Exploiting optical anisotropy to increase the external quantum efficiency of flexible P3HT:PCBM blend solar cells at large incident angles
Journal
Solar Energy Materials and Solar Cells
Journal Volume
95
Journal Issue
8
Pages
2141-2150
Date Issued
2011
Author(s)
Chuang, Shang-Yu
Yu, Chen-Chieh
Chen, Hsuen-Li
Su, Wei-Fang
Chen, Chun-Wei
Abstract
The external quantum efficiencies of P3HT:PCBM blend solar cells decrease significantly when they are bent or illuminated at large incident angles because of (i) optical anisotropy of the P3HT:PCBM films - primarily because a mismatch between the direction of the electric field of the incoming light and the orientation of the P3HT:PCBM blend nanocrystallites results in a significant reduction in the amount of TM-polarized light absorbed and (ii) interfacial reflection of multilayer structures primarily because the outermost airflexible substrate interface exhibits a distinct refractive index difference at large incident angles. Textured moth-eye structures fabricated by nanoimprint lithography on the flexible substrates of organic solar cells reduce the degree of interfacial reflection at high incident angles; they should allow more TE-polarized light to absorb in the P3HT:PCBM films (active layers) of the organic solar cells. © 2011 Elsevier B.V.
Type
journal article