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1.
Hu Li Za Zhi ; 68(1): 64-73, 2021 Feb.
Artículo en Zh | MEDLINE | ID: mdl-33521920

RESUMEN

BACKGROUND & PROBLEMS: Early rehabilitation exercise has been shown to reduce the onset of disability in patients following acute stroke. However, the clinical execution rate of early rehabilitation exercise for those patients remains low. Our medical team developed an early rehabilitation care plan for patients with acute stroke in 2013, at which time the execution rate of early rehabilitation exercise for these patients in our hospital was only 37.1%. The survey found that patients and caregivers had insufficient awareness of early rehabilitation exercise; hospital staffs lacked appropriate assistive devices, rehabilitation equipment, nursing guidance tools, and handover records; and new nursing staffs were insufficiently aware of the importance of early rehabilitation exercise. This care plan was developed to improve the execution rate of early rehabilitation exercise in patients with acute stroke to slow the progression of their disability. PURPOSE: The project was designed to improve the knowledge of new nursing staffs regarding early rehabilitation care and the early rehabilitation exercise completion rate of nursing staffs to raise the execution rate of early rehabilitation exercise in patients with acute stroke. RESOLUTION: After completing the cause analysis, multiple strategies were pursued: (1) nursing education sheets with texts, illustrations, video, and posters were used; (2) group in-service educational training was organized; (3) an innovative transfer belt was designed; (4) facilities were set up to deliver virtual-reality (VR) training; (5) standard procedures on early rehabilitation exercise in patients with acute stroke were revised and implemented; (6) nursing handover procedures were revised; and (7) education courses on early rehabilitation exercise for post-stroke patients were developed. RESULTS: The accuracy of knowledge related to early rehabilitation exercise among new nursing staff improved from 31.3% to 80%; the completion rate for nursing education increased from 53.6% to 98%; and the early rehabilitation exercise execution rate increased from 37.1% to 82.8%. CONCLUSIONS: This project successfully increased the motivation and confidence of patients in rehabilitation and the rate of exercise program execution, which may be expected to impact positively on patients' quality of life.


Asunto(s)
Rehabilitación de Accidente Cerebrovascular , Accidente Cerebrovascular , Realidad Virtual , Terapia por Ejercicio , Humanos , Calidad de Vida
2.
Worldviews Evid Based Nurs ; 17(2): 158-167, 2020 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-32212254

RESUMEN

BACKGROUND: Early rehabilitation has been shown to enhance functional outcomes. Whether the addition of virtual reality (VR) training could further improve muscle strength, mood state, and functional status for patients with acute stroke is unknown. AIMS: To investigate the effectiveness of VR training on muscle strength, mood state (depression, anxiety), and functional status in patients following acute stroke. METHODS: A randomized controlled trial was conducted. Patients with acute ischemic stroke (N = 152) were selected and randomly assigned with a 1:3 randomization ratio to either experimental group (EG) or comparison group (CG). Both groups received early rehabilitation. The EG received an extra 5 days of VR training (15 min of time, two times a day), started 24 hr to 3 days poststroke. Muscle strength, mood state, and functional status were collected at admission and at the day of discharge. Generalized estimating equations were applied to examine the intervention effects. RESULTS: A total of 143 participants (94%) completed the study, and 145 were included in the intention-to-treat analysis. Participants in the EG reported increased muscle strength of upper and lower limbs in both affected and unaffected sides, decreased depression and anxiety, and increased functional status at discharge. When the group-time interaction was examined, the EG had greater increased upper limb muscle strength of the unaffected side (ß = 0.34, p < .001) and decreased depression and anxiety scores (ß = -2.31, p = .011; ß = -1.63, p = .047) at discharge compared with the CG. However, there was no difference in the functional status change scores from baseline between EG and CG. LINKING EVIDENCE TO ACTION: A poststroke program that includes both early rehabilitation and VR training has greater benefit in relation to mood state and muscle strength at discharge than early rehabilitation alone. Therefore, an early physical rehabilitation program that includes VR training for acute stroke inpatients should be considered for implementation in clinical settings.


