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The development of portable X‐ray detectors is necessary for diagnosing fractures in unconscious patients in emergency situations. However, this is quite challenging because of the heavy weight of the scintillator and silicon photodetectors. The weight and thickness of X‐ray detectors can be reduced by replacing the silicon layer with an organic photodetectors. This study presents a novel bithienopyrroledione‐based polymer donor that exhibits excellent photodetection properties even in a thick photoactive layer (~700 nm), owing to the symmetric backbone and highly soluble molecular structure of bithienopyrroledione. The ability of bithienopyrroledione‐based polymer donor to strongly suppress the dark current density (Jd ~ 10−10 A cm−2) at a negative bias (−2.0 V) while maintaining high responsivity (R = 0.29 A W−1) even at a thickness of 700 nm results in a maximum shot‐noise‐limited specific detectivity of Dsh* = 2.18 × 1013 Jones in the organic photodetectors. Printed organic photodetectors are developed by slot‐die coating for use in X‐ray detectors, which exhibit Dsh* = 2.73 × 1012 Jones with clear rising (0.26 s) and falling (0.29 s) response times upon X‐ray irradiation. Detection reliability is also proven by linear response of the X‐ray detector, and the X‐ray detection limit is 3 mA. [ABSTRACT FROM AUTHOR]

With the drive toward the development of large‐area organic solar cells (OSCs), there is a critical need for advanced fabrication techniques that ensure both their efficiency and scalability. In particular, a shift from toxic halogenated solvents to safer non‐halogenated alternatives such as o‐xylene, which have lower environmental and health impacts, is required. However, transitioning to non‐halogenated solvents can lead to serious problems, including aggregation within the active layer, which compromises film morphology and the resulting efficiency of OSCs. To address this aggregation, in the present study, the 2‐ethylhexyl (EH) groups in L8‐BO(EH‐EH) are replaced with longer chains (2‐heptylundecyl [HU], 2‐decyltetradecyl [DT], and 2‐dodecylhexadecyl [DH] groups) to synthesize the non‐fullerene acceptors (NFAs) of L8‐BO(HU‐HU), L8‐BO(HU‐DT), and L8‐BO(HU‐DH). The NFAs with the longer alkyl chains are highly soluble in o‐xylene and produce highly uniform films, making them more suitable for use in large‐area OSCs. Using the NFAs, slot‐die‐coated organic solar modules with an active area of 200 cm2 are fabricated; the L8‐BO(HU‐DT)‐based module exhibits an impressive power conversion efficiency of 11.44%. This work thus underscores the asymmetrical elongation of alkyl chains in the NFAs to mitigate severe NFA phase separation and improve film printability in the practical production of organic solar modules. [ABSTRACT FROM AUTHOR]

Photoelectrochemical (PEC) cells offer a promising method for producing green hydrogen through the splitting of water using solar energy. However, the cost‐effective synthesis of highly crystalline p‐type semiconductor materials for PEC cells remains a significant challenge for industrial applications. Herein, a CuInS2 photoelectrode is fabricated using a scalable and economical wet chemical spin‐coating technique. To enhance the crystallinity and photoelectrochemical activity of the photoelectrode, the grain size is precisely controlled by adjusting the atomic ratio, thickness, morphology, and Ag doping. Evaluating a novel growth mechanism of CuInS2 from Cu–In–O reveals that Ag doping significantly promotes grain growth. Consequently, the CuInS2 photocathode achieves one of the highest photoelectrochemical activities (−9.8 mA cm−2 at 0 VRHE) reported for CuInS2 photoelectrodes synthesized via wet chemical methods. Bias‐free water splitting is achieved using a CuInS2‐based photoelectrode in a photovoltaic–PEC cell configuration. These results highlight the potential of CuInS2, prepared through wet chemical methods, for cost‐effective photoelectrochemical water splitting. [ABSTRACT FROM AUTHOR]

