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A high-efficiency blue phosphorescence organic light-emitting diode (OLED) with a new ambipolar organic compound, 9-(2-(4,5-diphenyl-4H-1,2,4-triazol-3-yl)phenyl)-9H-carbazole (CbzTAZ) as the host, structurally engineered the emitting layer (EML) and electron-transporting layer (ETL) to achieve the great carrier balance in the EML. The chemical structure of CbzTAZ contains an electron-transporting 1,2,4-triazole segment and a hole-transporting carbazole ring. By scanning the composite ratio between the CbzTAZ host and the blue emitter iridium(III)bis[4,6-(di-fluorophenyl)-pyridinato-N,C2′]picolinate to be an efficient EML, and then by fine-tuning the layer thicknesses of the ETL and EML, a highly efficient blue PhOLED was obtained because of the improved electron-hole balance and broad recombination zone coverage in the EML. The blue PhOLED exhibited a maximum current efficiency $(\eta _{C})$ of 48 cd/A, a power efficiency $(\eta _{P})$ of 42.2 lm/W, and an external quantum efficiency $(\eta _{{\rm EQE}})$ of 22.9%. In addition, the device demonstrated a satisfactory efficiency roll-off (ηC of 41.1 cd/A, $\eta _{P}$ of 18.1 lm/W, and $\eta _{{\rm EQE}}$ of 19.8%) at a high brightness value of 1000 cd/m2.

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...

Application of poly(Nʹ, Nʺ, N‴-tris[N, N-bis-(4ʹ-diphenylamino-biphenyl-4-yl)phenyl]-1, 3, 5-benzene tricarboxamide) (PG1), a triphenylamine dendritic polymer, in an complementary electrochromic device (ECD) has been studied. Electrochromic transitions of PG1 itself give very significant transmittance change (∆T) of 58.4% at 485 nm and 81.8% at 780 nm with rather good cycling stability. A complementary ECD based on the PG1 thin film and poly(3,4-ethylenedioxythiophene) (PEDOT) thin film was assembled to demonstrate panchromatic absorption characteristic through a simple fabrication process. This ECD exhibits black-to-transmissive electrochromism when switched from −0.4 to 1.5 V. Large variation in L* value in CIE L*a*b* coordinate (45.6) and ∆T (55.5% at 510 nm) is observed. In fact, the ∆T value achieved in this work is comparable to the highest value (58%) among all reported triphenylamine derivative/PEDOT ECDs after an extensive literature search. Furthermore, good cycling stability is achieved in the proposed ECD, which still retained panchromatic absorption characteristic and maintained 91.7% of the initial ∆T value at 510 nm after continuous 10,000 switchings.

An ambipolar material with a high triplet energy of 3.1 eV, 9-(2-(4,5-diphenyl-4H-1,2,4-triazol-3-yl)phenyl)-9H-carbazole (CbzTAZ), was synthesized by conjugating an electron-transporting 1,2,4-triazole and a hole-transporting carbazole and employed as the host doping with blue emitter iridium(III)bis[4,6-(difluorophenyl)-pyridinato-N,C2′]picolinate (FIrpic) to be the emitting layer (EML) of an efficient blue phosphorescent organic light-emitting diode (PhOLED). By adjusting the ratio between CbzTAZ and FIrpic, an efficient OLED performance with a current efficiency (ηC) of 50 cd/A and an external quantum efficiency (ηEQE) of 23.8% can be obtained. The position of the recombination zone located inside the EML close to the electron-transporting layer (ETL) can be detected by partially doping FIrpic in one of the three EML regions. By fine-tuning the thickness of the ETL to balance electrons and holes in the EML, a highly efficient blue PhOLED with a maximum ηC of 52.1 cd/A, a maximum power efficiency of 46...

Blue phosphorescent organic light-emitting diodes (PhOLEDs) was successfully fabricated by using newly imidazole-based host doped with bis [2-(4’,6’-difluoro)phenylpyridinato- N,C2’]iridium(III) picolinate with 57.24 cd/A, 50.42 lm/W and 25.67 % in external quantum efficiency.

