Concentration and LBL cycle evolution to the Cu-BTC metal organic framework: Optimization as functional layer to the solar cell devices

Abstract

Metal-organic frameworks are rational self-assembly of metal-ions and organic-linkers, and are class of hybrid porous materials those endowed with unique physiochemical properties. To seek cost effective renewable energy resources, solar cell technology has potential to cater futuristic energy need of society, where MOFs may play an important role to develop cost effective and eco-friendly devices. Therefore, in this work, properties of Copper-based MOFs are investigated in aspect to functional layer applications to solar cell devices where synthesis of Cu3(BTC)2 MOFs is accomplished by establishing coordination between Copper (II) ions and 1,3,5 benzene tricarboxylic acid (BTC) linker using solvothermal method. Developed Cu3(BTC)2 MOFs are subjected to various characterization tools where, structural analysis revealed dominance of (222) reflection and successful formation of Copper-based frameworks. Thermogravimetric analysis indicated first and second weight losses corresponding to temperature ranges of 114–130 °C and 360–375 °C, respectively. FTIR analysis exposed presence of symmetric and asymmetric modes of carboxylic groups and CH bending mode. Surface morphological analysis revealed to the formation of pyramidal coordination geometry of Copper-based frameworks whereas compositional analysis confirmed successful synthesis of Cu3(BTC)2 frameworks. The solar cell devices having architecture as Glass/FTO/TiO2/Cu-BTC/CuSCN/Ag are fabricated with 5, 10, and 15 LBL cycles of Cu-BTC MOFs. The device with 10 LBL cycles exhibited better performance vis-à-vis the others. The attained results signify that synthesized bulk Cu-BTC MOF material and device fabricated with 10 LBL cycles draw attention to further undertake materials evolution for development of high performance solar cell devices.