Enhancing charge separation and photocurrent response of CuO nanocone array by constructing CuO/PC₆₁BM hybrid bulk heterojunction

An inorganic-organic hybrid bulk heterojunction (BHJ) consisting of a CuO nanocone array (NCA)/methyl [6,6]-phenyl-C-61-butyrate (PC61BM) was fabricated on a fluorine-doped tin oxide substrate using a hydrothermal method. Scanning electron microscopy showed that the CuO-NCA/PC61BM BHJ hybrid structure was wellformed and that the PC61BM compactly filled the interspaces between the CuO nanocones. A FTO/CuO-NCA/PC61BM/LiF/Ag hybrid BHJ photodiode had a favorable type-II band alignment for charge separation, and this photodiode showed a nearly 10-fold enhanced photocurrent response compared with a FTO/CuO-NCA/LiF/Ag Schottky junction photodiode. Photoelectmchemical impedance spectroscopy and transient absorption spectroscopy demonstrated that the FTO/CuO-NCA/PC61BM/LiF/Ag BHJ device had better photogenerated charge transfer properties and a longer carrier lifetime compared with the FTO/CuO-NCA/LiF/Ag device.