Indolo[3,2-b]carbazole Research Articles

DFT simulations of photovoltaic parameters of dye‐sensitized solar cells with new efficient sensitizer of indolo[3, 2‐b]carbazole complexes

AbstractDeveloping economical and high‐performing sensitizers is crucial in advancing dye‐sensitized solar cells (DSSCs) and optoelectronics. This research paper explores the potential of novel red light‐absorbing organic dyes based on Indolo[3,2‐b]carbazole (ICZ) as the donor applied in co‐sensitizer‐free DSSCs for breakthroughs in photovoltaic (PV) applications. DFT and TD‐DFT based computational methods were employed to calculate the conduction band levels, electron injection capabilities, and power conversion efficiency (PCE) of metal‐free organic dyes (ICZ1–ICZ9) having D‐A‐π‐A architecture. Comprehensive analyses included NBO, DOS, FMO, ICT, MEP, binding energy, and TDM analysis. Quantum chemical calculations of the structural, photochemical, and electrochemical properties, as well as the key parameters, reveals that all the designed dyes could be an excellent candidate for high‐efficiency DSSCs due the small energy gap (2.130–1.947 eV), longer wavelength absorption (759.47–520.63 nm), longer lifetimes (15.65–6.67 ns), a lower ΔGreg (0.29–0.14 eV), a significant dipole moment changes (31.489–16.195D), LHE (0.95‐0.46), the large qCT (0.962–0.689), small DCT (7.657, 4.897 Å), and VOC (1.13–0.86 eV). This quantum simulation showed that, when compared to reference D8, the photovoltaic dyes ICZ8, ICZ2, and ICZ7 are recognized as being eye‐catching. Furthermore, dye@(TiO2)9 cluster model results demonstrate promising prospects for enhancing the photovoltaic (PV) performance of ICZ1–ICZ9 dyes by electron injection and conduction band (CB) engineering. This study will help the experimentalists for developing ICZ‐based PVs as more efficient and sustainable energy solutions.

Synthesis and luminescent properties of the indolo[3,2-b]carbazole derivatives containing coumarin fluorophores

Two new indolo[3,2-b]carbazole derivatives containing coumarin fluorophores (2,8-ICZ-C and 3,9-ICZ-C) were synthesized by the introduction of two 7-diethylamino-3-coumarinyl fluorophores at 2,8-positions and 3,9-positions of the indolo[3,2-b]carbazole (ICZ) core, respectively, as the organic emitters for organic light-emitting devices (OLEDs). The photophysical and electrochemical properties and thermal stabilities of the compounds were systematically investigated. These compounds exhibited good thermal stability as well as strong blue emission (Φf of 79.67 % for 2,8-ICZ-C and Φf of 55.90 % for 3,9-ICZ-C) in CH2Cl2 solution. The doped devices with a structure of ITO/PEDOT:PSS (50 nm)/2,6DCzPPy:ICZ derivative (x, wt%) (30 nm)/TPBi (20 nm)/Liq (3 nm)/Al (130 nm) were fabricated by solution-processed the emitting layers, in which the 2,8-ICZ-C device exhibited a maximum luminance (Lmax) of 1425 cd/m2, a maximum current efficiency (CEmax) of 1.24 cd/A and a maximum external quantum efficiency (EQEmax) of 0.71 %, and the 3,9-ICZ-C device showed Lmax, CEmax and EQEmax of 1005 cd/m2, 1.14 cd/A and 0.53 %, respectively.

