Gallium Using gallium doping technology to mitigate light-induced degradation in photovoltaic cells
Following the granting of intellectual property rights for its gallium doping technology in October of last year, JA Solar, the Chinese company behind it, has recently announced that it is to supply modules to two 50 MW solar power plants in Spain with 100 MW high-efficiency mono PERC modules. But what is it that makes this technology so promising?
It is widely known that solar cells that make use of boron-doped p-type silicon wafers suffer from light induced degradation (LID). This occurs in the very first hours that the crystalline p-type boron doped silicon solar cells are exposed to the sun, causing a loss of performance and a general degradation of conversion efficiency.
This LID is associated with the formation of the boron oxygen complex, which acts as a harmful defect and reduces the minority carrier diffusion length. Although lots of research has gone into the characterisation and mitigation of LID to date, industrial solar cells still suffer from different types of light-induced efficiency losses.
Using gallium doping to prevent LID
However, there is an industrial alternative to boron doped silicon—gallium doped silicon. It is thought to be immune from LID, particularly when it is used in PERC cells.
In October 2019, a Chinese-based company, JA Solar, was awarded intellectual property rights for its own gallium doping technology that is used in photovoltaic (PV) cell production. JA Solar explained that its proprietary technology can effectively mitigate the LID effect on PV modules that are assembled with p-type silicon wafers.
"Using Ga-doped silicon wafers for solar cell application definitely results in better performance of solar cells and PV modules, as well as the improvement of their long-term reliability,” said chairman and board of directors Jin Baofang.
The company also holds several patents on gallium doping in silicon crystals and on using gallium-doped p-type crystalline silicon wafers in the production of PV cells.
Investing CNY 6.6 billion in new solar PV manufacturing plants
According to JA Solar, the application of its Ga-doped silicon wafers can mitigate the initial LID that boron-doped p-type silicon wafers suffer from. This will enable their solar modules to perform better in the long term, be inherently more stable, and provide a better return on investment due to improved conversion efficiency.
The company certainly seems hopeful that this will be the case; it is spending CNY 6.6 billion (USD 947.7 million) on building two new solar PV manufacturing plants in China. These will see the company achieve an annual production capacity close to 15 GW.