Monolithic bifacial perovskite-CdSeTe tandem thin film solar cells for harvesting light from the environment


Project #D2021-04

Invention Description

The University of Toledo has developed a new tandem solar cell design the bifacial tandem (Fig. 1) that enabled the first realization of a working monolithic tandem solar cell comprising wide-bandgap metal halide perovskite and narrow-bandgap cadmium selenide telluride (CdSeTe, or CST). The bifacial strategy is the key innovation since it enables efficient perovskite-CST tandem solar cells while harvesting the reflected and deflected light from the ground. Therefore, this technology is critical to developing low-cost, efficient, and stable monolithic bifacial perovskite-CST tandem thin-film solar modules. Based on theoretical calculation (Fig. 2), the monolithic bifacial tandem design can boost the output power density limit of conventional CST solar modules by up to 50% with a light color concrete ground (albedo = 0.1 to 0.3). Our proof-of-concept bifacial tandem device shows an equivalent bifacial efficiency of more than 20% with an open-circuit voltage of more than 2 V. Implementation of our monolithic bifacial tandem design could result in the overall efficiency enhancement, leading to a reduced $/W cost for the current CST photovoltaic technology. 


  • Improves power output of CST solar panels by harvesting the reflected and diffused light from the ground
  • Reduces $/W cost for the current CST photovoltaic technology
  • Can be easily integrated into the industrial production lines of CST thin-film solar panels
  • Our proof-of-concept device demonstrated a greater than 25% conversion efficiency improvement compared with the single-junction devices
  • Compatible with wide-bandgap (FA,MA,Cs)Pb(Br1-x,Ix)3 perovskite and narrow-bandgap CdSeTe
  • Additional costs of producing perovskite cell component layers on the commercial CST solar cells are estimated to be less than 15% of the total cost of the current CST solar modules




IP Status:                           Patent pending

Patent Information:
For Information, Contact:
Katherine Pollard
Licensing Associate
The University of Toledo
Yanfa Yan
Zhaoning Song
Kamala Subedi
Randall Ellingson