Indenofluorene Derivatives Research Articles

Photophysical Investigation of One Pot Synthesized Novel Indenofluorene Derivative (BDP) as a Fluorescent Chemosensor for the Detection of Fe3+ Ion.

An Indane-1-one derivative 11-(1-benzyl-1H-indol-3-yl)-10,12-dihydrodiindeno[1,2-b:2',1'-e]-pyridine (BDP) has been synthesized by the reaction of Indan-1-one with 1-benzyl-1H-indole-3-carbaldehyde. FT-IR, 1H-NMR, 13N-NMR and Mass spectroscopic techniques has been used to confirmed the structure of BDP. The observed photophysical changes in BDP across various solvents were associated. The impact of various interactions on photophysical parameters, including Stokes shift, dipole moment, oscillator strength, and fluorescence quantum yields, has been assessed in relation to solvent polarity. Moreover, BDP demonstrates potential as a selective fluorescent chemosensor for detecting Fe3+ ion within a range of cations in an aqueous DMSO environment. A thorough investigation into the recognition mechanism of BDP towards Fe3+ ion has been conducted using Benesi-Hildebrand and Stern-Volmer, measurements. BDP forms a 2:1 complex with the Fe3+ ion, exhibiting fluorescent quenching behaviour.

A wide-bandgap nonplanar small molecule acceptor having indenofluorene core for non-fullerene polymer solar cells

Recently, the nonplanar non-fullerene acceptors (NFAs) are attractive in active layers in highly efficient polymer solar cells (PSCs) because of their up-shifted energy levels, improved absorption as well as charge transportation performances. However, presently nonplanar NFAs always absorb the lights in the long-wavelength region and even to near-infrared (NIR) region, which limits their further utilization in low-bandgap polymer donor-based PSCs. To further probe the performances of nonplanar NFAs in low-bandgap polymer-based PSCs, a new twisted NFA (i-IF-4F) having indenofluorene derivatives as the electron-donating fused-ring core was synthesized. Due to the relatively weak electron-donating ability of the indenofluorene core, this newly designed NFA has wide optical bandgap (1.79 eV) with absorption spectrum ranged from 450 to 690 nm, suitable lowest unoccupied molecular orbital (LUMO, −3.71 eV) and highest occupied molecular orbital (HOMO, −5.55 eV) energy levels, which ensure its matching well with the typically low-bandgap polymer (PTB7-Th) to achieve complementary absorption and proper differences in energy levels. After thermal annealing treatment, the film morphologies, charge transfer properties and charge recombination performances of i-IF-4F:PTB7-Th-based device was improved to a certain degree, leading to an optimized power conversion efficiency (PCE) of 6.47%. The work in this manuscript demonstrates the applicability of wide-bandgap twisted acceptors in PSCs and the possible approach to further improve the performances of wide-bandgap nonplanar acceptors in PSCs.

A new wide bandgap small molecular acceptor based on indenofluorene derivatives for fullerene-free organic solar cells

An efficient wide bandgap small molecular electron acceptor 2,2'-((2Z,2′Z)-(((6,6,12,12-tetraoctyl-6,12-dihydroindeno[1,2-b]fluorene-2,8-diyl)bis(thiophene-5,2-diyl))bis(methanylylidene))bis(3-oxo-2,3-dihydro-1H-indene-2,1-diylidene))dimalononitrile (IFTIC) based on indenofluorene for organic solar cells was developed. With strong and broad absorption in shortwave region (470–690 nm) and suitable energy levels (HOMO = −5.42 eV, LUMO = −3.85 eV), this newly designed wide bandgap acceptor was able to preferably match the most typical low bandgap polymer donor material poly({4,8-bis[(5-(2-ethylhexyl)-2-thienyl]benzo[1,2-b:4,5-b′]dithiophene-2,6-diyl}{3-fluoro-2-[(2-ethylhexyl)carbonyl]thieno[3,4-b]thiophenediyl}) (PTB7-Th). Benefit from its up-shifted LUMO energy level and complementary absorption spectrum, the inverted device based on IFTIC and PTB7-Th processed power conversion efficiencies (PCE) up to 6.56% and relatively high open circuit voltage (Voc) value (0.92 V). These results demonstrate that the indenofluorene type wide bandgap small molecule could be the promising electron acceptor in organic solar cells.