Hole-transporting photocurable blends of (4-(AcOCH2)C6H4)3N (1) or ((4-(AcOCH2)C6H4)2NC6H4)2 (2), poly(fluorene-co-triphenylamine)s (PFTs) and diphenyliodonium 9,10-dimethoxyanthracene-2-sulfonate (DIAS, a photoacid generator (PAG)) have been successfully formulated. Under UV irradiation (λ > 200 nm), PAG decomposes to release protons that catalyze the heterolytic decomposition of 1 and 2 to give benzylic cation intermediates. Friedel–Crafts type electrophilic aromatic substitution would then occur at the triphenylamine (TPA) units of PFT, leading to a photo-curing phenomenon. The curing efficiency is therefore highly dependent on the content of TPA in the PFT. This approach can be implemented to PLED applications. Under the optimized conditions, the polymeric light-emitting device of ITO/photo-cross-linkable HTL/PVK-Ir(ppy)3-t-PBD/Mg–Ag, with a turn-on voltage of 9.4 V (1 cd/m2), a maximum brightness of 7630 cd/m2, and a current efficiency of 15.8 cd/A was achieved. The lifetime of the device has also been improved by 1.8 times when compared with that of the STD device.

DTAB-PVKs are prepared by post-functionalization of poly(N-vinylcarbazole) (PVK) with di(4-tolyl)aminobenzyl acetate (DTABOAc) as the pendant groups via the Friedel–Crafts reaction. Introduction of the methyl substituents at the para-position of DTABOAc is essential for suppression of its self-condensation. The details of the reactions mechanisms are elucidated by 1H NMR study. The Fermi level of DTAB-PVKs could be tuned by controlling the amounts of DTABOAc content in the polymer and DTAB-PVKs are found to be good hosts for phosphorescent polymer light-emitting diodes (PLEDs). In a device of PLED comprising PEDOT: PSS/DTAB-PVK-Ir(ppy)3-PBD/Mg–Ag, low turn on voltage at 6.5 V is found with a reasonably high current efficiency of 11.5 cd/A at 13.0 V. The power efficiency reaches 2.7 lm/W at 12.0 V. More importantly, the device performance related to the Fermi level of DTAB-PVKs.

A series of two-dimensional donor–acceptor–donor (D1–A(D2)) type of conducting polymers (CPs) all with electroactive bulky side chain structure has been designed, synthesized, and investigated by introducing the donor–acceptor (D1–A) thiophene–quinoxaline moiety in the main chain alongside and additional donor and hole transporting units in the side chain. All the UV-vis spectra of the 2D polymers, PTPQT, PFPQT, and PCPQT, each with triphenylamine, fluorene, and carbazole units as the D2 side chain, possess strong intramolecular charge transfer absorption, thus resulting in better light harvesting. Their optical and electronic properties were thoroughly explored experimentally and computationally. The effect of molecular weight of the narrow polydispersity polymers on their optoelectronic property was studied in detail. In summary, the 2-D CPs show potential for use as an active material in optoelectronic devices. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014, 52, 1217–1227

Novel dendritic triphenylamine substituted fullerene as a rigid scaffold for electropolymerization have been prepared through cycloaddition reactions. Oxidative electrochemical polymerization of the dendritic molecules leads to thick freestanding fullerene/polytriphenylamine composite films. Due to their porous properties that allow n-Bu 4 NBF 4 and n-Bu 4 NClO 4 migrating in and out of the electrochemical deposition (ECD) layers, the films are highly electrochemically active with amphoteric properties. However, the fullerene reduction can be swept out and become silent after a high reduction potential of -2.4 V being applied to the film. If one considers the status before being treated by a high reduction potential as “1” that could be read out by the fullerene reduction currents, and the status after being treated as “0”, in which the reduction current is silent, information of “1” or “0” could then be written on the plate through electrochemistry. Since the channel of anodic oxidation of the polytriphenylamine component still maintains electrochemically active after the reduction shock, the anodic oxidation current can be used as reference for alignment.

Two novel bipolar carbzol-triazole derivatives was synthesized by conjugating hole transporting moiety carbazole (Cbz) with electron transporting moiety triazole (TAZ) to achieve the bipolar molecules, which were employed as the hosts of emitting layer doped with blue emitter FIrpic inside blue phosphorescence OLEDs with high current efficiency of 50 and 50.6 cd/A, and EQE of 20% and 21.6%.

Ambipolar triplet hosts comprising 1,2,4-triazole and carbazole in ortho-positions have been developed. The blue PHOLED has a high current efficiency of 47.1 cd A(-1), power efficiency of 41.2 lm W(-1), and low efficiency roll-off. The high efficiency was attributed to the successful control of π-conjugation through orthogonal arrangement of the substituents so that a wide T1-S0 gap could be maintained.

