Department of Physical and Analytical Chemistry, Uppsala University, Box 259, 751 05 Uppsala, Sweden.
Phys Chem Chem Phys. 2011 Aug 28;13(32):14767-74. doi: 10.1039/c1cp20911f. Epub 2011 Jul 11.
The energy loss in dye-sensitized solar cells calculated from the energy difference between the lowest electronic transition of the dye and the obtained open-circuit voltage is often 1 eV or even more. To minimize this loss, it is important to accurately determine the energy alignment at the TiO(2)/dye/redox-mediator interface. In this study, we compared the results from electrochemistry and photoelectron spectroscopy for determining the energy alignment of three rylene dyes, two of which absorb relatively far in the red. The trends observed with the methods were different, as in the former, the energy alignment is measured relative to an external reference and includes contributions from solvent reorganization energies, while in the latter, it is measured relative to the energetics of the TiO(2) and is lacking such contributions. The influence of the dyes' dipole moments on the energetics of the TiO(2) was also measured and explained some of the differences in trends. Finally, we compared the injection efficiencies of the two red-absorbing dyes and found that the differences in injection efficiencies can be better explained using the energy alignment determined from photoelectron spectroscopy. This shows that the method for measuring the energetics of a DSC should be chosen according to what process one intends to study.
染料敏化太阳能电池中的能量损失是通过染料最低电子跃迁和开路电压之间的能量差计算得出的，通常为 1 eV 或更高。为了最小化这种损失，准确确定 TiO2/染料/氧化还原介体界面的能量排列非常重要。在这项研究中，我们比较了电化学和光电子能谱两种方法确定三种苝染料能量排列的结果，其中两种染料在红光区的吸收相对较远。这两种方法观察到的趋势不同，因为前者是相对于外部参考测量能量排列，包括溶剂重组能的贡献，而后者是相对于 TiO2 的能量测量，缺乏这种贡献。我们还测量了染料偶极矩对 TiO2 能量的影响，并解释了一些趋势差异。最后，我们比较了两种红光吸收染料的注入效率，发现使用光电子能谱确定的注入效率可以更好地解释注入效率的差异。这表明，应该根据要研究的过程选择测量 DSC 能量的方法。