Asunto(s)
Recuperación de la Función , Rehabilitación de Accidente Cerebrovascular/normas , Accidente Cerebrovascular/complicaciones , Factores de Tiempo , Afecto/fisiología , Anciano , Femenino , Estado Funcional , Humanos , Masculino , Persona de Mediana Edad , Fuerza Muscular/fisiología , Accidente Cerebrovascular/fisiopatología , Rehabilitación de Accidente Cerebrovascular/métodos , Resultado del Tratamiento , Terapia de Exposición Mediante Realidad Virtual
3.
Opt Express ; 27(8): A372-A384, 2019 Apr 15.
Artículo en Inglés | MEDLINE | ID: mdl-31052889

RESUMEN

We report a corrugated structure to effectively extract the surface plasmon polaritons (SPP) and waveguiding modes in organic light-emitting diodes (OLEDs). This structure is formed by nano-imprint of blazed gratings. To study the optimum extraction condition in terms of grating pitches, we compare the light extraction efficiency of corrugated OLEDs with three kinds of pitches, showing a 42.00% external quantum efficiency (EQE) enhancement ratio with this internal structure. Due to the transfer of SPP and waveguiding modes into substrate mode, the EQE enhancement ratio can be further pushed to 103.02% by attaching a macrolens. The simulation verifies the experimental results and shows the extraction mechanism of the corrugated structure towards transverse electric (TE) and transverse magnetic (TM) waves. We foresee that this method is able to enhance the optical efficiency of devices for both mass-production OLED lighting and display in a cost-effective way.

4.
Phys Chem Chem Phys ; 20(43): 27449-27455, 2018 Nov 07.
Artículo en Inglés | MEDLINE | ID: mdl-30357176

RESUMEN

Exciton dynamics in a solid-state exciplex sensitized triplet-triplet annihilation (ESTTA) system are studied using transient photoluminescence (TrPL) measurements. The ESTTA system is a trilayer structure with 4,4',4''-tris(N-3-methyphenyl-N-phenyl-amino)triphenylamine (m-MTDATA) acting as the electron donor, 1-(2,5-dimethyl-4-(1-pyrenyl)phenyl)pyrene (DMPPP) as a triplet-diffusion-singlet-blocking (TDSB) layer, and 9,10-bis(2'-naphthyl) anthracene (ADN), acting as the electron acceptor and emitter. The thicknesses of the m-MTDATA and ADN layers are 30 nm, while the thickness of the DMPPP layer is varied to characterize its effect on the singlet quenching of the ADN emission. We find that electron transfer via tunneling through the DMPPP layer is the dominant quenching channel, with a characteristic length of ∼5 nm. Doping the high photoluminescence quantum yield molecule 4,4'-bis[2-(4-(N,N-diphenylamino)phenyl)vinyl]biphenyl (DPAVBi) into the ADN layer enhanced the overall intensity of the ESTTA signal but did not prevent quenching by exciplex formation. The trilayer configuration (m-MTDATA/DMPPP/ADN) can effectively prevent ADN singlets from being quenched by electron transfer and exciplex formation, and a key property of the DMPPP is its tendency to not undergo electron transfer to the ADN.

5.
J Fluor Chem ; 171: 148-161, 2015 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-25722499

RESUMEN

Novel tumor-targeting drug conjugates, BLT-F2 (1) and BLT-S-F6 (2), bearing a fluorotaxoid as the warhead, a mechanism-based self-immolative disulfide linker, and biotin as the tumor-targeting module, were designed and synthesized as 19F NMR probes. Fluorine atoms and CF3 groups were strategically incorporated into the conjugates to investigate the mechanism of linker cleavage and factors that influence their plasma and metabolic stability by real-time monitoring with 19F NMR. Time-resolved 19F NMR study on probe 1 disclosed a stepwise mechanism for release of a fluorotaxoid, which might not have been detected by other analytical methods. Probe 2 was designed to bear two CF3 groups in the taxoid moiety as "3-FAB" reporters for enhanced sensitivity and a polyethylene glycol oligomer insert to improve solubility. The clean analysis of the linker stability and reactivity of drug conjugates in blood plasma or cell culture media by HPLC and 1H NMR is troublesome, due to the overlap of key signals/peaks with background arising from highly complex ingredients in biological systems. Accordingly, the use of 19F NMR would provide a practical solution to this problem. In fact, our "3-FAB" probe 2 was proven to be highly useful to investigate the stability and reactivity of the self-immolative disulfide linker system in human blood plasma by 19F NMR. It has also been revealed that the use of polysorbate 80 as excipient for the formulation of probe 2 dramatically increases the stability of the disulfide linker system. This finding further indicates that the tumor-targeting drug conjugates with polysorbate 80/EtOH/saline formulation for in vivo studies would have high stability in blood plasma, while the drug release in cancer cells proceeds smoothly.

