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In this paper, we demonstrate that the performance of perovskite solar cells can be largely boosted with sub-nm pyridine-containing small-molecule electron interfacial layers. These vacuum-deposited sub-nm layers between perovskites and electron transport layers create a permanent dipole moment that improves the interfacial energy level alignment and facilitates a fast electron sweep-out. With these interfacial layers, the devices exhibit exceptional power conversion efficiencies up to 18.8%, a 25% increase compared to that of the one without the interfacial layer.

Varying the structures of conjugated side chains can be an efficient approach toward tailoring the optoelectronic properties of conjugated polymers. In this study, we synthesized four indacenodithiophene (IDT)-based side chain conjugated donor–acceptor alternating polymers. We introduced four different acceptor units (difluorobenzothiadizole: PIDTHT-FBT ; difluoroquinoxaline: PIDTHT-QF ; dicyanoquinoxaline: PIDTHT-QCN ; diketopyrrolopyrrole: PIDTHT-DPP ) to study the effects of the conjugated side chains on the optoelectronic properties (absorption spectra, energy levels, hole mobility) of the polymers and their resulting organic photovoltaic (OPV) devices. The energy levels of the highest occupied molecular orbitals for the new polymers were deeper when they featured alkylthiophene side chains. Films of these materials blended with PC 71 BM exhibited sufficiently high space-charge-limited current (SCLC) hole mobilities (>1.2 × 10 −5 cm 2 V −1 s −1 ) for efficient charge carrier extraction. The greatest OPV performance was that of the device incorporating PIDTHT-QF , with a power conversion efficiency of 5.15% under illumination with AM 1.5G solar light (1000 W m −2 ). Thus, side chain conjugated (two-dimensional) IDT polymers incorporating optimized acceptor groups are prospective materials for OPV applications.

After the revelation of nonvisual lighting impact on human health, the lighting engineers are more concerned about the human benign light with low cost and high efficiency. The solution-processed fabrication technique with smart device engineering for high efficacy OLED devices is being anticipated to drastically reduce the fabrication cost leading to affordable desired end product. The co-host matrix could be a potential solution to improve device performance multi-folds with suitable band-gap engineering and most effective energy transfer from mixed host to guest. Here, rationally configured device architecture with two novel host materials possessing wide energy gap, high triplet energy, and excellent thermal and morphological stability resulted in highly-efficient solution-processed green, red and low color temperature (CT) OLEDs with sub-bandgap level driving voltage of 2.1 V i.e. record lowest within its own category. Perfect triplet energy match of our newly developed host materials with commercial p-type host m-MTDATA and the common phosphors enabled efficient energy transfer with very low energy loss led to high efficiency of resulting OLED. The resultant solution-processed triplet emitter based green and red OLED devices displayed a maximum efficacy of 75.0 and 30.2 lm W−1 without using light extraction out-coupling techniques, respectively. The designed blue-hazard free 2048 K low CT OLED exhibited a ηPE of 44.5 lmW−1, a ηCE of 47.6 cdA-1 and an EQE of 20.7% as the maximum value, the highest known so far within its own category. The melatonin suppression sensitivity (MSS) of the engineered low CT OLED is only 1.0% to that of the 480 nm blue light, which is much safer compared to other light sources. The impact of our design engineering was established by fabricating 1 cm × 1 cm device area prototype.

The Heck reaction is a well-established transition-metal catalyzed reaction for coupling alkenes with sp2 alkyl halides to give novel unsaturated compounds. Herein we report an analogous Heck-inspired, simple efficient coupling of sp3 alkyl halides with electron-withdrawing alkenes to form reductive coupling products where saturated esters are obtained. A range of acrylates were coupled with sp3 alkyl halides in the presence of Ni(PPh3)2Cl2 catalyst, Zn metal powder, CH3CN solvent, and water, at 80 °C to form the reductive Heck type saturated ester products in good yields. This strategy was further extended to couple oxabenzonorbornadiene with the alkyl halides resulting in ring opening to give rise to bicyclic alcohol products. The mechanism for both the reactions appears to be the usual oxidative-addition driven alkene insertion reaction where the water appears to act as the protonating agent.

