Pendent Triphenylamine Research Articles

Novel organosoluble aromatic polyimides bearing pendant methoxy‐substituted triphenylamine moieties: Synthesis, electrochromic, and gas separation properties

AbstractFour series of polyimides I–VI with pendent triphenylamine (TPA) units having inherent viscosities of 0.44–0.88 dL/g were prepared from four diamines with two commercially available tetracarboxylic dianhydrides via a conventional two‐step procedure that included a ring‐opening polyaddition to give polyamic acids, followed by chemical cyclodehydration. These polymers were amorphous and could afford flexible films. All the polyimides had useful levels of thermal stability associated with high softening temperatures (279–300 °C), 10% weight‐loss temperatures in excess of 505 °C, and char yields at 800 °C in nitrogen higher than 58%. The hole‐transporting and electrochromic properties were examined by electrochemical and spectroelectrochemical methods. Cyclic voltammograms of the polyimide films cast onto an indium‐tin oxide (ITO)‐coated glass substrate exhibited a or two reversible oxidation couples at 0.65–0.78 and 1.00–1.08 V versus Ag/AgCl in acetonitrile solution. The polymer films revealed electrochromic characteristics with a color change from neutral pale yellowish to blue doped form at applied potentials ranging from 0.00 to 1.20 V. The CO2 permeability coefficients (P) and permeability selectivity (P/P) for these polyimide membranes were in the range of 4.73–16.82 barrer and 9.49–51.13, respectively. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 7937–7949, 2008

New host homopolymers containing pendant triphenylamine derivatives: Synthesis, optical, electrochemical properties and its blend with Ir(ppy)3 for green phosphorescent organic light‐emitting devices

AbstractTwo vinyl homopolymers poly(N‐(4‐(4‐(4‐vinylbenzyloxy)styryl)phenyl)‐N‐phenylbenzenamine) (PVST) and poly(4‐vinyltriphenylamine) (PTPA) containing pendant hole‐transporting triphenylamine and 4‐oxystyryltriphenylamine groups, respectively, were synthesized by radical polymerization and employed as hosts for tris(2‐phenylpyridine) iridium [Ir(ppy)3] phosphor. Structural influences of the hole‐transporting groups upon optoelectronic properties were investigated by photophysical, electrochemical, and electroluminescent methods. The polymers were readily soluble in common organic solvents and their weight‐average molecular weights (Mw) were 5.68 × 104 and 1.90 × 104, respectively. The emission spectra (both photoluminescence, PL and electroluminescent, EL) of the blends [PTPA with 4 wt % Ir(ppy)3] showed dominant green emission (517 nm) attributed to Ir(ppy)3 due to efficient energy transfer from PTPA to Ir(ppy)3. The HOMO levels of PVST and PTPA, estimated from onset oxidation potentials in their cyclic voltammograms, were −5.14 and −5.36 eV, which are much higher than −5.8 eV of the conventional poly(9‐vinylcarbazole) (PVK) host owing to high hole‐affinity of the triphenylamine groups. The optoelectronic performances of phosphorescent EL devices, using PVST and PTPA as hosts and Ir(ppy)3 as dopant (indium tin oxide, ITO/poly(3,4‐ethylenedioxythiophene): poly(styrene sulfonate) (PEDOT:PSS)/PVST or PTPA:Ir(ppy)3(4 wt %):PBD(40 wt %)/BCP/Ca/Al), were investigated. The maximum luminance and luminance efficiency of the PTPA device were 9220 cd/m2 and 6.1 cd/A, respectively, which were significantly improved relative to those of PVK and PVST. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 7960–7971, 2008

New host copolymers containing pendant triphenylamine and carbazole for efficient green phosphorescent OLEDs

A series of vinyl copolymers (P1–P6) containing pendant hole-transporting triphenylamine (11–88mol%) and carbazole chromophores were synthesized by radical copolymerization to investigate the influence of triphenylamine groups upon optoelectronic properties. The copolymers were readily soluble in common organic solvents and their weight-average molecular weights (Mws) were between 1.41×104 and 2.24×104. They exhibited moderate thermal stability with Td=402–432°C at 5% weight loss. The emission spectra (both PL and EL) of the blends [P1–P6 with 4wt% Ir(ppy)3] showed dominant green emission (517nm) attributed to Ir(ppy)3 due to efficient energy transfer from P1–P6 to Ir(ppy)3. The HOMO levels of P1–P6, estimated from onset oxidation potentials in cyclic voltammeter, were −5.42 to −5.18eV, which are much higher than −5.8eV of conventional poly(9-vinylcarbazole) (PVK) host owing to high hole-affinity of the triphenylamine groups. The optoelectronic performances of phosphorescent EL devices, using P1–P6 as hosts and Ir(ppy)3 as dopant (ITO/PEDOT:PSS/P1–P6:Ir(ppy)3 (4wt%):PBD (40wt%)/BCP/Ca/Al), were greatly improved relative to that of PVK. The best performance was obtained with P4 device, in which the maximum luminance and luminance efficiency were 11 501cd/m2 and 10.6cd/A, respectively.

