Light trapping schemes in organic solar cells: A comparison between optical Tamm states and Fabry-Pérot cavity modes
Light trapping schemes in organic solar cells: A comparison between optical Tamm states and Fabry-Pérot cavity modes
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DOI：
10.1016/j.orgel.2013.03.029
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发表时间：
2013-06
影响因子：
3.2
通讯作者：
Xu-Lin Zhang;Junfeng Song;Xianbin Li;Jing Feng;Hongbo Sun
中科院分区：
文献类型：
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作者：
Xu-Lin Zhang;Junfeng Song;Xianbin Li;Jing Feng;Hongbo Sun
近年来，金属/光子晶体界面的光学Tamm态作为一种新的光捕获方案被应用于薄膜有机太阳能电池（OSC）中，以增强光子吸收。在这项工作中，我们从理论上深入研究了这种方案，以优化这种基于光学Tamm态的OSC（OTS-OSC）的吸收性能。我们发现，OTS-OSC的整体吸收率可以通过使用具有更高折射率对比度的光子晶体双层来提高，这是有源层中更强烈增强的场强度的结果。传统的基于法布里-珀罗腔模的OSC（FP-OSC）也进行了研究比较，其吸收性能被发现是强烈依赖于附加介质层的折射率。这两种方案的OSC表现出相当的吸收性能方面的吸收增强，场分布和角度效应的平面情况下。然而，如果两种OSC在平面情况下表现出相同的总吸收率，则所提出的OTS-OSC在波纹情况下表现出比FP-OSC高10%的总吸收率。波纹状FP-OSC中的降低的吸收是金属中的强散射引起的损耗的结果，这可以通过OTS-OSC中的光子晶体双层来避免。因此，所提出的基于Tamm状态的方案在波纹状OSC中显示出更高的价值。
Recently optical Tamm states at metal/photonic crystals interface have been applied in thin-film organic solar cells (OSCs) as a new light trapping scheme for photon absorption enhancement. In this work, we theoretically investigate this scheme thoroughly to optimize the absorption performance for such optical Tamm states based OSCs (OTS–OSCs). We find that the overall absorptivity of the OTS–OSCs can be improved by using photonic crystals bilayers with a higher refractive index contrast, which is a result of the more strongly enhanced field intensity in the active layers. The conventional Fabry–Pérot cavity modes based OSCs (FP–OSCs) are also studied for comparison, whose absorption performance is found to be strongly dependent on the refractive index of the additional dielectric layer. These two schemes based OSCs exhibit comparable absorption performance in aspects of absorption enhancement, field distributions, and angle effect in the planar case. However, the proposed OTS–OSCs exhibit ∼10% higher overall absorptivity than that for the FP–OSCs in the corrugated case, if both OSCs exhibit the same overall absorptivity in the planar case. The reduced absorption in the corrugated FP–OSCs is a result of the strong scatterings induced losses in the metal, which can be avoided by the photonic crystals bilayers in the OTS–OSCs. Therefore, the proposed Tamm states based scheme shows a higher value in corrugated OSCs.