Silicon solar cells: state of the art

The vast majority of photovoltaic (PV) solar cells produced to date have been based on silicon wafers, with this dominance likely to continue well into the future. The surge in manufacturing volume over the last decade has resulted in greatly decreased costs. Multiple companies are now well below the US$1 W⁻¹ module manufacturing cost benchmark that was once regarded as the lowest possible with this technology. Despite these huge cost reductions, there is obvious scope for much more, as the polysilicon source material becomes more competitively priced, the new 'quasi-mono' and related controlled crystallization directional solidification processes are brought fully online, the sizes of ingot produced this way increase, wafer slicing switches to much quicker diamond impregnated approaches and cell conversion efficiencies increase towards the 25 per cent level. This makes the US Government's 'SunShot' target of US$1 W⁻¹ installed system cost by 2020 very achievable with silicon PVs. Paths to lower cost beyond this point are also explored.