Future energy harvesting solar cell technology with high efficiency and visual permeability has been developed by Korean researchers.
Energy Harvesting is a technology that harvests or collects energy left in daily life, such as sunlight, wind, water, vibration, and temperature, and reproduces it into electric energy.
The Korea Institute of Energy Technology recently announced that it has developed a core technology called “High-Efficiency CIGS Double-Sided Flooding Solar Cell” that secures visual floodworthiness by transmitting some of the sunlight.
With this technology, it secured more than 10% of transmittance of light and secured 10% of power generation efficiency on both sides and 15% of power generation performance on both sides. The power generation efficiency of non-tumor-type solar electricity is about 20%.
Transparent solar cells can be combined with electricity production and visible light transmission. Solar cells are expected to be various energy Harvesting batteries such as exterior walls, windows, urban structures, mobility, and devices. However, solar cell technology with efficiency, flood resistance, durability, and power generation performance has not been developed yet.
Some transparent solar cells, which are currently partially commercialized, are made by scratching or drilling parts of existing solar cells, resulting in low performance, high production costs, and visual inconvenience caused by the intersection of transparent and opaque parts.
To solve this problem, the team used transparent electrodes of Sn-doped indium oxide (ITO) instead of conventional molybdenum (Mo) metal electrodes on both sides of the CIGS photoabsorbent layer, a durable inorganic material with light irradiation or temperature.
It also developed a two-sided transparent solar cell technology that can penetrate itself by precisely controlling the thickness of the light absorption layer to less than 0.3 micrometers so that part of the visible light can penetrate.
This technology is very simple compared to the complex three-stage simultaneous evaporation process used in the manufacture of CIGS solar cells. In particular, using a single-stage simultaneous evaporation process with excellent reproducibility, deposition time was reduced to half and the thickness of the light absorption layer was reduced from 2 to 0.3 micrometers, dramatically reducing the material usage and process time by one-tenth.
In addition, the production yield is high and the manufacturing cost is greatly reduced as the device structure using a thin light absorption layer and a two-sided transparent electrode can secure natural light permeability.
In addition, this technology can reduce deposition time and reduce process temperature from 650 degrees to 550 degrees, which can significantly improve efficiency by inhibiting the generation of electrical resistors caused by unnecessary chemical reactions between CIGS light absorption layer and transparent electrode.
The research team said it is planning to commercialize this technology after increasing efficiency and transmittance of visible light. It also said that this study will contribute to the expansion of solar power generation and the creation of new industries in the future to realize carbon neutrality and Green New Deal policies.
Shin, Min & Lee, Ahreum & Cho, Ara & Kim, Kihwan & Ahn, Seung & Park, Joo & Yoo, Jin-su & Yun, Jae & Gwak, Jihye & Shin, Donghyeop & Jeong, Inyoung & Cho, Jun-Sik. (2020). Semitransparent and bifacial ultrathin Cu(In,Ga)Se2 solar cells via a single-stage process and light-management strategy. Nano Energy. 82. 105729. 10.1016/j.nanoen.2020.105729.