Chinho Park

Bio: Chinho Park is an academic researcher from Yeungnam University. The author has contributed to research in topics: Thin film & Solar cell. The author has an hindex of 25, co-authored 148 publications receiving 2019 citations. Previous affiliations of Chinho Park include University of Ulsan.

Perspectives on SnSe-based thin film solar cells: a comprehensive review

Abstract: Currently, selenium (Se)-based compound semiconductors (CISe, CIGSe and CZTSe) are considered as the active materials in the photovoltaic world. However, these materials exhibit couple of issues related to stoichiometry maintenance and scarcity of their constituent elements (In, Ga), which limit their massive production for future energy demands. These issues could be rectified by introducing a non-toxic, inexpensive and earth-abundant binary material. One such material is a tin monoselenide (SnSe), which exhibits a high chemical stability along with attractive physical properties namely, suitable band gap (1.3 eV), high absorption coefficient (105 cm−1) and p-type conductivity. These properties indicate SnSe as a competitive substitute in place of conventional absorbers in thin film solar cells. Despite of its remarkable properties, only a few reports were published on the fabrication of SnSe-based solar cells with poor efficiency (≤1 %). This indicates a need to review on the physical properties of SnSe and its device structures in a deeper sense. In this context, the present review describes the different methods of preparation of SnSe films and their physical properties along with the details of photovoltaic device fabrication. We highlighted the different factors that are limiting the efficiency of SnSe solar cells, and a few suggestions were included to overcome these problems for further improvement of these cells. This review will enrich and stimulate the readers to further investigate the growth of SnSe thin films and their devices, for the development of >20 % efficient SnSe solar cells.

I and i

Abstract: There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality. Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

Promises, Challenges, and Recent Progress of Inorganic Solid-State Electrolytes for All-Solid-State Lithium Batteries

Abstract: All-solid-state lithium batteries (ASSLBs) have the potential to revolutionize battery systems for electric vehicles due to their benefits in safety, energy density, packaging, and operable temperature range. As the key component in ASSLBs, inorganic lithium-ion-based solid-state electrolytes (SSEs) have attracted great interest, and advances in SSEs are vital to deliver the promise of ASSLBs. Herein, a survey of emerging SSEs is presented, and ion-transport mechanisms are briefly discussed. Techniques for increasing the ionic conductivity of SSEs, including substitution and mechanical strain treatment, are highlighted. Recent advances in various classes of SSEs enabled by different preparation methods are described. Then, the issues of chemical stabilities, electrochemical compatibility, and the interfaces between electrodes and SSEs are focused on. A variety of research addressing these issues is outlined accordingly. Given their importance for next-generation battery systems and transportation style, a perspective on the current challenges and opportunities is provided, and suggestions for future research directions for SSEs and ASSLBs are suggested.

Ligand exchange and the stoichiometry of metal chalcogenide nanocrystals: spectroscopic observation of facile metal-carboxylate displacement and binding.

Abstract: We demonstrate that metal carboxylate complexes (L–M(O2CR)2, R = oleyl, tetradecyl, M = Cd, Pb) are readily displaced from carboxylate-terminated ME nanocrystals (ME = CdSe, CdS, PbSe, PbS) by various Lewis bases (L = tri-n-butylamine, tetrahydrofuran, tetradecanol, N,N-dimethyl-n-butylamine, tri-n-butylphosphine, N,N,N′,N′-tetramethylbutylene-1,4-diamine, pyridine, N,N,N′,N′-tetramethylethylene-1,2-diamine, n-octylamine). The relative displacement potency is measured by 1H NMR spectroscopy and depends most strongly on geometric factors such as sterics and chelation, although also on the hard/soft match with the cadmium ion. The results suggest that ligands displace L–M(O2CR)2 by cooperatively complexing the displaced metal ion as well as the nanocrystal. Removal of up to 90% of surface-bound Cd(O2CR)2 from CdSe and CdS nanocrystals decreases the Cd/Se ratio from 1.1 ± 0.06 to 1.0 ± 0.05, broadens the 1Se–2S3/2h absorption, and decreases the photoluminescence quantum yield (PLQY) from 10% to <1% (CdSe) an...