Solar cell defect analysis advances with new transient response technique

by Riko Seibo

Tokyo, Japan (SPX) Nov 26, 2025

Researchers from the Korea Institute of Energy Research and Chungbuk National University have pinpointed two distinct types of defects responsible for power loss in silicon heterojunction solar cells. The team, led by Dr. Hee-Eun Song of KIER and Professor Ka-Hyun Kim of CBNU, identified slow and fast component defects using a refined method of Deep Level Transient Spectroscopy that captures the full transient response of the device.

The study revealed that the key defect previously believed to be singular is actually a superposition of deep-level and shallow-level types. Analysis of each component enabled precise measurement of defect energy levels, their positions within the solar cell, and atomic bonding configuration. Findings indicate that quantitative and qualitative assessments of such defects are necessary to optimize device performance and interaction with passivation technologies.

The team established that atomic bonding in defects can shift depending on fabrication method and operating conditions. Hydrogen atoms within the device play a significant role in driving these transformations. This research may accelerate development of high-efficiency silicon heterojunction and tandem solar cells integrating KIER’s proprietary techniques.

“This study will accelerate the development of high-efficiency silicon heterojunction solar cells and, furthermore, enable us to realize world-class tandem solar cells using KIER proprietary technologies,” said Dr. Hee-Eun Song.

“This study provides a fundamental understanding of the relationship between defects and passivation,” stated Professor Ka-Hyun Kim. “The developed analysis method can be extended not only to solar cells but also to a wide range of semiconductor and display applications including sensors LEDs and CMOS devices.”

Research was carried out using SHJ solar cells manufactured at KIER’s Center for Advanced Solar PV Technology and analysis was performed at CBNU. The results provide a foundation for future tandem solar cell development.

Research Report:Unraveling Mixed-Defect Transformations and Passivation Dynamics in Silicon Heterojunction Solar Cells