Professor

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Being with my “ARYA”

Research history

My research background is mainly focused on synthesizing photoactive and charge transporting polymers, investigating interfaces formed from the polymers and other materials to understand various electronics and electrochemical reactions, and explore their potential towards efficient energy devices. Previously during my Ph.D., I have synthesized various ion chelating triarylamines copolymers with fluorenes, phenyl, vinylene phenylene, and their derivatives as organic hole transporting materials (HTMs) for solid-state dye-sensitized solar cells (ssDSCs). I also unraveled the unique potential of ion chelating triarylamines copolymers in inducing charge stabilization and retarding recombination reactions of photoinduced electrons at the interface of the ssDSSC in collaboration with Professor James R. Durrant (Imperial College, UK) (Ph.D. studies were carried out under the supervision of Professor Andrew B. Holmes at University of Cambridge). During my post-doctoral period, I synthesized a highly stable quadruply hydrogen-bonded heterocomplex (ADDA type) inspired by DNA duplex formation and applied it to the nanoscale supramolecular construction. (Post-doctoral research was conducted under the direction of Professor Steven C. Zimmerman at University of Illinois (Urbana), USA. Ever since I started my independent career at Pohang University of Science and Technology (POSTECH), Korea, in March 2007, my students and I have expanded my research interest in the area of investigating interfaces constructed with various organic, inorganic, and metal oxide materials for understanding various electronics and electrochemical reactions. I believe this will give us an insight in designing and developing novel photoactive conducting materials for a potential towards efficient energy devices. To this end, we have not only focused our research efforts on the photophysical study of the solar cell devices using a home-made transient absorption / mobility spectrophotometer (TAS/TMS) but also various types of photoactive and charge transporting polymers. We also further extended the research subjects on modulating the interfaces to construct well-defined nanostructures via self-assembly processes, giving us a better theoretical description of our experimental findings. I believe that our findings and research efforts in this direction will contribute to the advances in polymer material, electrochemical, and chemical engineering research societies.

Mission in research

There are strong relations between material properties and device functions. Understanding both aspects are highly important for material chemists and engineers to transfer new technologies based on optoelectronic devices to real markets. In particular, optoelectronic devices such as thin film transistors, light emitting diodes, sensors, or photovoltaics involve interfaces constructed by physical or chemical contacts between metal/organic, organic/organic, and organic/inorganic semiconductor heterojunctions, at which the process of charge transfer plays an important role in these areas of technology. The optimization of such devices requires a good theoretical and experimental description of the interfaces involved. This, in turn, has motivated detailed studies of device functions and material properties through mechanistic study of interfacial charge-transfer reactions at the heterojunctions, fundamentally originated from intrinsic characteristics of material properties for efficient design and synthesis of novel organic materials.  The ultimate goal of my research activity is to conceptually create new organic materials (small molecules and polymers) and to modulate interfaces in a molecular level to understand properties of heterogeneous interfaces in photovoltaic devices such as dye-sensitized solar cells, bulk-heterojunction solar cells, or organic-inorganic hybrid solar cells. To achieve this goal, we have focused our research efforts on designing and synthesizing new smart organic materials using various organic chemical reactions. We have also continuously investigating the various heterogeneous interfaces such as metal/organic, organic/organic, and organic/inorganic semiconductor heterojunctions even in self-assembled nanostructures. We are focused toward development of next generation polymeric materials for highly efficient energy devices.

Representative publications

14) Dohyun Kim,‡ Hyuntae Choi,‡  Eun Young Park, Nam Joong Jeon,* Seulki Song,* Taiho Park* "Phase transition engineering for effective defect passivation of highly efficient and stable perovskite solar cells"  Energy Environ. Sci. 2023, 16, 2045 - 2055.

13) S Lim,‡ S Han,‡ D Kim, J Min, J Choi,* T Park* "Key Factors Affecting the Stability of CsPbI3 Perovskite Quantum Dot Solar Cells: A Comprehensive Review" Adv. Mater. 2023, 35, 2203430.  

12). X Liu, J Min, Q Chen, T L, G Qu, P Xie, HX J-J Liou,* T Park,* Z-X Xu* "Synergy Effect from π-conjugated Ionic Compound: Dual Interfacial Energy Level Regulation and Passivation to Promote VOC and Stability of Planar Perovskite Solar Cells" Angew. Chem. Int, Ed. 2022, 61, e202117303. (Cover article)  

11) K Choi,‡ J Lee,‡ H Choi, HI Kim, G-W Kim, T Park* "Heat dissipation effects on the stability of planar perovskite solar cells" Energy Environ. Sci., 2020, 13, 5059 .

