Electrically Conductive Photoluminescent Porphyrin Phosphonate Metal-Organic Frameworks

Abstract

Herein, the design and synthesis of a highly photoluminescent and electrically conductive metal-organic framework [Zn{Cu-p-H(6)TPPA}]center dot 2 [(CH3)(2)NH] (designated as GTUB3), which is constructed using the 5,10,15,20-tetrakis [p-phenylphosphonic acid] porphyrin (p-H(8)TPPA) organic linker, is reported. The bandgap of GTUB3 is measured to be 1.45 and 1.48 eV using diffuse reflectance spectroscopy and photoluminescence (PL) spectroscopy, respectively. The PL decay measurement yields a charge carrier lifetime of 40.6 ns. Impedance and DC measurements yield average electrical conductivities of 0.03 and 4 S m(-1), respectively, making GTUB3 a rare example of an electrically conductive 3D metal-organic framework. Thermogravimetric analysis reveals that the organic components of GTUB3 are stable up to 400 degrees C. Finally, its specific surface area and pore volume are calculated to be 622 m(2) g(-1) and 0.43 cm(3) g(-1), respectively, using grand canonical Monte Carlo. Owing to its porosity and high electrical conductivity, GTUB3 may be used as a low-cost electrode material in next generation of supercapacitors, while its low bandgap and high photoluminescence make it a promising material for optoelectronic applications.