A new multifunctional blue-emitting terfluorene derivative ( TFDPA ) featured with triphenylamine groups for hole-transportation and long alkyl chains for solution processability on the conjugation inert bridge centers was reported. TFDPA can give homogeneous thin film by solution process and exhibits high hole mobility ( μ h ≈ 10 −3 cm 2 V −1 s −1 ) and suitable HOMO for hole injection. Particularly, TFDPA performs efficient deep-blue emission with high quantum yield (∼100% in solution, 43% in thin film) and suitable triplet energy ( E T = 2.28 eV), making solution-processed OLED devices of using TFDPA as blue emitter and as host for iridium-containing phosphorescent dopants feasible. The solution-processed nondoped blue OLED device gives saturated deep-blue electroluminescence [CIE = (0.17, 0.07)] with EQE of 2.7%. TFDPA -hosted electrophosphorescent devices performed with EQE of 6.5% for yellow [(Bt) 2 Ir(acac)], 9.3% of orange [Ir(2–phq) 3 ], and 6.9% of red [(Mpq) 2 Ir(acac)], respectively. In addition, with careful control on the doping concentration of [(Bt) 2 Ir(acac)], a solution-processed fluorescence–phosphorescence hybrided two-color-based WOLED with EQE of 3.6% and CIE coordinate of (0.38, 0.33) was successfully achieved.

In this research, two styrene-derivative monomers based on bicarbazole and carbazole-bithiophene-carbazole (StCz2 and StCzT2Cz) were prepared and further free-radical polymerized (PStCz2 and PStCzT2Cz) to form graft π-conjugated polymers. The thermal, optical, and electrochemical properties of these studied monomers and polymers were fully characterized for studying the relationships of the structures to the properties. The field-effect characteristics of the polymers were also studied, a highest hole mobility on the order of 1.1 × 10−3 cm2V−1s−1 was obtained with PStCzT2Cz. The morphology of the polymeric active layers was also investigated with X-ray diffraction and atomic force microscopy to realize the relationships of the structures to the electric characteristics.

In this report, we demonstrated a series of blue phosphorescent organic light-emitting diodes (OLED) using the mixed host as the partial emitting layer to achieve ultrahigh external quantum efficiency over 30%. The blue phosphorescent emitter was FIrpic and these host materials was developed by Professor Leung in Department of Chemistry, National Taiwan University. By well optimizing the doping ratio among hosts and FIrpic, and designing the device structure to balance carrier in the emitting layer, a ultrahigh efficiency blue OLED could be obtained with external quantum efficiency over 30%.

The two novel benzimidazole/carbazole hybrid ambipolar molecules, o-CbzDiBz and m-CbzDiBz, were synthesized as hosts for blue PHOLEDs. Bis[2-(4,6-diiluorophenyl)pyridinato-C2,N](picolinato)iridium(III) (FIrpic)-based devices can achieve 41.86 and 49.31 cd/A of current efficiency in o-CbzDiBz and m-CbzDiBz matrix, respectively.

We demonstrated a blue phosphorescent organic light-emitting diode with the maximum current efficiency and power efficiency of 57.4 cd/A and 51.6 lm/W, respectively, based on trizaole derivatives as the host of the emitting layer.

We reported a blue phosphorescent organic light-emitting diode (OLED) with the highest current efficiency of 55.2 cd/A, power efficiency of 50.5 lm/W and external quantum efficiency (EQE) of 24.8%, by using a tetraphenylsilane host in the emitting layer doped with blue emitter, bis[2-(4,6-difluorophenyl)pyridinato-C2,N](picolinato)iridium(in) (FIrpic).

A new organic host material, PCT comprising pyridine, carbazole and triazole moieties, was doped with a blue emitter bis[2-(4,6"difluorophenyl)pyridinato-C2,N](pico]inato)iridium(III) (FIrpic) to be an emitting layer (EML) of a phosphorescent organic light-emitting diodes device (PhOLED). With various FIrpic concentration (12%, 15% and 18% by volume ratio) in the EML, a series of high efficiency blue PhOLED was demonstrated showing the external quantum efficiency over 20%.

