'World's Highest Efficiency' Next-Generation Large-Area Solar Cell Development

KRICT Completes Patents and Enters Commercialization Phase

Domestic researchers have developed a next-generation large-area solar cell with the world's highest efficiency, completing the patent process and entering commercialization.

The Korea Research Institute of Chemical Technology announced on the 2nd that Dr. Jeonnamjung's research team, in collaboration with Professor Seo Jangwon of KAIST, developed an ionic liquid-type dopant with excellent solubility to replace the conventional highly hygroscopic dopants, successfully securing world-class perovskite solar cell efficiency and stability simultaneously.

A dopant is an impurity intentionally added to a material or process to achieve a desired effect. It plays a very important role in improving electrical conductivity by being included in the hole transport layer of perovskite solar cells. Through the development of a new dopant, the research team achieved an efficiency of 18.24% on large-area perovskite solar cells over 200㎠. Based on the active area, this is a world-class efficiency of 19.91%. Previously, the highest was 17.9%.

Perovskite solar cells have attracted global attention because they can achieve high efficiency through solution processing while enabling flexible and much lighter solar cells. Currently, research on perovskite solar cells has focused on improving efficiency in small areas (~0.1㎠). For commercialization through economic feasibility, it is essential to implement the same performance over a wide area and maintain it for a long time. In particular, the organic small molecule material (Spiro-OMeTAD) mainly used in the hole transport layer of perovskite solar cells has advantages in securing efficiency but is very vulnerable to heat. On the other hand, the organic polymer PTAA (polytriarylamine) is very stable at high temperatures but has limitations in maximizing efficiency.

To overcome these issues, the use of 'dopants' has been studied. Ion salt-based dopants such as lithium (Li), which have been mainly used, could increase efficiency by improving conductivity. The problem is that they have a strong affinity for water and tend to absorb moisture. Moisture decomposes the perovskite layer and hole transport layer over time, degrading performance.

The research team developed a new dopant that improves the electrical properties of the hole transport material while simultaneously compensating for the limitations of perovskite, dramatically enhancing efficiency and stability, successfully applying it to large-area perovskite solar cells. Inspired by acid-base reactions, they developed a new dopant by reacting ▲ an 'acidic substance' that can improve the conductivity of the hole transport polymer PTAA and ▲ an amine-based 'basic substance' that suppresses defects on the perovskite surface to secure stability. By adjusting the number of carbon atoms and concentration of the amine, they fully dispersed it in solution and successfully coated it on large areas over 200㎠. This achieved a world-class efficiency of 18.24%. Furthermore, after 1080 hours of accelerated light exposure, more than 89% of the initial efficiency was maintained, and under conditions of 85℃ and 85% humidity, more than 90% of the initial efficiency was preserved. By applying large-area coating technology and laser etching processes that the research team has been steadily developing since 2016, they realized large-area perovskite cells with high efficiency and high stability.

The research team stated, "We have secured the world's highest efficiency and long-term stability on large areas over 200㎠, similar in size to currently commercialized silicon solar cell cells," and added, "This is expected to bring us one step closer to the practical commercialization of low-light IoT solar cells and building-integrated solar cells."

The research team registered the related technology as a domestic patent last year and has completed patent applications in the United States, Japan, China, and Europe. They plan to transfer the technology to private companies possessing large-area perovskite solar cell mass production technology in Korea to promote commercialization.

The research results were published in the international scientific journal in the field of science and technology, ‘Energy Environmental Science,’ in March.

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