Cu-based metal-organic framework thin films: A morphological and photovoltaic study

This work explores the layer-by-layer (LbL) fabrication of [Cu-2(bdc)(2)(bpY)](n) thin films by using pyridine and acetic acid as capping agents onto mesoporous titania surface. While in the presence of acetic acid highly ordered crystals with nanoplate morphology are formed, modulation with pyridine gives rise to formation of leaf-like crystals. In addition, processing sequence also matters when modulator is added. According to our results, modulators should be added to metal solution rather than linker/pillar during LbL assembly. These films were subsequently shown to generate photocurrent in a sandwich-type Gratzel solar cell device in response to simulated 1 sun illumination. The results also demonstrated that the device consisted of well-aligned nanoplates exhibits higher power conversion efficiency than the similar cell with disordered leaf-like crystals after iodine loading.