Perception Study of Traditional Korean Medical Students on the Medical Education Using the Dundee Ready Educational Environment Measure

Background. In Korea, a few studies regarding traditional Korean medicine (TKM) education have been conducted. The aim of this study is to evaluate students’ perceptions regarding TKM education in Korea and compare them with those of other countries using a quantitative scale, Dundee Ready Educational Environment Measure (DREEM). Materials and Methods. We conducted a survey using DREEM in a TKM college. Totally, 325 students responded to this survey and we performed the descriptive statistics of scores in all items, subscales, and total. Additionally, subgroup comparisons according to gender, school year, and academic achievement were analyzed. Results. Mean overall DREEM score was 94.65 out of 200, which is relatively low compared to previous studies. Particularly, perceptions regarding subscales of learning, atmosphere, and self-perceptions were interpreted as problematic. There was no statistically significant difference between genders in spite of some differences among groups based on school year or academic achievement. Conclusions. We could examine students’ perceptions regarding TKM education at a TKM college using DREEM for which validity and reliability were verified. TKM education was perceived relatively poor, but these quantitative indicators suggested which parts of education need improvement. We expect DREEM to be used widely in TKM or traditional medical education field

Indium tin oxide-free small molecule organic solar cells using single-walled carbon nanotube electrodes

We demonstrated single-walled carbon nanotubes (SWNTs) electrode-based small molecule organic solar cells (OSCs) using diketopyrrolopyrrole donor, DPP(TBFu)2 as an electron donor with [6,6]-phenyl-C61-butyric acid methyl ester (PC61BM) as an electron acceptor. SWNT films with 60% transmittance (at 550 nm) were dry-transferred onto glass substrates to replace conventional indium tin oxide (ITO) electrodes. In order to improve the conductivity of the SWNT electrodes, MoOx thermal doping was applied followed by spin coating of poly(3,4-ethylenedioxythiophene):polystyrenesulfonate (PEDOT:PSS) to enhance doping and electrode blocking function. The indium-free devices showed a power conversion efficiency (PCE) of 1.00% while ITO-based devices showed a PCE of 3.79%.Peer reviewe

Dual Responsive Dependent Background Color Based on Thermochromic 1D Photonic Crystal Multilayer Films

In this paper, we present dual responsive one-dimensional (1D) photonic crystal (PC) multilayer films that utilize a high-humidity environment and temperature. Dual responsive 1D PC multilayer films are fabricated on precoated thermochromic film by sequential alternate layer deposition of photo-crosslinkable poly(2-vinylnaphthalene-co-benzophenone acrylate) (P(2VN-co-BPA)) as a high refractive index polymer, and poly(4-vinylpyrollidone-co-benzophenone acrylate) P(4VP-co-BPA) as a low refractive index polymer. The thermochromic film shows a vivid color transition from black to white at 28 °C. Three different colors of thermochromic 1D PC multilayer films are prepared by thickness modulation of P(4VP-co-BPA) layers, and the films on a black background exhibit visible spectrum color only in a high-humidity environment (over 90% relative humidity (RH)). For the three films placed on a hands display, three different composite colors are synthesized by the reflection of light, including yellow, magenta, and cyan, due to the changing of backgrounds from black to white with temperature. Additionally, the films show remarkable color transitions with reliable reversibility. The films can be applied as anti-counterfeiting labels and can be used for smart decoration films. To the best of our knowledge, this is the first report of dual response colorimetric films that change color in various ways depending on temperature and humidity changes, and we believe that it can be applied to various applications

Multi‐Functional MoO3 Doping of Carbon‐Nanotube Top Electrodes for Highly Transparent and Efficient Semi‐Transparent Perovskite Solar Cells

Abstract MoO3 doping of carbon‐nanotube top electrodes in perovskite solar cells is multi‐functional and facilitates p‐doping, favorable energy‐level alignment, and enhanced hole transport. The optimal layer thickness of MoO3 (8 nm) is determined for decreasing the sheet resistance of carbon‐nanotube electrodes without damaging the perovskite film. The sheet resistance decreases by approximately one‐third from its original value, which is a substantially better result than that previously reported for acid doping of carbon‐nanotube top electrodes. MoO3 deposition lowers the Fermi level of the carbon‐nanotube electrode, improving its energy‐level alignment and hole‐transfer performance. When coated with 2,2′,7,7′‐tetrakis[N,N‐di(4‐methoxyphenyl)amino]‐9,9′‐spirobifluorene (spiro‐MeOTAD), MoO3 crystallizes on the carbon nanotubes and further enhances hole collection. Semi‐transparent perovskite solar cells with MoO3‐doped carbon‐nanotube electrodes have a power conversion efficiency of 17.3% with a transmittance of approximately 60% (at a wavelength of 1000 nm). Because of their favorable transparency in the infrared region, these perovskite solar cells are evaluated for use in a tandem structure with silicon solar cells via computational simulations. The predicted device efficiency (23.7%) exceeds that of conventional indium‐tin‐oxide‐based tandem solar cells (23.0%)