Background Intradermal (ID) injection is an alternative route for influenza vaccine administration in elderly with potential improvement of vaccine coverage. This study aimed to investigate the cost-effectiveness of an influenza vaccination program offering ID vaccine to elderly who had declined intramuscular (IM) vaccine from the perspective of Hong Kong public healthcare provider. Methods A decision analytic model was used to simulate outcomes of two programs: IM vaccine alone (IM program), and IM or ID vaccine (IM/ID program) in a hypothetic cohort of elderly aged 65 years. Outcome measures included influenza-related direct medical cost, infection rate, mortality rate, quality-adjusted life years (QALYs) loss, and incremental cost per QALY saved (ICER). Model inputs were derived from literature. Sensitivity analyses evaluated the impact of uncertainty of model variables. Results In base-case analysis, the IM/ID program was more costly (USD52.82 versus USD47.59 per individual to whom vaccine was offered) with lower influenza infection rate (8.71% versus 9.65%), mortality rate (0.021% versus 0.024%) and QALYs loss (0.00336 versus 0.00372) than the IM program. ICER of IM/ID program was USD14,528 per QALY saved. One-way sensitivity analysis found ICER of IM/ID program to exceed willingness-to-pay threshold (USD39,933) when probability of influenza infection in unvaccinated elderly decreased from 10.6% to 5.4%. In 10,000 Monte Carlo simulations of elderly populations of Hong Kong, the IM/ID program was the preferred option in 94.7% of time. Conclusions An influenza vaccination program offering ID vaccine to elderly who had declined IM vaccine appears to be a highly cost-effective option.

The soluble styrene polymers, bearing dicarbazole, phenylcarbazole or phenyltriphenylamine side groups were investigated as a host material for green emitter in phosphorescent PLED devices. Those polymers were synthesized by free radical polymerization via azobisisobutyronitrile (AIBN) as initiator under 75 °C. All of the host materials exhibit high thermal stability with high decomposition ( T d,5% weight loss > 398 °C) and glass transition temperatures ( T g > 172 °C). The HOMO ( ca. −5.39 ‒ −5.69 eV) and LUMO ( ca. −2.22 ‒ −2.41 eV) levels with the triplet energy of ca. 2.50–2.93 eV suggest that polymers are suitable for host materials for green emitter. The devices based on the emissive layers containing host materials doped with Ir(ppy) 3 (4 wt%) display stable green emission with high device performances. The brightness and current efficiency reach 15,800 cd/m 2 and 17.5 cd/A, respectively, at the optimum blending with 40 wt% 2-(4-biphenyl)-5-(4- tert -butylphenyl)-1,3,4-oxadiazol ( t- PBD). Furthermore, the device performance reached higher brightness (23,400 cd/m 2 ) and current efficiency (12.3 cd/A) when mixture with 2,4,6-triphenyl-1,3,5-triazine (TRZ) and t- PBD.

The study of the electrochemical fluorescence switching properties of the conjugated copolymers containing fluorene, triphenylamine, and 1,3-diphenylimidazolidin-2-one moieties is reported. The polymers show high fluorescence quantum yields, excellent thermal stability, and good solubility in polar organic solvents. While the polymer emits blue light under UV irradiation, the fluorescence intensity is quenched upon electrochemical oxidation. The fluorescent behavior can be reversibly switched between nonfluorescent (oxidized) state and strong fluorescence (neutral) state with a high contrast ratio (If/If0) of 16.3. The role of the electrochemical oxidation of the triphenylamine moieties is to generate the corresponding radical cations that lead to fluorescence quenching in the solid matrix. © 2012 Wiley Periodicals, Inc. J. Polym. Sci. Part A: Polym Chem, 2012

Novel hole-transporting polyurethane, denoted as P1 , resulting from the condensation of 9, 9-bis(4-hydroxyphenyl)fluorene and isophorone diisocyanate (denoted as IPDI) has been developed. When P1 is thermally consolidated in the presence of 2-(phosphonooxy)ethyl methacrylate ( P2M ), it forms a distinguished hole-transport layer that leads to an extremely good performance of the phosphorescent PLED. In the study, the device of ITO/PEDOT: PSS/ P1 - P2M /Ir(ppy) 3 - t -PBD-PVK/Mg/Ag shows a high current efficiency of 27.6 cd/A and a low turn-on voltage of 6 V. In particular, the stable output efficiency of 17–22 cd/A within the range of 420–4400 cd/m 2 at 12–20 V makes P1 a promising hole-transport material for phosphorescent PLED applications.

