Bifacial perovskite solar can achieve bifaciality of 90% when tilted at 20 degrees

IIT Bombay researchers have shown that bifacial perovskite solar cells can achieve a 2% higher power conversion efficiency with a tilt angle of 20 degrees. They also developed a bifacial perovskite solar cell for applications in both tandem or single-junction PV devices.

December 26, 2024 Emiliano Bellini

Image: Ricardo Gómez Angel, Unsplash

Researchers from the Indian Institute Of Technology Bombay have conducted a quantitative analysis of optimal values for albedo and tilt angle in bifacial perovskite solar cells and have found that enhancing the rear-side albedo to 0.5 and using a tilt angle of 20 degrees results in the highest efficiency levels.

“Our study presents the fabrication of efficient bifacial perovskite solar cells and investigates their unique properties using various characterization techniques, including Lambertian reflection effects through tilt angle arrangements and bottom albedo illuminations,” the research’s lead author, Paul Ananta, told pv magazine.

The scientists said that the core component of their bifacial solar cells is the transparent back contact made of indium zinc oxide (IZO), which they claim has excellent conductivity, high mobility, and optimum transparency. The device has an active area of 0.175 cm2
when illuminated through the front side and 0.14 cm2 from the rear.

The cell was designed to have a transparent fluorine-doped tin oxide (FTO) substrate, an electron transport layer (ETL) made of tin oxide (SnO2), a perovskite absorber, a hole transport layer (HTL) relying on spiro-OMeTAD and molybdenum oxide (MoO_x), the IZO layer, a molybdenum oxide (MoO_x),

“The control device achieved a maximum power conversion efficiency of 17.46% under front-side 1 Sun AM1.5G illumination,” Ananta explained. “A significant influence of ground Lambertian reflection is observed with tilt angle variations, resulting in increased efficiency from 17.46% to 18.82% as the tilt angle reached 20 degrees.”

Additionally, the researchers found that enhancing the rear-side albedo to 0.5 Sun yielded a maximum efficiency of 26% with a bifaciality factor of 89.3% at a tilt angle of 20 degrees.

“Consequently, the synergistic effect of 0.5 Sun albedo and a 20-degree angular light inclination led to developing bifacial perovskite solar cells with an efficiency of 26.46%” Ananta went on to say. “SCAPS-1D simulations are further employed to validate the experimental Lambertian reflection effects.”

The researchers also ascertained that the cells exhibited intrinsic self-encapsulation and chemical robustness. “Our study anticipates that cost-effective and highly efficient bifacial perovskite solar cells will emerge as a leading PV technology in both single-junction and tandem PV configurations for electricity generation in the near future,” they concluded.

Their findings can be found in the study “Quantitative Estimation of Albedo and Tilt Angle Variation in Bifacial Perovskite Solar Cells,” which was recently published in ACS Applied Materials & Interfaces.

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