Abstract
We demonstrate numerically a 2-D nanostructured design for light trapping in a low band-gap polymer solar cell. Finite element method simulations are used to study the effect of varying nanostructure periodicity, height, and shape on active layer absorption. Maintaining a constant active layer thickness of 100 nm we observe an enhancement in solar absorption of almost 40% relative to a planar cell. Improvements of this magnitude enable single-junction, low-band-gap cells to achieve power conversion efficiencies of 11.2% and perform competitively with even state-of-the-art tandem cells. Our design is also shown to significantly outperform tandem cells at off-normal angles of incidence.
Highlights
Recent progress in polymer solar cell (PSC) research has been rapid, with power conversion efficiencies reaching 8-9% in single junction cells [1,2,3] and 10.6% in tandem cells [4]
A fundamental limitation facing PSCs is the requirement that active layer thickness remain on the order of charge carrier diffusion lengths, typically ~100-300nm for bulk hetero-junction (BHJ) cells
Nanostructured cells have been optically modeled using a variety of computational techniques, including finite-difference time-domain (FDTD) [2,12,13,14,15], rigorous coupled wave analysis (RCWA) [6], scattering matrix method (SMM) [9,10] and finite element method (FEM) [11]
Summary
Recent progress in polymer solar cell (PSC) research has been rapid, with power conversion efficiencies reaching 8-9% in single junction cells [1,2,3] and 10.6% in tandem cells [4]. One popular approach has been to incorporate highly ordered periodic nanostructures in the cell The goal of such structures is to use wave optics or plasmonics to guide the flow of light and increase absorption without increasing active layer thickness. Nanostructured cells have been optically modeled using a variety of computational techniques, including finite-difference time-domain (FDTD) [2,12,13,14,15], rigorous coupled wave analysis (RCWA) [6], scattering matrix method (SMM) [9,10] and finite element method (FEM) [11] Of these theoretical investigations, the highest reported enhancement in absorption relative to a planar cell is 40% [11]. In this work we use a state-ofthe-art low band-gap polymer as an active material, and demonstrate large enhancement relative to a planar cell with a full-thickness active layer, leading to a projected power conversion efficiency (PCE) of 11.2% over a wide range of incident angles. The design is studied for off-normal angles of incidence and shown to outperform a state-of-the-art tandem cell
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
