Understanding Quantum Confinement of Charge Carriers in Layered 2D Hybrid Perovskites
Understanding Quantum Confinement of Charge Carriers in Layered 2D Hybrid Perovskites
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DOI：
10.1002/cphc.201402428
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发表时间：
2014-12-01
期刊：
影响因子：
2.9
通讯作者：
Katan, Claudine
中科院分区：
文献类型：
--
作者：
Even, Jacky;Pedesseau, Laurent;Katan, Claudine
层状杂化有机钙钛矿（HOP）结构是一类低成本二维材料，具有与介电和量子限制效应相关的出色光学特性。尽管传统半导体对量子限制的建模和理解已经非常成熟，但二维 HOP 仍然缺乏此类知识。在这项工作中，我们仔细研究了有效质量和量子阱的概念，并讨论了它们在 2D HOP 中的适用性。对于超薄层，有效质量模型失效。超晶格耦合的缺失和非抛物线效应的重要性阻碍了基于有效质量和包络函数近似的简单经验模型的使用。建议采用另一种方法，将 2D HOP 视为复合材料，并引入计算能带偏移的第一原理方法。这些发现也可能与其他类别的层状二维功能材料相关。
Layered hybrid organic perovskites (HOPs) structures are a class of low-cost two-dimensional materials that exhibit outstanding optical properties, related to dielectric and quantum confinement effects. Whereas modeling and understanding of quantum confinement are well developed for conventional semiconductors, such knowledge is still lacking for 2D HOPs. In this work, concepts of effective mass and quantum well are carefully investigated and their applicability to 2D HOPs is discussed. For ultrathin layers, the effective-mass model fails. Absence of superlattice coupling and importance of non-parabolicity effects prevents the use of simple empirical models based on effective masses and envelope function approximations. An alternative method is suggested in which 2D HOPs are treated as composite materials, and a first-principles approach to the calculation of band offsets is introduced. These findings might also be relevant for other classes of layered 2D functional materials.