A Summary of the Havemor Project - Process Development of Shaped and Coloured Solar Cells for BIPV Applications

Abstract

The use of photovoltaic modules in architectural applications is now firmly established and large modules of glass-glass construction produced specifically for the BIPV market are available. In 1995 Mason et al [1] investigated colour and efficiency of laser grooved buried contact (LGBC) solar cells as a function of the thickness of the low pressure chemical vapour deposition (LPCVD) silicon nitride antireflective coating (ARC). In the late 1990’s the BIMODE project produced coloured solar cells using this technique and modules of efficiencies in the range of 6.3% to 12.1% [2,3,4] were fabricated. The HAVEMOR project which started in 2007 is aimed at understanding and controlling the processes that affect thickness and hence colour of the silicon nitride ARC to achieve maximum colour uniformity and reproducibility, thereby raising manufacturing yields. This process optimization is focused on allowing subsequent commercialization of coloured cells for use in the BIPV market. Initial theoretical background and results of preliminary experiments were presented by Roberts et al [5] on the formation of ARC’s with thicknesses in the range 90nm to 400nm on LGBC solar cells. In this paper, recent experimental results on coloured multicrystalline LGBC cells will be reported, along with a study of the colour uniformity obtainable in large production runs and an investigation into the use of different shaped cells to allow intricate module design..