A frontier Zn- and N-rich complex grafted onto reduced graphene oxide for the electrocatalysis of dye-sensitized solar cells.

This paper proposes a novel µ-hydroxo-bridged dinuclear macrocyclic zinc complex, {[Zn(C10H20N8)]2(OH)}(BF4)3. The structure was determined by X-ray crystallography: Monoclinic, C2/c, a = 25.4632(6), b = 10.9818(3), c = 15.7522(4) Å, Z = 8, R1 = 0.0233, wR2 = 0.0557, based on reflections I > 2σ(I). The complex was successfully reacted with graphene oxide to form a µ-hydroxo-bridged dinuclear macrocyclic Zn complex/reduced graphene oxide composite. To evenly disperse the Zn- and N-rich complex onto the surface of the reduced graphene oxide, and to enhance the electrocatalytic property of the graphene composites, a soluble molecular grafting method was used here. The graphene-based composites were applied as the counter electrodes (CEs) of dye-sensitized solar cells. Current density-voltage measurements revealed that the conversion efficiency of the GO/Zn (1 : 10) sample was 7.78%, which was better than that of Pt CE (7.49%). GO/Zn (1 : 10) CE exhibited the lowest impedance (RCE = 9.90 Ω), which was better than that of Pt CE (RCE = 66.1 Ω), showing that GO/Zn CEs can reduce the impedance at the CE/electrolyte interface. The proposed method is simple, and the composite materials can potentially replace conventional Pt, optimizing efficiency and reducing production cost.

Reduced graphene oxide/macrocyclic iron complex hybrid materials as counter electrodes for dye-sensitized solar cells.

A novel series of reduced graphene oxide (RGO)/macrocyclic iron (Fe) complex hybrid materials were synthesized and then used in the production of counter electrodes (CEs) for dye-sensitized solar cells (DSSCs). The electrode properties of various CEs were comprehensively analyzed using scanning electron microscopy, transmission electron microscopy, atomic force microscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, energy dispersive spectroscopy, Raman spectroscopy, X-ray diffraction, and cyclic voltammetry analyses. DSSCs, based on various CEs, were characterized using current density-voltage, incident monochromatic photon-to-current conversion efficiency, and electrochemical impedance spectroscopy measurements. DSSCs fabricated using the RGO/macrocyclic Fe nanocomposite CEs yielded an efficiency of 6.75%. The RGO/Fe CEs exhibited efficient electrocatalytic capability because catalytic Fe particles were uniformly distributed on the surface of RGO. The results indicated that a DSSC with a RGO/Fe CE can exhibit an efficiency comparable to that of a platinum (Pt) CE DSSC and can therefore replace conventional Pt CE DSSCs to lower the cost of solar cells.