Gnanasekar Subashini, Sonar Prashant, Jain Sagar M, Jeong Soon Kwan, Grace Andrews Nirmala
Centre for Nanotechnology Research, VIT Vellore 632014 Tamil Nadu India
School of Chemistry and Physics, Queensland University of Technology Brisbane Queensland 4000 Australia.
RSC Adv. 2020 Nov 11;10(67):41177-41186. doi: 10.1039/d0ra06984a. eCollection 2020 Nov 9.
A vanadium nitride xerogel (VNXG) was synthesised by a simple and effective method of ammonialising a vanadium pentoxide xerogel at a higher temperature. Xerogel-structured materials possess salient features such as high surface area, tunable porosity and pore size that result in enhancing the catalytic activity by a fast electron-transport pathway and increase electrolyte diffusion channels. Metal nitrides are reported as promising alternate low-cost counter electrodes to replace the conventional and expensive platinum (Pt) counter electrode. Though few studies are reported on aerogel-based CEs for DSSCs, the present work is the first attempt to synthesize and evaluate the performance of xerogel-structured metal nitrides as counter electrode materials for dye-sensitized solar cells. The synthesized material was well characterized for its structural and morphological characteristics and chemical constituents by photoelectron spectroscopy. Finally, the VNXG was tested for its electrocatalytic performance as a choice of counter electrodes for dye-sensitized solar cells (DSSCs). The photo-current studies were performed under standard 1 SUN, class AAA-simulated illumination with AM1.5G. The consolidated results revealed that the vanadium nitride xerogel exhibited good photocatalytic activity and low charge transfer resistance. This identified it as a promising low-cost counter electrode (CE) material for dye-sensitized solar cells. The photo-current conversion efficiency of the vanadium nitride xerogel CE-based DSSC reached 5.94% comparable to that of the conventional thermal decomposed Pt CE-based DSSC, 7.38% with the same iodide/triiodide electrolyte system. Moreover, the 28 days stability study of VNXG CE DSSCs provided an appreciably stable performance with 37% decrement in the PCE under the same test condition.
通过在较高温度下对五氧化二钒干凝胶进行氨化的简单有效方法合成了一种氮化钒干凝胶（VNXG）。干凝胶结构材料具有诸如高表面积、可调节的孔隙率和孔径等显著特征，这些特征通过快速电子传输途径提高催化活性并增加电解质扩散通道。据报道，金属氮化物是有望替代传统且昂贵的铂（Pt）对电极的低成本替代对电极。尽管关于用于染料敏化太阳能电池（DSSC）的气凝胶基对电极的研究报道较少，但本工作是首次尝试合成并评估干凝胶结构的金属氮化物作为染料敏化太阳能电池对电极材料的性能。通过光电子能谱对合成材料的结构、形态特征和化学成分进行了充分表征。最后，对VNXG作为染料敏化太阳能电池（DSSC）对电极的选择进行了电催化性能测试。光电流研究在标准1太阳光照、AM1.5G的AAA级模拟光照下进行。综合结果表明，氮化钒干凝胶表现出良好的光催化活性和低电荷转移电阻。这表明它是一种有前景的用于染料敏化太阳能电池的低成本对电极（CE）材料。基于氮化钒干凝胶对电极的DSSC的光电流转换效率达到5.94%，与基于传统热分解铂对电极的DSSC相当，在相同的碘化物/三碘化物电解质体系下为7.38%。此外，VNXG对电极DSSC的28天稳定性研究在相同测试条件下提供了明显稳定的性能，光电转换效率（PCE）下降了37%。
