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South Korean scientists have developed a new building-integrated photovoltaic (BIPV) solar cell that incorporates a distributed Bragg reflector (DBR) electrode. This innovation is expected to improve light scattering and meet aesthetic standards.
South Korean researchers have developed a BIPV cell that incorporates a transparent distributed Bragg reflector (DBR) electrode.
DBRs are made up of alternating dielectric layers, often serving as dielectric reflectors and mirrors, and their multi-layer composition alternates between high and low refractive indices, resulting in customizable reflection spectra.
DBR structures are light blue in color and use transparent conductive oxides (TCOs) derived from aluminum doped zinc oxide (AZO) and indium tin oxide (ITO). This choice of materials improves the dispersion of light. The connection between the TCOs and the DBR electrode incorporates a diffusing layer that serves as a transparent front electrode.
“The AZO diffusing layer was chemically etched and the light scattering structure was controlled by varying the etching time,” the researchers explain. "As the etching time increased, the reflectance spectra tended to decrease across the entire wavelength range, due to the surface texture of the diffusing layer."
The researchers noted that textured PV cells exhibit higher intensity in external quantum efficiency (EQE) across the entire wavelength spectrum, in contrast to flat PV cells. EQE stands for energy conversion efficiency, calculated considering all incident sunlight or photons.
“The absorption of the PV cells improved with increasing light scattering with a higher etched DBR scattering electrode, but the spectral response of the EQE decreased at the higher 150-second light scattering structure,” the scientists explained.
They noted that they will now investigate these interfacial defects in solar cells with higher light scattering.
“The results of the DBR electrode and diffusion layer optimization will be applied not only to a-Si:H, but also to other colored thin-film solar cells, and will help BIPV to investigate utility and aesthetics,” they affirmed.
They described the cell technology in “ Surface modification of color-clarifying layer in transparent conductive oxide based distributed Bragg reflector-diffuser electrode for building-integrated photovoltaics ”. Distributed Based on Transparent Conductive Oxide for Building-Integrated PV Systems), recently published in Solar Energy . The research team consists of scientists from the Korea Institute of Materials Science, the University of Science and Technology (UST) and Pusan ??National University. |
