•The dyes especially suitable for Zn2SnO4 were investigated.•The PSP dyes exhibited a higher efficiency of 4.68% than that of N719 and D131.•The pre-calcination of Zn2SnO4 resulted in a 17% enhancement of efficiency.•The charge collection efficiency was enhanced greatly after the pre-calcination.Zinc stannate (ZTO) is a class of ternary oxides that are known for their stable properties and high electron mobility. Also, its chemical compositions and band structures are easy to be controlled, and which is thus ideal for applications in dye-sensitized solar cells (DSCs). However, the structures of most dyes are optimized for the widely used TiO2. Therefore, the efficient dyes that are especially suitable for ZTO are highly desired. In this study, the dyes containing phenylene-thiophenylene-phenylene bridge (PSP) were found to match well with the band structures of ZTO and could be used as efficient sensitizers for ZTO-based solar cells. Moreover, the pre-calcination temperatures have great influence on the band structures of ZTO. When ZTO nanoparticles were pre-sintered, although the adsorption amount of dyes was decreased, the charge collection efficiency was confirmed to be enhanced greatly. A cell sensitized by optimized PSP dyes exhibited a power conversion efficiency of 4.68%, which was much higher than that of widely used N719 and D131.

•Co-additives without TBP were first applied in the electrolyte of DSCs.•The synergetic effect of benzimidazole and 2-ethylimidazole has been researched.•By optimizing the ratio, an efficiency of 7.93% was got with a high Voc of 0.817 V.The co-additives of benzimidazole and 2-ethylimidazole in electrolyte have an obvious effect on the performance of dye-sensitized solar cells due to their good coordination ability of titanium dioxide, which could affect the energy levels and charge transfer process. Through a balance of the concentrations, the best efficiency of 7.93% with a high open-circuit voltage of 0.817 V is achieved for a cell fabricated with the electrolyte contains benzimidazole and 2-ehtylimidazole by a molar ratio of 9.5/0.5.

•MOF derived carbon materials were firstly applied as a counter electrode of DSCs.•An efficiency of 7.32% can achieved which was comparable to that of Pt electrode.•Calcination temperature influenced the properties of carbon counter-electrode.•The residual ZnO influenced the electrical conductivity of carbon counter-electrode.Metal-organic frameworks, ZIF-8, derived carbon materials are firstly applied as a counter electrode of dye-sensitized solar cells due to their easy fabrication, large specific surface area and high catalytic activities towards the reduction of I3− ions. An efficiency of 7.32% is achieved under the illumination of 1 sun (AM 1.5, 100 mW/cm2), which is comparable to that of the solar cell based on Pt electrode.Metal-organic frameworks (ZIF-8) derived carbon was firstly used as a counter electrode in dye-sensitized solar cells, and achieved an efficiency of 7.32%, which was comparable to that of Pt-based DSC.

Metal–organic frameworks (MOFs) have been generating a great deal of interest due to their high specific surface area, regular pore structure, and adjustable aperture. However, only a few studies explored their application in the field of photovoltaic devices. In the present work, MIL-125(Ti), one kind of MOFs, was investigated as the precursor for TiO2 photoanode of dye-sensitized solar cells for the first time. Herein, pure anatase TiO2 with a hierarchical structure was synthesized through the decomposition of MIL-125(Ti), which avoids the use of templates and fussy operation of sol–gel methods. The obtained TiO2 has a specific surface area of 147 m2 g–1 and a mean pore size value of 10 nm. When used as a photoanode material in dye-sensitized solar cells, the device gave rise to an overall energy conversion efficiency of 7.20%, which is better than the performance of the P25 based photoanode.

Dye-sensitized solar cells (DSSCs) provide a promising alternative solar cell technology because of their high efficiency, environmental friendliness, easy fabrication, and low cost. Power conversion efficiency is an important parameter to measure the performance of DSSCs, but the severe charge recombination that occurs at the photoanode hinders the future improvement of power conversion efficiency. Therefore, one of the key goals for achieving high efficiency is to reduce the energy loss caused by the unwanted charge recombination at various interfaces. From this perspective, surface modification of the photoanode is the simplest method among the various approaches available in the literature for enhancing the performance of DSSCs by inhibiting the interfacial charge recombination. After some brief notes on DSSCs, in this review, we present a comprehensive discussion on surface modifications of different photoanodes that have been adopted in the literature not only for reducing recombination but also for enhancing light harvesting. Depending on the electrode materials, we discuss surface modifications of binary oxides such as TiO2 and ZnO and ternary oxides, including Zn2SnO4, SrSnO3, and BaSnO3. We also talk about methods of surface modification and the materials suitable for surface treatment. Finally, we end with a brief future outlook of DSSCs.染料敏化太阳电池因其高效率、环境友好、制作工艺简单、生产成本低等优点而极具应用前景. 光电转换效率是衡量染料敏化太阳电池性能的重要参数之一, 然而光阳极上发生的电子复合阻碍了光电转换效率的进一步提高. 因此, 减少由各个界面处不利的电子复合引起的能量损失是提高光电转换效率的关键之一. 从这个方面来说, 光阳极表面修饰是抑制界面电子复合以提高染料敏化太阳电池光电转换效率的最简便方法之一. 这篇综述简单地介绍了染料敏化太阳电池的工作原理, 综合讨论了目前文献中所采用的不同光阳极的表面修饰方法. 这些表面修饰方法不仅能减少电子复合, 还能提高对太阳光的吸收. 根据光阳极材料的特点, 本文讨论了二元氧化物, 例如TiO2和ZnO, 以及包括Zn2SnO4、SrSnO3和BaSnO3在内的三元氧化物的表面修饰. 此外, 本文讨论了表面修饰的具体方法以及适用于表面处理的材料. 最后, 展望了染料敏化太阳电池的发展前景.

The surface treatment of zinc stannate (Zn2SnO4) film for use in dye-sensitized solar cells has been carried out with zinc tin oxide precursor solutions through chemical-bath deposition (CBD). Mott–Schottky measurements demonstrate that the flat band of Zn2SnO4 has a moderate positive shift owing to the surface treatment, which leads to a slightly decreased Voc. Although UV-vis spectroscopy reveals that the adsorption amounts of N719 and D131 dyes are decreased, EIS results and OCVD data suggest that the decreased charge recombination rate and prolonged electron lifetime give rise to an apparently improved efficiency of cells. Consequently, an enhancement of 13.5% is obtained after CBD surface treatment under the illumination of one sun (AM 1.5, 100 mW cm−2).