Fabrication and Performance of Copper Phthalocyanine/Squaraine Dye/Perylene Composite with Bulk Heterojunctions by the Solution Blending Process

In this paper, copper tetra-(2, 4-dimethyl-3-pentoxy) phthalocyanine (CuPc-712), 2-[2-methylene-1,1,3-trimethyl-1H-benzo[e]inline]-4-[1-ethanol-2-methylquino]-cyclobutadienylium-1,3-diolate (SQ700), and 3,4,9,10-tetra-(heptyl acetate)-perylene (Pery-C7), attached with functional groups by covalent bonds were synthesized. In addition, bulk heterojunction diodes made from ITO/PEDOT:PSS (CuPc-712+SQ-700+Pery-C7)/Al have been realized and studied by I-V characteristic measurements in the dark and under illumination (ITO is indium tin oxide; PEDOT:PSS is poly(3,4-ethylene dioxythiophene) oxidized (doped) with poly(4-styrene sulfonate)). Enhanced photosensitivity was observed in the photoreceptor made from the composite (CuPc-712+SQ:700+Pery-C7), which was interpreted in terms of the expansion of light absorption spectrum and to charge separation by the bulk heterojunctions. In addition, the presence of a thin PEDOT:PSS film at the ITO/(CuPc-712+SQ:700+Pery-C7) interface allows one to achieve a significant photovoltaic efficiency of similar to 0.2%.