Quinacridone Research Articles

Enhanced photoelectric and photocatalysis performances of quinacridone derivatives by forming D-π-A-A structure

Five D-π-A-A type of heterocyclic polycyclic aromatic hydrocarbons (hetero-PAHs) organic molecules with quinacridone (QA) derivatives as the core bridge connected with different donor groups of triarylamine (T), indoline derivative (W), and carbazole (K) and the auxiliary acceptor groups benzobisthiadiazole (B) and furan (F) have been designed. The potential application of designed sensitizers in solar cells and photocatalysis have been investigated. Microscopic major processes involve dye regeneration, electrons recombination, intramolecular charge transfer (ICT) properties and key parameters of molecular photoelectric performance. Besides, the coupling strength, energy gaps, dipole moments, molecular fluorescent lifetime and the bonding type between dye and TiO2 were estimated to reveal the nature of photocatalysis. Results indicated that introducing W or B unit should improve the photoelectric performance among all design strategies (especially, simultaneously introducing two moieties) due to the excellent electron-donating ability of W and the pull electrons' ability of B auxiliary acceptor. Designing WQAB@TiO2 and WQAF@TiO2 to have better photocatalytic properties owing to the stronger interaction and surface charge transfer, particularly for WQAB. Current molecular strategies using controlling moieties provide a choice for potential applications in solar cells and photocatalytic fields.

Structure and properties of nucleated polypropylene fibres

This work is focused on the evaluation of the structure and properties of the nucleated polypropylene (PP) fibres prepared by melt spinning technique at lower take-up velocities as pre-oriented fibres (POY) containing 0.3–1.5 wt. % of additives - nucleating agents like 1,3:2,4-dibenzylidene sorbitol (DBS), quinacridone (QA) and calcium carbonate (CC). The thermal properties of nucleated PP fibres were determined by using differential scanning calorimetry (DSC). Used additives promote nucleation activity, DBS and QA better than CC, as they increased the crystallization temperature to higher extent than CC. Effect of CC seems to be negligible, due to very little impact on melting point and crystallization temperature. Morphological characteristic of the PP fibres were observed by means of scanning electron microscopy. The morphology of nucleated PP is different significantly from that of reference non-nucleated PP fibre. The measured values of the above mentioned properties were compared with parameters of non-nucleated PP fibre prepared under same technological conditions.

A quinacridone derivative with intensive emission in both solution and the solid state via a facile preparation for cell imaging applications

tert-Butyloxycarbonyl (TBOC) substituted quinacridone (QA) derivative TBOC-QA was synthesized via a one-step simple chemical reaction and showed intense emission in both solution and the solid state.

Dopant-free novel hole-transporting materials based on quinacridone dye for high-performance and humidity-stable mesoporous perovskite solar cells

A series of novel pristine hole-transporting materials based on a quinacridone (QA) dye have been developed and used to fabricate mesoporous perovskite solar cells for the first time achieving an efficiency of 18.2%.

First theoretical probe for efficient enhancement of nonlinear optical properties of quinacridone based compounds through various modifications

In this study, first attempt has been made for theoretical designing of quinacridone (QA) dye and new QA-based compounds (QA-1 to QA-9) were proposed by installing auxiliary donors (dimethylvinyl, methoxy, and N,N-dimethylamine), donor (diphenylamine) and acceptors (cyanoacrylic acid, CN and NO2) segments into fixed π-bridge QA. DFT and TDDFT calculations with B3LYP/6-31G(d,p) and CAM-B3LYP/6-31G(d,p) functional were used to shed light on the promising structure, charge transport and NLO properties. Introduction of auxiliary donors/donor and acceptor successfully modified the structure which led to superior NLO properties. An eye-catching NLO response was observed in all designed compounds. Interestingly, QA-9 exhibits appealingly large enhancement in NLO properties through ICT process with <α> and βtot computed to be 716.02 (a.u) and 128082.15 (a.u) respectively. UV–Vis results indicates the QA-9 most red shifted among all studied compounds with λmax = 489.02 nm. QA-1 to QA-9 showed narrow HOMO-LUMO energy gap as compared to QA which results in enhanced NLO response. NBO analysis confirms the formation of charge separation state in QA-1 to QA-9 due to successful migration of electrons from auxiliary donors/donor to acceptors via π-bridge. The present research evokes the scientific interest regarding the development of QA based tempting NLO compounds that can be beneficial in modern hi-tech applications.

