Improving efficiency by hybrid TiO₂ nanorods with 1,10-phenanthroline as a cathode buffer layer for inverted organic solar cells

We reported a significant improvement in the efficiency of organic solar cells by introducing hybrid TiO₂:1,10-phenanthroline as a cathode buffer layer. The devices based on polymer thieno[3,4-b]thiophene/ benzodithiophene:[6,6]-phenyl C₇₁-butyric acid methyl ester (PTB7:PC₇₁BM) with hybrid buffer layer exhibited an average power conversion efficiency (PCE) as high as 8.02%, accounting for 20.8% enhancement compared with the TiO₂ based devices. The cathode modification function of this hybrid material could also be extended to the poly(3-hexylthiophene):[6,6]-phenyl-C₆₁-butyric acid methyl ester (P3HT:PC₆₁BM) system. We anticipate that this study will stimulate further research on hybrid materials to achieve more efficient charge collection and device performance.