Surfactant-assisted synthesis of large Cu-BTC MOF single crystals and their potential utilization as photodetectors

Abstract

In this study, we discovered a method to synthesize large single crystals of Cu-BTC MOFs (Cu-s) with the assistance of a surfactant (PF-127) in an ethanol–water mixture solution. Single crystal and powder XRD (X-ray diffraction) measurements revealed that Cu-s, with the appearance of long rods, has the chemical formula Cu(BTC)₃·H₂O. We proposed the growth mechanism of Cu-s by a series of experiments and demonstrated that the addition of surfactant PF-127 can effectively inhibit the contact between Cu²⁺ ions and BTC ligands, which favoured the growth of Cu-s along the a-axis and suppressed the fast formation of porous Cu-BTC MOFs (HKUST-1). Considering that the photoactive properties of Cu-s and its relatively large size (an average length of up to ∼3 mm), we constructed a simple photo-detector device, showing excellent photo-sensing properties under illumination.