Metal–organic frameworks (MOFs) have emerged as promising materials for triboelectric nanogenerators (TENGs), but the effects of ligand choice on triboelectric charge remain underexplored. Hence, this paper demonstrates the effect of single, binary, and ternary ligands on TENG performance of cobalt/cerium‐based (Co─Ce) bimetallic MOFs utilizing 2‐methylimidazole (2Melm), terephthalic acid (BDC), and benzene tricarboxylic acid (BTC) as ligands. The detailed structural characterization revealed that varying ligand chemistries led to distinct MOF features affecting TENG performance. Single ligand bimetallic MOFs (designated as CoCe‐2MeIm, CoCe‐BDC, CoCe‐BTC) has lower performance than binary ligand (designated as CoCe‐2MeIm‐BDC, CoCe‐2MeIm‐BTC, CoCe‐BDC‐BTC) and ternary ligand MOFs (designated as CoCe‐2MeIm‐BDC‐BTC). Among all, the binary ligand MOF, CoCe‐2MeIm‐BTC, shows the best results (598 V, 26.7 µA) due to the combined effect of imidazole ring and (─COO─) groups. This is attributed to lone pairs on nitrogen atoms and a delocalized π‐electron system in imidazole system in this material. CoCe‐BTC has the lowest results (31 V, 3.2 µA) due to the bulkier nature of the electron‐withdrawing (─COO─) groups and their impact on the π‐electron system of the benzene ring. This study showcases the potential of ligand chemistry manipulation to control triboelectric charge and thereby enhance MOF‐based TENG performance. [ABSTRACT FROM AUTHOR]

It remains challenging to fabricate efficient, scalable large-area organic solar cells (OSCs) owing to the unfavorable morphology of photoactive blend films. To address this challenge, two asymmetric nonfullerene acceptors (NFAs) IPC1CN-BBO-IC2F and IPC1CN-BBO-IC2Cl are synthesized, where 12,13-bis(2-butyloctyl)-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 (BBO) is the molecular core, and two types of end groups are appended to its ends, namely the 9H-indeno[1,2-fe]pyrazine-2,3,8-tricarbonitrile (IPC1CN) end group and one of 2-(5,6-dihalo-3-oxo-2,3-dihydro-1H-inden-1-ylidene)malononitrile end groups (IC2F or IC2Cl). These NFAs facilitate effective tuning of light absorption and energy levels, offer high carrier mobilities, and allow for the formation of appropriate morphologies. Note that these benefits apply even to large-area devices, unlike typical Y6-based NFAs. In addition, a random copolymer PM6-PBDBT(55) is synthesized and its energy levels are optimally matched with those of the asymmetric NFAs. The blade-coated 1 cm2-area OSCs based on PM6-PBDBT(55):IPC1CN-BBO-IC2Cl exhibit a PCE of 14.12%, which is higher than that of PM6-PBDBT(55)-IPC1CN-BBO-IC2F-based OSCs. More importantly, the PM6-PBDBT(55):IPC1CN-BBO-IC2Cl-based large-area (58.50 cm2) modules yield an impressive PCE of 11.28% with a small cell-to-module loss in fill factor. These results suggest that a combination of the asymmetric molecular design using the IPC1CN group and the terpolymer strategy will pave a new path for fabricating highly efficient and scalable large-area OSCs. [ABSTRACT FROM AUTHOR]

A low‐bandgap PBDTDTPD polymer is synthesized. It is a donor‐acceptor‐type polymer that consists of dialkylthiophenyl benzodithiophene (BDT) donor unit and N‐octyl‐2,7‐dithia‐5‐aza‐cyclopenta[a]pentalene‐4,6‐dione (DTPD) acceptor unit. The thienothiophene‐fused strong‐electron‐withdrawing DTPD effectively reduces the bandgap of the resulting polymer and keeps its highest occupied molecular orbital low. Moreover, PBDTDTPD is thermally stable and dissolves well in typical organic solvents. PBDTDTPD:PC71BM(1:1) blend film showed a power conversion efficiency of 3.18% and a largely elevated open‐circuit voltage of 0.75 V compared to that of well‐known P3HT:PC61BM blend film. In this work, we prove that the DTPD moiety can be utilized to develop a future low‐bandgap material that can absorb a broad wavelength of light and have high thermal stability, which are important characteristics for next‐generation high‐performance organic solar cells. [ABSTRACT FROM AUTHOR]

