Morphology controlled bulk-heterojunction layers of fully electro-spray coated organic solar cells

Electro-spray (e-spray) is emerging as an attractive printing method for the thin-film fabrication of organic materials because of the simple apparatus and its high efficiency. Here, we demonstrate a fully e-sprayed organic solar cell (OSC) with high performance by using an additive in the poly(3-hexylthiophene):[6,6]-phenyl C61-butyric acid methyl ester (P3HT:PCBM) layer without any post-processing treatment. The P3HT:PCBM film fabricated with 6 vol% 1,8-diiodooctane (DIO) showed improved surface macro- and nano-morphologies, which resulted in an enhanced photovoltaic performance. Using optimized conditions, we obtained a 2.98% efficient OSC (as-prepared condition) with the e-spray method, and post-annealing increased the power conversion efficiency (PCE) slightly to 3.08%.