The conversion efficiency of solar cells is limited by light absorption, carrier transport, and carrier collection. For monocrystalline silicon solar cells, because the excess energy of the upper photonic band gap is transmitted to the photons of the lower band gap, the theoretical maximum value of its conversion efficiency is 28%. Only by minimizing losses can solar cells with sufficiently high efficiency be developed.
A few days ago, a team of scientists from the Australian National University used laser processing technology to produce a double-sided solar cell module with a front conversion efficiency of 24.3%, a back conversion efficiency of 23.4%, and a double-sided coefficient equivalent to 96.3%, setting a record.
The effective power output represented by this performance data is about 29%, far exceeding the best single-sided solar cells.
Lead researcher Dr. Marco Ernst Ernst said: "This is a world record for selective laser doping solar cells and one of the highest efficiency records set by bifacial solar cells."
This type of solar cell is bifacial, which means that both the front and back of the cell can generate electricity. Lead researcher Dr. Kean Chern Fong said that the performance of double-sided solar cells can easily surpass single-sided silicon solar cells.
"We have developed a true double-sided solar cell in my opinion. This battery has almost symmetrical power generation capacity on both surfaces of the device. When installed in a traditional solar power station, the double-sided battery absorbs the direct incident. The light from the ground will also use the reflected light from the ground, which can contribute up to 30% of the additional power generation.
"In the promotion of solar power stations, double-sided solar cells are becoming more and more important. It is expected that the market share will exceed 50% in the next five years. Our work demonstrates the incredible capabilities of this technology."
According to reports, the team used a specific laser doping technology to manufacture these batteries. Dr. Ernst said: "Laser doping technology uses lasers to increase local conductivity. This is a low-cost, industry-compatible process that can improve solar cell efficiency. This allows the research team to break cell efficiency records."
Through the Australian Renewable Energy Agency and the Australian Advanced Photovoltaic Centre, this work has been supported by the Australian government. The Australian Government’s research agency, the Federal Organization for Scientific and Industrial Research, has independently verified the results.