纳米半导体PbS中的多重激子效应及其应用

发布时间：2018-05-21 06:11

  本文选题：多重激子效应 + 阈值能量　； 参考：《江西理工大学》2017年硕士论文

【摘要】：能源枯竭的危机和逐渐恶化的环境等问题,给清洁能源的发展带来了契机。因而,太阳能的研发与利用受到了广泛的关注。而当前太阳电池的关键问题是如何提高其能量转换效率,甚至突破传统单结太阳电池的理论极限。另一方面,随着社会的电气化发展,制备高性能的电子元器件的重要性逐渐凸显了出来。最近在纳米半导体体系中发现的多重激子效应为提升纳米半导体太阳电池的效率和制备高性能的新一代光电器件提供了一种新方案。虽然多重激子效应从发现至今才只是短短的十年左右,但已经发表了大量的研究结果。本论文详细地综述了多重激子效应的研究历程、不同维度的纳米半导体中多重激子的产生情况、实验研究手段和理论解释方法以及光电器件方面的应用情况,并展望了其应用前景。当前,尽管Ⅳ-Ⅵ族窄带半导体PbS具有制备简单、性能稳定等特点且在遥感和环境监测等方面有许多应用,但对纳米PbS中多重激子效应的研究报道却较少。因而,本论文较详细地研究了PbS量子点中的多重激子效应及其对太阳电池效率的增强作用。利用多重激子效应的统计模型计算了纳米PbS中的多重激子产生情况。结果表明多重激子效率I_(QE)受光子能量hv和量子点尺度d(或禁带宽度E_g)的共同影响。I_(QE)随光子能量hv/E_g的增加而增大,且在I_(QE)曲线上发现了“台阶”状的特征——多重激子产生最有特征的图谱;I_(QE)随量子点直径d的增加先增大后减小。纳米PbS中多重激子产生的阈值能量Eth受其尺寸的调控,在4.00E_g到2.35E_g(t_S=50 fs)或2.50 E_g(t_S=150 fs)之间变化。利用改进的细致平衡模型探索了多重激子效应对纳米PbS太阳电池效率。结果表明多重激子效应对较大尺度的PbS量子点太阳电池的极限效率u(E_g)和能量转换效率η均有增强效果。多重激子效应可以将纳米PbS太阳电池的最大效率η_(max)从49.0%提高到52.5%,其最佳尺度从d=4.4 nm(E_g=1.12 eV)增大到了11.6 nm(E_g=0.56 eV)。“理想”多重激子效应将甚至可以将最大效率提高到84.9%。但多重激子效应对尺度较小(或E_g较大)的纳米PbS半导体太阳电池转换效率的增强效果不明显。
[Abstract]:The crisis of energy depletion and the deteriorating environment bring opportunities to the development of clean energy. Therefore, the research and development and utilization of solar energy have received extensive attention. At present, the key problem of solar cells is how to improve their energy conversion efficiency and even break through the theoretical limits of traditional single-junction solar cells. On the other hand, with the development of electrification, the importance of preparing high-performance electronic components is becoming more and more important. The multiple exciton effect found recently in nanoscale semiconductor systems provides a new scheme for improving the efficiency of semiconductor solar cells and preparing a new generation of optoelectronic devices with high performance. Although the multiple exciton effect has only been discovered for only about ten years, a large number of studies have been published. In this paper, the research history of multiexciton effect, the generation of multiple excitons in different dimensions of nanoscale semiconductors, the experimental research methods and theoretical explanation methods, and the applications of optoelectronic devices are reviewed in detail. The prospect of its application is also prospected. At present, although 鈪，

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