과학기술정보통신부 글로벌프론티어 (재)멀티스케일 에너지 시스템 연구단은 나노기술과 에너지 기술의 융합을 통하여 혁신적 미래 광에너지와 분자에너지 원천기술 개발을 목표로 하는 멀티스케일 에너지 시스템 연구사업을 추진하고 있습니다. 연구단에서 멀티스케일 에너지 강좌를 개최하오니 관심 있는 분들의 많은 참석 바랍니다.

1. 제  목 : Defect engineering of thin-film kesterite solar cells towards scalable and low-cost manufacturing

2. 연  사 : Yun Seog Lee (Mechanical and Aerospace Engineering Department, SNU, Korea)

3. 일  시 : 2017년 10월 19일 (목), 16:00~17:00

4. 장  소 : 서울대학교 301동 1420호

5. 내  용:
Kesterite Cu2ZnSn(SxSe1-x)4 (CZTS) has been considered as a promising candidate material class for scalable photovoltaic applications, due to its elemental abundance and controllable bandgap. However, the CZTS-based thin-film solar cells have shown significant open-circuit voltage (VOC) deficit problem, largely due to deep trap states and band tailing. Theoretical calculations predict that the pure selenide phase possesses shallower defect levels than pure sulfide phase. We study various approaches to improve microstructure of CZTS thin-films and to passivate their interface defects by using a rapid thermal process and novel interfacial layers. Quantum efficiency and capacitance-based measurements of the device indicate that significantly improved minority carrier diffusion length, resulting in a record VOC-deficit below 600 mV. Microstructural analysis and a comparative study of photoluminescence properties between the sulfide and selenide phases are discussed. Silver-containing kesterite materials are also investigated to overcome the intrinsic bulk defect problems of CZTS thin-films. Furthermore, solution-based approaches and flexible substrates towards scalable and low-cost manufacturing are discussed.

6. 약  력 :
Dr. Yun Seog Lee is an Assistant Professor in Mechanical and Aerospace Engineering Department at Seoul National University. He received his B.S. degree from Seoul National University (2006), M.S. degree from Stanford University (2007), and Ph.D degree from MIT (2013). From 2013 to 2014, he worked as a postdoctoral researcher at the Laboratory for Manufacturing and Productivity at MIT. From 2014 to 2017, he worked as a research staff member at the IBM Thomas J. Watson Research Center, where he received the IBM Invention Plateau Award and the IBM Research Outstanding Accomplishment Award. His research interests include novel materials and innovative nano-scale manufacturing technologies for high-performance energy devices (e.g. thin-film solar cells and solid-state batteries) and next-generation semiconductor devices such as neuromorphic computing devices.