High-Efficiency Tandem Solar Cell Design Achieves 26.06% Efficiency

Strategic Insights -

Researchers from the Visvesvaraya National Institute of Technology have designed and simulated a high-efficiency tandem solar cell using SCAPS-1D, exploiting tandem perovskite technology to enhance performance. The study aims to minimize losses associated with single-junction solar cells by absorbing a broader spectrum of sunlight using CsGeI/CIGS tandem solar cell technology. The researchers optimized lead-free, wide bandgap (1.6 eV) CsGeI perovskite and narrow bandgap (1.1 eV) CIGS solar cells individually and proposed a tandem solar cell structure using a filtered spectrum approach.

Key Takeaways:

  • The researchers designed a tandem solar cell structure that achieved a conversion efficiency of 26.06% with a voltage of 1.73 V, a current density of 19.32 mA cm, and a fill factor of 77.98%.
  • The proposed CsGeI/CIGS tandem solar cell device structure was simulated using SCAPS 1D and showed a promising route for developing high-efficiency, low-cost tandem solar cells.
  • The study investigates the impact of thickness, parasitic resistance, temperature, quantum efficiency, band diagram, absorption coefficients, and two-diode model equivalent circuit parameters on solar cell performance.
  • The researchers used experimental data to calibrate the top and bottom solar cells and compared the simulated results with experimental findings to ensure the accuracy of the simulated results.
  • The study proposes a tandem configuration with a thickness of 273 nm for the top cell and 1000 nm for the bottom cell, achieving conversion efficiencies of 16.93% and 16.49%, respectively.
  • The study's lead author, Sushama M. Giripunje, notes that the perovskite-CIGS tandem design demonstrates a promising route for developing high-efficiency, low-cost tandem solar cells.

Statistics:

  • 26.06% conversion efficiency achieved by the tandem solar cell design.
  • 1.73 V voltage achieved by the tandem solar cell.
  • 19.32 mA cm current density achieved by the tandem solar cell.
  • 77.98% fill factor achieved by the tandem solar cell.
  • 16.93% conversion efficiency achieved by the top cell.
  • 16.49% conversion efficiency achieved by the bottom cell.
  • 273 nm thickness of the top cell.
  • 1000 nm thickness of the bottom cell.

Sources:

  • Numerical Simulation Analysis of Two-Terminal Monolithic Perovskite-CIGS Tandem Solar Cell for Enhanced Photovoltaic Performance Using SCAPS-1d. Langmuir, 2025.
  • Visvesvaraya National Institute of Technology. Reports Findings in Mathematics (Numerical Simulation Analysis of Two-Terminal Monolithic Perovskite-CIGS Tandem Solar Cell for Enhanced Photovoltaic Performance Using SCAPS-1d). Energy Weekly News. August 8, 2025; p 1109.