Poly(4-vinyltriphenylamine): Optical, electrochemical properties and its new application as a host material of green phosphorescent Ir( ppy) 3 dopant

Vinyl polymer PTPA containing pendant triphenylamine chromophore, which possesses hole-transport characteristics, was used as a host material in green phosphorescent light-emitting diodes. The PL spectrum of PTPA showed an intrinsic peak (375 nm) attributed to triphenylamine groups and an excimer emission (440 nm). The PL and EL spectra of the blends [PTPA:Ir( ppy) 3] showed dominant green emission attributed to Ir( ppy) 3 due to efficient energy transfer from PTPA to Ir( ppy) 3. The HOMO level of PTPA, estimated from cyclic voltammetric data, was −5.36 eV, which is higher than −5.8 eV of PVK owing to hole-affinity characteristics of the pendant triphenylamine groups. The best performance was obtained with the EL device (ITO/PEDOT:PSS/PTPA:Ir( ppy) 3 (1 wt%):PBD (40 wt%)/Ca/Al), the maximal luminance and the maximal luminance efficiency were 8358 cd/m 2 and 4.5 cd/A, respectively. The present study suggests that the polymer PTPA is versatile host materials for green phosphorescent polymer light-emitting diodes applications.

Novel electrochromic aromatic poly(amine–amide–imide)s with pendent triphenylamine structures

Three new aromatic poly(amine–amide–imide)s (PAAIs) having pendent triphenylamine units were prepared from the phosphorylation polyamidation reactions of a newly synthesized diamine, N, N-bis(4-aminophenyl)- N′, N′-diphenyl-1,4-phenylenediamine, with three imide ring-preformed dicarboxylic acids. These PAAIs had inherent viscosities of 0.54–0.86 dL/g, and they were amorphous and readily soluble in many organic solvents and could be solution cast into transparent, tough, and flexible films with good mechanical properties. They displayed relatively high glass-transition temperatures (279–287 °C) and good thermal stability, with 10% weight-loss temperatures in excess of 522 °C in nitrogen and char yields at 800 °C in nitrogen higher than 67%. The solutions of polymers in NMP exhibited strong UV–vis absorption bands with a maximum around 315 nm. The hole-transporting and electrochromic properties were examined by electrochemical and spectroelectrochemical methods. Cyclic voltammograms of the PAAIs prepared by casting polymer solution onto an indium-tin oxide (ITO)-coated glass substrate exhibited two reversible oxidation redox couples at 0.67 and 1.08 V vs. Ag/AgCl in acetonitrile solution. All the PAAIs revealed very stable electrochromic characteristics, changing color from original pale brownish to green, and then to blue at 0.67 and 1.08 V, respectively.

Novel family of triphenylamine‐containing, hole‐transporting, amorphous, aromatic polyamides with stable electrochromic properties

AbstractWe report the preparation and characterization of a series of novel electrochromic, aromatic poly(amine amide)s with pendent triphenylamine units. The synthesis proceeded via direct phosphorylation polycondensation between a novel diamine, N,N‐bis(4‐aminophenyl)‐N′,N′‐diphenyl‐1,4‐phenylenediamine, and various aromatic dicarboxylic acids. All the poly(amine amide)s were amorphous and readily soluble in many common organic solvents and could be solution‐cast into transparent, tough, and flexible films with good mechanical properties. They exhibited good thermal stability and 10% weight‐loss temperatures above 540 °C. Their glass‐transition temperatures were 263–290 °C. These polymers in N‐methyl‐2‐pyrrolidinone solutions exhibited strong ultraviolet–visible absorption peaks at 307–358 nm and photoluminescence peaks around 532–590 nm in the green region. The hole‐transporting and electrochromic properties were studied with electrochemical and spectroelectrochemical methods. Cyclic voltammograms of poly(amine amide) films prepared by the casting of polymer solutions onto an indium tin oxide coated glass substrate exhibited two reversible oxidation redox couples at 0.65 and 1.03 V versus Ag/AgCl in an acetonitrile solution. All the poly(amine amide)s showed excellent stability with respect to their electrochromic characteristics; the color of the films changed from pale yellow to green and then blue at 0.85 and 1.25 V, respectively. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 2085–2098, 2005

Synthesis, luminescence and electrochromism of aromatic poly(amine–amide)s with pendent triphenylamine moieties