With the goal of applying them in organic photovoltaics (OPVs), in this study we synthesized two organometallic alternating conjugated polymers, TPT–TPyPt and TPT–TIqPt , consisting of indacenodithiophene (thiophene/phenylene/thiophene; TPT ) and cyclometalated platinum(II) moieties and compared their optical, electrochemical, and photovoltaic properties, their space charge limited currents, and their structures (density functional theory) with those of related platinum-free organic polymers, TPT–TPy and TPT–TIq . The absorption bands of the metal-based polymers were significantly red-shifted relative to those of the metal-free polymers. We fabricated OPVs incorporating blends of these polymers and [6,6]-phenyl-C 71 -butyric acid methyl ester at various weight ratios. One of these devices exhibited a power conversion efficiency (PCE) of 2.9%, with a short-circuit current density of 7.7 mA/cm 2 , an open-circuit voltage of 0.78 V, and a fill factor of 0.48, under AM 1.5 G (100 mW/cm 2 ) illumination. To the best of our knowledge, this PCE is the highest reported for a PSC based on a cyclometalated platinum-type polymer.

Two phosphorescent iridium complexes (psbi)2Ir(acac) and (ppbi)2Ir(acac) (psbi = 1-phenyl-2-styryl-1H-benzo[d]imidazole, ppbi = 1-phenyl-2-(1-phenylprop-1-en-2-yl)-1H-benzo[d]imidazole, acac = acetylacetonate) were synthesized, and their photophysical, electrochemical and electroluminescent properties were also studied. Organic light-emitting devices with these two complexes as dopant emitters having the structure ITO/NPB (10 nm)/TCTA (20 nm)/x%Ir:CBP (y nm)/BCP (10 nm)/LiF (1 nm)/Al (100 nm) were fabricated. The device based on (psbi)2Ir(acac) exhibited a maximum brightness of 56,162 cd m−2, while the device based on (ppbi)2Ir(acac) gave a maximum brightness of 31,232 cd m−2. At high brightness of 1000 cd m−2 and 10,000 cd m−2, high current efficiencies of 25.7 cd A−1 and 20.7 cd A−1 were achieved, respectively, for the (psbi)2Ir(acac)-based EL device. For the EL device based on (ppbi)2Ir(acac), current efficiencies of 20.1 cd A−1 at 1000 cd m−2 and 14.2 cd A−1 at 10,000 cd m−2 were observed.

By utilizing the relatively broad orange–red excimer emission of an iridium complex (DMBA) 2 Ir(acac) (DMBA = 5,6-dihydro-9,10-methylenedioxy-benzo[c]acridine, acac = acetylacetonate) together with an efficient blue phosphorescent iridium complex FIrpic, two types of efficient white organic light-emitting diodes were fabricated. Through the optimization of the thickness, location, and doping concentration of each emitting layer, both of the two types of devices exhibited pure white emission with CIE coordinates close to the ideal white emission (0.33, 0.33). Compared with the double-emitting-layer structure, a triple-emitting-layer device structure with a blue-emitting layer sandwiched between two orange–red-emitting layers led to more stable white emission at different biases/brightnesses with maximum efficiencies of up to 12.2%, and 27.0 cd A −1 for the forward viewing direction, corresponding to the total efficiencies of 19.7%, 45.9 cd A −1 and 32.1 lm W −1 . At a high brightness of 1000 cd m −2 , the EL efficiencies remained high at 8.8% and 19.2 cd A −1 .

A red-emitting iridium complex (DMBA)2Ir(acac) (DMBA = 5,6-dihydro-9,10-methylenedioxy benzo[c]acridine, acac = acetylacetone) containing rigid cyclometalated ligand DMBA was synthesized and its photophysical, electrochemical and electroluminescent properties were characterized. Organic light emitting devices utilizing the complex as dopant emitter were fabricated. When double hole-transporting layers were adopted, the brightness and efficiencies of electroluminescent devices were improved greatly. Based on the excimer emission, a maximum brightness of 66,312 cd m−2 at 15 V, together with a maximum external quantum efficiency of 17.7% at 5.0 V was achieved at a doping concentration of 5%. The result suggests that the introduction of a methylenedioxy group into the N-heterocycle of the cyclometalated ligand leads to higher-energy MLCT transitions and a blue shift of the photoluminescence spectrum.

