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CPOS Seminar:Understanding the correlation between energy-state mismatching and open-circuit voltage loss in bulk heterojunction solar cells

Date and Time
Location
HYBRID: In-person:PSBN 2520D / Zoom
Professor Sung Heum Park - Department of Physics, Pukyong National University, Republic of Korea
Professor Sung Heum Park - Department of Physics, Pukyong National University, Republic of Korea

Speaker: Professor Sung Heum Park - Department of Physics, Pukyong National University, Republic of Korea

Abstract: Photoinduced intermolecular charge transfer (PICT) determines the voltage loss in bulk heterojunction (BHJ) organic photovoltaics (OPVs), and this voltage loss can be minimized by inducing efficient PICT, which requires energy-state matching between the donor and acceptor at the BHJ interfaces. Thus, both geometrically and energetically accessible delocalized state matching at the hot energy level are crucial for achieving efficient PICT. In this study, an effective method for quantifying the hot state matching of OPVs was developed. The degree of energy-state matching between the electron donor and acceptor at BHJ interfaces was quantified using a mismatching factor (MF) calculated from the modified optical density (MOD) of the BHJ. Furthermore, the correlation between the open-circuit voltage (Voc) of the OPV device and energy-state matching at the BHJ interface was investigated using the calculated MF. The OPVs with small absolute MF values exhibited high Voc values. This result clearly indicates that the energy-state matching between the donor and acceptor is crucial for achieving a high Voc in OPVs. Because the MF indicates the degree of energy-state matching, which is a critical factor for suppressing energy loss, it can be used to estimate the Voc loss in OPVs.

 

 

Bio:
Affiliation: Professor of Department of Physics, Pukyong National University, Republic of Korea;
Experiences & careers
2011. 03 – present  - Professor, Department of Physics, Pukyong National University
2024. 03 – present - Visiting Professor, CPOS, UC Santa Barbara
2022. 03 – present - Team leader, Physics team of Brain-Korea 21 plus and 4th project.
2018. 01 – present - CEO, Himtech cor. in Korea.
2022. 03 – present - Director of research institute of Phosphor bank.
2019. 07 – present - Director of research institute of Smart materials and devices.
2021. 03 – 2023.02 - Director of research institute of Nano-science and technology.
2020. 09 – 2022.08 - Director of Center of Research Facilities
2017. 07 – 2019. 06 - Director of research institute of Nano-science and technology.
2014. 06 – 2015. 08 - Vice Dean of College of Natural Science
2009.10 – 2011.02   - Research Professor, Heeger Center for Advanced Materials, Gwangju Institute of Science &Technology (GIST)
2007.09 – 2009. 09  - Postdoctoral Fellow, Center for Polymer and Organic Solids (CPOS), University of California at Santa Barbara