New interdigital design for large area dye solar modules using a lead-free glass frit sealing

A new interdigital design for large area dye solar modules is developed for an area of 30 x 30 cm(2). This design requires fewer holes in the glass substrate for electrolyte filling, than the conventional strip design. A complete manufacturing process of this module-ranging from screen printed layers to semi-automated colouring and electrolyte filling-in a laboratory-scale baseline is illustrated. As primary sealing method, a durable glass frit sealing is used. It is shown, that the lead (Pb) content present in many glass frit powders contaminates the catalytic platinum electrode during the sintering process, resulting in a lowering of the fill factor. A screen printable lead-free glass frit paste is developed, which solves this problem. Long term stability tests are presented on 2.5 cm(2) dye solar cells, which have been completely sealed with glass fit. In consecutively performed accelerated ageing tests under 85 degrees C in the dark (about 1400 h) and continuous illumination with visible light (1 sun, about 1700 h), a 2.5 cm(2) dye solar cell with an electrolyte based on propylmethylimidazolium iodide showed an overall degradation of less than 5% in conversion efficiency. In a subsequently performed thermal cycling test (-40 degrees C to + 85 degrees C, 50 cycles) a 2.5cm(2) dye solar cell with the same electrolyte composition also showed only a slight degradation of less than 5% in conversion efficiency.