A phosphorescent iridium(III) complex Ir(PBQ) 2 (acac) (PBQ: 4-phenylbenzoquinoline, acac: acetylacetone) was designed and synthesized, and the single crystal of this complex was obtained. This complex shows well optoelectronic properties. The organic light emitting devices (OLEDs) based on this complex were successfully fabricated with the device configuration of ITO/NPB or TCTA (40 nm)/Ir-complex: CBP (7%, 30 nm)/BCP (15 nm)/Alq (30 nm)/LiF (1 nm)/Al (100 nm). Using TCTA as the hole-transporting material, the device gives an extremely high external quantum efficiency of 14.6% at 5.0 V, a brightness of 61,693 cd/m 2 at 16.0 V, and a power efficiency of 37.0 lm/W at 3.5 V.

Two phosphorescent complexes Ir(FFBI)2(pmp) and Ir(FFBI)2(pti) based on cyclometalated ligand 1-(4-fluorobenzyl)-2-(4-fluorophenyl)-1H-benzo[d]imidazole (FFBI) and ancillary ligands 2-(phenyliminomethyl)phenol (pmp) or 3-(pyridin-2-yl)-4,5,6,7-tetrahydro-2H-indazole (pti) were synthesized. The single crystal of Ir(FFBI)2(pmp) was obtained. The light emitting and electrochemical properties of these complexes were studied. The electroluminescent devices based on these two complexes with the structure of ITO/NPB (40 nm)/Ir complex: CBP (30 nm)/BCP (15 nm)/Alq (30 nm)/LiF (1 nm)/Al (100 nm) emitted cyan color, with high brightness and efficiencies. The maximum external quantum efficiencies reached to 6.8% and 11.6%, respectively.

Two phosphorescent iridium(III) complexes Ir(DFPP)2(acac) and Ir(DFPP)2(pic) (DFPP, 2-(2,4-difluorodephenyl)-3-phenylpyridine; acac, acetylacetone; pic, 2-picolinic acid) were synthesized. The complexes have strong phosphorescent characters. The organic light emitting devices (OLEDs) based on these complexes with the configuration of ITO/NPB (40 nm)/Ir complex: CBP (7%, 30 nm)/BCP (15 nm)/Alq (30 nm)/LiF (1 nm)/Al (100 nm) were fabricated. The device based on Ir(DFPP)2(acac) emits green color with a maximum external quantum efficiency of 4.14%, a brightness of 28,786 cd m−2; and the device based on Ir(DFPP)2(pic) emits cyan color with a maximum external quantum efficiency of 3.05%, a brightness of 24,220 cd m−2.

Two red emitting iridium complexes (DBA) 2 Ir(acac) and (BA) 2 Ir(acac) (DBA = 5,6-dihydro-benzo[c]acridine, BA = benzo[c]acridine, acac = acetylacetone) were synthesized. Organic light-emitting devices using these complexes as dopant emitters have been fabricated. The results showed that these complexes have strong phosphorescent characters and the devices emit pure red light. The maximum brightness of the device based on (DBA) 2 Ir(acac) is 9540 cd/m 2 with an external quantum efficiency of 4.66%.

This paper investigated the blue shift of photoluminescence and the changes of surface morphology of Alq 3 films by ionic argon plasma bombardment. Plasma with different conditions was applied to bombard thin Alq 3 films, modifying both the physical and chemical properties of the films. After characterizing Alq 3 films treated with different RF power by XPS, PL and AFM, we proposed the mechanisms to explain the absence of PL blue shift and chemical shift after the films were exposed in the air for more than 3 h. Experimental results showed that molecular structure damages would affect the bandgap of Alq 3 , leading to the blue shift effect. XPS results also showed that binding energy shifts are caused by enriched oxygen covalent bonds formed inside the films after plasma treatment. Also, surface roughness improves as RF power is increased.