A series of novel oxygen-linked N-phenylcarbazole (NPC) dendritic wedges (3–5) and triphenylamine-centered dendrimers (CBD-G0 to -G2) have been synthesized and extensively studied. The aryl–oxygen–aryl (Ar–O–Ar) linkages were established on 3,6-positions of carbazole and 4-position of N-phenyl group. UV–vis spectra revealed that the Ar–O–Ar linkage would break down the π conjugation and make NPC units manifest their individual absorption moiety. Both steady-state luminescence and fluorescence decay dynamics at room temperature and 77 K in tetrahydrofuran suggested that the transfer of energy from the carbazole wedges to the triphenylamine (TPA) core operates in CBD-G1, so that the luminescence mainly arises from the core unit. The quenching of the emission from carbazole wedges by the TPA core becomes less effective as the generation develops into CBD-G2. The oxidation potential of the NPC derivatives clearly revealed the mesomeric electron-donating effect of the oxygen atom and inductive electron-withdra...

A photolithographic hole transport material of 4,4′,4″-tris(acetoxymethylene)triphenylamine (1), polyvinylcarbazole (PVK), and diphenyliodonium 9,10-dimethoxyanthracene-2-sulfonate (DIAS, a photoacid generator) has been successfully formulated. After exposure to UV irradiation (λ > 200 nm) through a patterned UV (λ >200 nm) photomask for 6 min, followed by a standard postbaking treatment at 130 °C for 5 min under vacuum and development in CH2Cl2, a negative tone image was established through the photoinduced chemical cross-linking reactions. This approach can be implemented to PLED applications. Under the optimized conditions, the polymeric light-emitting device (PLED) of ITO/photolithographic HTL/PVK–Ir(PPy)3–PBD/Mg–Ag, with a turn-on voltage of 13.0 V (100 cd/m2), a maximum brightness of 8220 cd/m2, and a current efficiency of 9.0 cd/A was achieved. Our study reviewed that three parallel mechanisms, including the photodimerization of the carbazole units, the Crivello onium salt sensitization mechanism, ...

A new class of triphenylamine substituted methanofullerene derivatives, bis(4'-(diphenylamino)biphenyl-4-yl)methanofullerene (1) and the bisadduct (2), were synthesized. The incident photon to current efficiency (IPCE) studies revealed that the diphenylamino components have contribution to the photocurrent that expands the light harvesting window around 400 nm. When being blended with poly (3-hexylthiophene) (P3HT) to fabricate the solar cell, the device of P3HT:1 (1:0.7) shows high open circuit voltage (Voc) of 0.69 V under the illumination of AM 1.5, 100 mW/cm2 with high power conversion efficiency (PCE) of 3.16%, which is about 0.1 V higher than that of the corresponding [6,6]-phenyl C61 butyric acid methyl ester (PCBM) devices. This indicates that the arylamine substituents on 1 have played some special roles on the high Voc performance. Similar effects are also observed for 2. The device of P3HT:2 (1:1) shows even higher Voc of 0.87 V with the PCE of 1.83%. These results indicate that 1 and 2 are alternative high performance acceptors.

Two novel conjugated polymers denoted TAZF2 and TAZBTF, having electron-deficient main chains and electron-rich triphenylamine pendant groups, were designed and synthesized. While TAZF2 was constructed with fluorene and electron-deficient 1,2,4-triazole as the major components of the main chain, fluorene, 1,2,4-triazole, and 2,1,3-benzothiadiazole were employed to form TAZBTF. The number-average molecular weights (Mw) of the polymers fell in the range of 1.28 × 104–2.56 × 104 with polydispersity indexes (PDI = Mw/Mn) of 1.49–1.95. The polymers had glass transition temperatures (Tg) in the range of 153–185 °C. While TAZF2 exhibited blue photoluminescence, TAZBTF exhibited yellow–green emission. Thermal stability of the conjugated polymers was enhanced due to the introduction of rigid bipolar components. The incorporation of 2,1,3-benzothiadiazole into TAZBTF reduced the coplanarity of the conjugated polymer, which prohibited the polymer from aggregation. Intramolecular and intermolecular energy transfer was clearly evidenced by the shift in light emission to the yellow–green region. TAZBTF exhibited maximum electroluminescence efficiency as high as 2.60 cd/A, demonstrating that a good balance of charge carriers is injected into our devices.