Two green heteroleptic Ir(III) complexes are reported, namely, bis[5‐(2‐ethylhexyl)‐8‐trifluoromethyl‐5H‐benzo[c][1,5]‐naphthyridin‐6‐one](2‐(5‐phenyl‐1,3,4‐oxadiazol‐2‐yl)phenolate)iridium (III) (Ir(CF3BNO)2‐pop) and bis[5‐(2‐ethylhexyl)‐5H‐benzo[c][1,5]naphthyridin‐6‐one](2‐(5‐phenyl‐1,3,4‐oxadiazol‐2‐yl)phenolate)iridium (III) (Ir(BNO)2‐pop) for solution‐processed phosphorescent organic light‐emitting diodes (PHOLEDs). Both the Ir(III) complexes exhibit high external quantum efficiency (EQE) and intense green emission upon using poly(3,4‐ethylenedioxythiophene):polystyrene sulfonic acid (PEDOT:PSS) as a hole injection layer (HIL); Ir(CF3BNO)2‐pop based PHOLEDs perform better with an EQE of 23% and a current efficiency of 82 cd A−1 than Ir(BNO)2‐pop based PHOLEDs. In addition, to improve device operational lifetime, a crosslinkable HIL material, 9,9'‐(cyclohexane‐1,1‐diylbis(4,1‐phenylene))bis(N‐phenyl‐N‐(4‐(((4‐vinylbenzyl)oxy)methyl)phenyl)‐9H‐carbazol‐3‐amine) (CPCzDPAX‐1) is designed and synthesized. Device operational lifetimes of Ir(CF3BNO)2‐pop and Ir(BNO)2‐pop PHOLEDs incorporating the CPCzDPAX‐1 HIL show 14‐fold and 6‐fold improvement, compared to the corresponding devices incorporating the PEDOT:PSS HIL. To the best of the authors' knowledge, this is the best device lifetime performance by using the combination of new Ir(III) complexes and HIL materials for solution‐processed green PHOLEDs. [ABSTRACT FROM AUTHOR]

Despite the outstanding photovoltaic performance of symmetrical Y6, its use is limited in that only chloroform (CF), a highly volatile processing solvent, can induce favorable morphology. This dependence on a particular solvent poses an obstacle to mass production. Here, we investigate the effect of symmetry‐breaking of nonfullerene acceptors (NFAs) on device performance and processability by employing chlorobenzene (CB) or CF processing solvents. In organic solar cells (OSCs) based on a symmetrical Y6 acceptor, a significant difference in the power conversion efficiency occurs between the OSCs fabricated using CB and those fabricated using CF. However, in OSCs based on IPC‐BEH‐IC2F with asymmetrical structure, no difference in photovoltaic performance occurs between the two OSCs. Grazing‐incidence wide‐angle X‐ray scattering measurements indicate that IPC‐BEH‐IC2F exhibits nearly identical diffraction features in both the CB‐ and CF‐processed photoactive films, whereas Y6 shows markedly different stacking structures. Because of these morphological features, OSCs based on Y6 are associated with a relatively large energy loss difference in CB and CF, whereas OSCs based on IPC‐BEH‐IC2F show no significant difference in energy loss. The introduction of an asymmetrical structure can therefore be an important strategy to enhance the versatile processability of OSCs based on NFAs for future mass production. [ABSTRACT FROM AUTHOR]

Inverted type perovskite solar cells (PSCs) have recently emerged as a major focus in academic and industrial photovoltaic research. Their multiple advantages over conventional PSCs include easy processing, hysteresis‐free behavior, high stability, and compatibility for tandem applications. However, the maximum power conversion efficiency (PCE) of inverted PSCs still lags behind those of conventional PSCs because suitable charge‐selective materials for inverted PSCs are limited. In this study, excellent hole‐selective materials for inverted PSCs are introduced. A series of tricyclic aromatic rings containing O, S, or Se, respectively, as a core heteroatom, along with a phosphonic acid anchor, form a self‐assembled monolayer (SAM) that directly contacts the perovskite absorber. The influence of heteroatoms in the aromatic structure on the molecular energetics and operating characteristics of the corresponding inverted PSCs is investigated using complementary experimental techniques as well as density functional theory (DFT) calculations. It is found that all of the SAMs formed an energetically well‐aligned interface with the perovskite absorber. The interaction energy between the Se‐containing SAM and perovskite absorber is the strongest among the series and it reduces the interfacial defect density, in turn leading to an extended charge carrier lifetime. As a result, PSCs incorporating the Se‐containing SAM achieves a PCE of 22.73% and retains ≈96% of their initial efficiency after a maximum power point tracking test of 500 h without encapsulation under ambient conditions. All of the SAMs are then employed in organic solar cells (OSCs). Again, the Se‐containing SAM‐based OSCs demonstrates the highest PCE of 17.9% among the three molecular SAM‐based OSCs. This study demonstrates the great potential for precisely engineered SAMs for use in high‐performance solar cells. [ABSTRACT FROM AUTHOR]

