For the employment of organic photovoltaic cells in wearable electronic systems, improvements in energy conversion efficiency and omnidirectionality (angular coverage) are highly appreciated. This study aims at those improvements by introducing shell-shaped active layers. The proposed device structures enhance light absorption and angular range through light coupling to guided modes in the active layer. Two shapes, i.e., a triangle and a semicircle, are examined for the shell cross-sections. Numerical simulation using finite-element analysis and finite-difference time-domain methods demonstrates that the devices with the triangular-shell-shaped active layers exhibit an average absorption enhancement of up to 63% for transverse electric (TE)-polarization and up to 32% for transverse magnetic (TM)-polarization when compared with the flat active layers of the same thicknesses. The average enhancements of the semicircular-shell-shaped active layers are found to be slightly lower than those values, with 60% for TE and 28% for TM. The examined structures also show good omnidirectionality with decent absorption up to an 81 deg incidence angle for the triangular-shell-shaped device and up to a 76 deg angle for the semicircular one when TM polarization is considered. These absorption enhancements and improved angular coverages make the proposed structures highly attractive for wearable electronic system applications.

中文翻译：

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用于全向有机光伏电池的壳形活性层

对于在可穿戴电子系统中使用有机光伏电池，能量转换效率和全向性（角覆盖）的改进受到高度评价。本研究旨在通过引入壳形活性层来实现这些改进。所提出的器件结构通过光耦合到有源层中的导模来增强光吸收和角度范围。检查两种形状，即三角形和半圆形的壳横截面。使用有限元分析和有限差分时域方法的数值模拟表明，具有三角形壳形有源层的器件对横向电 (TE) 极化的平均吸收增强高达 63%，高达 32与相同厚度的平坦有源层相比，横向磁 (TM) 极化的 %。发现半圆形壳状有源层的平均增强略低于这些值，TE 为 60%，TM 为 28%。所检查的结构还显示出良好的全向性，当考虑 TM 偏振时，三角形壳形器件的入射角高达 81 度，半圆形器件的入射角高达 76 度。