Ternary MEH-PPV-CuInS_2/ZnO solar cells with tunable CuInS_2 content

摘要

The paper reports novel ternary MEH-PPV-CuInS2/ZnO solar cells fabricated by incorporating CuInS_2 quantum dots (QDs) into pristine MEH-PPV as light-harvester and vertically aligned ZnO nanorod array as electron acceptor. Results show that, MEH-PPV-CuInS_2/ZnO solar cells exhibit increased photovoltaic performance compared to MEH-PPV/ZnO devices and the performance dependent on the weight ratio (R) between CuInS_2 and MEH-PPV, resulting in a peak power conversion efficiency of 2.48% for R - 0.6 at 15.85 mW/cm2 monochromatic illumination. It is revealed that the increased J_(sc) is due to the improved light-harvesting, additional MEH-PPV/CuInS_2 interfaces for exciton dissociation, and the formation of CuInS_2 channels for effective charge transport, while the increased V_(oc) and the decreased charge recombination are attributed to the modification of ZnO surface by CuInS_2 QDs which reduces the surface defect concentration of ZnO. However, the decreased J_(sc), V_(oc) at too high R value are attributed to the serious aggregations of CulnS_2 QDs resulting in the inorganic nanocrystals not well dispersed in organic matrix.