Centre of Microelectronic Technologies, Institute of Chemistry, Technology and Metallurgy, University of Belgrade, Njegoseva 12, 11060 Belgrade, Serbia.
Photochem Photobiol Sci. 2019 Aug 1;18(8):2023-2030. doi: 10.1039/c9pp00118b. Epub 2019 Jul 10.
Rising demands for renewable energy sources have led to the development of dye sensitized solar cells. It is a challenge to find a good and low cost sensitizer, which has a low environmental impact. In this work, we conducted spectroscopic and electrochemical experiments, as well as quantum-chemical calculations of the natural pigment hypericin, in order to provide insight into its sensitizing efficiency. To this end, three identical cells were made and characterized. Although this pigment exhibited good adsorption onto a semiconductor surface, a high molar absorption coefficient (43 700 L mol cm) and favorable alignment of energy levels and provided a long lifetime of electrons (17.8 ms) in the TiO photoanode, it was found that the efficiency of hypericin-sensitized solar cells was very low, only 0.0245%. We suggest that this inefficiency originated from a low injection of electrons into the conduction band of TiO This conclusion is supported by the density functional theory calculations which revealed a low electron density in the anchoring groups of electronically excited hypericin. The results of this work could be valuable not only in the photovoltaic aspect, but also for application of hypericin in medicine in photodynamic therapy.
对可再生能源的需求不断增加，推动了染料敏化太阳能电池的发展。寻找一种良好且低成本、环境影响小的敏化剂是一项挑战。在这项工作中，我们进行了光谱和电化学实验以及天然色素金丝桃素的量子化学计算，以深入了解其敏化效率。为此，我们制作并表征了三个相同的电池。尽管这种颜料在半导体表面具有良好的吸附性，摩尔吸收系数高（43700 L mol cm），能级排列有利，并在 TiO 光阳极中提供了长寿命的电子（17.8 ms），但我们发现金丝桃素敏化太阳能电池的效率非常低，仅为 0.0245%。我们认为这种低效率源于电子向 TiO 导带的低注入。密度泛函理论计算结果表明，电子激发态金丝桃素的锚固基团中的电子密度较低，这一结论得到了支持。这项工作的结果不仅在光伏方面具有价值，而且在光动力疗法中金丝桃素的应用方面也具有价值。
