Nitrogen-doped mesoporous carbon combined with carbon nanotubes as counter electrode catalysts for quantum dot sensitized solar cells with record efficiency

The fabrication of a counter electrode possessing elevated catalytic efficiency and steadfast stability is a crucial prerequisite for the high-performance quantum dot sensitized solar cells (QDSCs). Mesoporous carbon (MC) has been adopted as the desired CE material in the past years, but the disadvantage of its poor conductivity has limited further development of the performance of QDSCs. In this study, we present a straightforward approach for producing highly effective counter electrodes through the integration of nitrogen-doped mesoporous carbon (N-MC) with carbon nanotubes (CNTs), forming a composite material that is deposited onto a titanium mesh substrate. The counter electrode (CE) based on composite materials shows excellent electrocatalytic performance, synergistically benefiting from large specific areas of N-MC and high conductivity of CNTs. Electrochemical measurements reveal that the optimal CEs exhibit excellent catalytic reduction activity as well as high electron mobility. Consequently, the corresponding QDSCs show a record power conversion efficiency of 16.68 %.