Light trapping with titanium dioxide diffraction gratings fabricated by nanoimprinting

Abstract

Dielectric scattering structures are a promising way of trapping light in solar cells. Titanium dioxide is a particularly attractive candidate material because of its high refractive index and ability to be deposited on a finished solar cell. Here, we present an experimental demonstration of photocurrent enhancement in thin film recrystallised silicon solar cells using TiO2 pillar arrays fabricated on the rear of the cells using nanoimprint lithography. A short circuit current enhancement of 19% is measured experimentally, and excellent agreement with numerical simulations is obtained. We show numerically that by replacing the Ag capping present on the cells with a detached rear Ag back reflector, the enhancement could reach 37%. Copyright © 2012 John Wiley & Sons, Ltd.

Light absorption enhancement for ultra-thin Cu(In1−xGax)Se2 solar cells using closely packed 2-D SiO2 nanosphere arrays

“…Previously, light absorption enhancement for CIGSe solar cells was achieved by coating an anti-reflection layer of MgF 2 [4,5] or by improving the internal reflection at the CIGSe/Mo interface via inserting a dielectric layer [6] or via transferring the cells from the typical Mo back contact onto Au which has a better reflectivity [7]. Recently, a number of innovative nanoscale lighttrapping structures have shown the potential to better improve the light absorption including plasmonic structures [8][9][10][11], dielectric diffractive nanostructures [12,13] and photonic crystals [14,15]. However, these innovative structures are mainly for Si-based, GaAs and organic solar cells, a few have been reported for CIGSe solar cells but were limited to theoretical investigations [16][17][18].…”

Nanoimprint technology for patterning functional materials and its applications

“…The etching masks are typically made of metal patterns defined by NIL [48,49]. For example, nano-scaled patterns on epitaxial Ba 0.7 Sr 0.3 TiO 3 (BST) ceramic films were fabricated by NIL.…”

Prototyping of nanophotonic grating back contacts for light trapping in planar silicon solar cells

“…As a novel light‐trapping approach also the application of nanophotonic grating back contacts to wafer‐based solar cells has been investigated in several fundamental studies, till today . An estimation of the high potential of the concept applying such nanophotonic grating back contacts for light trapping was given, even if the content of these studies was usually restricted to absorptance measurements.…”