Several experiments with solar technology have pushed cell efficiency beyond 40 percent, but for conventional silicon designs the theoretical ceiling is estimated at 29 percent. Any option that surpasses 20 percent is ideal for commercial applications, and the Japanese company Kaneka has just presented a new solar cell capable of achieving 26.6 percent efficiency, setting a new record.
One of the most delicate and complicated aspects of adopting solar energy for personal use is cost, especially when it comes to the installation process. Users need to know precisely how long it will take them to recover the total investment, and a good starting point in reducing that factor is to get panels with the best efficiency. Experts suggest an upper limit for silicon cells in the order of 29 percent (29.1-29.4). Technically it has already been crossed, but those prototypes require much more exotic designs and materials, which again breaks the cost-benefit ratio. The market will look to squeeze every option in silicon, and the latest news takes us to Japan, where the Kaneka Corporation has just broken a new record.
Its new solar cell of 180.4 square centimeters records an efficiency of 26.6 percent, one point above the previous mark (which was held by Panasonic). Initially, the cell had reached 26.3 percent, but a series of optimizations allowed developers to extract that additional 0.3 percent. The key behind this cell is a proprietary heterojunction technique that minimizes energy bands, and added to this are a series of low-resistance electrodes on the back of the cell, which help collect a greater number of photons. The cell's manufacturing is compatible with available industrial methods, so its improvements should not be lost in the laboratory.
Even so, patience is required. More work and additional testing are needed before the cells can form a solar panel ready to be installed. Kaneka's research was funded by the Japanese government through its NEDO agency, and the next goal is to keep lowering costs.
