Liu Jia, Huang Fei, Meng Lin, Yu Hao-ran, Chen Ying-hua
Guang Pu Xue Yu Guang Pu Fen Xi. 2015 May;35(5):1290-3.
Fe-S series, especially FeS2 and Fe1-x S is the main component of crustal rocks as important metal sulphides. Pyrite (FeS2) shows a promising vision in solar cell materials for its high absorption coefficient and suitable band gap. Predecessors have done some researches on the photovoltaic properties of Fe-S series under different conditions. However, little researches have been done on the coexisted sulphide of FeS2 and Fe1-xS. FeS2 and Fe1-xS often appear as symbiotically due to their similar formation conditions. So the study on the optical absorption characteristics of FeS2 and Fe1-xS are of important significance. In order to study the optical absorption characteristics of FeS2-Fe1-xS heterostructures, using the SEM and XRD to characterize the morphology, composition and structure, respectively. The results show that the samples were cubic pyrite with a certain amount of pyrhotite (Fe1-xS). The crystal partical size was between 5 and 10 nm. Measurement of the absorption spectrum was performed using Cary 500 UV-Vis-NIR spectrophotoineter, acquiring the results of 1 860-1 889 nm, and the absorption peak in 1879nm. According to the band gap (eV) formula, the band gap value is calculated to be 0. 657 8 eV. The extreme electrical-to-optical conversion efficiency achieved was about 15%. By the first principles, we analysed the reason of the changing of the band gap value, and then compared the result with previous one. The internal structure of mineral is the important factor affecting the photoelectric conversion. The light absorption characteristics of FeS2-Fel-xS heterostructures synthesized under hydrothermal conditions is better than the characteristics from natural pyrite with defects of Co and Ni. The heterostructures can improve the electrical-to-optical conversion efficiency and provide scientific basis for the absorption characteristics research of Fe-S series materials.
铁硫系列，尤其是二硫化铁（FeS₂）和Fe₁₋ₓS作为重要的金属硫化物，是地壳岩石的主要成分。黄铁矿（FeS₂）因其高吸收系数和合适的带隙，在太阳能电池材料方面展现出广阔前景。前人已对不同条件下铁硫系列的光伏特性进行了一些研究。然而，对于FeS₂和Fe₁₋ₓS共存硫化物的研究却很少。由于形成条件相似，FeS₂和Fe₁₋ₓS常共生出现。因此，研究FeS₂和Fe₁₋ₓS的光吸收特性具有重要意义。为研究FeS₂ - Fe₁₋ₓS异质结构的光吸收特性，分别使用扫描电子显微镜（SEM）和X射线衍射仪（XRD）对其形貌、成分和结构进行表征。结果表明，样品为含有一定量磁黄铁矿（Fe₁₋ₓS）的立方黄铁矿。晶体颗粒尺寸在5到10纳米之间。使用Cary 500紫外 - 可见 - 近红外分光光度计测量吸收光谱，得到1860 - 1889纳米的结果，吸收峰位于1879纳米处。根据带隙（eV）公式，计算出带隙值为0.6578 eV。实现的最高光电转换效率约为15%。通过第一性原理，我们分析了带隙值变化的原因，然后将结果与之前的进行比较。矿物的内部结构是影响光电转换的重要因素。水热条件下合成的FeS₂ - Fe₁₋ₓS异质结构的光吸收特性优于含钴和镍缺陷的天然黄铁矿。该异质结构可提高光电转换效率，为铁硫系列材料的吸收特性研究提供科学依据。