In this paper, we investigated the effects of dopants on the electrical and optical characteristics of dichromatic and white organic light-emitting devices (OLEDs) with a double emitting layer (DEML). Such a DEML consisted of two host materials with bipolar transport characteristics doped with two distinct types of phosphorescent emitters. The host for EML1 (adjacent to the anode side) was N,N-dicarbazolyl-3,5-benzene (mCP), with a hole mobility higher than the electron mobility, whereas the host for EML2 (adjacent to the cathode side) was 2,2′-bis[5-phenyl-2-(1,3,4)oxadazolyl]biphenyl (OXD), with a higher electron mobility than the hole mobility. Phosphorescent blue emitters, 9% iridium(III)bis[4,6-di-fluorophenyl-pyridinato-N,C2]picolinate (FIrpic), and phosphorescent green emitters, 9% fac-tris(phenylpyridine) iridium [Ir(ppy)3], were doped into EML1 and EML2, respectively for dichromatic emission. In the dichromatic blue/green OLEDs, both the blue and green dopants helped to reduce the driving voltage. The dopants essentially played the role of carrier traps and recombination centers, from which the current density–voltage characteristics and electroluminescence (EL) spectra were derived. In this structure, EML1 and EML2 exhibited hole- and electron-rich bipolar transporting characteristics, respectively. Hence, the recombination was extended to the two EMLs, which reduced the efficiency roll-off and resulted in high efficiency levels even at high luminance levels. Through further incorporation of 0.5% of tris(2-phenylquinoline)iridium(III) [Ir(2-phq)3] into EML1, a white OLED with maximum current efficiency of 35.8 cd/A and quantum efficiency of 10.73% at 0.643 mA/cm2 was obtained. In this white OLED, the current efficiency decreased slightly by 2.51% from 35.8 cd/A at 230 cd/m2 to 34.9 cd/A at 1000 cd/m2. Carrier confinement was achieved at the D-EML interface, which not only contributed to the high current efficiency, but also resulted in stable color coordinates that varied a mere (−0.014, 0.004) from 100 to 10,000 cd/m2, without additional blocking layers between the two EMLs.

6,6′-Bis(triphenylamine)-1,1′-binaphthyl-2,2′-diol (1) is highly fluorescent in visible region. On treatment with a variety of anions, the UV–vis absorption as well as the fluorescent behavior of 1 in CH2Cl2 is substantially changed. Among the tetrabutylammonium (TBA) salts we tested, including F−, OH− (from TBAOH in MeOH), Cl−, Br−, I−, OAc−, HSO4−, TsO− (Et4N salt), and H2PO4−, F− was found to be the most effective fluorescence quencher. Quantitative fluorescence analysis of the titration data revealed that the anions are classified into two categories: (1) Simple mono-anions, such as F− ( log β 2 F = 11.00 ± 0.08 ) , OH− ( log β 2 OH = 9.05 ± 0.01 ) , and Cl− ( log β 2 = 9.96 ± 0.70 ) that follow the stoichiometry of 1:2, indicating the formation of (1·X2)2− complexes; (2) Oxo-anions, such as OAc− ( log β 1 OAc = 5.13 ± 0.012 ) , H2PO−4 ( log β 1 HP = 4.87 ± 0.03 ) , and TsO− (using tetraethylammonium salt, ( log β 1 OTs = 3.36 ± 0.02 ) that show the stoichiometry of 1:1, indicating the formation of (1·X)− complexes. The complexation behaviors were further confirmed by 1H NMR spectroscopy. In the co-crystal prepared from 1,1-binaphthyl-2,2′-diol (BINOL) and Et4NF, F− and BINOL are assembled to form a linear polymeric array, with a dimeric group of BINOL/BINOL anions linked as the side-chains. Intramolecular hydrogen bond was observed within the BINOL anion. This provides structural insights about the BINOL–fluoride complex formation.

A novel carbazole-triazole derivative was used as a bipolar host of a phosphorescent blue organic light-emitting diode doped with bis[2-(4,6-difluorophenyl)pyridinato-C2,N](picolmato)iridmm(III) (FIrpic). Maximum current efficiency, power efficiency, and external quantum efficiency of this blue phosphorescent OLED reached 50.30 cd/A and 25.03%, respectively. Efficiency roll-off was alleviated due to the wide recombination zone, and current efficiency slightly reduced to 46.67 cd/A at 1000 cd/m2.