High-Crystalline Regioregular Polymer Semiconductor by Thermal Treatment for Thickness Tolerance Organic Photovoltaics

To successfully develop a regioregular polymer, poly[4,8-bis(5-(2-hexyldecyl)thiophen-2-yl)benzo[1,2-b:4,5-b ']dithiophene][5,5 '-bis(7-(4-(2-butyloctyl)thiophen-2-yl)-6-fluorobenzo[c][1,2,5]thiadiazol-4-yl)-2,2 '-bithiophene] (PDBD-FBT), a symmetric monomer synthesized in high yield by tin homo-coupling reactions. PDBD-FBT is suitable as a donor material in organic photovoltaics (OPVs) because it shows high crystallinity and strong face-on packing properties. These properties were amplified by thermal annealing (TA). This causes a power conversion efficiency (PCE) enhancement in PDBD-FBT-based OPVs. Using PDBD-FBT as a polymer donor and 2,2 '-((2Z,2 ' Z)-((12,13-bis(2-heptylundecyl)-3,9-diundecyl-12,13-dihydro-[1,2,5]thiadiazolo[3,4-e]thieno[2 '',3 '':4 ',5 ']thieno[2 ',3 ':4,5]pyrrolo[3,2-g]thieno[2 ',3 ':4,5]thieno[3,2-b]indole-2,10-diyl)bis(methanylylidene))bis(5,6-difluoro-3-oxo-2,3-dihydro-1H-indene-2,1-diylidene))dimalononitrile (Y6-HU) as an electron acceptor, a PCE of 7.91% was achieved without any additive and TA at optimized active layer film thickness of approximately 100 nm. After TA, a PCE of 12.53% was achieved with a 58% increase compared with the reference devices. Owing to the strong crystallinities, trap-assisted recombination occurs by excessively formed grain boundaries; however, efficient exciton dissociation sufficiently covers these drawbacks. Even in the approximately 340 nm-thick film condition, this tendency is more pronounced (73% PCE enhancement is observed from 6.17% to 10.69% of PCE in the without and with TA devices, respectively). Our study demonstrates that it is possible to manufacture thickness-insensitive OPVs based on regioregular polymers with strong crystallinity and face-on characteristics, thereby providing a solution to the thickness variation of large-area organic solar cell modules

Room-Temperature Hydrogen Sensor with High Sensitivity and Selectivity using Chemically Immobilized Monolayer Single-Walled Carbon Nanotubes

Although semiconducting single-walled carbon nanotubes (sc-SWNTs) exhibit excellent sensing properties for various gases, commercialization is hampered by several obstacles. Among these, the difficulty in reproducibly fabricating sc-SWNT films with uniform density and thickness is the main one. Here, a facile fabrication method for sc-SWNT-based hydrogen (H-2) sensors with excellent reproducibility, high sensitivity, and selectivity against CO, CO2, and CH4 is reported. Uniform-density and monolayer sc-SWNT films are fabricated using chemical immobilized through the click reaction between azide-functionalized polymer-wrapped sc-SWNTs and immobilized alkyne polymer on a substrate before decorating with Pd nanoparticles (0.5-3.0 nm). The optimized sc-SWNT sensor has a high room-temperature response of 285 with the response and recovery times of 10 and 3 s, respectively, under 1% H-2 gas in air. In particular, this sensor demonstrates highly selective H-2 detection at room temperature (25 degrees C), compared to other gases and humidity. Therefore, the chemical immobilization of the monolayer SWNT films with reproducible and uniform density has the potential for large-scale fabrication of robust room-temperature H-2 sensors

Tuning of the Stretchability and Charge Transport of Bis‐Diketopyrrolopyrrole and Carbazole‐Based Thermoplastic Soft Semiconductors by Modulating Soft Segment Contents

