Highly Efficient Perovskite/Cu(In, Ga)Se2 Tandem Solar Cell

Tech ID: 29724 / UC Case 2018-019-0


UCLA researchers in the Department of Materials Science and Engineering have developed Perovskite/Cu(In, Ga)Se2 (PVSK/CIGS) tandem photovoltaic devices with ~22% efficiency.


Perovskite solar cells have generated extensive research interest, as their device efficiencies have increased from 14% to ~23% in just 5 years (National Renewable Energy Lab). One approach to further increasing the device efficiency is by adopting tandem architecture. This design uses multi-junction solar cells to harness a broader range of the solar spectrum and is commonly used in III-V semiconductor solar cells with efficiencies of ~30%. However, these III-V semiconductor solar cells are not widely adopted due to high fabrication costs. While perovskites could reach these efficiencies at a reduced cost due to solution processing techniques, major challenges remain in designing a high quality interconnection layer between PVSK and CIGS solar cell for efficient cells in a cost-effective and environmental-friendly manner.


UCLA researchers have developed perovskite/Cu(In, Ga)Se2 (PVSK/CIGS) tandem photovoltaic devices with ~22% efficiency. These PVSK/CIGS tandem solar cells have double the efficiency as similar structures (~11% Adv. Energy Mater. 2015). Moreover, the PVSK/CIGS tandem solar cells reported here offer a promising solution for both high performance and low-cost. The solar cells do not require high vacuum facilities for processing, which would reduce the fabrication costs. Moreover, when comparing to Silicon/PVSK tandem solar cells which need a high-quality silicon rear cell, the PVSK/CIGS solar cell only needs a commercialized CIGS rear cell to achieve high efficiencies. Additionally, because this is a thin film solar cell, flexible tandem solar cells could be fabricated by this method.


  • Grid solar cells 
  • Portable solar cells 
  • LEDs 
  • Field-effect transistors 
  • Wearable electronics


  • Double the efficiency as similar reported devices 
  • Cost-effective (avoids high-cost vacuum facilities) 
  • Only requires commercialized CIGS rear cell without additional procedures

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Full Perovskite Portfolio

Patent Status

Country Type Number Dated Case
Patent Cooperation Treaty Published Application WO2019200327 10/17/2019 2018-019

Additional Patent Pending


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  • Yang, Yang

Other Information


Perovskites, CIGS, Tandem solar cells, solution processing, thin films, flexible tandem solar cells

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