End-capped engineering of carbazole based dopant free hole transporting material with improved power conversion efficiency

Perovskite solar cells (PSCs) belonging to third-generation of solar cells are reported to have better power conversion efficiency, cost-effectiveness, and many other benefits. This computational investigation focuses on designing five indolo(3,2-b) carbazole (ICZ) central core containing small hole transport materials (HTMs) to discover photovoltaic properties as donors for perovskite solar cells accompanied by enhanced charge mobility. New HTMs with A–π–D–π–A skeleton has been designed by thiophene-bridged end-capped acceptor engineering on reference molecule (ICZ-R). Absorption spectra, frontier MOs, density of state analysis, molecular electrostatic potential surfaces, transition density matrix, non-covalent interactions, iso-surface maps, and planarity parameters were analyzed through different softwares for better-predicting performance of perovskite solar cells. All tailored HTMs showed better absorption profiles. Among them, ICZ-D3 exhibited the maximum absorbance λmax at 695 nm in dichloromethane solvent and the greatest full-width half maximum (313.93 nm). ICZ-D2 showed the lowest Eg of 1.62 eV, and the highest dipole moment (8.35 D) in the solvent phase, showing admirable solubility. Designed HTMs exhibited decelerated HOMO values (−4.62 to −5.25), lower values of binding energies (0.0323–0.388 <0.542 eV), better intrinsic charge transfer percentage (10.74–72.71%>7.88), lower hardness (0.81–1.11 <1.78 eV) and greater softness values (0.90–1.23 >0.56 eV) as compared to ICZ-R. All designed HTMs demonstrated higher estimated VOC and power conversion efficiency (PCE=11.81–25.90%) than ICZ-R, leading to fruitful applications. ICZ-D4 resulted in the highest PCE (25.90%) with better VOC (1.25 eV). These outstanding findings paved a new way to develop better-performing HTMs for PSCs.

Indolo[3,2-b]carbazole-based non-fullerene acceptors for organic photovoltaic cells

Two indolo[3,2-b]carbazole-based non-fullerene acceptors (ICZ-IC and ICZ-ICF) with a A-π-D-π-A structure were synthesized by end-capping either non-fluorinated or fluorinated 1,1-dicyanomethylene-3-indanone into the indolo[3,2-b]carbazole (ICZ) core via the thiophene linker. Their photophysical and electrochemical properties were investigated. The photovoltaic device fabricated PBDB-T:ICZ-IC exhibited a maximum power conversion efficiency of 2.51% with an open-circuit voltage of 0.98 V without any post-treatment, while the photovoltaic device fabricated PBDB-T:ICZ-ICF showed a maximum power conversion efficiency of 1.26% with an open-circuit voltage of 0.82 V. By addition of chloronaphthalene and chlorobenzene solvent vapor annealing, the power conversion efficiency of the optimized device fabricated PBDB-T:ICZ-IC was increased to 3.20%.

Singlet Fission, Polaron Formation, and Energy Transfer in Indolo[3,2-b]carbazole Thin Films and Single Crystals

The ultrafast excited-state relaxation dynamics of indolo[3,2-b]carbazole (ICZ) molecules were investigated in thin films and single crystals. In the ICZ film, singlet fission (SF) was directly obs ...

Acid condensation products of indole-3-carbinol and their in-vitro (anti)estrogenic, (anti)androgenic and aryl hydrocarbon receptor activities

The objective of the study was to investigate the (anti)estrogenic, (anti)androgenic and aryl hydrocarbon receptor (AhR) agonistic activities of a mixture of acid condensation products of indole-3-carbinol, termed RXM, and to identify the compounds most responsible for the observed effects, using in vitro receptor-reporter gene transcriptional activation bioassays. For this, HPLC-fractions of RXM were prepared and tested. LC-MS/MS analysis was carried out for the identification of some of the acid condensation products. The RXM displayed weak estrogenic and anti-androgenic, and strong AhR agonistic properties. The fraction containing 3,3-diindolylmethane (DIM) displayed a weak estrogenic and relatively strong anti-androgenic activity. DIM was confirmed to be an androgen receptor (hAR) antagonist and a partial estrogen receptor (hERα) agonist. Also the fraction containing the trimer [2-(indol-3-ylmethyl)indol-3-yl]indol-3-ylmethane (LTr1) showed anti-androgenic activities. It was shown for the first time that DIM is not only estrogenic and anti-androgenic, but also possesses anti-estrogenic properties. Though indolo[3,2-b]carbazole (ICZ) is a potent AhR activator and was detected in the RXM, it did not contribute to AhR-agonist activity. Instead, fractions containing the trimers LTr1 and 5,6,11,12,17,18-hexahydrocyclonona[1,2-b:4,5-b′:7,8-b″]tri-indole (CTr), as well as some unidentified compounds showed the highest AhR activation. The fraction, containing the linear trimer LTr1, showed a weak anti-androgenic activity which has not been reported before. The study demonstrates the importance of a bioassay directed approach for identifying compounds that contribute most to the effects of mixtures.

