Solar PV cell efficiency taken to new levels

Date: 27/09/2013
Last week there were two announcements related to innovation in increasing solar PV efficiency. Both are from a team of companies rather than individual company.

In the established silicon PV cell domain imec, RENA, and SoLayTec have achieved solar PV cell efficiency of 20.1% on a Passivated Emitter and Rear Cells (PERC) type silicon solar cells, which are made using atomic layer deposition (ALD) Al2O3 passivation and standard screen printed contacts.

These silicon solar cells are manufactured on imec’s silicon solar cell pre-pilot line using RENA’s InPilot tool for rear-side polishing and emitter removal, and SoLayTec’s spatial ALD tool for Al2O3 deposition. A top efficiency of 20.6% was reached when applying Cu-plated contacts at the front instead of silver screen printed contacts.

ALD Al2O3 passivation process by SolaYTec is aimed at lower cost of ownership (< 2€ct/layer) without effecting the cell efficiency, which is ready to be implemented in an industrial environment.

While silicon-based solar PV getting better, researchers are exploring III-IV group semiconductor materials to develop high-efficiency solar cells for concentrated solar photovoltaic applications. The CPV is suitable for areas where sunlight intensity is very higher.

In another announcement on solar PV efficiency achievement, The Fraunhofer Institute for Solar Energy Systems ISE, Soitec, CEA-Leti and the Helmholtz Center Berlin have jointly achieved a new record efficiency of 44.7%. Scientists have used multi-junction solar cells to achieve increased efficiency, several cells made out of different III-V semiconductor materials are stacked on top of each other. Each material is designed to convert light radiation into electricity for different wavelengths such as infrared, ultraviolet and visible light. Multiple semiconductor wafers were bonded one over the other.

Concentrator modules are produced by Soitec (started in 2005 under the name Concentrix Solar, a spin-off of Fraunhofer ISE).