Longi sets 28.29% world record for single-junction silicon solar cell efficiency

Chinese solar panel maker Longi says it has set a new world record for solar cell efficiency, converting 28.29% of sunlight into electricity with a silicon solar cell. The result was verified by an independent German lab, the Institute for Solar Energy Research Hamelin. It's Longi's third record this year, up from 28.04% to 28.13% and now 28.29%. The company says this is close to the theoretical limit for this type of cell, at just over 96% of the maximum possible efficiency.

This particular cell uses a design Longi calls HIBC, short for hybrid interdigitated-back-contact, which arranges the electrical contacts on the back of the cell rather than the front. The design combines several technical tweaks, including special coatings that cut energy losses and a manufacturing process that uses lasers to improve how the cell conducts electricity. Longi says the approach could eventually be adapted for a different, more common cell type called heterojunction, though it says more work is needed first.

For homeowners, this is lab news rather than something you can buy yet. Standard rooftop solar panels today typically run well below this efficiency level, and record-setting lab cells usually take years to show up in commercial products. Still, steady efficiency gains like this are part of why solar panels have gotten better and cheaper over time, so it's worth watching whether this technology eventually makes its way into panels sold for home installations.