6.
Nano Lett ; 13(4): 1422-8, 2013 Apr 10.
Artículo en Inglés | MEDLINE | ID: mdl-23432577

RESUMEN

A 3D trenched-structure metal-insulator-metal (MIM) nanocapacitor array with an ultrahigh equivalent planar capacitance (EPC) of ~300 µF cm(-2) is demonstrated. Zinc oxide (ZnO) and aluminum oxide (Al2O3) bilayer dielectric is deposited on 1 µm high biomimetic silicon nanotip (SiNT) substrate using the atomic layer deposition method. The large EPC is achieved by utilizing the large surface area of the densely packed SiNT (!5 × 10(10) cm(-2)) coated conformally with an ultrahigh dielectric constant of ZnO. The EPC value is 30 times higher than those previously reported in metal-insulator-metal or metal-insulator-semiconductor nanocapacitors using similar porosity dimensions of the support materials.


Asunto(s)
Materiales Biomiméticos , Capacidad Eléctrica , Óxido de Zinc/química , Metales/química , Nanoestructuras/química , Tamaño de la Partícula , Porosidad , Silicio/química
7.
Phys Chem Chem Phys ; 14(11): 3837-42, 2012 Mar 21.
Artículo en Inglés | MEDLINE | ID: mdl-22327323

RESUMEN

In this paper, we have employed different shadow masks attached on top of organic photovoltaic (OPV) devices to study the optical effects of the former on the short circuit current (J(SC)). To rule out possible lateral electrical conduction and simplify the optical effects inside the device, a small-molecular heterojunction OPV device with a clear donor/acceptor interface was employed with a hole extraction layer exhibiting high resistance intentionally. Careful calibration with a shadow mask was employed. By attaching two layers of opaque masks in combination with a suitable holder design to shield the light from the edges and backside, the value of J(SC) approached that of the dark current, even under 1-sun radiation. With different illumination areas, we found that the photons illuminating the non-active region of the device contributed to 40% of the J(SC) by optical effect within the width of about 1 mm around the active region. When illuminating the non-active area with 12 mm to the active area, a 5.6 times improvement in the J(SC) was observed when the incident angle was 75°. With the introduction of a microstructured film onto the OPV device and an increase in the reflection from the non-active region, a 15% enhancement of the J(SC) compared to the control device was achieved.

8.
J Org Chem ; 76(15): 6240-9, 2011 Aug 05.
Artículo en Inglés | MEDLINE | ID: mdl-21671593

RESUMEN

Formal enantioselective total synthesis of schulzeines A-C was accomplished, featuring highly efficient Pd-catalyzed asymmetric allylic amination using novel diphosphonite ligands (BOPs) to provide 1-vinyltetrahydroisoquinoline key intermediates, as well as Ru-catalyzed ring-closing metathesis reaction to construct the key tricyclic cores in enantiopure form with correct absolute configurations.