Through the Stille coupling polymerization, a series of soluble acceptor/donor quinoxaline/thiophene alternating conducting polymers with a hole-transporting moiety of carbazole as a side chain (PCPQT) has been designed, synthesized, and investigated. The UV-vis measurement of the charge-transferred type PCPQTs of different molecular weights with low polydispersity exhibits a red shifting of their absorption maximum from 530 to 630 nm with increasing chain length (M n : from 1100 to 19,200). The HOMO and LUMO energy levels of PCPQT can be determined from the cyclic voltammetry measurement to be -5.36 and -3.59 eV, respectively. Solar cells made from PCPQT/PCBM bulk heterojunction show a high open-circuit voltage, V oc of ∼0.75 V, which is significantly higher than that of a solar cell made from conventional poly(3-hexyl thiophene)/PCBM as the active polymer PCPQT has lower HOMO level. Further improvements are anticipated through a rational design of the new low band-gap and the structurally two-dimensional donor-acceptor conducting polymers.

The morphology of the thin films obtained from electrochemical deposition of poly(4-vinyltriphenylamine)s (PVTPAs) on ITO surface varies as their molecular weight increases. The SEM studies revealed that while uniform coating could be obtained from low molecular weight PVTPAs (approximately 2700), uneven and rough coating with numerous cracks on the surface would be formed from high molecular weight PVTPAs. These defects could be reduced by using our surface modification strategy, in which the ITO surface was first primed with a thin layer of electrochemical coating of poly(methylenetriphenylamine) (PMTPA). This coating would turn the highly polar ITO surface into a nonpolar conducting surface that benefits for the PVTPA deposition. Our electroluminescence test suggested that this type of PMTPA/PVTPA composite film is good for hole injection and transportation.

A bipolar dibromo monomer, bis-(4-bromophenyl)[4-(3,5-diphenyl-1,2,4-triazole-4-yl)-phenyl]amine (9), containing electro-rich triphenylamine and electro-deficient 1,2,4-triazole moieties was newly synthesized and characterized. Two fluorescent fluorene-based conjugated copolymers (TPAF, TPABTF) were prepared via facile Suzuki coupling from the dibromo bipolar monomer, 4,7-dibromo-2,1,3-benzothiadiazole (BTDZ), and 9,9-dioctylfluorene. They were characterized by molecular weight determination, IR, NMR, DSC, TGA, solubility, absorption and photoluminescence spectra, and cyclic voltammetry. The polymers showed good solubility in common organic solvents such as dichloromethane, chloroform, tetrahydrofuran, and dichlorobenzene at room temperature. They had glass transition temperatures (T g ) higher than 135 °C and 5% degradation temperatures in nitrogen atmosphere were higher than 428 °C. Single layer polymer light-emitting diodes (PLED) of ITO/ PEDOT:PSS/polymer/metal showed a blue emission at 444 nm and Commission Internationale de I'Eclairage (CIE) 1931 color coordinates of (0.16, 0.13) for TPAF. The device using TPABTF as emissive material showed electroluminescence at 542 nm with CIE1931 of (0.345, 0.625), low turn-on voltage of 5 V, a maximum electroluminance of 696 ed/m 2 , and a peak efficiency of 2.02 cd/A.

In this paper, an organic light-emitting device (OLED) with low reflection for the entire visible range and at different viewing angles by using an absorptive and photo-sensitive material, N,N'-Bis(2,6-diisopropylphenyl)-1,7-bis(4-methoxyphenyl)perylene-3,4,9,10-tetracarboxydiimide (MPPDI), as a black layer (BL) structure was demonstrated. A semitransparent double-metal structure, Al/Ag, was used to reduce the driving voltage and enhance the destructive interference of the BL structure. Combined with the broad absorption band of the MPPDI, the reflectance of such a device shows a 12-times decrease compared to the conventional OLED. Also, a photocurrent enhancement effect was observed in our BL-OLED due to the photosensitive quality of the MPPDI.