This work reports on the fabrication of an efficient polymer light-emitting device by applying iridium (Ir) complex, dibenzo[ f , h ]-quinoxaline iridium (acetylacetonate) [Ir(DBQ) 2 (acac)], as the phosphorescent dopant, poly(9-vinylcarbazole) as the matrix layer, and 2-(4-biphenylyl)-5-(4- tert -butyl-phenyl)-(1,3,4-oxadiazole) as the electron transport material. The trapping of charge carriers at the Ir(DBQ) 2 (acac) dopant sites dominates the electroluminescence (EL) of the devices. The device emits red electrophosphorescence centered at 610 nm, exclusively from the Ir dopant and an EL efficiency of 8.5 cd/A (1287 cd/m 2 ) biased at 14.5 mA/cm 2 .

Several iridium complexes {iridium(III)bis[2-(3-methoxyphenyl)-1,3-benzothiozolato-N,C 2′ ] acetylacetonate (MeO-BT) 2 Ir(acac), iridium(III)bis[2-(2,4-difluorophenyl)-1,3-benzothiozolato-N,C 2′ ] acetylacetonate (2F-BT) 2 Ir(acac), and iridium(III)bis[2-(2,4-difluorophenyl)-6-fluoro-1,3-benzothiozolato-N,C 2′ ] acetylacetonate (3F-BT) 2 Ir(acac)} having different substituents on 2-phenylbenzothiazole have been synthesized. The phosphorescent light emitting diodes (PHOLEDs) using these iridium complexes as dopant emitters were fabricated. The experimental results revealed that the emissive colors of PHOLEDs could be finely tuned by suitable modification of the substituents on the 2-phenylbenzothiazole ligands. Furthermore, these iridium complexes show better emissive properties than the known iridium(III)bis(2-phenylbenzothiozolato-N,C 2′ ) acetylacetonate (BT) 2 Ir(acac).

In the presence of CoX 2 (PPh 3 ) 2 /3 PPh 3 and zinc metal conjugated alkenes (CH 2 CHCOOR, CH 2 CHCN, CH 2 CHSO 2 Ph and CH 2 CHCONEt 2 ) undergo reductive tail-to-tail dimerization to yield the corresponding saturated linear products. Under similar reaction conditions, vinylarenes (ArCHCH 2 ) give stereoselective head-to-tail dimerization products, trans -1,3-diarylbut-1-ene, in good to excellent yields.

Two small non-aromatic organic molecules, 1,2,3,4,5,6,7,8,9,10-decahydro-1,8-acridinedione (DAD) and 3,3,6,6-tetramethyl-1,2,3,4,5,6,7,8,9,10-decahydro-1,8-acridinedione (TDAD) were synthesized and used as blue light-emitting dopants in organic electroluminescent devices. A general device structure, ITO/NPB (20 nm)/CBP (20 nm)/DAD:TPBI (X%, Y nm)/TPBI (Z nm)/Mg:Ag (10:1; 55 nm)/Ag (100 nm) was employed for this study, where NPB, CBP and TPBI stand for 4,4′-bis[N-(1-naphthyl)-N-phenyl-amino]-biphenyl, 4,4′-dicarbazolyl-1,1′-biphenyl and 2,2′,2″-(1,3,5-phenylene)tris-[1-phenyl-1H-benzimidazole], respectively. Efficient blue emission with excellent Commission Internationale de L’Eclairage (CIE) coordinates (X=0.15, Y=0.08) and maximum luminance >1000 cd/m2 were obtained from the devices. The performances of the devices depend greatly on the dopant concentration and thickness of the emitting layer.

An efficient method for the preparation of various monosubstituted arylallenes, disubstituted allenes and alkenylallenes via palladium-catalyzed coupling of allenylstannanes with aryl iodides or alkenyl iodides is described. The coupling reaction was carried out in the presence of Pd(PPh 3 ) 4 and LiCl using DMF as solvent. The possible role of LiCl in this coupling process is discussed based on the 119 Sn NMR studies.

Aryl or alkenyl iodides react regioselectively with allenes and hexaalkylditins in the presence of Pd(dba) 2 to give substituted allylstannanes.