Asunto(s)
Compuestos Alílicos/química , Compuestos Heterocíclicos con 3 Anillos/química , Compuestos Heterocíclicos con 3 Anillos/síntesis química , Lactamas/química , Lactamas/síntesis química , Paladio/química , Quinolizidinas/química , Quinolizidinas/síntesis química , Ésteres del Ácido Sulfúrico/química , Ésteres del Ácido Sulfúrico/síntesis química , Aminación , Catálisis , Ligandos , Estructura Molecular , Estereoisomerismo
9.
Int J Mol Sci ; 12(1): 476-505, 2011 Jan 17.
Artículo en Inglés | MEDLINE | ID: mdl-21339999

RESUMEN

This paper introduces the fundamental physical characteristics of organic photovoltaic (OPV) devices. Photoelectric conversion efficiency is crucial to the evaluation of quality in OPV devices, and enhancing efficiency has been spurring on researchers to seek alternatives to this problem. In this paper, we focus on organic photovoltaic (OPV) devices and review several approaches to enhance the energy conversion efficiency of small molecular heterojunction OPV devices based on an optimal metal-phthalocyanine/fullerene (C(60)) planar heterojunction thin film structure. For the sake of discussion, these mechanisms have been divided into electrical and optical sections: (1) Electrical: Modification on electrodes or active regions to benefit carrier injection, charge transport and exciton dissociation; (2) Optical: Optional architectures or infilling to promote photon confinement and enhance absorption.


Asunto(s)
Suministros de Energía Eléctrica , Fulerenos/química , Indoles/química , Electrodos , Isoindoles
10.
Bioinorg Chem Appl ; 2011: 173782, 2011.
Artículo en Inglés | MEDLINE | ID: mdl-22216015

RESUMEN

A split Hopkinson pressure bar is used to investigate the dynamic mechanical properties of biomedical 316L stainless steel under strain rates ranging from 1 × 10(3) s(-1) to 5 × 10(3) s(-1) and temperatures between 25°C and 800°C. The results indicate that the flow stress, work-hardening rate, strain rate sensitivity, and thermal activation energy are all significantly dependent on the strain, strain rate, and temperature. For a constant temperature, the flow stress, work-hardening rate, and strain rate sensitivity increase with increasing strain rate, while the thermal activation energy decreases. Catastrophic failure occurs only for the specimens deformed at a strain rate of 5 × 10(3) s(-1) and temperatures of 25°C or 200°C. Scanning electron microscopy observations show that the specimens fracture in a ductile shear mode. Optical microscopy analyses reveal that the number of slip bands within the grains increases with an increasing strain rate. Moreover, a dynamic recrystallisation of the deformed microstructure is observed in the specimens tested at the highest temperature of 800°C.

11.
ACS Omega ; 5(30): 18738-18745, 2020 Aug 04.
Artículo en Inglés | MEDLINE | ID: mdl-32775875

RESUMEN

Water scarcity is one of the most critical problems that humans have to face. Working toward solving this problem, we have developed a thin-film composite (TFC) membrane using the modified molecular layer-by-layer (modified mLBL) method to fabricate polyamide (PA) active layers on different substrates. Besides, it has been found that graphene oxide (GO) contains abundant functional groups such as hydroxyl and epoxide groups, which are able to improve both the physical and chemical properties of the forward osmosis (FO) membrane. Thus, we have employed graphene oxide (GO) as the substrate and used the modified mLBL method to prepare active polydopamine/graphene oxide (PDA/GO) layers to enhance the water flux of the forward osmosis (FO) membrane. PDA/GO-coated layers could enhance the hydrophilic nature of the substrate and lower its surface roughness, which would facilitate the formation of the PA layer. Moreover, the PDA/GO coating can be applied to all substrates because of the high degree of adhesion of PDA to different substrates. In this study, the highly hydrophilic poly(vinylidene fluoride) membrane is superior in FO properties, with a water flux of 17.32 LMH and a reverse solute flux of 4.34 gMH. In addition, an excellent performance of 60.15 LMH and 14.88 gMH can be achieved when the pressure-retarded osmosis (PRO) test mode with a draw solution concentration of 2.0 M is used in the test. It shows that the membrane prepared using the novel method showed excellent FO performance, which has high potential in industrial applications such as desalination.

