(Yilan, Taiwan, June 20, 2012) —Sunrise Global Solar Energy Co. Ltd. (Sunrise) achieved peak efficiency of 20.2% in industrial grade Czochralski p-type cells. The high performance cell, called the ‘CELCO’ cell, use the rear passivation and local contacting methods. The cells are now commercially available to the market.
Sunrise, a world leading solar cell producer in Taiwan, recently achieved another technological breakthrough in their high-efficiency cells. A peak efficiency of 20.2% in Cz-grade p-type cells was reached in their mass-production of CELCO technology. The efficiency gain is a significant improvement over their previous record-breaking 19.4% cell from last year. The device structure combined Sunrise’s innovative processing steps with the rear passivation and local rear-contacting technology.
The high quality rear passivation, together with rigorously-optimized front structure leads to very low surface recombination velocity. In addition to these, the carefully selected high-quality Cz wafers used for the CELCO cell leads to low J0 and high VOC. The overall high lifetime of the wafer and rear reflectance property of the rear passivation leads to very high JSC in excess of 39mA/cm2. The front metal electrode and local rear contact is also designed to maintain high FF of the cell. The efficiency of the cell is on par with the best of world-record cells on p-type Cz such as Schott Solar’s 20.2% PERC cell and Suntech’s (STP, NYSE) 20.3% Pluto cell.
Sunrise CTO, Dr. Budi Tjahjono, commented, “There were initially numerous challenges transferring this technology from R&D to the mass production phase due to multiple unique additional steps introduced in this technology. However, from Sunrise’s combined expertise in processing know-how and production control, we overcame many of these challenges step by step. Currently, daily efficiency is averaging around 19.7% and there is still relatively large efficiency distribution. But from our past history in adapting new technology, as we learnt from continuous production, the gap between average and peak efficiency can be closed fairly quickly. We also believe that there is still much room for improvement in multiple aspects of the fabrication steps, enabling even better cell performance in the near future”.
One of the cell’s major benefits is the improved IQE and EQE in the long wavelength region. This will not be affected by the typical EVA cut-off, allowing most of the high current to be retained at module level. The cell design and structure are also nearly identical to the standard cell in the market, therefore does not require modification in stringing and module -manufacturing.
Sunrise COO, Ted Szpitalak said, “We are very pleased to finally unveil the CELCO cells. We believe this is the first time that such high efficiency cells of this type have been commercially launched into the market. We expect that after all the kinks in the production have been figured out and further improvements have been made, efficiency of 20.3% and beyond are within realm of possibility”. Sunrise CEO and Chairman, Kuei-Chang Hsu, added“Sunrisealways strives to provide the best commercial solar cells, both in term of high efficiency and consistent quality and reliability. We have several long-term collaborators and technologically-minded customers that have been waiting for such high performance cells from us. With the peak efficiency of CELCO cells, we expect that our customers will be able to reach up to 280W in 60 cells module and achieve the overall benefit in the cost of the PV system”.