PV Breakthrough?

Terrific news has emerged in the last few days of a performance breakthrough for photovoltaics. Two companies in the US have hit new highs in terms of efficiency of solar panels.

Alta Devices have stated their standard pv panels now achieve 23.5% efficiency whilst Semprius have announced their concentrated pv systems (using lenses to enhance the light) hit 33.9% output.
This is an incredible performance and here's hoping both companies are able to make these panels commercial realities. Intriguingly their use of gallium arsenide has been key. Although dearer than silicon, it does have better electronic properties... as evidenced by their performance figure announcement.