Computational study of quinacridone on silver and gold clusters: Applications to organic light emitting diodes and nonlinear optical devices

Interaction of quinacridone (QA) on silver and gold clusters has been investigated using computational methods. This interaction induces variations in the structural parameters of QA, which are confirmed by the electrostatic potential plot and the vibrational analysis. The red shift in the simulated UV–Vis spectra confirms the process of adsorption on metal clusters, which is mainly due to the electrostatic interaction between the metals and QA. Reduction in the hole reorganization energy along with the increment in hyperpolarizability points to a possible use of QA adsorbed on silver cluster as an effective material in organic light emitting diodes (OLED) and nonlinear optical (NLO) devices.

Design and synthesis of a series of N-donor quinacridone derivatives with novel nonlinear optical properties

In this work, five new quinacridone (QA)-based dyes containing a N-donor moiety have been synthesized, defined as C12QA–F, C12QA–G, C12QA–H, C12QA–I and C12QA–J, for the application of third-order nonlinear optical (NLO) responses. A new design has been put forward with the first step of connecting a long alkyl chain on the planar structure of parent ring of QA, with the aim to increase the solubility of the compound and reduce its π-π intermolecular stacking and the second step of connecting N-donor groups to enhance the effect of molecule. Electrochemical measurement data indicated that the tuning of the HOMO and LUMO energy levels can be easily realized by introducing the N-donor moiety. The theoretical calculations showed a smaller dihedral angle between the QA moiety and the N-donor than the usual, implying an excellent planarity between the two groups, which is beneficial for the intramolecular charge transfer (ICT). NLO tested under similar Z-scan measurements conditions showed that, the second-order hyperpolarizability (γ) of the five synthesized compounds ranged from 2.136 × 10−33 esu to 13.856 × 10−33 esu, with the maximum of C12QA-H was more than 13 times higher than N,N-di(n-dodecane) quinacridone(C12QA) of 0.964 × 10−33 esu. The results suggested that the designed QA-based compounds had good thermal stability and superior third-order NLO properties, very promising for integrated NLO devices.

Quinacridone derivative as a new photosensitizer: Photodynamic effects in cells and in vivo

The lack of ideal photosensitizers is the major limitation for clinical photodynamic therapy (PDT). Quinacridone (QA) is a mass-produced industrial organic pigment. QA derivatives are widely investigated for many applications in various fields, but rarely involved in biological applications. Here we report the PDT effects of N,N'-bis(methylpiperazinylpentyl) QA (QAP) in cells and in vivo. QAP shows low dark-toxicity and high photo-toxicity in cells through generating reactive oxygen species (ROS) under irradiation; and greatly inhibits the tumor growth in a mouse subcutaneous xenograft model after irradiation with a 532 nm laser. The high photodynamic efficiency of QAP shows the great potential of QA derivatives to be a new class of leading compound of photosensitizers in PDT.

Green phosphorescent organic light-emitting devices based on different electron transport layers combining with fluorescent sub-monolayer

We report a small molecule host of 4,4(-N,N)-dicarbazole-biphenyl (CBP) doped with 8% tris(2-phenylpyridine) iridium (Irppy3) for use in efficient green phosphorescent organic light-emitting devices (PHOLEDs) combined with different electron transport layers of Alq and BAlq. The PHOLEDs exhibit maximum current efficiency and power efficiency of 19.8 cd/A and 6.21 lm/W, respectively. The high performance of such PHOLEDs is attributed to the better electron mobile ability of BAlq and sub-monolayer quinacridone (QAD) as carrier trapping layer and equal charge carrier mobilities of hole and electron to form the broad carrier recombination zone in the emitting layer, which can reduce the triplet-triplet annihilation and improve the efficiency of the device.

