◇ 연사 : 포항공대 가속기연구소 박상한 박사

◇ 일시 : 2025년 4월 3일 목요일 16시 30분

◇ 장소 : 자연과학대학 4호관 215호 

◇ 주제 : Latest Research at Pohang Accelerator Laboratory X-ray Free Electron Laser (PAL-XFEL)

◇ 초록 :  The launch of PAL-XFEL in 2017 marked a new era in scientific research, providing ultra-short, high-brilliance X-ray pulses for groundbreaking experiments across multiple disciplines. This facility enables advanced techniques such as X-ray absorption spectroscopy (XAS), allowing element-specific and energy-level-specific investigations of material properties.

Using soft XFEL, we directly probe carrier dynamics in TiO₂, a model photocatalyst, through femtosecond time-resolved XAS. Our study reveals that photo-generated carriers are initially trapped by neutral defects, such as metal or oxygen vacancies, before recombining with oppositely charged polarons to form catalytically active sites.

These findings provide crucial insights into light-matter interactions and photocatalytic mechanisms, highlighting the significance of real-time, element-specific observations. Understanding such ultrafast carrier dynamics is key to advancing photocatalytic materials and solar energy applications.