Optimization of anti‐reflection moth‐eye structures for use in crystalline silicon solar cells

Abstract

An anti-reflection (AR) moth-eye structure made of acrylic resin and deposited on a polyethylene terephthalate (PET) substrate was optimized in the wavelength range from 400 to 1170 nm; crystalline silicon (c-Si) solar cells function efficiently in this wavelength range. The rigorous coupled wave analysis (RCWA) method was used for optical simulation, and the Taguchi method was used for efficient optimization. The simulation results showed that the reflectance of the optimized structure over the above-mentioned wavelength range was less than 0.87% and that a minimal reflectance of 0.1% was observed at 400 nm. Experimental results showed that the reflectance of a fabricated moth-eye structure was less than 1.0% in the wavelength range and that a minimal reflectance of 0.55% was observed at 700 nm. A c-Si solar cell, which was enclosed in a polyvinyl butyral (PVB) layer of uniform thickness, was coated with the fabricated moth-eye film, and it was observed that the moth-eye film increased electric generation (EG) up to 15%, depending on the incident angle. Further, a daily increase in EG of up to 8.7% was estimated on a clear summer day in Japan when the moth-eye film was used.

Liquid transfer nanoimprint replication on non-flat surfaces for optical applications

“…Another important application for patterned nano structures on curved surface are photovoltaic devices. In photovoltaics the use of moth eye patterns to increase cell efficiency by reducing the reflection losses at the surface are of growing interest [6,7]. Sub wavelength patterns offer the highest performance but cannot be patterned easily on the non-flat surface of a multi crystalline wafer, which is the dominating substrate for the photovoltaic market.…”

Nanostructures for photon management in solar cells

“…An encapsulant that performs well at even high angles of incidence was fabricated by Yamada and colleagues. They analyzed the effect of the shape of a moth-eye structure using rigorous coupled wave simulations and fabricated an optimized coating for silicon solar cells (i.e., rounded nanocones) by nanoimprinting an acrylic resin [ 38 ]. When placed on top of a standard encapsulated silicon solar cell and deployed in Nagoaka, Japan, power output of the cell was improved by 4% at normal incidence and by up to 15% at angles as large as 80 ° or more.…”

Improving optical performance of concentrator cells by means of a deposited nanopattern layer

“…Regarding their application in photovoltaics (PV), different periodic nanometric structures have already been proposed for their use as solar cells ARC, known as moth-eye materials. These biologically inspired nanosurfaces [2,[4][5][6] are subwavelength-structured surfaces with a graded effective refractive index (n eff ) that smooth the optical transition between the air and the high-index transparent medium. The aforementioned n eff defines a nanostructured surface depending on the volume fraction of subwavelength structured material in air.…”