]-phenyl C61-butyric acid methyl ester (PCBM) film for depositing aqueous-solution-processed poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) (CLEVIOS™ PH500) (PH500) anode as well as enhancing the adhesion and bonding strength between the active layer (P3HT:PCBM) and conducting polymer electrode (PH500). The photovoltaic performance of the semi-transparent PSCs under top and bottom illumination was investigated and the highest PCE of about 1.86% was achieved under simulated AM 1.5 illumination (100 mW/cm2) from the bottom side with a reflective white paper back side. The semi-transparent Cell A have the potential for use as energy-generating color window glasses as well as the subcell of tandem solar cells. The all-spin-coating vacuum-free processing provides a possibility of high-throughput all-solution-processed fabrication of PSCs by roll-to-roll processing.