Theoretically a single-junction solar cell’s power generation will peak at 33.7% according to the Shockley-Queisser Limit. Achieving this limit has proved fruitless so far with figures in the mid-twenties being the closest that scientists have reached until now. The team at Alta Devices have managed to surpass all previous records and obtained a conversion efficiency of 28.2%.
Detailing the methods employed to achieve this record, Alta’s co-founder Eli Yablonovitch will present the findings and possibilities at the PVSC37 conference in Seattle this week. Prior to the presentation Mr Yablonovitch has stated that previous efforts have been focussed on maximizing the light collecting ability of a solar cell to increase the current flow. Instead, increasing the light emitting capabilities of a solar cell by increasing the number of photons maximizes the attainable voltage levels, which leads to more power generation and improves conversion efficiencies. This breakthrough has been heralded as a significant change of tact and opens new possibilities for solar cell technology.
Alta Devices were founded with the intention of making solar pv production cheaper and, therefore, more attractive to consumers seeking maximum return on renewable energy investments. The goal of $1 per watt set by the Dept of Energy (DoE) in the States resonates with Alta’s targets and mobilizes the company to reach this goal. Alta’s CEO, Christopher Norris, believes that his team will reach this goal based on their history of pushing limits and finding new ways to approach problems.
Stephen Charlick, Puurgen’s Operations Director, stated “this is fantastic news and certainly shakes up the commercial solar pv world. While higher efficiencies are achievable using solar cells with multiple junctions such as UTJs, the production cost of these cells rule out their use in commercial applications and are better suited to military or space applications. Attaining greater conversion efficiencies with commercial cells will help Puurgen drive down the cost of our Systems and ensure that we deliver leading-edge technology to our customers.”