Layer-by-layer processed polymer solar cells with self-assembled electron buffer layer

Layer-by-layer (LL) process is attracting more and more interests in fabricating polymer solar cells (PSCs) due to its potential advantage in realizing p-i-n like structure. Meanwhile self-organization of electron buffer layer (EBL) is drawing increasing attention. Here, we combined the two and LL processed P3HT:PCBM (poly(3-hexylthiophene):phenyl-C61-butyric acid methyl ester) PSCs with self-assembled PEGN-C60 (poly(ethylene glycol) modified [60]fullerene) EBL. Power conversion efficiency of 4.40% was achieved, considerably higher than that of the traditional P3HT:PCBM bulk-heterojunction device, which is 3.84%. The result demonstrates that the approach we developed here could be very useful in fabricating high-performance PSCs.