In this paper, we propose an ultrahigh‐resolution organic light‐emitting diodes (OLEDs) pixels patterned by conventional photolithography through by incorporating silicone into phosphorescent small‐molecule networks. This silicone‐integrated phosphorescent organic light‐emitting diode (SI‐phOLED), in which silicone molecules are homogeneously crosslinked with small‐molecule light‐emitting materials, can effortlessly achieve to 3,000 PPI ultrahigh‐resolution patterns using the photolithography process. [ABSTRACT FROM AUTHOR]

Quasi‐2D perovskite materials have promise to unlock the full potential of blue perovskite light‐emitting diodes (PeLEDs). However, the efficiency of blue emissive PeLEDs still lags behind the green‐ and red‐emitting counterparts. Here, a multifunctional passivating molecule of (2‐(3,6‐dichloro‐9H‐carbazol‐9‐yl)ethyl)phosphonic acid (36ClCzEPA) that can form a self‐assembled monolayer (SAM) on the indium tin oxide (ITO) electrode is reported. The 36ClCzEPA SAM facilitates hole injection by increasing the work function of ITO through the strong interfacial dipole layer formation at the interface between the perovskite emitter and the ITO electrode. Moreover, it allows a pure‐blue emission and reduces the exciton quenching of luminescence in the perovskite emitter considerably because of its neutral nature, compared to the commonly used acidic PEDOT:PSS. Furthermore, chlorine atoms in the 36ClCzEPA promote well‐ordered crystalline 2D perovskite phases and decrease interfacial trap‐assisted deactivation channels by interfacial passivation. These beneficial characteristics of the 36ClCzEPA SAM yield the excellent luminescence property of PeLEDs with a maximum luminance of 1253 cd m−2 and a peak external quantum efficiency of 4.80% at 473 nm. This work demonstrates that a well‐designed molecule forming an interfacial SAM can be an important component for enhancing the luminescence property of pure‐blue PeLEDs. [ABSTRACT FROM AUTHOR]

White light is attained by combining different‐colored emissions. White organic light‐emitting diodes, therefore, should be fabricated to obtain mixed emissions from different organic luminophores while suppressing energy transfer between each other. Here, the authors present a simple means to realize this goal by forming two‐color strip‐patterns of light‐emitting polymer (orange) and an iridium complex (sky‐blue) luminophores entirely through solution processes. The formation of the two‐color patterns is facilitated by i) the use of a highly efficient crosslinker permitting the construction of structurally robust orange primary strip‐patterns and ii) the contrast in the surface energy allowing selective wetting of the secondary sky‐blue patterns between the orange primary patterns. The emissive layer comprising the two‐color strip ‐patterns allows for the mixing ratio of the two colors to be adjusted by simply varying the areal ratio of the two patterns, which in turn, controls the white emission color‐temperature from 2119 to 7994 K. [ABSTRACT FROM AUTHOR]

The effect of molecular weight of a series of conjugated polymers (CPs) on the doping efficiency, electrical conductivity, and related thermoelectric properties of doped CPs is studied. Low (L), medium (M), and high (H) molecular weight batches of PDFD‐T polymers, based on difluorobenzothiadiazole and dithienosilole moieties, are synthesized and denoted as PDFD‐T(L), PDFD‐T(M), and PDFD‐T(H), respectively. Furthermore, to compare the effects of different donor moieties, donor units of PDFD‐T(L) are structurally modified from thiophene to thienothiophene (TT) and dithienothiophene (DTT), denoted as PDFD‐TT(L) and PDFD‐DTT(L), respectively. After doping the CPs with FeCl3, d‐PDFD‐T(H) exhibits an electrical conductivity of 402.9 S cm−1, which is significantly higher than those of d‐PDFD‐T(L), d‐PDFD‐T(M), d‐PDFD‐TT(L), and d‐PDFD‐DTT(L). The highest power factor of 101.1 µW m−1 K−2 is achieved through organic thermoelectric devices fabricated using PDFD‐T(H). Through various characterizations, it is demonstrated that CPs with a high molecular weight tend to have a high carrier mobility while maintaining their original crystallinity and good charge transport pathways even after doping. Therefore, it is suggested that optimizing the molecular weight of CPs is an essential strategy for maximal power generation from their doped CP films. [ABSTRACT FROM AUTHOR]