Design and Characterization of New D-A Type Electrochromic Conjugated Copolymers Based on Indolo[3,2-b]Carbazole, Isoindigo and Thiophene Units.

Two new donor–acceptor (D–A) type organic conjugated random copolymers were successfully synthesized by three-component Stille coupling polymerization of indolo[3,2-b]carbazole (ICZ), isoindigo (IID) and thiophene units, namely PITID-X (X = 1 and 2), with the controlled monomer feed ratios of 3:1:4 and 1:1:2, respectively. The strategy of incorporating different alkyl-branched donor/acceptor units and raw material feed ratios facilitated the improvement of optical properties, solubility, conjugated structure, and electrochromic performance. Cyclic voltammetry, UV-vis-NIR absorption spectra, kinetic and colorimetric measurements of the spray-coated films were recorded in the fabricated three-electrode cells. The results showed that PITID-2, whose optical/electrical properties were better than that of PITID-1, was the candidate electrochromic material due to low band gap of 1.58 eV accompanying the color changing from cyan (neutral state) to gray (oxidized state). The copolymer also illustrated fast bleaching/coloration response time of 2.04/0.33 and 1.35/1.50 s in a 4 s time interval, high coloration efficiency of 171.52 and 153.08 cm2 C−1 and stable optical contrast of 18% and 58% at the wavelength of 675 and 1600 nm, respectively.

Indolo[3,2‐b]carbazole‐based poly(arylene ethynylene)s through Sonogashira coupling for optoelectronic and sensing applications

ABSTRACTTwo indolo[3,2‐b]carbazole (ICZ)‐based polymers have been designed and synthesized using Sonogashira cross‐coupling based on dibromoindolo[3,2‐b]carbazoles and 2,7‐diethynylfluorene or 9,10‐diethynylanthracene. The 2, 8 positions of the ICZ moiety has been used for the bridging of arylene ethynylene structure to form the polymer backbone. The characterization has been done by Fourier transform infrared, proton nuclear magnetic resonance, ultraviolet–visible and (UV–vis) fluorescence spectroscopic methods. The polymers, moderately soluble in aprotic and chlorinated solvents, have been found to possess thermal stability above 300°C. The band gap examinations, executed through cyclic voltammetry and complemented by UV–vis studies, indicated their semiconducting nature and the possibility for their utilization for the fabrication of polymer solar cells and for optical switching applications. Interestingly, the new diethynylindolocarbazole systems have been found to act as Bronsted acid sensors as well as a Hg2+ receptors. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 46940

