Adhesive bonding for mechanically stacked solar cells

Mechanically stacked solar cells formed using adhesive bonding are proposed as a route to high-efficiency devices as they enable the combination of a wide range of materials and bandgaps. The concept involves adhesive bonding of subcells using polymeric materials widely used in semiconductor processing and outlines how the absolute efficiency can be maximised by optimisation of the adhesive layer thickness and optical matching of the adhesive layer with both the subcells and their anti-reflection coatings. A dual-junction, GaAs-InGaAs, mechanically stacked solar cell is demonstrated using a benzocyclobutene adhesive layer with a measured PV conversion efficiency of 25.2% under 1-sun AM1.5G conditions. Copyright (c) 2014 John Wiley & Sons, Ltd.