Donor–acceptor (D–A) copolymer‐based polymer solar cells (PSCs) processed with nonhalogenated solvents exhibit relatively low power conversion efficiencies (PCE) due to undesirable morphological properties, including high aggregation and unfavorable orientation. Moreover, they show very poor long‐term stability owing to excessive molecular aggregation and unfavorable phase separation. Thus, novel p‐type polymers are required for high‐efficiency and long‐lived PSCs that can be processed in ecofriendly nonhalogenated solvents. Herein, a novel series of 1D/2A terpolymers (PBTPBD) composed of 4,8‐bis(5‐(2‐ethylhexyl)‐4‐fluorothiophen‐2‐yl)benzo[1,2‐b:4,5‐b′]dithiophene (BDT‐F), 1,3‐bis(thiophen‐2‐yl)‐5,7‐bis(2‐ethylhexyl)benzo‐[1,2‐c:4,5‐c′]dithiophene‐4,8‐dione (BDD), and 1,3‐bis‐(4‐hexylthiophen‐2‐yl)‐5‐octyl‐4H‐thieno[3,4‐c]pyrrole‐4,6(5H)‐dione (HT‐TPD) is synthesized and characterized for high‐efficiency and long‐lived PSCs. A PBTPBD‐50:IT‐4F blended film exhibits a favorable face‐on orientation and superior hole and electron mobility. Therefore, the corresponding PBTPBD‐50:IT‐4F PSC, processed with a nonhalogenated solvent, exhibits a high PCE of 13.64%, which is 13% higher than that of the related nonhalogenated solvent‐processed PSCs. Furthermore, the PBTPBD‐50:IT‐4F PSC maintains 82% of the initial PCE even after 204 days at 85 °C, which is the highest thermal stability achieved among PSCs processed with nonhalogenated solvents. The high‐efficiency and superior long‐term thermal stability of the PBTPBD‐50:IT‐4F PSC are attributed to the excellent miscibility of PBTPBD‐50 and IT‐4F and the suppression of the morphological changes in the photoactive layer. [ABSTRACT FROM AUTHOR]

An inorganic p‐type CuInS2 semiconductor was combined with the semiconducting polymer of PNDI3OT‐Se1 and PNDI3OT‐Se2 with different HOMO/LUMO levels for photoelectrochemical hydrogen production. Charge transfer behaviors at polymer/CuInS2 junctions were investigated by electrochemical impedance spectroscopy. The heterojunction of p‐CuInS2 and n‐type polymer (both PNDI3OT‐Se1 and Se2) successfully made p‐n junctions and showed improved charge transfer. However, we found that higher HOMO levels of polymer than valence band maximum (VBM) of CuInS2 spurred charge recombination at interfaces. As a result, CuInS2/PNDI3OT‐Se1/TiO2/Pt, which has suitable energy levels matched between PNDI3OT‐Se1 and CuInS2, shows photocurrent (−15.67 mA cm−2) improved concretely when compared to a CuInS2/TiO2/Pt photoelectrode (−7.11 mA cm−2) at 0.0 V vs. RHE applied potential. Additionally, the photoelectrochemical stability of CuInS2/PNDI3OT‐Se1/TiO2/Pt photoelectrode was also investigated. [ABSTRACT FROM AUTHOR]

A scanning transmission X‐ray microscope is operational at the 10A beamline at the Pohang Light Source. The 10A beamline provides soft X‐rays in the photon energy range 100–2000 eV using an elliptically polarized undulator. The practically usable photon energy range of the scanning transmission X‐ray microscopy (STXM) setup is from ∼150 to ∼1600 eV. With a zone plate of 25 nm outermost zone width, the diffraction‐limited space resolution, ∼30 nm, is achieved in the photon energy range up to ∼850 eV. In transmission mode for thin samples, STXM provides the element, chemical state and magnetic moment specific distributions, based on absorption spectroscopy. A soft X‐ray fluorescence measurement setup has been implemented in order to provide the elemental distribution of thicker samples as well as chemical state information with a space resolution of ∼50 nm. A ptychography setup has been implemented in order to improve the space resolution down to 10 nm. Hardware setups and application activities of the STXM are presented. [ABSTRACT FROM AUTHOR]

