Improvement of Photovoltaic Properties by Addition of a Perylene Compound in P3HT:PCBM BHJ System

The synthesized n-type perylene derivative, N,N'-bis-(4-bromophenyl)-1,6,7,12-tetrakis(4-n-butoxyphenoxy)-3,4,9,10-perylene tetracarboxdiimide (PIBr), was applied as an additive to polymer solar cells (PSCs) with P3HT [poly(3-hexylthiophene)]:PCBM [[6,6]-phenyl C-61-butyric acid methyl ester] blend films. Without post thermal annealing, a considerable improvement of about 98% in power conversion efficiency was achieved by the addition of 1 wt% PIBr into a P3HT:PCBM layer, when compared with that of reference cell without the additive. The results, in combination with relevant data from UV-Vis. absorption, photoluminescence, X-ray measurements and carrier mobility studies, revealed that the addition of the perylene compound within active layer contributed to more effective charge transfer and enhanced electron mobility.