A new triphenylamine-containing aromatic dicarboxylic acid monomer, N,N-bis(4-carboxyphenyl)-N′,N′-diphenyl-1,4-phenylenediamine (2), was synthesized from the amination reaction between 4-aminotriphenylamine and 4-fluorobenzonitrile and subsequent alkaline hydrolysis of the dinitrile intermediate. A series of novel aromatic poly(amine–amide)s with triphenylamine units in the main chain and as the pendent group were prepared from the newly synthesized dicarboxylic acid and various aromatic diamines. These poly(amine–amide)s were amorphous and readily soluble in many organic solvents. All the polymers could be solution-cast into flexible films with good mechanical properties. They had excellent levels of thermal stability associated with high glass-transition temperatures (226–261 °C). These polymers exhibited strong UV–vis absorption bands at 350–365 nm in NMP solution. Their photoluminescence spectra showed maximum bands around 512–543 nm in the green region. The hole-transporting and electrochromic properties are examined by electrochemical and spectroelectrochemical methods. Cyclic voltammograms of the poly(amine–amide) 5a prepared from the dicarboxylic acid monomer 2 with a structurally similar diamine monomer N,N-bis(4-aminophenyl)-N′,N′-diphenyl-1,4-phenylenediamine (4a) exhibited four reversible oxidation redox couples in acetonitrile solution at E1/2 = 0.60, 0.80, 0.97 and 1.13 V, respectively. All the poly(amine–amide)s exhibited excellent reversibility of electrochromic characteristics by continuous five cyclic scans between 0.0 to 1.30 V, with a color change from the original pale yellowish neutral form to the green and then to blue oxidized forms.

Novel Aromatic Poly(Amine-Imide)s Bearing A Pendent Triphenylamine Group: Synthesis, Thermal, Photophysical, Electrochemical, and Electrochromic Characteristics

A new triphenylamine-containing aromatic diamine, N,N-bis(4-aminophenyl)-N‘,N‘-diphenyl-1,4-phenylenediamine, was synthesized from the amination reaction between 4-aminotriphenylamine and 4-fluoronitrobenzene and subsequent reduction of the dinitro intermediate. A series of novel aromatic poly(amine-imide)s with pendent triphenylamine units were prepared from the newly synthesized diamine and various tetracarboxylic dianhydrides by either a one-step or a conventional two-step polymerization process. All the poly(amine-imide)s were amorphous and readily soluble in many organic solvents such as N-methyl-2-pyrrolidone (NMP), N,N-dimethylacetamide, and chloroform. These polymers could be solution cast into transparent, tough, and flexible films with good mechanical properties. They had useful levels of thermal stability associated with relatively high glass transition temperatures (264−352 °C), 10% weight-loss temperatures in excess of 568 °C, and char yields at 800 °C in nitrogen higher than 63%. These polymers exhibited strong UV−vis absorption bands at 311−330 nm in NMP solution. The photoluminescence spectra showed maximum bands around 545−562 nm in the green region. The hole-transporting and electrochromic properties are examined by electrochemical and spectroelectrochemical methods. Cyclic voltammograms of the poly(amine-imide) films cast onto an indium−tin oxide (ITO)-coated glass substrate exhibited two reversible oxidation redox couples at 0.78 and 1.14 V versus Ag/AgCl in acetonitrile solution. The poly(amine-imide) films revealed excellent stability of electrochromic characteristics, with a color change from the pale yellowish neutral form to the green and blue oxidized forms at applied potentials ranging from 0.78 to 1.14 V.

Synthesis and Characterization of Hole-transport Materials in Polysiloxane

Triphenylamine(TPA) substituted polysiloxane was synthesized as the hole-transporting material. Field dependence of the hole mobility and photoconductivity were measured using the time-of flight and simple DC photocurrent measurement, respectively. We demonstrated that the film of polysiloxane with pendant TPA units higher hole mobility (3.2×10 −5 cm 2 /Vsec at E=6×10 5 ) than that of the conventional poly( N -vinylcarbazole) and carbazole substituted polysiloxane. Further experiments are required to test these new materials as hole transporting layers in photorefractive and electroluminescent devices.

Synthesis and Characterization of Hole-transport Materials in Polysiloxane

Triphenylamine(TPA) substituted polysiloxane was synthesized as the hole-transporting material. Field dependence of the hole mobility and photoconductivity were measured using the time-of flight and simple DC photocurrent measurement, respectively. We demonstrated that the film of polysiloxane with pendant TPA units higher hole mobility (3.2×10 −5 cm 2 /Vsec at E=6×10 5 ) than that of the conventional poly( N -vinylcarbazole) and carbazole substituted polysiloxane. Further experiments are required to test these new materials as hole transporting layers in photorefractive and electroluminescent devices.