Spectrolab raises solar efficiency to 40.7 percent
A team of engineers at solar cell manufacturer Spectrolab has produced a photovoltaic system with a record-breaking conversion efficiency of 40.7 per cent.
The US National Renewable Energy Laboratory has verified the milestone, which should help III-V semiconductor technology to increase its penetration of the market for terrestrial solar power systems.
Spectrolab CEO David Lillington hailed the achievement, and said that once the high-efficiency cells were qualified, they could be manufactured in very high volumes with little impact on production flow.
That s because Spectrolab already manufactures very similar structures for satellite power applications, where III-V materials are now firmly established as the technology of choice.
At Compound Semiconductor s Key Conference last month, Spectrolab's Hojun Yoon, part of the research team that developed the record-breaking cell, said that increasing conversion efficiency was the key to reducing the cost of concentrator photovoltaics (CPV) to a point that would be broadly acceptable in the terrestrial market.
"A 40-50 percent efficient cell could make the market explode," said Yoon, adding that III-V cells were en route to hit 45 percent efficiency within three years.
Richard King, the principal investigator within Spectrolab s high-efficiency solar cell development, said that the use of metamorphic "“ rather than lattice-matched "“ materials was a key part of the achievement. "The excellent performance of these materials hints at still higher efficiency in future solar cells," added King.
Spectrolab s metamorphic structures are based on three individual cells grown on top of one another using MOCVD and connected in series. Thick layers of p-doped GaInP, GaInAs, and the germanium substrate on which the chip structure is based each absorb individual wavelength bands of the solar radiation to yield the high-efficiency conversion.
Having recently had its cells deployed commercially as part of a 33 kW electricity generating system in Australia, Spectrolab said that it expects several more multi-million dollar supply contracts to be signed within the next few months.
Spectrolab s rivals in the III-V photovoltaics sector, Emcore and Sharp Corporation, have also been busy meeting production orders in what has become a key area of growth for the compounds sector (see related stories).