12.
Health Policy ; 123(4): 379-387, 2019 04.
Artículo en Inglés | MEDLINE | ID: mdl-30772103

RESUMEN

The study attempts to investigate the features and determinants of the performance of Taiwanese Traditional Chinese Medicine (TCM) Clinics with data for 4905 TCM clinics over the 1998 to 2012 period. The empirical results from the fixed effects model and the Hausman-Taylor Model with cluster-robust standard errors reveal several interesting findings. First, consumer characteristics such as the frequency of disabling injuries has positive impacts on the volume of medical services provided by TCM clinics. These results imply that people are likely to select TCM as the option for medical treatment when they face the occurrence of physical injury in Taiwan. In addition, the scale measurements for TCM clinics including the numbers of physicians, medical personnel and divisions have significantly positive effects on the performance of TCM clinics, while their survival length also has the same effect. Finally, the global budget system under the NHI plays a key role in suppressing the revenue of TCM clinics through the peer review mechanism.


Asunto(s)
Instituciones de Atención Ambulatoria/estadística & datos numéricos , Medicina Tradicional China/estadística & datos numéricos , Personal de Salud/estadística & datos numéricos , Humanos , Programas Nacionales de Salud/estadística & datos numéricos , Médicos/estadística & datos numéricos , Taiwán , Heridas y Lesiones/terapia
13.
ACS Appl Mater Interfaces ; 11(8): 8337-8349, 2019 Feb 27.
Artículo en Inglés | MEDLINE | ID: mdl-30714358

RESUMEN

Four new donor-acceptor-acceptor (D-A-A) type molecules (DTCPB, DTCTB, DTCPBO, and DTCTBO), wherein benzothiadiazole or benzoxadiazole serves as the central A bridging triarylamine (D) and cyano group (terminal A), have been synthesized and characterized. The intramolecular charge-transfer character renders these molecules with strong visible light absorption and forms antiparallel dimeric crystal packing with evident π-π intermolecular interactions. The characteristics of the vacuum-processed photovoltaic device with a bulk heterojunction active layer employing these molecules as electronic donors combining C70 as electronic acceptor were examined and a clear structure-property-performance relationship was concluded. Among them, the DTCPB-based device delivers the best power conversion efficiency (PCE) up to 6.55% under AM 1.5 G irradiation. The study of PCE dependence on the light intensity indicates the DTCPB-based device exhibits superior exciton dissociation and less propensity of geminated recombination, which was further verified by a steady photoluminescence study. The DTCPB-based device was further optimized to give an improved PCE up to 6.96% with relatively high stability under AM 1.5 G continuous light-soaking for 150 h. This device can also perform a PCE close to 16% under a TLD-840 fluorescent lamp (800 lux), indicating its promising prospect for indoor photovoltaic application.

14.
Sci Rep ; 9(1): 3654, 2019 Mar 06.
Artículo en Inglés | MEDLINE | ID: mdl-30842539

RESUMEN

In this study, we demonstrated a blue phosphorescent organic light-emitting diode (BPOLED) based on a host with two carbazole and one trizole (2CbzTAZ) moiety, 9,9'-(2-(4,5-diphenyl-4H-1,2,4-triazol-3-yl)-1,3-phenylene)bis(9H-carbazole), that exhibits bipolar transport characteristics. Compared with the devices with a carbazole host (N,N'-dicarbazolyl-3,5-benzene, (mCP)), triazole host (3-(biphenyl-4-yl)-5-(4-tert-butylphenyl)-4-phenyl-4H-1,2,4-triazole, (TAZ)), or a physical mixture of mCP:TAZ, which exhibit hole, electron, and bipolar transport characteristics, respectively, the BPOLED with the bipolar 2CbzTAZ host exhibited the lowest driving voltage (6.55 V at 10 mA/cm2), the highest efficiencies (maximum current efficiency of 52.25 cd/A and external quantum efficiency of 23.89%), and the lowest efficiency roll-off, when doped with bis[2-(4,6-difluorophenyl)pyridinato-C2,N](picolinato)iridium(III) (FIrpic) as blue phosphor. From analyses of light leakage of the emission spectra of electroluminescence, transient electroluminescence, and partially doped OLEDs, it was found that the recombination zone was well confined inside the emitting layer and the recombination rate was most efficient in a 2CbzTAZ-based OLED. For the other cases using mCP, TAZ, and mCP:TAZ as hosts, electrons and holes transported with different routes that resulted in carrier accumulation on different organic molecules and lowered the recombination rate.

