Being the next generation high profile cell, there are numerous studies regarding perovskite solar, and US scientists have recently introduced a brand new ultra-thin gold electrode, which not only produced a record 19.8% semi-transparent perovskite cell when applied on perovskite solar, but also achieved an efficiency of 28.3% when concatenated with silicon solar.
Perovskite solar cell is formed with 5 layers of materials, which are cathode, electron transporting layer, light-absorbing layer of perovskite, electron hole transporting layer, and anode. The cell automatically produces electrons and electron holes when absorbed with sunlight, and the scientists would control the electrons and electron holes using the transporting layer to further derive current and voltage, before using a platinum layer as the contact electrode of the cell.
Kai Wang, assistant professor of materials science and engineering at the Pennsylvania State University (PSU), commented that transparent solar can be expected to occupy a significant status in household and office windows, and generate electricity using the sunlight that would have been wasted. The research team has now made progress in this field by producing a high-efficiency semi-transparent solar cell.
The new electrode developed by the research team also helps with the development of the next generation solar technology that is perovskite solar cell. Shashank Priya, professor of materials science and engineering at PSU, said that the team used ultra-thin gold, the size of few atoms, to produce highly conductive electrode that will not impede the cell from absorbing sunlight.
（Source：PSU）
The production of electrodes for perovskite cells using ultra-thin gold film has been done before, but the poor conductivity derived from the unevenness of electrodes was proven to be a major issue. The team now managed to create a remarkable gold layer using “chromium” epitaxy, which produced a perovskite solar cell that contains a record breaking conversion efficiency of 18.9% among semi-transparent cells.
The research team commented that nanoparticles would gather and couple like islets when a thin layer of crystallization, like gold, is created by epitaxy. Chromium contains a relatively high level of surface energy, which provides an excellent growth environment for gold that will form a continuous thin film.
When concatenated with traditional silicon solar, the efficiency is arrived at 28.3%, which is higher than the current silicon solar at 23.3%. Priya commented that the 5% difference is actually quite prominent as it indicates that an additional 50W of solar is converted for each m2, and the power generation will grow evidently since solar plants are formed with several thousand units of solar panels.
Solar cells produced with gold electrode are proven to be relatively stable from laboratory tests. Scientists believe that the maintenance of the high efficiency may be able to produce perovskite solar cells and tandem cells that are higher in efficiency using transparent electrode in the future.
(Cover photo source: Flickr/Scott S cc by 2.0)