SiC2 Siligraphene and Nanotubes: Novel Donor Materials in Excitonic Solar Cells
SiC2 Siligraphene and Nanotubes: Novel Donor Materials in Excitonic Solar Cells
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SiC2 硅石墨烯和纳米管：激子太阳能电池中的新型供体材料
DOI：
10.1021/nl403010s
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发表时间：
2013
期刊：
影响因子：
10.8
通讯作者：
Wu Liming
中科院分区：
文献类型：
--
作者：
Zhou Liujiang;Zhang Yongfan;Wu Liming
在激子太阳能电池（XSC）中，功率转换效率（PCE）关键地取决于供体和受体材料之间的界面能带对准。石墨烯或硅烯由于其半金属特征（零带隙）而不适合作为供体材料;因此，非常期望在石墨烯或硅烯中打开能隙以扩展其在光电器件中的应用，特别是在光电子学中。基于全局粒子群优化算法和密度泛函理论，预测了一种直接带隙为1.09 eV的新型SiC 2硅化石墨烯（g-SiC 2），其中Si和C原子采用sp2杂化，C原子形成离域的4个C-畴，Si原子周期性地分隔开4个C-畴.这样的g-SiC 2硅石墨烯（具有能量的全局最小值）比含有平面4重配位硅的同分异构体pt-SiC 2硅石墨烯低0.41 eV/原子并且热稳定性更高（3000 K对1000 K）。有趣的是，衍生的（n，0），（n，n）纳米管（直径大于8.0 μ m）的带隙约为1.09 eV，这是独立的手性和直径。此外，还提出了一系列g-SiC 2/GaN双层结构和g-SiC 2 nanotube/ZnO单层结构的XSC，它们具有12- 20%的高PCE。
In excitonic solar cells (XSC), power conversion efficiency (PCE) depends critically on the interface band alignment between donor and acceptor materials. Graphene or silicene is not suitable for donor materials due to their semimetallic features (zero band gaps); it is therefore highly desired to open an energy gap in graphene or silicene to extend their application in optoelectronic devices, especially in photovoltaics. In this paper, based on the global particle-swarm optimization algorithm and the density functional theory methods, we predict a novel SiC2siligraphene (g-SiC2) with a direct band gap of 1.09 eV showing infinite planar geometry, in which Si and C atoms adopt sp2hybridization and C atoms form delocalized 4 C-domains that are periodically separated by Si atoms. Such a g-SiC2siligraphene (with a global minimum of energy) is 0.41 eV/atom lower and thermally stabler than the isomeric pt-SiC2silagraphene containing planar 4-fold coordinated silicon (3000 K vs 1000 K). Interestingly, the derivative (n, 0), (n,n) nanotubes (with diameters greater than 8.0 Å) have band gaps about 1.09 eV, which are independent of the chirality and diameter. Besides, a series of g-SiC2/GaN bilayer and g-SiC2nanotube/ZnO monolayer XSCs have been proposed, which exhibit considerably high PCEs in the range of 12–20%.