SEGMENTAL ARTERIAL MEDIOLYSIS: A COMMON MISDIAGNOSIS AND UNDER-RECOGNIZED PHENOMENON

Indole-3-carbinol (I3C) is a secondary plant metabolite produced in vegetables of the Brassica genus, including cabbage, cauliflower, and brussels sprouts. I3C is both an anti-initiator and a promoter of carcinogenesis. Consumption of I3C by humans and rodents can lead to marked increases in activities of cytochrome P-450-dependent monooxygenases and in a variety of phase II drug-metabolizing enzymes. We have reported previously that the enzyme-inducing activity of I3C is mediated through a mechanism requiring exposure of the compound to the low-pH environment of the stomach. We report here the aromatic hydrocarbon responsiveness-receptor Kd values (22 nM-90 nM), determined with C57BL/6J mouse liver cytosol and the in vitro- and in vivo-molar yields (0.1-6%) of the major acid condensation products of I3C. We also show that indolo[3,2-b]carbazole (ICZ) is produced from I3C in yields on the order of 0.01% in vitro and, after oral intubation, in vivo. ICZ has a Kd of 190 pM for aromatic hydrocarbon responsiveness-receptor binding and an EC50 of 269 nM for induction of cytochrome P4501A1, as measured by ethoxyresorufin O-deethylase activity in murine hepatoma Hepa 1c1c7 cells. The binding affinity of ICZ is only a factor of 3.7 x 10(-2) lower than that of the highly toxic environmental contaminant and cancer promoter 2,3,7,8-tetrachlorodibenzo-p-dioxin. ICZ and related condensation products appear responsible for the enzyme-inducing effects of dietary I3C.

Synthesis, characterization and printing application of alkylated indolo[3,2-b]carbazoles

The synthesis, characterization, and field-effect transistor (FET) properties of new alkylated indolo[3,2-b]carbazole (ICz) based materials are reported. Dialkyl substitution at the 2,8-positions of the ICz core structure do not affect strong NH⋯ π interactions, thus favoring a herringbone packing motif. OFET devices fabricated by compounds of this substitution pattern displayed a charge carrier mobility of ∼10−2cm2Vs−1. These interactions are suppressed when introducing substituents at the 5,11-positions, resulting in greatly enhanced solubility. A solution processable ICz derivative was finally used in a newly developed pneumatic printing setup to yield a crystalline film with aligned crystals along the printing direction.

High molecular weight broad band-gap polymers based on indolo[3,2-b]carbazole and thiazolo[5,4-d]thiazole derivatives for solar cells

Two broad band-gap high molecular weight polymers, poly[(5,11-di(9’-heptadecanyl)-indolo[3,2-b]carbazole-alt-2,5-bis(3-n-octylthiophene-2-yl)-thiazolo[5,4-d]thiazole (PICzOTzTz) and poly[(5,11-di(9’-heptadecanyl)-indolo[3,2-b]carbazole-alt-2,5-bis(3-n-n-dodecylthiophene-2-yl)-thiazolo[5,4-d]thiazole]) (PICzDOTzTz), consisting of indolo[3,2-b]carbazole (ICz) and thiazolo[5,4-d]thiazole (TzTz) derivatives were synthesized by Suzuki polycondensation. Their physical, electrochemical and optical properties were characterized in details. The thermogravimetric analysis displayed high thermal stability, and 5% degradation temperatures of PICzOTzTz and PICzDOTzTz were 427 and 435°C, respectively. The optical band gaps of PICzOTzTz and PICzDOTzTz were 2.13 and 2.07 eV, respectively. The hole mobilities of PICzOTzTz and PICzDOTzTz were investigated by the space charge limited current (SCLC) method, which gave the mobility values of 7.21 × 10–5 and 1.57 × 10–4 cm2/(V s) for each polymer, respectively. Through the photo-voltaic characterization in polymer solar cells, they showed that the power conversion efficiencies of PICzOTzTz and PICzDOTzTz were 0.64 and 0.99%, respectively.

The Brassica-derived phytochemical indolo[3,2-b]carbazole protects against oxidative DNA damage by aryl hydrocarbon receptor activation.