New types of polyurethanes (PUs) were prepared from condensation polymerization of isophorone diisocyanate (IPDI) with various combination of 9-butyl-3,6-bis(4-hydroxyphenyl)carbazole (Cz) and 2,5-bis(4-hydroxyphenyl)-1,3,4-oxadiazole (OXD), and end-capped with 4- tert- butyl phenol. The Cz-OXD PUs can also be used as host for phosphorescent dye. Red EL emission was obtained when Ir(btp) 2 (acac) or Ir(2-phq) 2 (acac) was used as the phosphorescent dyes in Cz-OXD (3:1) PU. Maximum brightness of 394 cd/m 2 and EL efficiency of 1 cd/A were achieved for the Ir(2-phq) 2 (acac) base device. In addition, white light PLED was demonstrated when co-dopant of Ir(btp) 2 (acac) and Firpic were used.

The oligomerization of 5-bromo-2-hydroxypyridine through a CuI catalyzed one-pot condensation tactics was developed. A series of oligopyridones, from dipyridione to penta-pyridone, were therefore synthesized via the CuI-promoted C–N coupling reactions. The oligopyridones favor to have folded conformations in polar aprotic solvents. These were confirmed by using 1H NMR, NOESY, and 1D-NOE experiments.

According to the World Health Organization (WHO), tobacco-related disease is the single largest preventable cause of death in the world today, killing around 5.4 million people a year – an average of one person every six seconds. The total number of death caused by tobacco consumption is higher than that of tuberculosis, HIV/AIDS and malaria combined. Unlike other communicable diseases, however, tobacco-related disease has a man-made consensus vector – the tobacco companies that play an active role to promote tobacco consumption, which directly heightens the disease morbidity. Any public health policy designed to curb smoking behavior has to prepare for opposite lobbying actions from tobacco companies that undermine the effects of the health measures. Another unique nature of the tobacco epidemic is that it can be cured, not by medicines or vaccines, but on the concerted actions of government and civil society. Many countries with a history of tobacco control measures indeed experienced a reduction of tobacco consumption. As most of these governments launched a range of measures simultaneously, it is hard to quantify the relative merits of different control strategies that contributed to the drop in the number of smokers. These packages of strategies can come in different forms but with some common features. Political actions with government support, funding, and protection are crucial. Without these, antismoking efforts in any part of the world are unlikely to be successful.

Electrochemically deposited layer (EDL) prepared from electropolymerization of oligo(5-vinyl-2-nitrobenzyl triphenylamine-4-carboxylate) on conductive indium tin oxide glass (ITO) showed photolithographic properties as well as good hole-injection and transport properties. Under the optimized conditions, the polymeric light-emitting device (PLED) of ITO/EDL/polyvinylcarbazole(PVK)-Ir(PPy)3-[2-biphenylyl-5-(4′-tert-butylphenyl)oxadiazole] (PBD)/Mg−Ag had a turn-on voltage of 13.5 V (100 cd/m2) with a maximum brightness of 9100 cd/m2, and the current efficiency of 10.3 cd/A. When the EDL was exposed to UV light (365 nm) through a patterned photomask and developed in CH2Cl2, a positive image was obtained. After irradiation for 8 min through a band-pass filter (17 mW/cm2) by a Xeon lamp, the EDL became soluble and could be depleted completely in CH2Cl2. Patterned PLED device was also fabricated by this technique.

N-[4-Tosyloxybutyloxymethyl]phenyl]-N,N-diphenylamine showed unexpected chemical reactivity and polymerized to form hyperbranched poly(p-methylenetriphenylamine) (PMTPA) under neat conditions. The hyperbranched PMTPA was electrochemically active and could be deposited on electrode surface when oxidized. The SEM study revealed that electropolymerization of PMTPA would form uniform coating on ITO surface. Polymeric light-emitting diodes (PLEDs) employing the electroactive hyperbranched PMTPA as hole-transport layer in ITO/electrochemically polymerized HTL/EML(PVK-PBD-Ir(ppy)3)/Mg/Ag demonstrated the brightness over 20 000 cd/m2 and low turn-on voltage. In particular, the device performance was very steady regardless of the thickness of the PMTPA layer, ranging from 4 to 10 nm.

The catalytic conditions of copper(I) iodide/potassium carbonate/ TRANS- N, N′-dimethylcyclohexane-1,2-diamine, either in toluene at reflux temperature, or by heating neat at 150 °C effectively promoted the C-N coupling of aryl bromides with cyclic ureas. By employing a protection-deprotection strategy, unsymmetrical diaryl-substituted cyclic ureas could also be synthesized.