Biomimetic spiral grating for stable and highly efficient absorption in crystalline silicon thin-film solar cells.

Jin Hou,Xiaohang Li,Wei Hong,Shaoping Chen,Chunyong Yang

doi:10.1364/oe.25.00a922

Abstract

By emulating the phyllotaxis structure of natural plants, which has an efficient and stable light capture capability, a two-dimensional spiral grating is introduced on the surface of crystalline silicon solar cells to obtain both efficient and stable light absorption. Using the rigorous coupled wave analysis method, the absorption performance on structural parameter variations of spiral gratings is investigated firstly. Owing to diffraction resonance and excellent superficies antireflection, the integrated absorption of the optimal spiral grating cell is raised by about 77 percent compared with the conventional slab cell. Moreover, though a 15 percent deviation of structural parameters from the optimal spiral grating is applied, only a 5 percent decrease of the absorption is observed. This reveals that the performance of the proposed grating would tolerate large structural variations. Furthermore, the angular and polarization dependence on the absorption of the optimized cell is studied. For average polarizations, a small decrease of only 11 percent from the maximum absorption is observed within an incident angle ranging from -70 to 70 degrees. The results show promising application potentials of the biomimetic spiral grating in the solar cell.

Highlights

To pursue renewable and green energy, research efforts have been concentrated on developing economical thin-film crystalline silicon (c-Si) solar cells [1,2]
Because the purpose of this paper is to study whether the spiral grating could favor stable and efficient absorption, we perform dependence studies on the key surface structural parameters (d and p) of spiral grating
We could conclude that the proposed spiral grating cell is insensitive to the angle of incident, and the spiral grating cell imitating the spiral phyllotaxis of plants does have an ability of achieving both stable and highly efficient light absorption

Summary

Introduction

To pursue renewable and green energy, research efforts have been concentrated on developing economical thin-film crystalline silicon (c-Si) solar cells [1,2]. An obvious dilemma is that the thin film tends to have weak light-absorption efficiency if the film thickness is lower than the absorption length of the material To overcome this issue, researchers have employed various light-trapping structures to enhance the absorption such as nano-periodic [3,4,5,6,7,8], random [9,10,11] and quasi-random [12,13,14,15,16] surface structures, including plasmonic nanoparticles structures [17,18,19]. Both absorption enhancement and dimension tolerance should be taken into account simultaneously to obtain solar cells with stable and efficient absorption. We could conclude that the proposed grating derived from the spiral phyllotaxis is effective for achieving both stable and highly efficient absorption in the c-Si thin-film solar cells

Structure of spiral grating cell and method

Structural engineering and absorption stability analysis

Findings

Conclusion