Magnetic field- and pressure- optical effects in CuInSe2, CuGaSe2 and CuInS2

为了减少对化石燃料的依赖，开发改良的可再生能源是极其重要的。太阳能是最环保和最丰富的能源，因为太阳传输到地球表面的能量是目前世界能源消耗的10万倍。太阳能电池采用了一系列材料，在这里，我们建议研究黄铜矿半导体，它具有特殊的优势，即(1)极高的吸收系数，高于任何其他已知的半导体；(2)接近地面和空间条件下的最佳值的能隙；(3)由于室温下有效的自修复机制，对高能质子和电子的照射具有鲁棒性和相对不敏感。要研究的材料是目前用于太阳能电池吸收层的CuInSe2， CuGaSe2和CuInS2半导体，它们在薄膜光伏器件中保持着创纪录的转换效率（Cu(InGa)Se2-光伏器件为19%，CuInS2基光伏器件为12%），并且与任何其他薄膜太阳能电池相比，具有优越的稳定性。CuInS2 （Eg ~ 1.53 eV）的带隙几乎理想地匹配太阳光谱，而在cuinsse2基电池中，通过合金cuinsse2 （Eg ~ 1.05 eV）和CuGaSe2 （Eg ~ 1.68 eV）达到最佳效率。迄今为止，基于Cu(InGa)(SSe)2的技术的进展主要是通过科学直觉而不是基于知识的设计来实现的。在这里，我们建议使用光谱学，在磁场和高压的存在下，提高对这些材料的理解，并将其应用于改进的太阳能电池的开发。

The development of improved sources of renewable energy is of extreme importance in order to reduce dependence on fossil fuels. Solar energy leads the way as the most environmentally friendly and abundant of such resources since the Sun transmits to the earth surface an amount of energy 100,000 times greater than present world energy consumption. A range of materials are employed for solar cells and here we propose work on chalcopyrite semiconductors which offer particular advantages, namely (1) extremely high absorption coefficients, higher than any other known semiconductor (2) energy gaps close to the optimal values for terrestrial and space conditions (3) robustness and relative insensitivity to irradiation by both high energy protons and electrons as a result of efficient self-healing mechanisms at room temperature. The materials to be studied are CuInSe2, CuGaSe2 and CuInS2 semiconductors as are currently used in the absorber layer of solar cells which hold record conversion efficiencies for thin-film photovoltaic devices (19% for Cu(InGa)Se2- photovoltaic devices and 12% for CuInS2-based ones) and demonstrate superior stability when compared to any other thin-film solar cell. The band-gap of CuInS2 (Eg ~ 1.53 eV) almost ideally matches the solar spectrum whereas in CuInSe2-based cells the optimum efficiency is achieved by alloying CuInSe2 (Eg ~ 1.05 eV) and CuGaSe2 (Eg ~ 1.68 eV). Progress so far with Cu(InGa)(SSe)2-based technologies has mostly been attained using scientific intuition rather than knowledge-based design. Here we propose to use optical spectroscopy, in the presence of magnetic fields and high pressure, to improve the understanding of these materials and apply this to the deveopment of improved solar cells.