Leaking Solar Energy? New Solar Cell Technology Captures Sunlight Efficiently

Development of Affordable and Flexible Core Material for Building Facade and Vehicle Sunroof Installation
UNIST Professor Seok Sang-il's Team Enhances Performance and Stability of Perovskite Solar Cell Photoactive Layer
Minimized Structural Deforma

Structure of the photoactive layer and operating principle of perovskite solar cells developed by Professor Seok Sang-il's team.

[Asia Economy Yeongnam Reporting Headquarters Reporter Kim Yong-woo] The most formidable renewable energy is solar power. In the eyes of renewable energy researchers, as much energy as the sunlight shining down on the Earth is leaking away. When will the technology to capture this energy become possible?

A study published online on October 2 in the world’s most prestigious scientific journal, Science, draws attention by providing an answer to this question.

The era is approaching when solar cells can be attached to every surface exposed to sunlight?building exteriors, roofs, vehicle sunroofs?to easily obtain electrical energy.

This is because a core technology has been developed that can simultaneously improve the power conversion efficiency and stability of inexpensive and flexible “perovskite solar cells.”

Professor Seok Sang-il’s team from the Department of Energy and Chemical Engineering at Ulsan National Institute of Science and Technology (UNIST) developed a technology that minimizes microstructural deformation in the photoactive layer of perovskite solar cells, achieving both high efficiency and stability.

The research team solved the problem caused by internal microstructural distortion or tilting by introducing a new method that evenly matches the sizes of particles (ions) constituting the photoactive layer.

Professor Seok Sang-il, UNIST.

Professor Seok’s perovskite solar cells recorded a power conversion efficiency of 25.17%, the highest efficiency reported in academic papers.

Unlike commercialized silicon solar cells, perovskite solar cells have the advantage of being installable on building exteriors or moving vehicles.

This is because they are less affected by the angle of sunlight and are lightweight. Moreover, they can be easily manufactured at low temperatures. If perovskite solar cells become commercialized, it would mark a historic paradigm shift in renewable energy.

Existing silicon solar cells require processing at high temperatures above 1400 degrees Celsius using expensive equipment, whereas perovskite can be processed as a liquid solution at a low temperature of about 100 degrees Celsius using inexpensive equipment.

Additionally, they can be attached to various substrates including flexible plastics, making them more versatile than rigid silicon wafers.

According to academia, the most important challenge for commercializing perovskite solar cells is developing a photoactive layer material that combines both stability and efficiency.

The photoactive layer plays a crucial role in absorbing sunlight, generating charge (electric) particles, and sending them to the electrodes. If there are many defects (vacancies) in the internal microstructure of the material, the efficiency of charge particle transfer decreases because charge particles disappear at the defects.

Professor Seok Sang-il’s team reduced internal defects and enhanced chemical stability by changing the types and ratios of ions constituting the perovskite photoactive layer.

They identified the main cause of defects as structural deformation caused by mismatched ion sizes.

If there are multiple large ions, the internal microstructure becomes distorted or tilted, creating defects. This is similar to how a building’s steel frame becomes unstable if it is twisted or tilted, causing certain parts to break and destabilize the entire structure.

The developed perovskite material not only alleviated internal pressure and deformation to achieve structural stability but also had fewer defects, resulting in higher efficiency in converting sunlight into electrical energy.

Performance representation of the battery according to the composition and ratio of ions.

Through this, the research team was able to obtain perovskite solar cells with a high efficiency of 25.17% (certified efficiency of 24.44%).

Professor Seok Sang-il explained, “Based on an in-depth understanding of perovskite structures and materials, we were able to develop a photoactive layer material that combines both efficiency and stability. Securing this fundamental material technology means we can gain a technological advantage in the next-generation solar cell market in the future.”

This research was conducted with support from the Ministry of Science and ICT’s Leader Research Program, the Global Frontier Program (Multiscale Energy System Research Group), and the Climate Change Response Program.

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