By greatly enhancing binding affinities against target biomolecules, multivalent interactions provide an attractive strategy for biosensing. However, there is also a major concern for increased binding to nonspecific targets by multivalent binding. A range of charge-engineered probes of a structure-specific RNA binding protein PAZ as well as multivalent forms of these PAZ probes were constructed by using diverse multivalent avidin proteins (2-mer, 4-mer, and 24-mer). Increased valency vastly enhanced the binding stability of PAZ to structured target RNA. Surprisingly, nonspecific RNA binding of multivalent PAZ can be reduced even below that of the PAZ monomer by controlling negative charges on both PAZ and multivalent avidin scaffolds. The optimized 24-meric PAZ showed nearly irreversible binding to target RNA with negligible binding to nonspecific RNA, and this ultra-specific 24-meric PAZ probe allowed SERS detection of intact microRNAs at an attomolar level. [ABSTRACT FROM AUTHOR]

Telomerase has attracted much attention as a universal cancer biomarker because telomerase is overexpressed in more than 85% of human cancer cells while suppressed in normal somatic cells. Since a strong association exists between telomerase activity and human cancers, the development of effective telomerase activity assay is critically important. Here, a nanogap-rich Au nanowire (NW) surface-enhanced Raman scattering (SERS) sensor is reported for detection of telomerase activity in various cancer cells and tissues. The nanogap-rich Au NWs are constructed by deposition of nanoparticles on single-crystalline Au NWs and provided highly reproducible SERS spectra. The telomeric substrate (TS) primer-attached nanogap-rich Au NWs can detect telomerase activity through SERS measurement after the elongation of TS primers, folding into G-quadruplex structures, and intercalation of methylene blue. This sensor enables us to detect telomerase activity from various cancer cell lines with a detection limit of 0.2 cancer cells mL−1. Importantly, the nanogap-rich Au NW sensor can diagnose gastric and breast cancer tissues accurately. The nanogap-rich Au NW sensors show strong SERS signals only in the presence of tumor tissues excised from 16 tumor-bearing mice, while negligible signals in the presence of heated tumor tissues or normal tissues. It is anticipated that nanogap-rich Au NW SERS sensors can be used for a universal cancer diagnosis and further biomedical applications including a diverse biomarker sensing. [ABSTRACT FROM AUTHOR]

We observed the collision of single Pt nanoparticles (NPs) onto an Au nanowire (NW) electrode by using electrocatalytic amplification. Previously, such observations had typically been performed by using a microscale disk-type ultramicroelectrode (UME). The use of a NW electrode decreased the background noise current and provided a shielding effect, owing to adsorption of the NPs onto the insulating sheath. Therefore, the transient current signal that was caused by the collision of single NPs could be more clearly distinguished from the background current by using a NW electrode instead of a UME. Furthermore, the use of a NW electrode increased the collisional frequency and the magnitude of the transient current signal. The experimental data were analyzed by using a theoretical model and a random walk simulation model. [ABSTRACT FROM AUTHOR]

Here, we demonstrate a novel process to convert TiO2 nanotubes into ferroelectric nanohoneycombs, comprised of vertically aligned PbTiO3 nanotubes. Tube bottom opening process enabled effective infiltration of lead acetate precursor into the nanotubes. Nanohoneycombs, which were converted via additional lead supplement process, showed uniform conversion and well-defined ferroelectric properties with the effective piezoelectric coefficient of approximately 20 pm/V, which was measured by piezoresponse force microscopy. [ABSTRACT FROM AUTHOR]

Many stimulus-induced release systems have been studied for the smart control of drug delivery. Mechanical strain is rarely investigated as means of stimulation for these systems, despite the fact that there are many biological processes and human body motions that involve strain changes. In this study, a design for a stretchable reservoir-based patch-type release system is suggested. The reservoir made of an elastomer undergoes a decrease in volume when the system is deformed by bending and stretching. The response is predicted by finite element method modeling studies. The release rate of the reservoir is finely controlled by attaching elastic microchannels with different channel lengths. Because the whole system is made of rubber, the patch is deformable and the solution can be refilled with a microsyringe. Systematic designs for on/off release, long-term release, and short-term release are suggested. [ABSTRACT FROM AUTHOR]

ABSTRACT The synthesis of donor-acceptor type semiconducting copolymers is described. Quinoxaline (QX) or difluorinated quinoxaline (DFQX) derivatives serve as electron acceptors, while thiophene (T) or selenophene (Se) serve as electron donors. Alternating polymers are synthesized through Stille cross-coupling, and their thermal stability, optical and electrochemical properties, field-effect carrier mobilities, film crystallinities, and photovoltaic performances are investigated. The intramolecular charge transfer between the electron-donating and electron-accepting units in the backbone induces absorption from 450 to 750 nm. The optical band-gap energies of the polymers are between 1.65 and 1.73 eV, and depend on the polymer structure. Organic photovoltaic cells fabricated using a polymer composed of DFQX and selenophene (PSe-DFQX) exhibit a power conversion efficiency of 5.14% with an open-circuit voltage of 0.78 V, a short-circuit current density of 11.71 mA/cm2, and fill factor of 0.57 under AM 1.5 G irradiation (100 mW cm−2). © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015, 53, 1904-1914 [ABSTRACT FROM AUTHOR]

