Silicon solar cell efficiency at 26.6% within 10% of theoretical silicon solar efficiency limit of 29.1%

Kaneka Corporation has achieved in a NEDO project the world’s highest solar power conversion efficiency of 26.33% in a practical size (180 cm2 ) crystalline silicon solar cell.

This record-breaking result will advance technical development of crystalline silicon solar cells and contribute significantly to reducing the cost of power generation through use of high-efficiency solar cells.

Kaneka Corporation developed a high conversion-efficiency crystalline silicon solar cell (heterojunction back-contact type) in NEDO New Energy Technology Department’s Development of High-Performance and Reliable PV Modules to Reduce LCOE project, and has achieved the world’s highest conversion efficiency of 26.33% in a crystalline silicon solar cell having a practical size (180 cm2). This achievement breaks the world record of 25.6% by ~0.7%, exceeding 26% for the first time in the world.

NEDO and Kaneka Corporation have been working to develop high conversion efficiency crystalline silicon solar cells targeting LCOE reduction. The desired result was achieved by means of a combination of heterojunction technology using high-quality amorphous silicon, low resistance electrode technology, and a back-contact structure that captures more solar energy, all of which were developed by Kaneka Corporation.

NEDO and Kaneka Corporation will continue to develop solar cell technology for reducing cost and improving performance and reliability to achieve the target electric power generation costs of 14 yen/kWh in 2020 and 7 yen/kWh in 2030.

Kaneka Corporation is planning to commercialize high-efficiency solar cells that utilize the results of NEDO’s project and will move ahead with development for practical use.

Kaneka researchers submitted an article to Nature Energy where they were able to further optimize their solar cell to achieve 26.6 percent efficiency.

Nature Energy – Silicon heterojunction solar cell with interdigitated back contacts for a photoconversion efficiency over 26%

Abstract

Improving the photoconversion efficiency of silicon solar cells is crucial to further the deployment of renewable electricity. Essential device properties such as lifetime, series resistance and optical properties must be improved simultaneously to reduce recombination, resistive and optical losses. Here, we use industrially compatible processes to fabricate large-area silicon solar cells combining interdigitated back contacts and an amorphous silicon/crystalline silicon heterojunction. The photoconversion efficiency is over 26% with a 180.4 cm2 designated area, which is an improvement of 2.7% relative to the previous record efficiency of 25.6%. The cell was analysed to characterize lifetime, quantum efficiency, and series resistance, which are essential elements for conversion efficiency. Finally, a loss analysis pinpoints a path to approach the theoretical conversion efficiency limit of Si solar cells, 29.1%.