Perovskite-on-CIGS tandem solar cell hits new high
- Auteur:Ella Cai
- Relâchez le:2018-09-07
Scientists at UCLA have spray-coated a perovskite solar cell onto thin-film CIGS solar cell to convert energy at 22.4% when the cells are connected in series.
Series connection is a tougher test that four-terminal connection, because both top and bottom cells care forced to work at the same current, making it unlikely that both are working at their individual peak efficiencies for a given strength of illumination.
The base cell is 2μm of Cu(In,Ga)Se2, built on glass, which on its own operates at 18.7 % efficiency.
On top of this went 1μm of Pb-iodine perovskite.
“With our tandem solar cell design, we’re drawing energy from two distinct parts of the solar spectrum over the same device area,” said Professor Yang Yang. “This increases the amount of energy generated from sunlight compared to the CIGS layer alone.”
Yang added that the technique of spraying on a layer of perovskite could be easily incorporated into existing solar-cell manufacturing processes – recently Belgian research lab IMEC demonstrated 27.1% efficiency by coating a silicon solar cell with perovskite – using a more flattering four-terminal connection.
To get a good electrical connection between its stacked cells, the UCLA team used nanoscale interface engineering to control of the roughness of the CIGS surface, and then used a heavily-doped organic hole transport layer (PTAA – poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] before adding the perovskite.
Perovskite materials are not as rugged as monolithic silicon solar cells, which can last 25 years.
According to the Science paper ‘High-performance perovskite/Cu(In,Ga)Se2 monolithic tandem solar cells‘, which describes the UCLA work, without encapsulation the cell retained 88% of its initial efficiency after 500 hours of ageing under continuous 1-sun illumination and ambient conditions.
The next goal of Yang’s research group is to push efficiency of its two-layer concept close to 30%.
Series connection is a tougher test that four-terminal connection, because both top and bottom cells care forced to work at the same current, making it unlikely that both are working at their individual peak efficiencies for a given strength of illumination.
The base cell is 2μm of Cu(In,Ga)Se2, built on glass, which on its own operates at 18.7 % efficiency.
On top of this went 1μm of Pb-iodine perovskite.
“With our tandem solar cell design, we’re drawing energy from two distinct parts of the solar spectrum over the same device area,” said Professor Yang Yang. “This increases the amount of energy generated from sunlight compared to the CIGS layer alone.”
Yang added that the technique of spraying on a layer of perovskite could be easily incorporated into existing solar-cell manufacturing processes – recently Belgian research lab IMEC demonstrated 27.1% efficiency by coating a silicon solar cell with perovskite – using a more flattering four-terminal connection.
To get a good electrical connection between its stacked cells, the UCLA team used nanoscale interface engineering to control of the roughness of the CIGS surface, and then used a heavily-doped organic hole transport layer (PTAA – poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] before adding the perovskite.
Perovskite materials are not as rugged as monolithic silicon solar cells, which can last 25 years.
According to the Science paper ‘High-performance perovskite/Cu(In,Ga)Se2 monolithic tandem solar cells‘, which describes the UCLA work, without encapsulation the cell retained 88% of its initial efficiency after 500 hours of ageing under continuous 1-sun illumination and ambient conditions.
The next goal of Yang’s research group is to push efficiency of its two-layer concept close to 30%.
