Silicon heterojunction solar cell with a certified 23.1 % energy conversion efficiency
After further optimization of the baseline process for industrial silicon heterojunction (SHJ) solar cells, the accredited metrology lab ISFH CalTeC now certified an efficiency of 23.1 % for a 4 cm² solar cell. This performance is among the best in the world and demonstrates the leading role of HZB in this technology in Germany and Europe.
Within the institute PVcomB at HZB we develop SHJ cells with the focus on improving industrial applicable materials and processes in collaboration with industry partners (e.g. Meyer Burger, Von Ardenne, Singulus). Moreover, new types of solar cells with the potential to surpass the efficiency limit of silicon-based cells, such as perovskite/SHJ tandem junctions, are developed at HZB, partially in collaboration with industry (Oxford PV). Results will be presented this year at the international PV conferences WCPEC (June 10-15, Hawaii) and EUPVSEC (Sep 24-28, Brussels).
Background
Silicon heterojunction (SHJ) solar cells are made of crystalline silicon wafers using passivated contacts for both polarities based on i/n and i/p stacks of thin-film silicon alloys, such as amorphous silicon, nano-crystalline silicon or silicon oxide. Due to a high silicon wafer quality and the excellent surface passivation SHJ solar cells reach very high conversion efficiencies with highest open circuit voltages >740 mV and low temperature coefficient <0.3 %/K. With this type of two-side contacted cell Kaneka Corp. (Japan) holds the world record with a 25.1 % conversion efficiency. Recently, they attracted attention with 26.7 % for an all-rear-side contacted (IBC) SHJ cell, which is currently the world record for a silicon-based solar cell. For commercial production, the lean process sequence consisting of only four major process steps, all below <200°C processing temperature, facilitate cost-effective cell production.
- Lithium-sulphur pouch cells investigated at BESSY IIA team from HZB and the Fraunhofer Institute for Material and Beam Technology (IWS) in Dresden has gained new insights into lithium-sulphur pouch cells at the BAMline of BESSY II. Supplemented by analyses in the HZB imaging laboratory and further measurements, a new picture emerges of processes that limit the performance and lifespan of this industrially relevant battery type. The study has been published in the prestigious journal Advanced Energy Materials.
- Two Humboldt-Fellows join HZBIn 2024, two young scientists joined HZB as Humboldt Fellows. Kazuki Morita joined Prof. Antonio Abate's group and brings his expertise in modelling and data analysis to solar energy research. Qingping Wu is an expert in battery research and works with Prof. Yan Lu on high energy density lithium metal batteries.
- Less is more: Why an economical Iridium catalyst works so wellIridium-based catalysts are needed to produce hydrogen using water electrolysis. Now, a team at HZB has shown that the newly developed P2X catalyst, which requires only a quarter of the Iridium, is as efficient and stable over time as the best commercial catalyst. Measurements at the EMIL lab at BESSY II have now revealed how the special chemical environment in the P2X catalyst during electrolysis promotes the oxygen evolution reaction during water splitting.