Researchers from TU Delft developed a new micro-textured hexagonal glass that improves light scattering by up to 50%, improving optical performance in thin-film silicon solar cells. The technology is promising for multi-junctional, flexible and energy-efficient solar energy applications.
Researchers from Delft University of Technology have investigated the application and properties of a new hexagonal glass texturing process in a superstrate configuration for thin-film silicon solar devices.
“Our research has shown up to 50% light scattering, even at near-infrared wavelengths, with honeycomb textures on glass. These high-performance glass structures could benefit thin-film multijunction cells,” Govind Padmakumar, corresponding author of the study, told us. pv magazine.
Referring to commercial modules with a glass superstrate and pin-device architecture, Padmakumar noted that the new texturing enables light diffraction channels in transmission mode, improving the optical performance of the solar cell.
The researchers also highlighted that when used with hydrogenated nanocrystalline silicon (nc-Si:H) technology, it can facilitate conformal, crack-free growth of silicon crystals on glass, and that deeper craters improve wide-angle light scattering.
The team showed that using hexagonal textured glass produced a cell with a photovoltaic conversion efficiency of 9.3% and a short-circuit current of 28.6 mA/cm2. “This is one of the highest current measurements reported on a single-junction nc-Si:H solar cell in a superstrate configuration without anti-reflective coating,” says Padmakumar.
Used in an amorphous silicon/nanocrystalline silicon superstrate tandem solar cell, this resulted in an efficiency of 12.3%.
The researchers foresee the use of the technology in solar cells for consumer electronics, solar-powered sensors and low-power off-grid applications. “With novelty in the application and results in the scientific study presented, this study will have a positive impact on the performance studies of solar cells, including multijunction solar cells, in the future,” Padmakumar said.
The group is currently working with Dutch flexible module manufacturer Lift PV (formerly HyET Solar Netherlands) to expand the use of hexagonal textures on alternative substrates and multijunction approaches to improve the performance of metal foils for use in flexible silicon and perovskite tandem devices.
The study describing the testing and application of the honeycomb microstructures to glass technology is detailed in “Microtextured hexagonal glass for high optical performance in thin-film silicon solar cells”, published in Solar energy.
In an earlier article “Engineering of hexagonal microtextures on glass”, published by ACS applied optical materialsthe same team from TU Delft Photovoltaic Materials and Devices (PVMD) reported the photolithography and wet etching processes, including detailed optimizations, involved in the development of the hexagonal texture on glass.
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