The major limitations of nanocarriers for drug delivery are the poor biocompatibility and low stability that may induce the unintended burst release of loaded drugs during blood circulation. To overcome these limitations, a photocrosslinkable amphiphilic block copolymer consisting of hydrophobic poly(ε-caprolactone) (PCL) block and a hydrophilic hyperbranched polyglycerol (hbPG) block with improved biocompatibility and stability for drug delivery is developed. They are readily prepared via UV-triggered chemical crosslinking with 4-hydroxycinnamic acid (CA) modification in the hbPG block. The photocrosslinked hbPG- b-PCL-CA nanoparticles are spherical and the size of nanoparticles is increased to 60 ± 30 nm. Photocrosslinked hbPG- b-PCL-CA nanoparticles exhibit significantly high stability in a physiological buffer and the loaded drug in sustained manner. In addition, photocrosslinked hbPG- b-PCL-CA nanoparticles show good biocompatibility in vitro and in vivo. These data imply the promising potential of photocrosslinked hbPG- b-PCL-CA nanoparticles as nanocarriers for drug delivery. [ABSTRACT FROM AUTHOR]

Facile postsynthetic oxidation of the thiol-laced UiO-66-type framework UiO-66(SH)2 enabled the generation of UiO-66(SO3H)2 with sulfonic acid groups covalently linked to the backbone of the system. The oxidized material exhibited a superprotonic conductivity of 8.4×10−2 S cm−1 at 80 °C and 90 % relative humidity, and long-term stability of the conductivity was observed. This level of conductivity exceeds that of any proton-conducting MOF reported to date and is equivalent to the conductivity of the most effective known electrolyte, Nafion. [ABSTRACT FROM AUTHOR]

A porous metal-organic framework (MOF), [Ni2(dobdc)(H2O)2]⋅6 H2O (Ni2(dobdc) or Ni-MOF-74; dobdc4−=2,5-dioxido-1,4-benzenedicarboxylate) with hexagonal channels was synthesized using a microwave-assisted solvothermal reaction. Soaking Ni2(dobdc) in sulfuric acid solutions at different pH values afforded new proton-conducting frameworks, H+@Ni2(dobdc). At pH 1.8, the acidified MOF shows proton conductivity of 2.2×10−2 S cm−1 at 80 °C and 95 % relative humidity (RH), approaching the highest values reported for MOFs. Proton conduction occurs via the Grotthuss mechanism with a significantly low activation energy as compared to other proton-conducting MOFs. Protonated water clusters within the pores of H+@Ni2(dobdc) play an important role in the conduction process. [ABSTRACT FROM AUTHOR]

Highly efficient copper-zinc-tin-selenide (Cu2ZnSnSe4; CZTSe) thin-film solar cells are prepared via the electrodepostion technique. A metallic alloy precursor (CZT) film with a Cu-poor, Zn-rich composition is directly deposited from a single aqueous bath under a constant current, and the precursor film is converted to CZTSe by annealing under a Se atmosphere at temperatures ranging from 400 °C to 600 °C. The crystallization of CZTSe starts at 400 °C and is completed at 500 °C, while crystal growth continues at higher temperatures. Owing to compromises between enhanced crystallinity and poor physical properties, CZTSe thin films annealed at 550 °C exhibit the best and most-stable device performances, reaching up to 8.0 % active efficiency; among the highest efficiencies for CZTSe thin-film solar cells prepared by electrodeposition. Further analysis of the electronic properties and a comparison with another state-of-the-art device prepared from a hydrazine-based solution, suggests that the conversion efficiency can be further improved by optimizing parameters such as film thickness, antireflection coating, MoSe2 formation, and p-n junction properties. [ABSTRACT FROM AUTHOR]