Growing low-dimensional supramolecular crystals directly from 3D particles

We show that one-dimensional (1D) nanostructures and two-dimensional (2D) supramolecular crystals of organic semiconductors can be grown on substrates under ambient conditions directly from three-dimensional (3D) organic crystals. The approach does not require dissolving, melting or evaporating of the source crystals and is based on organic solid–solid wetting deposition (OSWD). We exemplify our approach by using the pigment quinacridone (QAC). Scanning tunnelling microscopy (STM) investigations show that the structures of the resulting 2D crystals are similar to the chain arrangement of the alpha and beta QAC polymorphs and are independent of the 3D source crystal polymorph (gamma). Furthermore, distinct 1D chains can be produced systematically.

Ultrafast Electron Transfer in Organic/Inorganic Hybrid System

In this study, a donor acceptor type molecule based on quinacridone (QA) and diketopyrrolopyrrole (DPP) was synthesized. Through the grafting of DPP-QA molecule on the surface of ZnO nanorod, hybrid nanoconnposite DPP-QA/ZnO was obtained. The fluorescence of DPP-QA was significantly quenched in the hybrid DPP-QA/ZnO nanocomposite. The properties of photoinduced electron transfer in the studied system were investigated by time-resolved fluorescence spectroscopy and femtosecond transient absorption spectroscopy in the visible region. It was found that the electron transfer (ET) time constant in the hybrid system is 1.0 x 109 s(-1) and the quantum yield for ET is 75%. It provides a model system to understand the role of inorganic semicon ductors in the organic/inorganic hybrid photoelectrical and photovoltaic devices.

Quinacridone on Ag(111): Hydrogen Bonding versus Chirality

Quinacridone (QA) has recently gained attention as an organic semiconductor with unexpectedly high performance in organic devices. The strong intermolecular connection via hydrogen bonds is expected to promote good structural order. When deposited on a substrate, another relevant factor comes into play, namely the 2D-chirality of the quinacridone molecules adsorbed on a surface. Scanning tunneling microscopy (STM) images of monolayer quinacridone on Ag(111) deposited at room temperature reveal the formation of quasi-one-dimensional rows of parallel quinacridone molecules. These rows are segmented into short stacks of a few molecules in which adjacent, flat-lying molecules of a single handedness are linked via hydrogen bonds. After annealing to a temperature of T = 550–570 K, which is close to the sublimation temperature of bulk quinacridone, the structure changes into a stacking of heterochiral quinacridone dimers with a markedly different intermolecular arrangement. Electron diffraction (LEED) and photoelectron emission microscopy (PEEM) data corroborate the STM findings. These results illustrate how the effects of hydrogen bonding and chirality can compete and give rise to very different (meta)stable structures of quinacridone on surfaces.

Adsorption Study and Detection of the High Performance Organic Pigments Quinacridone and 2,9-Dimethylquinacridone on Ag Nanoparticles By Surface-Enhanced Optical Spectroscopy

In this work, surface-enhanced Raman scattering (SERS) and surface-enhanced fluorescence (SEF) were employed in the study of the adsorption and detection of the pigments quinacridone (QA) and 2,9-dimethylquinacridone (2,9-DMQA). These pigments are of great relevance in artwork and textile, plastic, and photochemical industries due to their condition as high performance pigments since they possess a high tinting strength. Due to this fact, they have been employed at relatively low concentrations. Therefore, the analysis and detection of these pigments requires the application of a highly sensitivity technique, such as SERS and SEF. The adsorption of QA and 2,9-DMQA on silver nanoparticles was extensively studied by means of SERS at different surface coverages. This study was completed by carrying out an in depth vibrational (Raman and IR) analysis of these pigments in solid state by ab initio density functional theory (DFT) calculations. In addition, UV-vis spectroscopy was employed to investigate the aggregation undergone by both pigments in solid state and in solution. 2,9-DMQA was demonstrated to have a lower tendency toward aggregation due to the presence of methyl groups. Even so, this molecule follows a BET adsorption mechanism on the metal nanoparticles due to its high tendency toward intermolecular interaction. From the analysis of the adsorption mechanism of this molecule, the limit of detection was deduced to be ca. 55 ppb.