Epidemiological studies suggest that a high intake of Brassica vegetables protects against colon carcinogenesis. Brassica vegetables are rich in glucosinolates which are hydrolysed during digestion to various products including indole-3-carbinol. In animal studies, a protective effect of indole-3-carbinol has been demonstrated in colon carcinogenesis. Indole-3-carbinol is highly unstable and, therefore, the observed protection likely results from condensation products of indole-3-carbinol, e.g. diindolylmethane or indolo[3,2-b]carbazole (ICZ). Interestingly, ICZ is a potent activator of the aryl hydrocarbon receptor (AhR), a transcription factor known to mediate toxic effects of environmental pollutants, such as dioxin and polycyclic aromatic hydrocarbons. Here, we show that ICZ protects against oxidative DNA damage in various cell lines including the colon carcinoma cell line Caco-2. When preincubated for 24h, ICZ decreases DNA single-strand break (SSB) and 8-oxo-dG formation induced by tertiary-butylhydroperoxide (t-BOOH), hydrogen peroxide or benzo[a]pyrene. Simultaneous addition of ICZ does not protect against t-BOOH-induced SSB formation, which disproves a direct radical scavenging effect. The repair of SSBs was not enhanced, but the data indicate that ICZ attenuates the ROS level following t-BOOH. The antioxidant response factor Nrf2 was not activated following ICZ. Functional inhibition of the AhR and AhR-/ARNT-defective cell lines demonstrate that the AhR/ARNT pathway is mandatory for the observed ROS defence caused by ICZ, supporting the hypothesis that AhR-mediated regulation of defence genes is involved. The data point to a hitherto unknown protective function of ICZ and a novel role of the AhR in the defence against oxidative DNA damage.

Indolo[3,2-b]carbazole-based poly(arylene ethynylene)s

A novel family of indolo[3,2-b]carbazole (ICZ)-based polymers was designed and synthesized using Sonogashira cross-coupling reaction between three bisbromine indolo[3,2-b]carbazoles and 1,4-diethynylbenzene. The new polymers have an arylene ethynylene structure with ICZ moiety interconnected in the main chain by 2,8-, 3,9- or 6,12- positions. The polymers were obtained as partially soluble materials, in chlorinated, aromatic and aprotic polar solvents. The structure of the polymers was studied by spectroscopic methods such as Fourier transform infrared, proton and carbon-13 nuclear magnetic resonance, ultraviolet–visible and photoluminescence spectroscopies, thermogravimetry and molecular weights determined by gel permeation chromatography. Electrochemical properties were investigated by cyclic voltammetry using films cast on platinum disc working electrode. Optical and electronic properties were discussed from the viewpoint of the connection positions of ICZ units in the polymer chain.

Synthesis of modified benzothiadiazole-thiophene-cored acceptor and carbazole/indolocarbazole alternating conjugated polymers and their photovoltaic applications

Two low band gap (LBG) copolymers PCz-DTBTT and PICz-DTBTT, featuring a modified 2,1,3-benzothiadiazole–thiophene-cored unit 2,5-di(4-(4-octylthiophen-2-yl)-2,1,3-benzothiadiazol-7-yl)thiophene (DTBTT) as acceptor and electron-rich building blocks carbazole (Cz) or indolo[3,2-b]carbazole (ICz) as donor, were synthesized via Suzuki crossing-coupling method. Both copolymers show good solubility in common organic solvents and thermal stabilities. The optical study exhibits a broad absorption in the range of 300–700 nm with the optical band gap (\(E_{g}^{\text{opt}}\)) of about 1.78 eV, while the electrochemical cyclic voltammetry (CV) measurement shows the relatively deeper highest occupied molecular orbital (HOMO) energy level (about −5.45 eV). Photovoltaic devices based on the blends of PCz-DTBTT/PC71BM (w:w; 1:2) and PICz-DTBTT/PC71BM (w:w; 1:2) with devices configuration as ITO/PEDOT:PSS/polymer:PC71BM/Ca/Al, show the power conversion efficiency (PCE) up to 2.07 and 2.21 %, with the open circuit voltage (Voc) of 0.75 and 0.80 V, short circuit current density (Jsc) of 6.47 and 6.40 mA cm−2, fill factor (FF) of 42.6 and 43.2 % under an AM1.5 simulator (100 mW cm−2), respectively. It is apparent that DTBTT-based devices exhibit the broad response range, covering from 300 to 720 nm.

