Neo Solar Power announced that is has created a 21.1% efficient solar cell with passivated emitter rear contact (PERC) technology. The maximum efficiency was certified by the Taiwan Industrial Technology Research Institute (ITRI).
A passivation layer is added at the rear side of the cell in PERC technology to increase conversion efficiency. Energy conversion rates of about 20.5% are typical for PERC monocrystalline solar cells. The efficiencies have been good, but costs have also been higher. Some more intriguing applications for these cells are for solar cars and space.
Interestingly, the passivated aspect seems to have been around for a long time: “In 1985, the UNSW-developed microgrooved PESC cell (passivated emitter solar cell) of Fig. 3.5a became the first silicon cell to exceed 20% energy conversion efficiency. The same basic approach was then used by several other groups to produce cells of similar efficiency, with commercial quantities produced for solar car racing and for space. The approach is characterised by the use of a thin thermally grown oxide to ‘passivate’ (reduce the electronic activity of) the top surface of the junction diffusion layer (the emitter of the cell), combined with the use of a shallow, high sheet resistivity phosphorus diffusion for this emitter. Another feature is the use of photolithography to produce a relatively small contact area to this emitter region by defining openings in the ‘passivating oxide’. Photolithography is also used to pattern the top contact fingers and to align these fingers to the oxide openings.”
Neo Solar Power is a Taiwan-based solar cell producer and the largest in that country by revenue. The company was founded in 2005, and merged with DelSolar in 2013. The company has its own rooftop solar system, with at least
Image Credit: NSP