Photophysical and electrochemical properties and temperature dependent geometrical isomerism in alkyl quinacridonediimines

Quinacridone diimines 1–10 were synthesized by the condensation of anilines with alkyl substituted quinacridones (QA). Photophysical and electrochemical properties of the compounds were investigated. Unconventional behavior of absorption spectra suggested a decrease in π_conjugation within the QA skeleton as well as lack of extended π_conjugation between the QA skeleton and the N-phenyl rings. A computational study of compounds 1–10, a variable temperature 1H NMR study of compounds 2, 7 and 10 (for instance), and single crystal X-ray analysis of 2, 3, 6, 7, 8 and 10 indicated that the anomalous behavior is due to the buckled, non-planar structure of the quinacridones. Moreover the molecules existed in two interconvertible geometric isomeric forms at different temperatures. Molecular orbital calculations were performed at B3LYP/6-31+G(d), B3PW91/6-31G(d) and PBEPBE/6-31G(d) levels of theory at B3PW91/6-31G(d) optimized structures for both isomers of all compounds (1–10); the results obtained are in close agreement with the experimentally determined values.

White organic light-emitting devices based on blue fluorescent dye combined with dual sub-monolayer

White organic light-emitting devices have been realized by using highly blue fluorescent dye 4,4′-Bis(2,2-diphenyl-ethen-1-yl)-4,4′-di-(tert-butyl)phenyl(p-TDPVBi) and [2-methyl-6-[2-(2, 3,6,7-tetrahydro-1H, red fluorescent dye 5H-benzo[ij] quinolizin-9-yl) ethenyl]-4H-pyran-4-ylidene] propane-dinitrile(DCM2), together with well known green fluorescent dye quinacridone (QAD). The fabrication of multilayer WOLEDs did not involve the hard-to-control doping process. The structure of the device is ITO/m-MTDATA (45nm)/NPB(8nm)/p-TDPVBi(15nm)/DCM2(xnm)/Alq3 (5nm)/QAD(ynm)/Alq3(55nm)/LiF(1nm)/Al, where 4,4′,4′′-tris{N,-(3-methylphenyl)-N-phenylamine}triphenylamine (m-MTDATA) acts as a hole injection layer, N,N′-bis-(1-naphthyl)-N, N′-diphenyl-1, 1′-biph-enyl-4, 4′-diamine (NPB) acts as a hole transport layer, p-TDPVBi acts as a blue emitting layer, DCM2 acts as a red emitting layer, QAD acts as a green emitting layer, tris-(8-hydroxyquinoline) aluminum (Alq3) acts as an electron transport layer, and WOLEDs of devices A, B, C and D are different in layer thickness of DCM2 and QAD, respectively. To change the thickness of dual sub-monolayer DCM2 and QAD, the WOLEDs were obtained. When x, y=0.05, 0.1, the Commission Internationale de 1’Eclairage (CIE) coordinates of the device change from (0.4458, 0.4589) at 3V to (0.3137, 0.3455) at 12V that are well in the white region, and the color temperature and color rendering index were 5348K and 85 at 8V, respectively. Its maximum luminance was 35260cd/m2 at 12V, and maximum current efficiency and maximum power efficiency were 13.54cd/A at 12V and 6.68lm/W at 5V, respectively. Moreover, the current efficiency is largely insensitive to the applied voltage. The electroluminescence intensity of white EL devices varied only little at deferent dual sub-monolayer. Device D exhibited relatively high color rendering index (CRI) in the range of 88–90, which was essentially voltage-independent.

Pentaphenylphenyl substituted quinacridone exhibiting intensive emission in both solution and solid state

Pentaphenylphenyl substituted quinacridone (QA) derivative BPP–QA with two propeller-like substituted groups was synthesized and showed intense emission in both solution and solid state.