Malassezia Yeasts Produce a Collection of Exceptionally Potent Activators of the Ah (Dioxin) Receptor Detected in Diseased Human Skin

Malassezia yeasts are commensal microorganisms, which under insufficiently understood conditions can become pathogenic. We have previously shown that specific strains isolated from diseased human skin can preferentially produce agonists of the aryl hydrocarbon receptor (AhR), whose activation has been linked to certain skin diseases. Investigation of skin scale extracts from patients with Malassezia-associated diseases demonstrated 10- to 1,000-fold higher AhR-activating capacity than control skin extracts. Liquid chromatography-tandem mass spectrometry analysis of the patients' extracts revealed the presence of indirubin, 6-formylindolo[3,2-b]carbazole (FICZ), indolo[3,2-b]carbazole (ICZ), malassezin, and pityriacitrin. The same compounds were also identified in 9 out of 12 Malassezia species culture extracts tested, connecting their presence in skin scales with this yeast. Studying the activity of the Malassezia culture extracts and pure metabolites in HaCaT cells by reverse transcriptase real-time PCR revealed significant alterations in mRNA levels of the endogenous AhR-responsive genes Cyp1A1, Cyp1B1, and AhRR. Indirubin- and FICZ-activated AhR in HaCaT and human HepG2 cells with significantly higher, yet transient, potency as compared with the prototypical AhR ligand, dioxin. In loco synthesis of these highly potent AhR inducers by Malassezia yeasts could have a significant impact on skin homeostatic mechanisms and disease development.

Malassezia-derived indoles activate the aryl hydrocarbon receptor and inhibit Toll-like receptor-induced maturation in monocyte-derived dendritic cells

The aryl hydrocarbon receptor (AhR) is a nuclear receptor and transcriptional regulator with pleiotropic effects. The production of potent AhR ligands by Malassezia yeasts, such as indirubin, indolo[3,2-b]carbazole (ICZ), tryptanthrin and malassezin, has been associated with the pathogenesis of seborrhoeic dermatitis and pityriasis versicolor. Antigen-presenting cells in the skin can encounter microbes in the presence of these bioactive metabolites that could potentially modulate their function. To study the effects of the aforementioned naturally occurring ligands on AhR activation and Toll-like receptor (TLR)-induced maturation in human monocyte-derived dendritic cells (moDCs). These indoles were screened for AhR activation capacity in moDCs employing CYP1A1 and CYP1B1 induction as read out and for their effects on the function of moDCs after TLR-ligand stimulation. Indirubin and ICZ were the most potent AhR ligands and were selected for subsequent experiments. Concurrent exposure of moDCs to indirubin or ICZ together with TLR agonists significantly augmented the AhR-mediated CYP1A1 and CYP1B1 gene expression. Additionally, mature DCs that were subsequently stimulated with AhR ligands showed increased AhR target gene expression. Moreover, these ligands limited TLR-induced phenotypic maturation (CD80, CD83, CD86, MHC II upregulation) of moDCs, reduced secretion of the inflammatory cytokines interleukin (IL)-6 and IL-12, and decreased their ability to induce alloreactive T-lymphocyte proliferation. These results demonstrate that AhR agonists of yeast origin are able to inhibit moDC responses to TLR ligands and that moDCs can adapt through increased transcription of metabolizing enzymes such as CYP1A1 and CYP1B1.

