New world record: Chinese solar cell delivers efficiency of 34.6 per cent

The efficiency of a solar cell indicates how much of the incident sunlight is converted into electricity. Researchers at the Chinese solar company Longi have now raised this value to 34.6 per cent. The record has already been confirmed by the European Solar Test Installation (ESTI).

For comparison: the cells installed in solar modules, which are used on house roofs or for solar systems in fields, for example, have an efficiency of just over 20 per cent. For those for mobile use, it is even lower. Manufacturers rely on monocrystalline cells for these mass market products. This guarantees a long service life - over 20 years - with consistently high performance.

New mineral does not yet deliver high performance long enough

Manufacturer Longi, the world's largest solar company, is relying on a combination of classic silicon-based technology with perovskite to increase efficiency. The mineral is used to convert light into electricity that silicon cells cannot utilise. (Here you can find a detailed chemical-physical explanation of the technology.)

With tandem solar cells, which combine the advantages of both technologies, it should indeed be possible to further improve efficiency. At present, however, production would still be significantly more expensive. And perovskite cannot yet compete with silicon in terms of durability. The mineral loses its performance and efficiency drops quickly. Too quickly to be considered for installation on the roof of a house. After all, the modules are intended to produce green electricity there for decades.

The differences in efficiency between previous technologies are rather small. This is another reason why Meyer Burger, one of the last remaining European manufacturers, is fighting for survival in a market characterised by price wars - despite the efficiency of its cells of up to 22 per cent. However, the Longi Group now also holds the record in terms of efficiency for classic solar cells with so-called heterojunction technology: 27.3 per cent.