Polymer semiconductors are promising materials for stretchable, wearable, and implantable devices due to their intrinsic flexibility, facile functionalization, and solution processability at low temperatures. However, the crystalline domain of the conjugated structure for high charge carrier mobility in semiconducting polymers exhibits lower stretchability than that of the semi-crystalline or amorphous domains. Herein, a set of thermoplastic soft semiconductors is synthesized with different ratios of diketopyrrolopyrrole-carbazole-diketopyrrolopyrrole (DPP-Cz-DPP)-based hard segments and thiophene-based aliphatic soft segments, having the similar structure of thermoplastic elastomers. The polymers exhibit decreased glassy temperatures with the increased content of the soft segments. The polymers show high crystallinity after copolymerization with a large-sized DPP-Cz-DPP core and non-conjugated segments due to an aggregation property of the conjugated core, still possessing a semi-crystalline domain after annealing. The polymer films exhibit stretchability under strains of up to 60%. Organic field-effect transistors fabricated using stretchable polymers show a mobility range of 0.125-0.005 cm(2) V-1 s(-1) with different proportions of the soft segment. The stretchability is improved significantly and the mobilities are decreased less when the content of the soft segment is increased. Therefore, this study presents a design principle for the development of a high-performance stretchable semiconducting polymer.11Nsciescopu

Two-Dimensional Dion-Jacobson Tin Perovskite Transistors with Enhanced Ambient Stability

Two-dimensional (2D) layered perovskites have garnered significant research interest within the perovskite community due to their potential as semiconducting materials characterized by high structural stability and favorable optoelectrical properties. Among various contenders, 2D Dion–Jacobson (DJ) perovskites featuring diammonium organic spacers stand out for their exceptional stability. This stability is attributed to the robust hydrogen bonding of the spacer, which leads to a shorter distance between the inorganic octahedral cage layers. In this study, we highlight the remarkable structural stability of 2D DJ perovskite in Sn2+ perovskite thin-film transistors, achieved through the incorporation of 3-(aminomethyl)piperidinium tin iodide (3AMPSnI4) and 4-(aminomethyl)piperidinium tin iodide (4AMPSnI4). The varying positions of the aminomethyl group determine the distortion of the crystal lattice, impacting their respective optical and electrical properties. The relatively low distortion 3AMPSnI4 demonstrates transistor performance with a 10-fold increase in field-effect mobility and 2 orders of magnitude improvement in the on/off current ratio through high film quality with grain size exceeding 10 μm and narrower bandgap. Moreover, the stability of both the film and device under ambient air exposure is markedly improved, with 2D DJ perovskites retaining their crystal structure for over 24 h, presenting a notable enhancement compared to 2D Ruddlesden–Popper perovskites

Adhesion Improvement of Solvent-Free Pressure-Sensitive Adhesives by Semi-IPN Using Polyurethanes and Acrylic Polymers

To improve the peel strength and holding time of polypropylene glycol (PPG)-based pressure-sensitive adhesives (PSAs), a semi-interpenetrating polymer network (semi-IPN) was prepared using acrylic polymers. In addition, to prevent air pollution due to volatile organic compound emissions and avoid the degradation of physical properties due to a residual solvent, the PPG-based semi-IPN PSAs were fabricated by an eco-friendly solvent-free method using an acrylic monomer instead of an organic solvent. PPG-based semi-IPN PSAs with different hard segment contents (2.9–17.2%) were synthesized; their holding time was found to depend on the hard segment contents. The peel strength was improved because of the formation of the semi-IPN structure. Moreover, the high degree of hard domain formation in the semi-IPN PSA, derived from the increase in the hard segment content using a chain extender, resulted in a holding time improvement. We believe that the as-prepared PSAs can be used in various applications that require high creep resistance

Tailoring the density of carbon nanotube networks through chemical self-assembly by click reaction for reliable transistors

Semiconducting single-walled carbon nanotubes (sc-SWNTs) are attracting considerable interest for use as active layers in various electronic applications such as field-effect transistors (FETs) because of their extremely high intrinsic charge carrier mobility and solution processability at low costs. However, it is challenging to achieve a constant sc-SWNT density for ensuring commercial-level, uniform performance in FETs based on random -network SWNT films formed by solution processing. This paper reports a facile method for sorting sc-SWNT and precisely controlling the density of random-network sc-SWNT films by azide-functionalized polymer. The chemical self-assembly of SWNTs is performed between azide-functionalized polymer-wrapped sc-SWNTs and alkyne-based substrate via click reaction. A high-purity sc-SWNT ink is obtained by the conjugated polymer wrapping method using an azide-functionalized polyfluorene in methylcyclohexane. The sc-SWNTs are then chemically bound to a substrate with an alkyne adhesive layer through a Cu-catalyzed azide-alkyne cycloaddi-tion reaction. FETs with dense and uniform SWNT films with a linear density of 30 (+/- 2) tubes mu m- 1 exhibit markedly high hole mobility of up to 25.4 cm2 V-1 s-1 and excellent performance uniformity. Furthermore, the SWNT films anchored on the substrates are highly resistant to exogenous disruptions, such as sonication in organic solvents, leading the great potential for applications such as biosensors that require strong adhesive strength