Bulk Heterojunction Solar Cells with Ternary Mixed PTB7:PCDTBT:PC71BM Active Layers

We report on bulk-heterojunction solar cells fabricated based on ternary mixed solutions of two donors of poly[[4,8-bis[(2-ethylhexyl)oxy]benzo [1,2-b:4,5-b’] dithiophene-2, 6-diyl] [3-fluoro-2- [(2-ethylhexyl) carbonyl]thieno[3,4-b]-thiophenediyl] (PTB7) and [N-9’-heptadecanyl-2,7-carbazole-alt-5,5-(4’,7’-di-2-thienyl-2’,1’,3’-benzothiadiazole)] (PCDTBT), and an accepter of [6,6]-phenyl C₇₁ butyric acid methyl ester (PC₇₁BM). The solar cells had a glass/ITO/NiO/PTB7:PCDTBT:PC₇₁BM/LiF/Al structure. Solar cells containing a 1-2% PCDTBT weight fraction showed a noticeable improvement in short circuit current density (J_sc), fill factor (FF), and power conversion efficiency (PCE). Solar cells with a 2% PCDTBT weight fraction exhibited an open circuit voltage (V_oc) of 0.77 V, J_sc of 13 mA/cm², FF of 0.42, and PCE of 4.23%. Possible mechanisms for the solar cell performance improvement by the introduction of the small amount of PCDTBT in the PTB7:PC₇₁BM active layer was discussed based on the active layer morphology changes and carrier transport mechanisms.     

Influence of Fe2O3 Doping on TiO2 Electrode for Enhancement Photovoltaic Efficiency of Dye-Sensitized Solar Cells

In this work, we report for the first time the improvement of the photovoltaic characteristics of dye-sensitized solar cells (DSSCs) by doping TiO₂ with Fe₂O₃. DSSCs were fabricated using various percentages of Fe₂O₃-doped TiO₂ composite nanoparticles. The Fe₂O₃-doped DSSCs exhibited a maximum conversion efficiency of 5.76% because of the effective electron transport. DSSCs based on Fe₂O₃-doped TiO₂ films showed better photovoltaic performance than cells fabricated with only TiO₂ nanoparticles. This result was attributed to the prevention of recombination between electrons in the TiO₂ conduction band with the dye or electrolytes. A mechanism was suggested based on impedance results, which indicated improved electron transport at the interface of the TiO₂/dye/electrolyte.     

基于ZnO电子传输层钙钛矿太阳能电池的研究进展

作为新一代低成本、高效率的光伏器件,以有机卤化铅CH₃NH₃PbX₃(MAPbX₃,X=Br、I、Cl)为光吸收层的钙钛矿太阳能电池(PSCs)相比于其他类型的光伏器件,具有原料丰富、工艺简单等特点。在较短的时间内,该类电池效率已由3.8%迅速攀升至25.7%,几乎可以媲美商用硅太阳能电池,成为能源应用领域的一颗新星。氧化锌(ZnO)因其具有材料易于加工、电子迁移率高、制造成本低廉且形貌结构多样等优点,被作为该类电池较为重要的一种电子传输层(ETL)而被广为研究。本文主要以不同结构的ZnO纳米薄膜ETL作为研究对象,对其在PSCs中的应用进行了总结,详细介绍了基于不同形貌ZnO纳米结构PSCs的研究进展,分析了该类电池面临的主要问题与解决处理方式,并对未来的发展趋势进行了展望。     

Characteristics of Dye-Sensitized Solar Cells Using TiO2 Nanotube Arrays with Large Surface Area by Spin-Coating Nanoparticle

Highly ordered TiO₂ nanotube arrays (TNAs) fabricated by anodization are very attractive for use in dye-sensitized solar cells (DSSCs), because of their superior charge percolation and slow charge recombination. Highly ordered, vertically aligned TNAs have been prepared by three-step anodic oxidation. In this work, we investigated such strategies for improving the efficiency of DSSCs. Based on one of these approaches, oxide semiconductors in the form of a TNA were used as a novel method for improving electron transport through a film. A solution containing an appropriate amount of TiO₂ nanoparticles was prepared, and the mixed slurry was spin-coated on a TNA film. The coated film provided a large surface area for dye adsorption. The DSSCs achieved a light-to-electric energy conversion efficiency of 5.91% under simulated solar irradiation at 100 mW/cm² (AM 1.5).