Organic polymer tandem cell reaches record 11.5% efficiency

Researchers from the University of California Los Angeles (UCLA) have this month achieved a world-record efficiency breakthrough in the production of organic polymer solar cells.

The UCLA team’s latest update on organic solar cell research has revealed the achievement of 11.5% efficiency in a triple-junction polymer solar cell, a rating that exceeds the previous world record – also set by the UCLA team – in the efficiency of organic solar cells.

Groundbreaking techniques were employed by the UCLA team of researchers – comprising Chun-Chao Chen, Wei Hsuan Chang, Ken Yoshimura, Kenichiro Ohya, Jingbi You, Jing Gao, Zirou Hong and Yang Yang – in using the triple junction tandem structure, similar to the GaInP/GaInAs/Ge structure demonstrated by champion III-V multijunction solar cells, to deliver an exceptional photovoltaic efficiency of 11.5%. Previous research into polymer solar cells rarely yielded an efficiency rating of more than 10%.

"Such results not only justify the route of exploring tandem structure for high efficiency organic solar cells, but also show that the device design capability of an organic solar cell can be as great as non-organic solar cells in many aspects," said Chun-Chao Chen, PHD student at the Department of Materials and Science Engineering, UCLA.

For the past decade, the organic solar cell technology, with particular emphasis on polymer-based material, has garnered a great deal of attention within the material and chemistry research society. The organic material is known for its solution processibility, which enables high volume, non-vacuum based roll-to-roll printing production. However, despite the advantages in processing and manufacturing, organic solar cells are still required to meet certain efficiency standards in order to compete with existing non-organic Si-based solar cell technology.

"Previously, organic solar has been considered merely as a cost-effective solar technology; here, we have demonstrated that it can be as highly efficient as well," added Chao Chen. The researchers from UCLA also believe that by continuously breaking the highest efficiency record, their work can accelerate the development, as well as the commercialization progress, of this still-fledgling solar cell technology.