Single-material TiO2 double-layer antireflection coatings

This paper demonstrates that a double-layer antireflection (DLAR) coating can be fabricated using a single material, titanium dioxide (TiO2). The optical properties of the top and bottom TiO2 layers were controlled by varying the deposition and sintering conditions, resulting in a range of refractive indices, n=1.73–2.63 at 600 nm. Weighted average reflectances of 6.5% (measured) and 7.0% (calculated) were achieved for TiO2 DLAR coatings in air and under glass, respectively. When implemented in a high-efficiency silicon solar cell, a short-circuit current density increase of ΔJsc=2.5 mA/cm2 can be expected for an optimised TiO2 DLAR coating when compared to a commercial TiO2 single-layer antireflection coating.