‘Super Solar Cell’ Commercialization Gains Momentum... ‘Green Film’ Developed to Enhance Both Lifespan and Efficiency

UNIST and University of Pittsburgh Block UV Rays Reaching Tandem Batteries and Increase Visible Light Absorption

Application to UV-Sensitive Organic Solar Cells and Diodes Published in Leading International Journal

Multifunctional reflective barrier film applicable to tandem solar cells. It turns green upon absorbing ultraviolet rays, improving the aesthetics of the solar cells.

[Asia Economy Yeongnam Reporting Headquarters, Reporter Kim Yong-woo] An all-weather film that increases light absorption while extending lifespan in the solar cell field has been developed, attracting global attention.

The ‘1+1 tandem cell’ method, which places a perovskite solar cell on top of a silicon solar cell, is a next-generation cell expected to be commercialized within a few years.

It is also called a ‘super solar cell’ due to its excellent efficiency, price competitiveness, and process convenience. A multifunctional film that can simultaneously improve the lifespan and efficiency of this cell has been developed, accelerating the pace of commercialization.

The research team led by Professor Choi Kyung-jin of the Department of Materials Science and Engineering at Ulsan National Institute of Science and Technology (UNIST) developed a multifunctional anti-reflective film that blocks ultraviolet rays included in natural sunlight while increasing the absorption of visible light.

By blocking harmful ultraviolet rays, the cell’s lifespan is extended, and the absorption of visible light, which is the effective wavelength band, is increased, thereby improving the solar cell’s electricity generation efficiency.

This research was conducted in collaboration with Professor Lee Joong-geon’s team at the University of Pittsburgh. Postdoctoral researchers Kim Chan-ul from UNIST’s Department of Materials Science and Engineering and Lee Seong-ha from the Department of Mechanical and Materials Engineering at the University of Pittsburgh participated as first authors.

The multifunctional film developed by the research team can be placed on top of the tandem cell. It contains fluorescent particles that absorb and block ultraviolet rays and silica particles that increase visible light absorption.

The fluorescent particles also convert the absorbed ultraviolet rays into visible light, further enhancing cell efficiency and making the cell appear green, thereby improving aesthetics.

Tandem Solar Cell Performance Analysis Table.

The effect of this anti-reflective film was confirmed through experiments. The efficiency of tandem solar cells using conventional anti-reflective films dropped to about 90% of the initial efficiency after 5 hours and sharply decreased to about 50% after 20 hours, whereas cells using the developed film maintained over 91% of the initial efficiency even after 120 hours. Additionally, the initial efficiency itself increased by approximately 4.5% compared to the conventional film.

The joint research team also revealed the operating principle of silica nanoparticles through computational simulations. It was found that the forward scattering effect created by silica nanoparticles offsets the backward scattering effect of fluorescent particles, reducing visible light loss. Backward scattering causes light loss, reducing the amount of light absorbed by the cell.

Due to its structure, the tandem solar cell’s perovskite layer, which is vulnerable to ultraviolet rays, is exposed to direct sunlight on the upper layer. Moreover, there is a challenge in applying existing surface treatment technologies that reduce light reflection.

Commercial silicon solar cells reduce light reflection by creating pyramid-shaped micro-textures on the surface, but tandem cells require a smooth silicon surface because the manufacturing process involves applying liquid perovskite material on top of the silicon solar cell.

The research team stated, “Unlike the conventional method of reducing sunlight reflection by creating surface textures, this new technology enhances absorption performance in the effective wavelength band by adding substances within the anti-reflective film. It also blocks ultraviolet rays, so it can be applied not only to tandem cell commercialization but also to fields such as organic solar cells and organic diodes, which are vulnerable to ultraviolet rays.”

The research results were published online on June 24 in the world-renowned journal in the field of functional materials, Advanced Functional Materials, and are scheduled for formal publication.

The research was supported by the ‘35% Super Solar Cell Development’ project under the Alchemist Project of the Korea Energy Technology Evaluation and Planning (KETEP).

(From right) Professor Choi Kyung-jin, Researcher Kim Chan-ul (first author), Researcher Noh Young-im.

This content was produced with the assistance of AI translation services.