15.
ACS Appl Mater Interfaces ; 10(49): 42723-42732, 2018 Dec 12.
Artículo en Inglés | MEDLINE | ID: mdl-30360065

RESUMEN

Four isomers of carbazol-9-yl-substituted 1,2-diphenylbenzimidazole at 7, 6, 5, and 4 positions, named as 1-CbzBiz, 2-CbzBiz, 3-CbzBiz, and 4-CbzBiz, respectively, have been synthesized. Instead of having an identical molecular weight, the CbzBiz's have their glass transition temperatures ( Tg) spanning a large range from 53 to 90 °C. Their Tg and melting point ( Tm) basically obey the Boyer-Kauzmann rule ( Tg = g· Tm with g ≈ 0.7) on the absolute temperature scale (in kelvins). However, while 1-CbzBiz and 4-CbzBiz demonstrate a small g value of 0.66, which is significantly smaller than other common organic glass molecules, 3-CbzBiz shows an unexpectedly high g value of 0.73, implying higher intermolecular interactions in the glass. These CbzBiz's are suitable hosts for bis[2-(4,6-difluorophenyl)pyridinato- C2, N](picolinato)iridium(III) (FIrpic) in phosphorescence organic light-emitting diodes (PhOLEDs). The optimized PhOLED of indium tin oxide/4,4'-cyclohexylidenebis[ N, N-bis(4-methylphenyl)benzenamine]/4Cbz/4-CbzBiz-FIrpic(15%)/diphenylbis(4-(pyridin-3-yl)phenyl)silane/LiF-Al shows a maximum brightness of 18 760 cd/m2, a current efficiency of 64.1 cd/A, and the external quantum efficiency of 30.9%.

16.
Adv Mater ; 30(50): e1804850, 2018 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-30368942

RESUMEN

Solid-state triplet-triplet annihilation upconversion (TTAUC) blue emission in an electroluminescence device (i.e., an organic light-emitting diode (OLED)) is demonstrated. A conventional green fluorophore, tris-(8-hydroxyquinoline)aluminum (Alq3 ), is employed as the sensitizer that generates 75% triplet under electrical pumping for the blue triplet-triplet annihilation emitter, 9,10-bis(2'-naphthyl) anthracene (ADN), with the heterojunction bilayer structure. The operation lifetime is elongated both for ADN blue (4.1x) and Alq3 green (34.8%) emission due to efficient use of excitons and separation of recombination and emission zone. To reduce the singlet quenching (SQ) of blue TTAUC signal by the Alq3 sensitizer with lower bandgap, 1-(2,5-dimethyl-4-(1-pyrenyl)phenyl)pyrene (DMPPP) is inserted between the Alq3 and ADN as a triplet-diffusion-and-singlet-blocking layer. DMPPP exhibits triplet energy close to Alq3 and higher than ADN, as well as higher singlet energy than both Alq3 and ADN. It allows triplet diffusion from Alq3 to ADN, but blocks the SQ of the blue TTAUC signal by Alq3 . 86.1% intrinsic efficiency of TTAUC is demonstrated in this trilayer (Alq3 /DMPPP/ADN) OLED.

17.
ACS Appl Mater Interfaces ; 10(50): 43842-43849, 2018 Dec 19.
Artículo en Inglés | MEDLINE | ID: mdl-30484304

RESUMEN

The inclusion of a tetraphenylbenzene (4Ph) unit in thermally activated delayed fluorescence emitters is demonstrated as a novel strategy for greatly enhancing the horizontally oriented alignment of the emitters without shifting the emission spectrum to longer wavelengths. Doping of blue-emitting 4PhOXDDMAC or greenish-blue-emitting 4PhOXDPXZ into o-DiCbzBz host layers yielded much higher degrees of horizontally oriented alignment for the emitter (up to 92%) compared to those when the 4Ph unit was excluded (69 and 75%, respectively). The enhanced alignment results in high outcoupling efficiencies of 24 and 35% in organic light-emitting diodes based on 4PhOXDDMAC and 4PhOXDPXZ, respectively, and boosts the external quantum efficiencies to values (8.8 and 29.2%, respectively) that are higher than what would be expected for randomly oriented emitters (outcoupling efficiency of 20%). These enhancements are achieved while avoiding the redshift that often occurs using the common strategy of increasing molecular length and, thereby, conjugation, to increase orientation.

