In situ implanting carbon nanotube-gold nanoparticles into ZnO as efficient nanohybrid cathode buffer layer for polymer solar cells.

ZnO, plasmonic gold nanoparticles and conductive carbon nanotubes were combined by in situ growing to improve the light absorption and the electron mobility and the performance of polymer solar cells. Gold nanoparticles decorated carboxylic CNT (CNT-Au) was prepared by simple dehydration-condensation reaction. While CNT provides the template for the in situ growth of ZnO to form homogeneous film with less defects and higher conductivity, gold nanoparticles induce the surface plasmon effect to increase the light absorption. Compared to the bare ZnO, ZnO@CNT-Au nanohybrids could increase photo-generated excitons, decrease the charge recombination and facilitate the electron collection. In consequence, the power conversion efficiency of inverted polymer solar cell based on thieno [3,4-b]thiophene/benzodithiophene (PTB7) [6,6]:– phenyl C 71 -butyric acid methyl ester (PC 71 BM) was improved to 7.9% by adopting ZnO@CNT-Au as cathode buffer layer. [ABSTRACT FROM AUTHOR]