Low-cost surface treatment makes better solar cells
- Author:Ella Cai
- Release on:2017-07-28
Osaka University has created front and back coatings to improve the efficiency of silicon solar cells, without resort to expensive vacuum treatment.
The front coating is anti-reflective – a component of almost all solar cells – and created using a wet process based on ‘surface structure chemical transfer’ (SSCT), using it to fabricate so-called ‘black silicon’ (see diagram).
Osaka solar black siliconThis treatment produces sub-micron silicon structures, which prevent light reflection and give a black appearance.
On top of this, Osaka has developed a way to passivate the black silicon against recombination loss over large areas by depositing phosphosilicate glass then heat-treating the result (see diagram).
Osaka solar passivate“This method can simultaneously form pn-junction to separate photo-generated electrons and holes, and therefore, it isn’t an additional process,” said the University.
On the back side, light-trapping microstructures have been created to increase the anoint of infra-red light captured using metal-assisted chemical etching.
With both front and rear treatments, 19.8% conversion efficiency was obtained.
“Making very high efficiency solar cells is important but we should also consider the economics and practicality of any processes used to increase efficiency,” said Group leader Hikaru Kobayashi. “The wet processes we have developed are simple yet effective, and our work with black silicon has real-world applications in making cost-effective silicon solar panels.”
‘Improvement of conversion efficiency of silicon solar cells by submicron-textured rear reflector obtained by metal-assisted chemical etching” is published in Solar RRL, and viewable in full, free.
The front coating is anti-reflective – a component of almost all solar cells – and created using a wet process based on ‘surface structure chemical transfer’ (SSCT), using it to fabricate so-called ‘black silicon’ (see diagram).
Osaka solar black siliconThis treatment produces sub-micron silicon structures, which prevent light reflection and give a black appearance.
On top of this, Osaka has developed a way to passivate the black silicon against recombination loss over large areas by depositing phosphosilicate glass then heat-treating the result (see diagram).
Osaka solar passivate“This method can simultaneously form pn-junction to separate photo-generated electrons and holes, and therefore, it isn’t an additional process,” said the University.
On the back side, light-trapping microstructures have been created to increase the anoint of infra-red light captured using metal-assisted chemical etching.
With both front and rear treatments, 19.8% conversion efficiency was obtained.
“Making very high efficiency solar cells is important but we should also consider the economics and practicality of any processes used to increase efficiency,” said Group leader Hikaru Kobayashi. “The wet processes we have developed are simple yet effective, and our work with black silicon has real-world applications in making cost-effective silicon solar panels.”
‘Improvement of conversion efficiency of silicon solar cells by submicron-textured rear reflector obtained by metal-assisted chemical etching” is published in Solar RRL, and viewable in full, free.
