MOF-Derived Co,N Codoped Carbon/Ti Mesh Counter Electrode for High-Efficiency Quantum Dot Sensitized Solar Cells.

Carbon supported on titanium mesh electrodes has been recognized as the best performing counter electrodes (CEs) in quantum dot sensitized solar cells (QDSCs). Herein, layered double hydroxides (LDHs) are applied as a scaffold template for the growth of cobalt-zeolite-imidazole framework (ZIF-67) crystals, and micrometer-sized Co,N codoped porous carbon materials (Co,N-C) are obtained through a carbonization process. The as-prepared Co,N-C exhibits favorable features for electrocatalytic reduction of polysulfide, including a high surface area of 491.36 m2/g, highly effective active sites, and a hierarchical micro/mesoporous structure. Due to the large particle size, the obtained Co,N-C can couple with a Ti mesh substrate for the fabrication of high-performance Co,N-C/Ti CEs for QDSCs. As a result, the corresponding QDSCs exhibit an average efficiency of 13.55% (Jsc = 25.93 mA/cm2, Voc = 0.778 V, FF = 0.672), which is a 10.5% enhancement compared to the previous best result from the N-doped mesoporous carbon counterpart.