Synthesis of Novel Quinacridone Dyes and Their Photovoltaic Performances in Organic Dye-sensitized Solar Cells

Solar Cell Research Center, Materials Science and Technology Division, Korea Institute of Science and Technology (KIST), Seoul 136-791, KoreaReceived March 8, 2011, Accepted June 13, 2011Two novel quinacridone (QNC) dyes with thiophene or benzene-conjugated bridge and cyanoacrylic acidacceptor were first designed and synthesized for use in dye-sensitized solar cells (DSSCs). The absorptionspectra, electrochemical and photovoltaic properties of these dyes were investigated. Under simulated AM1.5G irradiation conditions, the solar cell based on the quinacridone dye containing thiophene as a bridge unithad a short-circuit photocurrent density of 8.51 mA·cm

Solution processable quinacridone based materials as acceptor for organic heterojunction solar cells

Two series of novel quinacridone (QA) based materials that combined a strong absorption over a broad range in visible region with good electrical characteristics, which were used as the new electron-accepting materials for organic solar cells, are explored. Unique cyclic compounds 1– 6 are synthesized by incorporating electron withdrawing groups (CN, COOH) at carbonyl position of alkyl substituted quinacridones, which lead to the compounds possessing the characteristics of solution-processed and being suitable for photovoltaic applications. Heterojunction solar cells with simple device configuration using these soluble materials as acceptor and effective donor poly (3-hexyl thiophene) (P3HT) were fabricated. The maximum power conversion efficiency (PCE) achieved in the solar cell based on compound 5 is 0.42% under simulated AM 1.5 solar irradiation with J sc =1.80 mA cm −2, V oc =0.50 V and FF=47%. Although the aimed devices just exhibit moderate PCE, our results clearly suggest that the new-type electron-accepting materials different from fullerene have great potential as acceptor in heterojunction solar cell due to many advantages of the QA derivatives such as relatively inexpensive, good electrochemical stability and could be readily modified.

Fully solution processed p-i-n organic solar cells with an industrial pigment – Quinacridone

We report solution processed organic solar cells with quinacridone (QA), an industrial pigment, as the electron donor. Applying simple spin casting and thermal annealing, trilayer devices with a pure donor (p) layer, a bulk heterojunction (i) layer, and a pure acceptor (n) layer have been fabricated. Tert-butoxycarbonyl quinacridone ( t-BOC QA), a soluble yellow precursor of industrial red pigment of quinacridone, was synthesized by replacing the H atom of the NH group on QA with a t-BOC group. Uniform thin films were prepared by spin casting t-BOC QA solutions, which could be converted into insoluble thin films by thermal treatment to remove the solubilizing groups. This conversion allowed for the subsequent depositions of multiple layers without the use of orthogonal solvents. The p-i-n devices showed much higher device performance than their bilayer and simple bulk heterojunction counterparts, exhibiting power conversion efficiencies (PCEs) as high as 0.83%.

Ultrasound responsive organogels based on cholesterol-appended quinacridone derivatives with mechanochromic behaviors

A series of cholesterol-appended quinacridone (QA) derivatives 1a–1d have been synthesized, in which 1b and 1c could form stable organogels in a wide range of organic solvents upon ultrasound irradiation. Field emission scanning electronic microscope (FESEM) and transmission electron microscopy (TEM) of xerogels or precipitates indicated that 1b and 1c formed 1D fibrous nanostructure, while 1a assembled into 3D flower-like microstructures. The ultrasound-induced organogel process was characterized by kinetic UV-vis and photoluminescence spectroscopic methods suggesting the formation of π-π aggregates in the gel state. Experimental results demonstrated that the ultrasound could promote molecules to contact frequently in the solution and induce semistable initial aggregates, which propagate to form nano/micro superstructures. The aggregation model was optimized by semiempirical AM1 calculation suggesting the hierarchical self-assembly process. In addition, the formed xerogel film exhibited mechanochromic property, and the phase transition process was accompanied by the fluorescence changes between yellowish green and orange.