Perovskite solar panels encompass relatively high conversion efficiency gained from the unique crystal structure and adjustable band gap of perovskite, though it is the reason that solar cells are more prone to the effects of light, heat, oxygen, and moisture. Fortunately, South Korean scientists have recently succeeded in elevating the defensiveness of perovskite, with the conversion efficiency reaching 20.7%.
Perovskite is a chemical compound of ABX₃ structure, and is able to convert light into electricity, and vice versa; hence, it is a common component in LED, laser, and solar power. In addition, perovskite also possesses advantages such as easy obtainment of raw materials, simple synthesis method, and affordable prices. The performance of perovskite in the solar field has been remarkable, with a maximum conversion efficiency at 26% so far.
Though perovskite is relatively more sensitive toward ultraviolet and moisture, and its poor stability has prevented it from being commercialized in large scale, for which scientists must first resolve before introducing the chemical compound to the public.
In light of this, Korea Advanced Institute of Science and Technology (KAIST) has joined hands with Seoul National University and Sejong University, and infused phenethylammonium into perovskite through its internal 2D passivation layer, where they meticulously adjusted the mixing ratio of two-dimensional molecules to further enhance the efficiency and durability of perovskite cells. The experiment result also indicates that the highest conversion efficiency of a full perovskite solar cell has reached to 20.7%, and maintains 80% of conversion efficiency after continuous illumination for 1,000 hours.
▲Atomic structure of a 2D passivation layer（Source：KAIST）
The research pointed out that stacking up such perovskite cell with silicon solar cells will elevate the conversion efficiency to 26.7%. Byungha Shin, chief researcher, expressed that the team has researched and developed a high quality perovskite material of wide band gap, and the cells can also be concatenated with silicon solar cells, with the anticipation of developing a perovskite-silicon solar cell that is more efficient.
Wide band gap perovskite is the key in realizing tandem solar cells. In the research of tandem solar cells, a silicon solar cell is placed at the bottom, which is stacked with wide band gap; the wide band gap cell above is able to absorb the short wavelength from high energy such as blue light, whereas the silicon solar cell at the bottom absorbs long wavelength from low energy such as red light. The conversion efficiency of solar energy from such set up can be increased to 30%.
(Cover photo source: Flickr/SteFou! CC BY 2.0)