Indenofluorene‐Based Blue Fluorescent Compounds and Their Application in Highly Efficient Organic Light‐Emitting Diodes

AbstractBlue fluorescent compounds based on indenofluorene derivatives incorporating the (diphenylamino)arylvinyl group and di‐tert‐butylphenyl blocking units have been synthesized by Suzuki coupling and the Horner–Wadsworth–Emmons reaction. Their electroluminescence in multilayered OLEDs was examined; the devices have the structures ITO/DNTPD/NPB/MADN:blue dopant/Alq3/LiF/Al. A device with 7 % 2‐(3,5‐di‐tert‐butylphenyl)‐8‐(9,9‐diethyl‐2‐(diphenylamino)fluoren‐7‐ylethenyl)‐6,6,12,12‐tetraethylindeno[1,2‐b]fluorene (3) as blue dopant showed a luminous efficiency of 12.2 cd A–1, a power efficiency of 6.08 lm W–1, and an external quantum efficiency of 7.84 % at 20 mA cm–1 with CIE (Commission Internationale d'Énclairage) (x, y) coordinates of (0.148, 0.241) at 8.5 V. A deep‐blue OLED with CIE (x, y) coordinates of (0.153, 0.128) doped with 2‐(3,5‐di‐tert‐butylphenyl)‐8‐[9‐(3,5‐di‐tert‐butylphenyl)carbazol‐3‐ylethenyl]‐6,6,12,12‐tetraethylindeno[1,2‐b]fluorene (4) exhibited a luminous efficiency of 3.25 cd A–1, a power efficiency of 1.74 lm W–1, and an external quantum efficiency of 2.93 % at 20 mA cm–1.

A New Synthetic Procedure to 2,8-Diaminoindeno[1,2-b]fluorene as a Blue Light Emitting Material

Conjugated aromatic compounds are potential candidates as organic semiconductors for use in thin-film transistors (TFTs) and light-emitting diodes (LEDs), among which the fluorene-based compounds (Fig. 1) have received most attention owing to their good availability and processability. Therefore, the synthesis of indenofluorene derivatives draws significant interest for their proper supply in both designing a new derivative and manufacturing. Recently, 2,8-bis(diphenylamino)-6,6,12,12-tetramethyl-6,12-dihydroindeno[1,2b]fluorene (1) has been reported to have a good luminous efficiency and excellent life time, and good operation lifetime of its OELD device. These results prompted us to scale-up the synthesis of 1 for its further applications using the reported procedures as shown in Scheme 1. However we found a couple of problems in the reported synthesis, such as low yield, harsh reaction conditions and the formation of side products. Herein, we report an improved synthetic route to 1 which overcomes the problems found in the reported procedures. When we repeated the reported procedures (Scheme 1), we found three major synthetic problems. They are (i) formation of decarboxylated side products in the cyclization of 5 into 6 for parent indeno[1,2-b]fluorene ring; (ii) use of harsh reaction conditions of Wolff-Kishner reduction of 6 which are not suitable for large-scale preparation; and, (iii) low yield at the tetra-methylation of 7. In particular, when the tetra-methylation reaction of 7 was carried out by using n-BuLi and CH3I condition, tetrabutylindenofluorene was Figure 1. Structures of fluorine (i), indenofluorene (ii), and 2,8diaminoindenofluorene (1).

ChemInform Abstract: Synthesis of Fluorene and Indenofluorene Compounds: Tandem Palladium‐Catalyzed Suzuki Cross‐Coupling and Cyclization.

AbstractAn efficient and widely applicable method to prepare fluorene and indenofluorene derivatives is reported.