Substitution effect on molecular packing and transistor performance of indolo[3,2-b]carbazole derivatives

In this manuscript, two chloro-substituted derivatives of indolo[3,2-b]carbazole (ICZ), 2,8-dichloro-indolo[3,2-b]carbazole (CICZ) and 2,8-dichloro-5,11-dihexyl-indolo[3,2-b]carbazole (CHICZ) were designed and synthesized. The only difference between CICZ and CHICZ is at the N-5 and N-11 positions with or without long alkyl side chains. Interestingly, CICZ and CHICZ exhibited similar thermal, optical, and electrochemical properties, while their molecular packing motifs in solid state and corresponding charge transport properties were significantly different. The alkyl chains at N-5 and N-11 positions were proved not only enhancing the solubility and self-organization of the compounds but also shifting the molecular packing from herringbone (CICZ) to one-dimensional π–π stacking (CHICZ). Moreover, nearly no field-effect performance was observed for CICZ, while the mobility of CHICZ was as high as 0.14 cm2 V−1 s−1 for its thin films and 0.5 cm2 V−1 s−1 for its single crystals. These results confirmed that the chemical substitutions are a powerful molecular design tool to tune the molecular packing motifs of organic semiconductors and their corresponding electronic properties.

Syntheses and properties of copolymers containing indolocarbazole moiety in the side chain

Novel copolymers containing the indolo[3,2-b]carbazole (INC) moiety were synthesized, and the effects of the INC content on their physical properties were investigated. The homopolymer of the INC-containing monomer, 1-octyl-7-(4-vinylbenzyl)indolo[3,2-b]carbazole and copolymers with styrene were prepared by radical polymerization. Four kinds of copolymers with different compositions were obtained. The glass transition temperatures (Tgs) were observed in the range of 101–112 °C, and the decomposition temperatures were nearly 400 °C. The photonic properties of the copolymers were also evaluated in solution in tetrahydrofuran and for spin-coated films on a fused silica substrate. In the ultraviolet-visible absorption spectra, maximum absorption peaks were observed at 340–345 nm in both the solutions and the films. In the case of the solutions, the photoluminescence intensities of the copolymers increased with increasing INC monomer units in the copolymer. On the contrary, the photoluminescence intensities of the copolymer films decreased with increasing INC content in the copolymer, which is likely due to the concentration quenching caused by the condensation of intermolecular interactions derived from INC components. The copolymer with a low content of the INC moiety exhibited high emission and good film-forming ability. The syntheses of novel copolymers containing indolo[3,2-b]carbazole (INC) moiety were carried out, and the effect of INC content on the physical properties were investigated. All the copolymers were glassy and the decomposition temperatures were nearly 400 °C. It was found that the photoluminescence intensities of the copolymer films decreased with the increase of INC content, which would be caused by the concentration quenching by the intermolecular interaction between INC components. The copolymer with low content of INC moiety exhibited the high emission property and good film-forming ability.

Organic Field‐Effect Transistors: High‐Performance Organic Single‐Crystal Field‐Effect Transistors of Indolo[3,2‐b]carbazole and Their Potential Applications in Gas Controlled Organic Memory Devices (Adv. Mater. 43/2011)

The interaction between nitric oxide (NO) molecules and the organic crystal surface of indolo[3,2-b]carbazole (ICZ) can influence the charge carrier transport process of ICZ single crystal field-effect transistors. Random NO molecules come in contact with the crystal surface, initiate the reaction between NO and ICZ, and affect the threshold voltage of the device. As reported by Hui Jiang, Christian Kloc, Wenping Hu, and co-workers, this phenom-enon will uncover the potential applications of future gas-sensing and storage devices.

High‐Performance Organic Single‐Crystal Field‐Effect Transistors of Indolo[3,2‐b]carbazole and Their Potential Applications in Gas Controlled Organic Memory Devices

Single crystals of linear fused rings with nitrogen heteroatom, indolo[3,2-b]carbazole (ICZ), have been synthesized. In addition, field-effect transistors (FETs) of planar ICZ single crystals have been fabricated. The hole mobility approaches values of up to 1.0 cm2 V−1 s−1 with an on/off ratio of ∼106. The transistors exhibit sensitivity to nitric oxide (NO). The gas-sensitive behavior indicates the great potential for future low-cost and high-density storage devices.