ABSTRACT

Many researchers working on the development of Dye-sensitized solar cells (DSCs) continue to focus on the synthesis of photoanode materials with high surface area, along with high light scattering ability to enhance light harvesting efficiency (LHE). On the other hand, dye packing density, which can also affect the LHE significantly, is often overlooked. Solvothermally synthesized anatase TiO₂ nanoparticles (SANP) were obtained by a new and simple approach using a mixed solvent, ethanol and acetic acid. SANP were applied as a photoanodes material in DSCs using a metal-free organic dye (D149) or organometallic dye (N719) dyes. The dye loading (packing density) was examined in term of the isoelectric point (IEP) and the contribution of this, in addition to light scattering effects were shown to control the devices photovoltaic efficiency of the devices; specifically when compared with ones employing commercially available TiO₂ nanoparticles (either transparent or a bilayer structure with a transparent layer and a scattering one). SANP photoanodes sensitized with D149 dye were found to be optimised at 10 µm, yielding photovoltaic conversion efficiencies of 6.9%, superior to for transparent or transparent + scattering films from the commercial source (5.6% and 5.9%, respectively). Further to this, an efficiency of 7.7% PCE was achieved using a SANP photoanode sensitized with N719 dye, with 7.2% seen for the transparent photoanode and 7.9% with a scattering layer. The high efficiencies of devices based on of SANP photoanode are attributed to the high dye loading capability in addition to good light scattering. A further point of interest is that even with the increased reactivity of the surface towards dye adsorption, we did not observe any significant increase in recombination with the redox mediator, presumably due to this increased dye loading providing better shielding.

摘要

许多致力于染料敏化太阳能电池（DSC）开发的研究人员继续致力于合成具有高表面积的光阳极材料，以及具有高光散射能力以提高光收集效率（LHE）的材料。另一方面，常常会严重影响LHE的染料堆积密度。溶剂热合成锐钛矿TiO ₂通过使用混合溶剂，乙醇和乙酸的新的简单方法获得纳米颗粒（SANP）。使用不含金属的有机染料（D149）或有机金属染料（N719）染料将SANP用作DSC中的光阳极材料。以等电点（IEP）检验了染料的负载量（堆积密度），并显示了其贡献，此外还显示了光散射效应，以控制器件的光电效率。特别是与使用市售TiO _{2的产品相比时}纳米粒子（透明或具有透明层和散射层的双层结构）。发现用D149染料敏化的SANP光电阳极在10 µm时进行了优化，产生的光电转换效率为6.9％，优于商业来源的透明或透明+散射膜（分别为5.6％和5.9％）。除此之外，使用以N719染料敏化的SANP光电阳极可达到7.7％PCE的效率，其中透明光电阳极为7.2％，散射层为7.9％。基于SANP光电阳极的设备的高效率归因于良好的光散射以及高染料装载能力。另一个令人感兴趣的问题是，即使表面对染料吸附的反应性增加，