Tae Joo Shin

Abstract Tin sulfide (SnS) is one of the most promising solar cell materials, as it is abundant, environment friendly, available at low cost, and offers long‐term stability. However, the highest efficiency of the SnS solar cell reported so far remains at 4.36% even using the expensive atomic layer deposition process. This study reports on the fabrication of SnS solar cells by a solution process that employs rapid thermal treatment for few seconds under Ar gas flow after spin‐coating a precursor

Abstract The layered sodium transition metal oxide, NaTMO 2 (TM = transition metal), with a binary or ternary phases has displayed outstanding electrochemical performance as a new class of strategy cathode materials for sodium‐ion batteries (SIBs). Herein, an in‐depth phase analysis of developed Na 1− x TMO 2 cathode materials, Na 0.76 Ni 0.20 Fe 0.40 Mn 0.40 O 2 with P2‐ and O3‐type phases (NFMO‐P2/O3) is offered. Structural visualization on an atomic scale is also provided and the following fi

The imidization behavior and structural evolution in a microscaled film of poly(3,4‘-oxydiphenylene pyromellitamic acid) precursor are studied by time-resolved synchrotron wide-angle X-ray diffraction and infrared spectroscopy to investigate the relationship between thermal imidization and structural evolution in the precursor. The precursor film displays only short-range order, but its polyimide film shows a crystalline structure based on an orthorhombic crystal lattice unit. When the precursor

Abstract Understanding the cycling rate‐dependent kinetics is crucial for managing the performance of batteries in high‐power applications. Although high cycling rates may induce reaction heterogeneity and affect battery lifetime and capacity utilization, such phase transformation dynamics are poorly understood and uncontrollable. In this study, synchrotron‐based operando X‐ray diffraction is performed to monitor the high‐current‐induced phase transformation kinetics of LiNi 0.6 Co 0.2 Mn 0.2 O

The evolution of chemical composition and structure during the thermal imidization of an ester-type polyimide precursor, poly(4,4'-oxydiphenylene p-pyromellitamic diethyl ester), in micrometer scale films were studied for a heating rate of 2.0 degrees C/min with time-resolved synchrotron X-ray diffraction, in-situ infrared spectroscopy, and modulated differential scanning calorimetry. Our analyses show that the precursor polymer undergoes imidization in a two-step process. In the first step, the

Poly(amic ester) (PAE) is a soluble precursor of polyimide that has attracted interest from both the microelectronic and the flat-panel display industries because of its several important advantages, including excellent solubility, high hydrolytic stability, and solvent-free film formation, over the polyimide precursor, poly(amic acid), for which monomer-polymer equilibration always occurs in solution due to its carboxylic acid groups. In this study, poly(3,4'-oxydiphenylene pyromellitamic dieth

Owing to the increase in the demand for energy autonomy in electronic systems, there has been increased research interest in thermoelectric thin-film-based energy harvesters. However, the fabrication of such devices is challenging when considering material performance and integration processes. SnSe has emerged as among the best bulk thermoelectric materials capable of functioning at high temperatures; however, the thermoelectric performance of thin films is still limited. Herein, we present a s

The surfaces of layer-structured Li[Li 0.2 Co 0.1 Mn 0.7 ]O 2 nanodisks were nanocoated with polyaniline and examined by SEM and TEM studies, via the chemical oxidative polymerization of aniline in an acid medium for 10 min—Mn 4+ ions in the pristine lithium manganese oxides acted as oxidants. During this reaction, the crystal structure of the pristine nanodisks was retained, and the XRD patterns showed no evidence of H + exchange with the Li + located between the manganese oxide layers. The nan

Naphthalene diimide (NDI)-based conjugated polymers with bithiophene or dithienylethene (TVT) units can form large crystal domains through NDI-driven self-assembly and are widely used in organic electronic devices as n-type materials. However, improving electron transport in these semiconducting polymers has been a significant challenge mainly due to poor electrical connections between the crystal domains. Formation of an interconnected network of small domains with short-range ordering and mixe

Smart textiles based on conjugated polymers have been highlighted as promising fabrics that can intelligently respond to environmental stimuli based on the electrical properties of polymer semiconductors. However, there has been limited interest in the photothermal properties of conjugated polymers that can be applied to smart textiles. We prepared nanoparticles by assembling a conjugated polymer with a fatty acid via an emulsion process and nanocomposite fibers by distributing the conjugated po