Solliance boasts record 23 percent efficiency for flexible tandem cell

Eindhoven-based solar research institution Solliance and Californian panel manufacturer Miasolé Hi-Tech have established a new world record power conversion efficiency of 23 percent on a flexible solar cell. The solar cell combines a top perovskite and a bottom copper indium gallium selenide (CIGS) cell into a tandem stack. The absorption properties of both components are tuned to complement each other, which gives the combination its potential for high conversion efficiency.

CIGS has a proven track record as a high-efficiency and stable solar technology. It addresses markets where heavy and rigid panels cannot be used. Although a relatively young technology, perovskite solar cells have already achieved high efficiencies as well. They promise low-cost solutions based on abundant materials.

The significant cell performance gain was realized through process improvements in the bottom CIGS cell. These enabled a high efficiency with a spectral response better matched to the top perovskite cell. Further improvements in spectral matching and overall CIGS cell efficiency are expected to push the tandem cell efficiency well beyond 23 percent.