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We present the synthesis and characterization of seven new organic co-poly-ynes P1--P7 incorporating the phenothiazine (PTZ) motif and evaluate their optoelectronic properties and performance in polymer light-emitting diodes and polymer solar cells (PLEDs/PSCs). The co-poly-ynes were obtained in moderate to high yields via Sonogashira coupling reactions and characterized using analytical, spectroscopic and electrochemical techniques and complementary quantum-chemical modelling. The materials show strong optical absorption in the visible region of the spectrum and most also show strong emission with quantum yields in the range of 13-41% relative to rhodamine 6G (R6G). PLED devices based on the co-poly-ynes were prepared and the most promising was measured to have a brightness of up to 1.10 x 104 cd m-2. PSCs based on donor materials incorporating some of the polymers were prepared and demonstrated power conversion efficiencies of up to 0.24%. [ABSTRACT FROM AUTHOR]

The photophysical properties of two previously synthesized, highly efficient, bright red emitting complexes [Eu(btfa)3DPEPO] (CIE, 0.672; 0.326) (Eu-1) and [Eu(nta)3DPEPO] (CIE, 0.673; 0.326) (Eu-2) (btfa = 4,4,4-trifluoro-1-phenyl-1,3-butanedione, nta = 4,4,4-trifluoro-1-(2-naphthyl)-1,3-butanedione and DPEPO = bis(2-(diphenylphosphino)phenyl)ether oxide) are reported. The complexes have been used as dopants to fabricate several single and double emitting layer (EML) electroluminescent (EL) devices. At the optimum doping concentration of 4 wt%, the single EML device of Eu-1 exhibited a pure red color with an external quantum efficiency (EQE) of 2.9% and a maximum brightness (B) = 1320 cd m-2, maximum current efficiency (Zc) = 4.08 cd A-1, maximum power efficiency (Zp) = 3.37 lm W-1 with a very low turn-on voltage (Vturn-on) = 3.8 V. Importantly, the single EML device of Eu-2 at the optimum doping concentration exhibited pure red EL with EQE of 6.0% with the best EL performance: B = 2108 cd m-2, Zc = 8.45 cd A-1, and Zp = 6.98 lm W-1 at a very low Vturn-on = 3.5 V. The performances of this device are among the best reported for devices incorporating a europium complex as a red emitter. Furthermore, the EL performances were achieved at the current density of 10 mA cm-2, thereby alleviating a serious efficiency rolloff as a major obstacle to the development of Eu-complex based EL devices. [ABSTRACT FROM AUTHOR]

A novel near-infrared luminogen (TPE/TPY-Pt-PA/PEG) based on the terpyridyl Pt(II) complex with a tetraphenylethene periphery is synthesised and characterised. It displays aggregation-induced emission with the formation of self-assembled nanostructures. The nanoparticles fabricated with TPE/TPY-Pt-PA/PEG show excellent biocompatibility with high specificity to lysosomes in HeLa cells. [ABSTRACT FROM AUTHOR]

A phosphorescent CO2 gas probe based on an iridium(III) complex with 2-phenylimidazo-[4,5-f][1,10] phenanthroline ligand has been developed. Its phosphorescence is quenched by the addition of CH3COO-1. The quenched phosphorescence can be recovered by bubbling CO2 into the detecting solution. This phosphorescent CO2 probe exhibits higher photostability and reduced photobleaching than some of the reported organic fluorescent probes. A time-resolved photoluminescence experiment was performed for CO2 gas detection, which could effectively remove the background fluorescence and improve the sensitivity and signal-to-noise ratio of the sensor in complicated media. [ABSTRACT FROM AUTHOR]

Mononuclear Cu(I) complexes based on bis(pyrazol-1-yl-methyl)-pyridine derivatives and ancillary triphenylphosphine have been prepared and characterized by 1H NMR, mass spectroscopy and single-crystal X-ray analysis. The thermogravimetric analysis shows that the complexes exhibit high thermal stability. The electronic absorption spectra display two features in the regions of 230-260 and 290-350 nm attributable to mixed ligand-to-ligand (LLCT) and metal-to-ligand-charge-transfer (MLCT) excited states, which is supported by the results of density functional theory (DFT) and time-dependent DFT (TDDFT) calculations on these Cu(I) complexes. These complexes are strongly emissive in the solid state at ambient temperature. Intense blue or green emission in the poly(methyl methacrylate) film is observed in the region of 475-518 nm for these complexes with the emission lifetimes in the microsecond time scale (12-20 μs), indicating that the emission may be phosphorescence emission. Increasing the steric hindrance of the substituents on the pyrazole unit results in a blue-shift of the emission bands and enhanced emission quantum efficiency in PMMA films. The two most emissive complexes have been used for the fabrication of phosphorescent organic light-emitting diodes (POLEDs). [ABSTRACT FROM AUTHOR]

