Chinese solar PV company LONGi Solar has announced achieving 25.40% power conversion efficiency for its indium-free heterojunction (HJT) solar cells validated in testing by Germany's Institute for Solar Energy Research (ISFH) in Hamelin.
Going indium free is a prominent development since it would mean a significant reduction in costs when it goes into mass production, emphasized LONGi. In HJT processing, indium is part of the state-of-the-art transparent conducting oxide (TCO), which is indium-tin oxide (ITO), and is also a major contributor to the manufacturing costs, next to metallization pastes.
LONGi said it was able to achieve the 'new record' efficiency on M6 (274.5 cm2) full-size monocrystalline silicon wafers, with the use of its proprietary advanced surface passivation technology, and low-cost indium free targets that helped prepare TCO films.
Despite it being free of indium, the cells were able to maintain high conversion efficiency due to process innovations. According to the company, this confirms the basis for industrialization of the low cost technology route for HJT cells, following its ongoing research.
The announcement for 25.40% efficiency comes soon after it claimed a world record efficiency of 25.47% for gallium-doped P-type HJT cell (see 25.47% Efficiency For P-Type HJT Cell).
"LONGi has now achieved overall leadership in a number of new high-efficiency cell technologies, such as n-type and p-type TOPCon and n-type and p-type HJT, continually pushing the limits for commercial use of solar energy applications to new levels," stressed the management.