18.
Org Lett ; 9(2): 235-8, 2007 Jan 18.
Artículo en Inglés | MEDLINE | ID: mdl-17217273

RESUMEN

The fluorescence and phosphorescence of 2,2'-bis(5-phenyl-1,3,4-oxadiazol-2-yl)biphenyl shows good spectral matching with the absorption spectra of the MLCT1 and MLCT3 transitions of Ir(ppy)3. The red-shift of the 0-0 band in the phosphorescence at 77 K is due to the intramolecular pi-pi interactions between the oxadiazole side chains. Maximum brightness of 43,000 cd/m2 with an efficiency of 26 cd/A at 200 cd/m2 was achieved when BOBP was used as the host material for Ir(ppy)3 in the PHOLED study. [structure: see text].


Asunto(s)
Compuestos de Bifenilo/química , Sustancias Luminiscentes/química , Compuestos Orgánicos/química , Oxadiazoles/química , Compuestos de Bifenilo/síntesis química , Cristalografía por Rayos X , Electroquímica , Electrones , Iluminación , Modelos Moleculares , Estructura Molecular , Oxadiazoles/síntesis química , Fotoquímica , Estereoisomerismo
19.
J Colloid Interface Sci ; 308(1): 222-30, 2007 Apr 01.
Artículo en Inglés | MEDLINE | ID: mdl-17234203

RESUMEN

An experimental study was carried out to determine the minimum wet thickness of slot die coating for low-viscosity solutions. There exist three distinct coating regions (I, II, and III), depending on the physical properties of the coating fluid, die geometry, and flow conditions. A critical Reynolds number was found, below which viscous and surface tension effects are important. In Region I, the minimum wet thickness increases with increasing capillary number and becomes independent of capillary number in Region II. Region III exists above the critical Reynolds number where fluid inertia is dominant. In this region, the minimum wet thickness decreases as Reynolds number increases. Flow visualization on the coating bead reveals that the position of the downstream meniscus of the coating bead determines the types of coating region, whereas the shape and position of the upstream meniscus determine the type of coating defects. It was also observed that the downstream meniscus was not located at the die lip corner and both the static and dynamic contact angles varied under different conditions. These findings are critical for realistic theoretical study of slot die coating.

20.
ACS Appl Mater Interfaces ; 9(12): 10963-10970, 2017 Mar 29.
Artículo en Inglés | MEDLINE | ID: mdl-28274116

RESUMEN

A new concept for organic light-emitting diodes (OLEDs) is presented, which is called exciplex-sensitized triplet-triplet annihilation (ESTTA). The exciplex formed at the organic heterojunction interface of 4,4',4″-tris(N-3-methyphenyl-N-phenyl-amino) triphenylamine and 9,10-bis(2'-naphthyl) anthracene (ADN) is used to sensitize the triplet-triplet annihilation (TTA) process on the ADN molecules. This results in a turn-on voltage (2.2 V) of the blue emission from the OLED below the bandgap (2.9 eV). From the transient electroluminescence measurement, blue emission totally came from the TTA process without direct recombination on the ADN molecules. The blue singlet exciton from the TTA process can be quenched by energy transfer to the exciplex, as revealed by transient photoluminescence measurements. This can be prevented by blocking the energy transfer path and improving the radiative recombination rate of blue emission. With the insertion of the "triplet diffusion and singlet blocking (TDSB)" layer and the incorporation of the dopant material, an ESTTA-OLED with external quantum efficiency of 5.1% was achieved, which consists of yellow and blue emission coming from the exciplex and ESTTA process, respectively.

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