Atomic force microscopic study of nanoscale interaction between N719 dye and CdSe quantum dot in hybrid solar cells and their enhanced open circuit potential

Atomic Force Microscopy has been used to study the nanoscale interaction between N719 dye and CdSe QDs/CdSe QDs and N719 dye on a TiO2 surface in hybrid solar cells. The results of AFM study explains the factors like aggregation, linking and entrapment of sensitizers on TiO2 surface. The photoresponse of nano sized materials in a hybrid solar cell consisting of mesoscopic TiO2, layers of N719 dye and CdSe quantum dots in sequential order has been reported in this paper. CdSe nanoparticles sandwiched between TiO2 and N719 dye exhibited net power conversion efficiency of 1.16%. But the newly designed hybrid system where N719 dye anchored between TiO2 and CdSe showed a good stability by delivering a power conversion efficiency of 2.64% with an improved open circuit potential and enhanced fill factor. In the cascade structure of TiO2/N719-CdSe, the re-organization of energy levels forms a stepwise structure, which is advantageous for an electron injection and hole-recovery in N719 dye and CdSe QDs respectively. (c) 2015 Elsevier Ltd. All rights reserved.