ABSTRACT Low bandgap polymers with dithienylquinoxaline moieties based on 6H-phenanthro[1,10,9,8- cdefg]carbazole were synthesized via the Suzuki coupling reaction. Alkoxy groups were substituted at two different positions on the phenyl groups of the quinoxaline units of these polymers: in the para-position (PPQP) and in the meta-position (PPQM). The two polymers showed similar physical properties: broad absorption in the range of 400-700 nm, optical bandgaps of ∼1.8 eV, and the appropriate frontier orbital energy levels for efficient charge transfer/separation at polymer/PC71BM interfaces. However, the PPQM solar cell achieved a higher PCE due to its higher Jsc. Our investigation of the morphologies of the polymer:PC71BM blend films and theoretical calculations of the molecular conformations of the polymer chains showed that the polymer with the meta-positioned alkoxy group has better miscibility with PC71BM than the polymer with the para-positioned alkoxy group because the dihedral angle of its phenyl group with respect to the quinoxaline unit is higher. This higher miscibility resulted in a polymer:PC71BM blend film with a better morphology and thus in a higher PCE. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014, 52, 796-803 [ABSTRACT FROM AUTHOR]

Spatially and spectrally resolved cathodoluminescence (CL) is one of the most effective methods to explore the optical properties of a nanomaterials and reveals the spatial distribution as well as the correlation between the luminescence and the sample morphology and microstructure. Here, CL modulation of ZnS nanostructures by controlled morphologies, Fe/Mn doping, and measurement temperature is demonstrated. High quality ZnS nanobelts and nanorods are synthesized on an Au-coated Si substrate and an Au-coated GaAs substrate via a facile thermal evaporation route. A room-temperature sharp ultraviolet (UV) lasing-like peak in various ZnS is achieved. The main UV luminescence peaks appear at wavelengths between 330 and 338 nm. The low temperature (32 K) CL spectrum consists of a narrow and strong UV peak centered at 330 nm and two broad, low-intensity peaks in the visible region (514 and 610 nm). Temperature-dependent CL from such single-crystalline ZnS nanobelts in the temperature range of 32 to 296 K reveals two UV peaks at 3.757 and 3.646 eV. The effects of Fe doping and Fe/Mn co-doping on the CL property of ZnS nanobelts are further investigated. These results imply that ZnS nanostructures can be used for potential luminescent materials as well as short-wavelength nanolaser light sources. [ABSTRACT FROM AUTHOR]

The direct transfer of single-crystalline Au nanowires (NWs) onto Au substrates was achieved by a simple attachment and detachment process. In the presence of a lubricant, Au NWs grown vertically on a sapphire substrate were efficiently moved to an Au substrate through van der Waals interactions. We demonstrate that the transferred Au NWs on the Au substrate can act as sensitive, reproducible, and long-term-stable surface-enhanced (SERS) sensors by detecting human α-thrombin as well as Pb2+ and Hg2+ ions. These three biochemically and/or environmentally important analytes were successfully detected with high sensitivity and selectivity by Au NW-SERS sensors bound by a thrombin-binding aptamer. Furthermore, the as-prepared sensors remained in working order after being stored under ambient conditions at room temperature for 80 days. Because Au NWs can be routinely transferred onto Au substrates and because the resultant Au NW-SERS sensors are highly stable and provide with high sensitivity and reproducibility of detection, these sensors hold potential for practical use in biochemical sensing. [ABSTRACT FROM AUTHOR]

We studied the structural characteristics of poly imides (PI) chains according to the film thickness and the temperature treatment using the angle resolved near edge X-ray adsorption fine structure (AR-NEXAFS). The molecular directional angle a of the twisted nematic (TN) and the in-plane switching (IPS) mode alignment film (AF) decrease the tilt angle as increasing the film thickness. These films also shows the temperature dependence of C=C * according to the annealing conditions. In case TN mode sample lost its angular dependency after annealing 230 °C for 2400 sec on the hot plate, but IPS mode sample maintained its angular dependency after same annealing condition with TN mode sample. [ABSTRACT FROM AUTHOR]

Nanoscale ferroelectric honeycombs, comprised of vertically aligned PbTiO3 nanotubes, are fabricated by vapor phase reaction between lead acetate-infiltrated TiO2 nanotubes and PbO vapor. PbTiO3 nanohoneycombs converted by vapor phase reaction at 550°C showed well-aligned nanoscale structure with alignment angle less than 1° and well-defined ferroelectric properties with the effective piezoelectric coefficient of 44 pm/V. This novel nanoscale structure is expected to facilitate high efficiency sensing of electromechanical and electrochemical stimuli. [ABSTRACT FROM AUTHOR]