2,3-Dimethyl-1,3-butadiene and cyclic dienes react with β-iodoenones (RI: 3-Iodo-2-cyclohexen-1-one, 5,5-dimethyl-3-iodo-2-cyclohexen-1-one and 3-iodo-2-cyclopenten-1-one) in the presence of Zn and catalytic amount of NiBr2 to afford the corresponding homo 1,4-addition products in good yields. For 2,3-dimethyl-1,3-butadiene, only the products RCH2C(CH3)=C(CH3)CH2R with Z geometry were observed. For cyclic dienes, the products observed are RCHCH=CHCHR(CH2)nCH2 in which the two alkenyl substituents R are cis to each other.

A model organic light-emitting diodes (OLEDs) with structure of tris(8-hydroxyquinoline) aluminum (Alq 3 )/ N , N ′-diphenyl- N , N ′-bis[1-naphthy-(1,1′-diphenyl)]-4,4′-diamine (NPB)/indium tin oxide (ITO)-coated glass was fabricated for diffusion study by ToF-SIMS. The results demonstrate that ToF-SIMS is capable of delineating the structure of multi-organic layers in OLEDs and providing specific molecular information to aid deciphering the diffusion phenomena. Upon heat treatment, the solidity or hardness of the device was reduced. Complicated chemical reaction might occur at the NPB/ITO interface and results in the formation of a buffer layer, which terminates the upper diffusion of ions from underlying ITO.

Norbornadiene undergoes [2 + 2] reaction in THF in the presence of NiX2 and zinc metal powder to give an exo-trans-exo dimer and an exo-trans-exo-trans-exo trimer. In these products, the norbornadiene molecules are linked to each other by forming cyclobutane rings with all cyclobutane carbons occupying exo positions relative to the bridging carbons on the two norbornadiene fragments. Polymerization of norbornadiene occurs if the catalyst NiX2 is replaced by Ni(PPh3)2Cl2. 1,4-Dihydro-1,4-epoxynaphthalene, 5,8-dimethoxy-1,4-dihydro-1,4-epoxynaphthalene, 5-methoxy-1,4-dihydro-1,4-epoxynaphathalene and methyl 1,4-dihydro-1,4-iminonaphthalene-9-carboxylate also dimerize to give exo-trans-exo products in excellent yields in toluene in the presence of Ni(PPh3)2Cl2 and Zn powder. For the dimerization products of 5-methoxy-1,4-dihydro-1–4-epoxynaphthalene, cis and trans isomers with respect to the orientation of methoxy groups in about 1 : 1 ratio were oberved. Under similar reaction conditions for the dimerization of norbornadiene, norbornene undergoes reductive dimerization to afford a product which consists of two norbornyl groups. The structure of this product is also exo-trans-exo.

Coprecipitation using triethylammonium carbonate ((Et 3 HN) 2 CO 3 ) as precipitant was used to prepare the YBa 2 Cu 3 O 7 (Y 1-2-3) and YBa 2 Cu 4 O 8 (Y 1-2-4) high- T c superconductive materials. Theoretical calculations were carried out to estimate the optimal conditions for coprecipitation. A series of precipitation experiments under different pH values were conducted. The residual ions and pH of the filtrate after each precipitation were measured. In agreement with the theoretical prediction, the optimal pH for coprecipitation is above 6.0. The precipitate was dried, calcined, compressed into pellets and sintered. The characterization of the sintered pellets by X-ray diffraction, scanning electron microscope (SEM), electron probe microanalysis (EPMA), electrical resistivity and magnetic susceptibility measurements is reported.

The superconducting properties and crystal structure of YSr 2 (Cu 0.9 Ti 0.1 ) 3 O 7+δ were investigated. These ceramic samples were prepared in air via the solid-state method. Single-phase samples were obtained and annealed at different temperature between 300–700°C. After the annealing, YSr 2 (Cu 0.9 Ti 0.1 ) 3 O 7+δ exhibited superconductivity with a transition temperature of 35 K. The magnetic susceptibility measurement and iodometry titration have revealed that the superconducting transition temperature of YSr 2 (Cu 0.9 Ti 0.1 ) 3 O 7+δ increases as the hole concentration, (Cu-O) + p , and the oxygen content increase. All these samples with different oxygen content are tetragonal and in the powder X-ray results it was indicated that the Ti atoms preferentially occupy the sites of the chain copper atoms.

