Hydrothermal growth of MoS2/Co3S4 composites as efficient Pt-free counter electrodes for dye-sensitized solar cells

Abstract

MoS2/Co3S4 composite films were prepared via a facile one-step hydrothermal method, and used as efficient and low-cost Pt-free counter electrodes (CEs) for dye-sensitized solar cells (DSSCs). Characterizations revealed that Co3S4 and MoS2 were obtained simultaneously during the facile hydrothermal process. The composites afforded a promising synergistic effect on the catalyzing of triiodide reduction. Enhanced electrocatalytic performance of the resultant composite films was confirmed through cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) analyses. DSSCs using MoS2/Co3S4 composite CEs outperform the devices with pristine MoS2 or Co3S4 CEs in power conversion efficiency (PCE). Furthermore, a PCE of 6.77% is obtained for the optimized devices using MoS2/Co3S4 composite CEs measured under standard 1 sun illumination (100 mW cm −2 , AM 1.5G), which is comparable to that of the devices fabricated under the same conditions with conventional thermally deposited Pt CEs (7.14%). The results demonstrate that MoS2/Co3S4 composites are promising alternatives to Pt to be applied as CEs for DSSCs.

A down-shifting Eu 3+ -doped Y 2 WO 6 /TiO 2 photoelectrode for improved light harvesting in dye-sensitized solar cells

“…According to Yin et al ., the TiO 2 :Y 1.86 Eu 0.14 WO 6 (100:2.5) must have the smaller Rct value. This implies that the electron transfer from the TiO 2 :Y 1.86 Eu 0.14 WO 6 to the electrolyte is more efficient than that of the pristine TiO 2 electrode [35].

Figure 9.Nyquist plots of the DSSCs based on TiO 2 /Y 1.86 Eu 0.14 WO 6 (100:0; 100:1; 100:2.5 and 100:3) photoelectrodes measured at V oc under one-sun illumination.

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Improved performance of hole-transporting layer-free perovskite solar cells by using graphene oxide sheets as the nucleation centers

“…Thus the improvement can only be attributed to the increased charge carrier transporting property and collection efficiency, which is related to the anode/perovskite interface and/or the bulk properties of the perovskite layer. [6][7][8] The work function of GOS is 4.7 eV, 29 which is comparable to that of ITO of 4.8 eV. 30 This rules out the increased work function to the improved performance of the devices.…”

“…[1][2][3][4] To boost the PCE, extensive research has been devoted to PSC devices, such as improving charge collection and transport efficiency, optimizing cell structure, and enhancing the quality of each layer. [5][6][7][8] Perovskite solar cells have two types of cell structures: planar heterojunction and mesoscopic structure. Most of efficient mesoscopic PSCs employed meso-superstructure or condensed metal oxides such as TiO 2 and Al 2 O 3 , and required high-temperature (500 C) during the high-quality metal oxides produce processing, which is not suitable for fabricating on exible plastic substrates.…”

Effective iron-molybdenum-disulfide counter electrodes for use in platinum-free dye-sensitized solar cells

“…In the overall performance of DSSCs, the counter electrode (CE) is one of the crucial and indispensable components, because its functions are accelerating the triiodide/iodide (I 3 -/I -) reduction reaction and collecting electrons from external circuit [3]. The common strategy to reduce the cost of CE is seeking for low-cost substitutes to replace expensive platinum (Pt), such as Pt-metal alloys [4][5][6], carbon based materials [7,8], conducting polymers [9][10][11], and transition metal compounds [12][13][14][15][16][17].…”