A new synthesis route for preparing Dawson-type polyoxometalate (POM) based inorganic-organic hybrid materials is presented. Two new heteropolytungstate-based dimeric and oligomeric Pt(II) acetylide inorganic-organic hybrid compounds (2PtOD and PPtOD) were prepared by Hagihara's dehydrohalogenating coupling of a terminal diacetylene POM hybrid containing diphosphoryl functionality and an appropriate platinum(II) halide precursor. This method provides a rigid covalent linkage between the POM and the organometallic Pt(II) acetylide moiety. The redox potential of the polyanion can be tuned by grafting the organic and organometallic groups on it. The photoelectric properties of hybrid LB films derived from these inorganic-organic composites were studied. [ABSTRACT FROM AUTHOR]

A new approach has been illustrated for the development of stable, efficient, and environmentally "friendly" white phosphorescent materials. Under mild conditions, a new one-dimensional coordination polymer has been prepared from benzo-18-crown-6 with CuI in the presence of KI, which is capable of emitting direct white light in the solid state. [ABSTRACT FROM AUTHOR]

Four new heteroleptic ruthenium sensitizers [Ru(4,4′-carboxylic acid-2,2′-bipyridine)(L)(NCS)2] (L = 5,5′-bis(4-octylthiophen-2-yl)-2,2′-bipyridine (1), 5,5′-bis(N,N-diphenyl-4-aminophenyl)-2,2′-bipyridine (2), 5,5′-bis(5-(N,N-diphenyl-4-aminophenyl)-thiophen-2-yl)-2,2′-bipyridine (3) and 5,5′-bis(4-octyl-5-(N,N-diphenyl-4-aminophenyl)-thiophen-2-yl)-2,2′-bipyridine (4)) were synthesized, characterized by physicochemical and computational methods, and utilized as photosensitizers in nanocrystalline dye-sensitized solar cells (DSSCs). The λmaxof the metal-to-ligand charge transfer (MLCT) absorption of these four ruthenium dyes (527 nm for 1, 535 nm for 2, 585 nm for 3and 553 nm for 4) can be tuned by various structural modifications of the ancillary ligand and it was shown that increasing the conjugation length of such ligand reduces the energy as well as the molar absorption coefficient of the MLCT band. The maximum incident photon to current conversion efficiency (IPCE) of 41.4% at 550 nm, 38.6% at 480 nm, 39.4% at 470 nm and 31.1% at 480 nm for 1-, 2-, 3- and 4-sensitized solar cells were obtained. Respectable power conversion efficiencies of 3.00%, 2.51%, 2.00% and 2.03% were realized, respectively, when the sensitizers 1, 2, 3and 4were used in DSSCs under the standard air mass (AM) 1.5 sunlight illumination (versus5.9% for standard N719). [ABSTRACT FROM AUTHOR]

Treatment of [NnBu4][OsVI(N)Cl4] with a stoichiometric amount of H2L (L = N,N′-bis(salicylidene)-o-cyclohexylenediamine dianion) in the presence of PF6−or ClO4−in MeOH affords [OsVI(N)(L)(OH2)](PF6) 1aand [OsVI(N)(L)(CH3OH)](ClO4) 1b, respectively. The structure of 1bhas been determined by X-ray crystallography and the OsN bond distance is 1.627(3) Å. In the presence of a N-donor heterocyclic ligand in CH3CN, 1areacts at room temperature to afford the mixed-valence μ-N2(salen)osmium species [(X)(L)OsIII–NN–OsII(L)(X)](PF6), 2–14(X = py 2; 4-Mepy 3; 4-tBupy 4; pz 5; 3-Mepz 6; 3,5-Me2pz 7; Im 8; 1-MeIm 9; 2-MeIm 10; 4-MeIm 11; 1,2-Me2Im 12; 2-Meozl 13; 4-MeTz 14). These complexes are formed by ligand-induced NN coupling of two [OsVIN]+to give initially [OsIII–N2–OsIII]2+, which is then reduced to give the more stable mixed-valence species [OsIII–N2–OsII]+. Cyclic voltammograms (CVs) of 2–14show two reversible couples, attributed to OsIII,III/OsIII,IIand OsIII,II/OsII,II. The large comproportionation constants (Kcom) of (5.36–82.3) × 1013indicate charge delocalization in these complexes. The structures of 3and 14have been determined by X-ray crystallography, the salen ligands are in uncommon cis-β configuration. Oxidations of 4and 14by [Cp2Fe](PF6) afford the symmetrical species [(X)(L)OsIII–NN–OsIII(L)(X)](PF6)2(X = 4-tBupy 15; 4-MeTz 16). These are the first stable μ-N2diosmium(iii,iii) complexes that have been characterized by X-ray crystallography. [ABSTRACT FROM AUTHOR]