10) HI Kim,1,2 S-W Baek,1 O Ouellette,1 M-J Choi,1 H Choi,2 K Choi,2 B Chen,1 B Scheffel,1 S Hoogland,1 FP García de Arquer,1 T Park,2* EH Sargent1* "Monolithic Organic/Colloidal Quantum Dot Hybrid Tandem Solar Cells via Buffer Engineering" Adv. Mater. 2020, 32, 2004657. 

9) J Lee,‡ K Parida,‡ MW Ming Tan,‡ G Thangavel, SA Park, T Park,* PS Lee* “Water-processable transparent ionic conductors with enhanced [LPS(1] stretchability, self-healing, and thermal stability for thermal actuators and sensors” Adv. Mater. 2020, 32, 1906679. (Front cover)

8) HI Kim,‡ S-W Baek,‡ HJ Cheon,‡ SU Ryu, S Lee, M-J Choi, K Choi, M Biondi, S Hoogland, FP García de Arquer, S-K Kwon, Y-H Kim,* T Park,* EH Sargent* "A Tuned Alternating D-A Copolymer Hole-Transport Layer Enables Colloidal Quantum Dot Solar Cells with Superior Fill Factor and Efficiency" Adv. Mater. 2020,  32, 2004985. 

7) K Choi,‡ J Lee,‡ HI Kim, CW Park, G-W Kim, H Choi, S Park, SA Park, T Park* “Thermally Stable, Planar Hybrid Perovskite Solar Cells with High Efficiency” Energy & Environ. Sci. 2018,11, 3238-3247. 

6) J Lee,§ MM Byranvand,§ G Kang, SY Son, S Song, G-W Kim, T Park* “Green Solvent Processable, Dopant-Free Hole Transport Materials for Robust and Efficient Perovskite Solar Cells” J. Am. Chem. Soc. 2017, 139, 12175–12181. 

5) G-W Kim,§ G Kang,§ J Kim, G-Y Lee, H Kim, L Pyeon, J Lee, T Park* “Dopant-free Polymeric Hole Transport Material for Highly Efficient and Stable Perovskite Solar Cells” Energy & Environ. Sci. 2016, 9, 2326-2333. (Front cover) 

4) SY Son,§ Y Kim,§ J Lee, G-Y Lee, W-T Park, YY Noh, C Park,* T Park* "High Field-Effect Mobility of Low-Crystallinity Conjugated Polymers with Localized Aggregates" J. Am. Chem. Soc. 2016, 138, 8093-8103. (Front cover)  Featured in JACS spotlights 

3) J Lim, T Kim, T Park* “Fast cascade neutralization of an oxidized sensitizer by an in situ-generated ionic layer of I- species on a nanocrystalline TiO2 electrode” Energy & Environ. Sci. 2014, 7, 4029-4034. (Front cover) 

2) YS Kwon,‡ J Lim,‡ H-J Yun, Y-H Kim,* T Park* “Diketopyrrolopyrrole-Containing Hole Transporting Conjugated Polymer for use in Efficient Stable Organic-Inorganic Hybrid Solar Cells based on a Perovskite” Energy & Environ. Sci. 2014, 7, 1454-1460.

1) S-H Park,‡ IY Song,‡ J Lim, YS Kwon, J Choi, S Song, J-R Lee, T Park* "A novel quasi-solid state dye-sensitized solar cell fabricated using a multifunctional network polymer membrane electrolyte" Energy & Environ. Sci. 2013, 6, 1559-1564.

Professional Societies

Korean Chemical Society (KCS), The Polymer Society of Korea (PSK), Korean Institute of Chemical Engineering (KICE), Korean Society of Industrial and Engineering Chemistry (KSIEC), Korean Organic Solar Cells Society, Korean Photovoltaic Society, Korean Society of Photoscience, American Chemical Society (ACS), Material Research Society (MRS)

Services for Science Communities (representatives)

- Committee on Organization of The 14th International Meeting on Information Display (2014)

- Committee on Organization of Macromolecular session in the IUPAC-2015, 45th World Chemistry Congress (2014~2015)

- General Secretary, Korea-Japan Forum, International Conference on Organic Materials for Electronics and Photonics (JKF-ICOMEP) (2010, 2011)

- General Secretary, Daegu-Kyungbuk Province, The Polymer Society of Korea (2012)

- General Secretary, The 6th Asian Conference on Organic Electronics (A-COE 2013)

- General Secretary, The 8th Korea-Japan Joint Symposium, Korean Chemical Society (2014)

Professional Duties (representatives)

Editorial Board Member of Polymer Science and Technology (2009 ~ 2012) bimonthly issued by The Polymer Society of Korea, Photoscience World (2012) bimonthly issued by Korean Society of Photoscience, and Macromolecular Research (2012 ~ present)