Project Acronym COBRA
Project Title organic COBalt based low-cost pRintable

large-Area photovoltaics

Project Start Date 01/03/2013
Project Duration 36 Months
Partners’ names and countries Merck KGaA, Germany
3GSolar Photovoltaics Ltd., UK
Colour Synthesis Solutions, UK

Project Coordinator:

Name: Nicolas Blouin

Organization: Merck KGaA


The COBRA project targets an emerging PV cell concept. The DSSC (dye sensitised solar cells) technology converts light to electricity via a photochemical reaction between a dye absorbed on a TiO2 semiconductor layer and an electrolyte containing a redox couple. This project focuses on the development of novel electrolytes based on copper (initially cobalt) redox mediators, dyes specifically designed for these novel redox couples and material integration into a solar cell. In this consortium, three active members (Merck, Colour Synthesis Solutions [CSS] and 3GSolar) represent the full value chain related to a DSSC device. Merck’s role is to design and synthesise redox mediators and prepare and deliver novel electrolytes from them. CSS’s role is to design, synthesize and deliver new and known DSSC dyes to the consortium to allow electrolyte matching development by Merck. 3GSolar’s role focuses on the material integration (e.g. electrolytes from Merck and dyes from CSS) and the solar cell assembly. The project is supported by Uppsala University, which provides advanced characterisation measurements and technical recommendations. Thus, all key aspects of the DSSC technology are under evaluation in the three work packages, i.e. Electrolyte; Dyes; and Materials Integration and Solar Cell Assembly.

The project original aim was directed toward cobalt-based redox mediators. In early 2013, ECHA (European Chemicals Agency) included CoCl2 in the list of substances of very high concern for authorisation due to its carcinogenic potential. Immediate actions were taken to realign the project towards less toxic redox mediators. After careful consideration, the consortium took the decision to refocus to project toward copper-based electrolytes ensuring long term commercial viability for the current project and foreground. Since this change in October 2013, key progress has been made leading to a power conversion efficiency over 7% under outdoor condition. Focusing on low toxicity chemicals, the project will enable photovoltaic indoor application such as smart shelf labelling, smart household sensors, etc resulting in new market opportunities in the energy harvesting market.