Reactions of heterobimetallic 3d–4f Schiff base complexes of the formula [ZnLnL(H2O)(NO3)3] (1a–e) with KOCN or NH4SCN in refluxing MeCN produce either one dimensional polymeric materials [ZnLnL(NO3)2(H2O)(OCN)]∞(2a–c) or trinuclear complexes of the formula [Zn2LnL2(NO3)(SCN)2] (3a–e) (a(La), b(Nd), c(Er), d(Tb), e(Eu); H2L = N,N′-bis-(3-methoxysalicylidene)ethylene-1,2-diamine). The structures of 2a,band 3b–ehave been determined by single-crystal X-ray diffraction studies. Structural differences between the complexes affect the photophysical properties, which have been studied in acetonitrile solutions. [ABSTRACT FROM AUTHOR]

Organic light-emitting diodes (OLEDs) show great promise of revolutionizing display technologies in the scientific community. One successful approach for improved device efficiency has been to maximize the electron-hole recombination using dopants that emit from the triplet excited state. In this context, heavy transition metal complexes have recently gained tremendous academic and industrial research interest for fabricating highly efficient phosphorescent OLEDs by taking advantage of the 1:3 exciton singlet/triplet ratio predicted by simple spin statistics. Traditional room-temperature phosphorescent dyes are monofunctional materials working only as light-emitting centres but other key issues including charge generation and transport remain to be addressed in the electroluminescence. This Feature Article highlights recent and current advances in developing new synthetic strategies for multifunctional organometallic phosphors, which integrate both luminescent and charge carrier injection/transport functions into the same molecules so that they perform most, if not all, of the necessary functional roles (viz. photoexcitation, charge injection and transport as well as recombination) for achieving high-efficiency devices. Considerable focus is placed on the design concepts towards the tuning capability of charge-transport characteristics and phosphorescence emission colour of this prominent class of metallophosphors. In particular, the latest research endeavor in accomplishing novel triplet emitters with enhanced charge injection/charge transport of both hole and electron carriers is criticially discussed, which can provide good implications regarding their possible routes for future research development in the field. [ABSTRACT FROM AUTHOR]

By fusing an electron-deficient ring system with the phenyl ring of a 2-phenylpyridine (ppy)-type ligand, a new and synthetically versatile strategy for the phosphorescence color tuning of cyclometalated iridium(III) and platinum(II) metallophosphors has been established. Two robust red electrophosphors with enhanced electron-injection/electron-transporting features were prepared by using an electron-trapping fluoren-9-one chromophore in the ligand design. The thermal, photophysical, redox and electrophosphorescent properties of these complexes are reported. These exciting results can be attributed to a switch of the metal-to-ligand charge-transfer (MLCT) character of the transition from the pyridyl groups in the traditional IrIIIor PtIIppy-type complexes to the electron-deficient ring core, and the spectral assignments corroborate well with the electrochemical data as well as the time-dependent density functional theory (TD-DFT) calculations. The electron-withdrawing character of the fused ring results in much more stable MLCT states, inducing a substantial red-shift of the triplet emission energy from yellow to red for the IrIIIcomplex and even green to red for the PtIIcounterpart. Electrophosphorescent organic light-emitting devices (OLEDs) doped with these red emitters fabricated by using vacuum evaporation technique have been realized with reasonable performance. [ABSTRACT FROM AUTHOR]

The synthesis, characterization and photophysics of some solution-processable intensely coloured polyplatinynes functionalized with the thienopyrazine–thiophene hybrid spacer and their model molecular complexes are described. These metallated polymers possess extremely low bandgaps of 1.47–1.50 eV, which extend towards the near-infrared (NIR) range of the solar spectrum, and represent the lowest optical bandgaps ever reported for metallopolyynes in the literature. Both polymers can be used to fabricate efficient solar cells with power conversion efficiencies (PCEs) of up to 0.63% under air mass (AM1.5) simulated solar illumination, and the possibility of covering the 600–900 nm solar-radiation range to harvest photocurrent has been demonstrated. The influence of the thienyl core as well as its substituent group, on the optical and photovoltaic behavior of these metallopolymers was investigated in detail. The power dependencies of the solar cell parameters (including the short-circuit current density, open-circuit voltage, fill-factor and PCE) were also studied. The present work offers an attractive avenue towards conjugated materials with broad solar absorptions and demonstrates the potential of metallopolyynes for both visible and NIR light power generation. [ABSTRACT FROM AUTHOR]

