MOF-199: A simple strategy for improvement of crystallinity and photovoltaic property

In this study, thin films of MOF-199 were prepared using a Layer-by-Layer deposition approach and applied as sensitizing materials in TiO2-based solar cells. Our results indicate that by introducing 3,4-dihydroxybenzoic acid at the interface of TiO2-MOF via a simple surface modification step, TiO2 surface roughness is reduced and texture quality of MOF-199 polycrystalline film enhances along 〈111〉 crystallographic direction while the overall conversion efficiency of the cell increases as well. The improvement in Jsc could be a consequence of enhanced crystallinity, reduced surface roughness and enhanced light-harvesting properties of surface-modified photoanode. Dark I-V characteristics of the cells also indicate that the interfacial charge recombination at TiO2-MOF interface is inhibited upon introducing DHBA thus, Voc is improved.