China-based PV manufacturer Trina Solar says its State Key Laboratory (SKL) of PV Science and Technology (PVST) has set a new record of 24.13% total-area efficiency for a large-area (156 x 156mm2) n-type mono-crystalline silicon (c-Si) interdigitated back contact (IBC) solar cell.
According to the company, the record-breaking n-type mono-crystalline silicon solar cell was fabricated on a large-sized phosphorous-doped Cz Silicon substrate with a low-cost industrial IBC process, featuring conventional tube doping technologies and fully screen-printed metallization. The 156×156 mm2 solar cell reached a total-area efficiency of 24.13%, as independently measured by the Japan Electrical Safety & Environment Technology Laboratories. The IBC solar cell has a total measured area of 243.3cm2 and was measured without any aperture. Trina says the cell presents the following characteristics: an open-circuit voltage Voc of 702.7mV, a short-circuit current density Jsc of 42.1 mA/cm2 and a fill factor of 81.47%.
In February 2014, Trina Solar and the Australian National University (ANU) jointly announced a world-record aperture efficiency of 24.37% for a laboratory-scale 4cm2 IBC solar cell, fabricated on a float zone n-type substrate and using photolithography patterning. In December 2014, Trina Solar announced a 22.94% total-area efficiency for an industrial-version, large-size (156x 156mm2, 6″ substrate) IBC solar cell. In April 2016, the company announced an improved industrial low-cost IBC solar cell with a total-area efficiency of 23.5%. The new record of 24.13% total-area efficiency is just 0.24% absolute below the small-area laboratory cell record aperture-efficiency jointly established by the company and ANU. Total-area efficiencies are always lower than aperture-efficiencies, due to efficiency losses related to the edges of the cells and electrical contact areas, according to the company.
“We are very delighted to announce the latest achievement from our research team at the SKL PVST. Over the last few years, our R&D team has managed to continuously improve the efficiency of our n-type IBC solar cells, pushing the limits and surpassing our previous records, and approaching very closely to the performance of our best small-area laboratory cell developed in collaboration with ANU three years ago,” says Dr. Pierre Verlinden, vice president and chief scientist of Trina Solar. “IBC solar cells are one of the most efficient silicon solar cells available today and are particularly suitable for applications for which the requirement of a high power density is more important than levelized cost of electricity.”