With the goal to provide organometallic triplet emitters with good hole-injection/hole-transporting properties, highly amorphous character for simple solution-processed organic light-emitting diodes, and negligible triplet–triplet (T–T) annihilation, a series of new phosphorescent cyclometalated IrIII and PtII complexes with triphenylamine-anchored fluorenylpyridine dendritic ligands were synthesized and characterized. The photophysical, thermal, electrochemical and electroluminescent properties of these molecules are reported. The incorporation of two sterically hindered electron-rich triphenylamino groups to the 9-position of the fluorene skeleton was found not only to afford triplet emitters in the glassy state with high Tg, but also to elevate the HOMO levels and confer the hole-injection ability to the phosphorescent center. These highly amorphous metal phosphors can serve as doped emitters in a small molecular host for spin-coated emission layer in suitable OLED structures to achieve good device performance with a maximum luminance of 29380 cd m−2 at 23 V, a peak external quantum efficiency of 7.0%, a luminance efficiency of 21.4 cd A−1 and a power efficiency of 2.9 lm W−1. Both the electrophosphorescent device characterization as well as the theoretical simulation results show that these iridium electrophosphors show negligible T–T annihilation even at high operating current densities and moderately high doping levels. Our investigations indicate that attaching the triphenylamino moieties to the fluorene ring is an effective way to overcome the T–T annihilation caused by the strong interactions among the emitting molecules. [ABSTRACT FROM AUTHOR]

With the simple dinuclear Zn–Nd complex [ZnNdL(H2O)(NO3)3] (1) (H2L = N,N′-bis(3-methoxysalicylidene)ethylene-1,2-diamine) as the precursor, tetranuclear [Zn2Nd2L2(4,4′-bpy)(NO3)6]·Et2O (2) and [Zn2Nd2L2(4,4′-bpe)]·2H2O (3) (4,4′-bpy = 4,4′-bipyridine, 4,4′-bpe = trans-bis(4-pyridyl)ethylene) complexes are formed: suitable choice of bidentate linkers could construct multinuclear heterometallic 3d–4f Schiff-base complexes with improved luminescent properties, and the controlling of linker character shows a potentially effective way to the fine-tuning properties of NIR luminescence from Nd ions. [ABSTRACT FROM AUTHOR]

This article highlights recent progress in the development of rigid-rod metallopolyyne polymers of late transition metals which can exhibit easily tunable luminescent and electronic properties. Considerable focus is placed on the design strategies towards the tuning capability of phosphorescence emission color and optical bandgap of this class of luminescent metallopolymers, and the evaluation of their suitability as emitters in light-emitting applications, optical power limiters for sensor protection and semiconductors in organometallic photovoltaic cells. An effective approach based on structural modification of the spacer group can be devised to achieve the full-color phosphorescence emission spanning almost the whole visible spectrum and to tune the material properties of these functional organometallic polymers. The major advances, ongoing challenges and future perspectives of this research frontier are also discussed. [ABSTRACT FROM AUTHOR]

Real-time tracking of fast axonal transport of acidic vesicles in live adult mouse dorsal root ganglion (DRG) and cortical neurons in brain slices was visualized by the use of binuclear cycloplatinated complexes, {[Pt(L1)]2(μ-dppm)}2+(1) and {[Pt(L1)]2(μ-dppm)}2+(2), as lysosome-specific two-photon imaging probes. [ABSTRACT FROM AUTHOR]

Simple single-dopant white organic light-emitting devices (WOLEDs) with optimized efficiency/color quality/brightness trade-offs are developed; the white light produced shows the best color quality ever exhibited by WOLEDs at very high brightness, and is even able to duplicate the natural sunlight source. [ABSTRACT FROM AUTHOR]

Chiral double-stranded helicates, formed between Cu(i) ion and C2-symmetric oligopyridines, were used for catalytic asymmetric cyclopropanation of alkenes; low catalyst loadings (0.2 mol%), high TONs (up to 404) and short reaction times (30–60 min) were achieved with [Cu2L2]OTf2(L = chiral C2-symmetric terpyridine). [ABSTRACT FROM AUTHOR]