Organic halides react with 7-heteroatom benzonorbornadiene derivatives 1 – 4 in the presence of Pd(PPh 3 ) 2 Cl 2 and zinc powder to give cis -1,2-dihydro-1-naphthol or methyl N-( cis -1,2-dihydro-l-naphthyl) carbamate derivatives stereoselectively.

The selectivity of N-phenylcarbamate from the reductive carbonylation of nitrobenzene using Rh(CO)4− or Ru3(CO)12Et4N+Cl− as the catalyst is much higher in t-butyl alcohol than in primary or secondary alcohols; the latter two alcohols are readily involved in the reduction of nitrobenzene to aniline leading to lower selectivity of the corresponding carbamates. For example, when 2-butanol was used as the solvent for the reductive carbonylation of nitrobenzene, 2-butanone and aniline were observed in a molar ratio of 1:1. Similarly, the reductive carbonylation of p-nitrotoluene to give the corresponding carbamate in t-butyl alcohol is also higher in yield than in 2-butanol or in butanol. However, for dinitroarenes the selectivity of carbamates is low using either tBuOH or other primary and secondary alcohols.

The reactions of (η 2 -RCHCHCOR′)Fe(CO) 4 (R = Ph, R′ = H; R = H, R′ = H and R = H, R′ = CH 3 ) with aniline or its derivative afforded η 4 -azadiene complexes 1 , 2 and 3 in various yields. The azadiene ligands in 2 and 3 are too reactive to isolate at ambient temperature, but 2 and 3 are stable up to ca 110 ° C. Treatment of (η 2 -CH 2 CHCHO)Fe(CO) 4 with Ph 3 PCHCOOMe gave a η 2 -diene complex 4 which was converted to (η 4 -CH 2 CHCHCHCOOMe)Fe(CO) 3 on heating, or reacting with (CH 3 ) 3 NO.

The reaction of Mo(NN)(CO)4 (NN = bipyridine, phenathroline) with CH3OOCCCCOOCH3 (DMAC) gives Mo(NN)(CO)4(DMAC)2. An X-ray diffraction study of the product (NN = bipyridine) indicates that the two CO groups are cis to each other, while the two DMAC ligands are in trans arrangement, and are mutually perpendicular with each DMAC eclipsing and NMoCO vector. In solution, the DMAC ligands appear to rotate about the MoDMAC bond as shown by the fluxional behavior in the NMR spectra of the products.

The water gas shift catalyst system composed of K2PtCl4 and SnCl45H2O in HCl/HOAc/H2O Torr of CO and 180 Torr of ethylene or propylene hydrogenates the olefin when heated at 88°C. The reaction with ethylene proceeds cleanly according to the equation C2H4 + CO + H2O → C2H6 + CO2 yielding 31 turnovers per Pt for a 24 h reaction time; the reaction with propylene is less clean, showing concurrent H2 production from the shift reaction and isopropyl chloride formation from direct reaction of C3H6 with the HCL-containing medium. No evidence for significant hydroformylation is obtained. For the case of ethylene, no water gas shift catalysis is observed as long as olefin is present, and if H2 is added to the reactant gases, it is not consumed in the course of ethane formation. Hydrogenation is thus thought to proceed via a metal hydride formed from CO oxidation, its reaction with olefin and protonation.

The rhodium(I) complex [Rh(CO)(PEt3)(mnt)]− (mnt = maleonitriledithiolate) reacts with a variety of alkyl halides to form acyl complexes isolated in the presence of excess PEt3 as five-coordinate species of formula [Rh(COR)(PEt3)2(mnt)]. The structure of the complex for R = n-Pr has been determined by an X-ray analysis, and is found to be a square-based pyramid with the acyl group in the apical position. Addition of HClO4 to the rhodium(I) anion in the presence of excess PEt3 yields rhodium(III) hydride, [RhH(CO)(PEt3)2(mnt)], while addition of acid to the rhodium(I) complex in CH3CN solution with ethylene present leads slowly to formation of an acyl complex which is isolated as [Rh(COEt)(PEt3)2(mnt)] upon phosphine addition. A novel alkyl group migration from the acyl carbon to a donor S atom is also observed in monophosphine systems.