关键词: 有机太阳能电池/
表面等离子共振/
短节距金属光栅
English Abstract
Optical and electrical properties of short-pitch solar cells with finite-difference frequency-domain method
Sun Long1,2,3,Ren Hao4,
Feng Da-Zheng1,2,
Wang Shi-Yu1,5,
Xing Meng-Dao1,2
1.National Laboratory of Radar Signal Processing, Xidian University, Xi'an 710071, China;
2.Collaborative Innovation Center of Information Sensing and Understanding, Xidian University, Xi'an 710071, China;
3.No. 38 Research Institute, China Electronics Technology Group Corporation, Hefei 230088, China;
4.Key Laboratory of Intelligent Computing and Signal Processing, Ministry of Education, Anhui University, Hefei 230039, China;
5.School of Technical Physics, Xidian University, Xi'an 710071, China
Fund Project:Project supported by the National Natural Science Foundation of China (Grant Nos. 61701001, 61601166, 61701003), the Natural Science Foundation for Universities of Anhui Province, China (Grant Nos. KJ2017ZD02, KJ2017ZD51), and the National Natural Science Fund for Excellent Young Scholars of China (Grant No. 61722101).Received Date:26 April 2018
Accepted Date:04 June 2018
Published Online:05 September 2018
Abstract:Organic solar cells (OSCs) have attracted intensive attention in recent years due to their distinct advantages of rich material resources, easy fabrication, and good flexibility. The standard structure of OSCs consists of an anode, an active layer and a cathode. Indium tin oxide (ITO) is often used as a transparent anode. However, the indium in ITO is not only very low in content, but also can penetrate into other layers of OSCs and affect the battery life. The ITO is not suitable for flexible OSCs because of its brittleness. Therefore, researchers have been trying to find alternatives to ITO, which should have transparent and flexible electrodes. The multilayer film consisting of MoO3/Ag/MoO3 is a very promising candidate as an alternative of ITO to work as the transparent anode in OSCs. However, in MoO3/Ag/MoO3 based thin OSCs structure, the absorption of light is quite poor. Here, we introduce a short-pitch metallic grating in which there are used the surface plasmon polaritons (SPPs) to enhance the light absorption of the active layer. The finite-difference frequency-domain method is used to solve the Maxwell's equations and semiconductor equations for revealing the optical and electrical properties of OSCs. As is well known, the contradiction between the long light absorption path and the short exciton diffusion length results in a relatively low power conversion efficiency (PCE) of the OSCs. Metallic gratings can be introduced into conventional OSCs for improving the light absorption due to the surface plasmon resonance. The light absorption can be enhanced compared with that in the conventional OSCs without metallic gratings. At the same time, the small periodic structure is introduced into the MoO3/Ag/MoO3 anode-based OSCs. The small spacing between gratings creates a strong interaction between two adjacent metal nanowalls. These nanostructures and metal nanostructures will further enhance the light absorption. In this work, it is proposed that short-pitch metallic gratings be introduced into the MoO3/Ag/MoO3 anode-based OSCs for improving the light absorption and PCE. It is found that the light absorption of plasmonic structure with short-pitch metallic gratings can be greatly enhanced compared with standard structure without metallic gratings. Meanwhile, with an optimal groove width of 4 nm, PCE is improved by 49% compared with the case with the planar structure. These results contribute to better developing the ITO free OSCs.
Keywords: organic solar cells/
plasmonic/
short-pitch metallic grating