An aromatic imine group enhances the EL efficiency and carrier transport properties of highly efficient blue emitter for OLEDs

This study not only describes the synthesis and characterization of a novel indenofluorene derivative, 6,6,12,12-tetraethyl-2,8-bis-[1,1′;3′,1′]terphenyl-4′-yl-6,12-dihydro-indeno[1,2-b]fluorine (TP-EIF), for use as an emitting material in blue organic light emitting diodes (OLEDs), but also the comparison with 6,6,12,12-tetraethyl-2,8-bis-[1,1′;3′,1′]terphenyl-4′-yl-6,12-dihydro-diindeno[1,2-b;1′,2′-e]pyrazine (TP-EPY). UV-visible and PL spectra showed that the TP-EPY absorption and emission bands were red-shifted with narrow full widths at half maxima (FWHMs) compared to TP-EIF, both in solution and as a film. Density functional theory electronic structure calculations suggested that the spectral differences arose from the electron withdrawing properties of the imine group in the indenopyrazine, which increased conjugation in the core group and decreased conjugation in the side group at the LUMO level. The lower energy of the LUMO in TP-EPY resulted in increased active electron injection in electron-only devices and cyclic voltammetry (CV) measurements. The hole mobilities, which were measured by time of flight (TOF) methods, were 1.8 × 10−3 and 1.1 × 10−4 cm2 V−1 s for TP-EPY and TP-EIF, respectively, which demonstrated that TP-EPY displayed excellent hole transport abilities. The electron mobility was also high in TP-EPY (8.3 × 10−5 cm2 V−1 s). TP-EPY was, therefore, shown to be bipolar, unlike TP-EIF. The electroluminescence (EL) performance of TP-EPY in OLED devices was higher than that of TP-EIF: the luminance efficiencies were 1.72 and 0.76 cd A−1, and the power efficiencies were 0.65 and 0.27 lm W−1, for TP-EPY and TP-EIF, respectively. In particular, the FWHMs of the EL spectral bands were 54 nm for TP-EPY and 73 nm for TP-EIF, which demonstrated enhanced emission spectral purity. The external quantum efficiency of TP-EPY was 5.1%, which was more than twice the value for TP-EIF (2.19%).

A Facile Synthesis of Elusive Alkoxy-Substituted Hexa-peri-hexabenzocoronene

Oxidative cyclodehydrogenation of hexakis(4-alkoxyphenyl)benzene produces a quantitative yield of an indenofluorene derivative rather than the expected alkoxy-substituted hexa-peri-hexabenzocoronene (HBC). The structure of the unexpected indenofluorene was established by X-ray crystallography. The mechanistic considerations for the formation of the indenofluorene derivative led us to devise an alternative synthesis of elusive alkoxy-substituted HBC-a potentially important, disk-shaped structure for the preparation of liquid crystalline materials for practical applications in the emerging areas of molecular electronics and nanotechnology.

Dispirofluorene–Indenofluorene Derivatives as New Building Blocks for Blue Organic Electroluminescent Devices and Electroactive Polymers

A series of new dispiro[fluorene-9',6,9'',12-indeno[1,2b]fluorenes] (DSF-IFs) has been synthesised. These new building blocks for blue-light-emitting devices and electroactive polymers combine indenofluorene (IF) and spirobifluorene (SBF) properties. We report here our synthetic investigations towards these new structures and their thermal, structural, photophysical and electrochemical properties. These properties have been compared to those of IF and SBF. We also report the anodic oxidation of DSF-IFs that leads to the formation of non-soluble transparent three-dimensional polymers. The structural and electrochemical behaviour of these polymers has been studied. The first application of these building blocks as new blue-light-emitting materials in organic light-emitting diodes (OLED) is also reported.

Hybrid Organic/Inorganic Transistors Utilizing an Indenofluorene Derivative as Emitter

The molecular semiconductors are widely used on a great diversity of electronic and optoelectronic devices. The incorporation of molecular semiconductors to semiconductor- metal-semiconductor transistors (SMS) simplified the required production technology and, more importantly, allowed the construction of devices in vertical architecture with nearly ideal common-base current gains. In this work we present the results of the construction of SMS transistors utilizing an organic semiconductor, an indenofluorene derivative (DPIF), as emitter. The base and collector are respectively tin (Sn) and p- doped silicon (Si-p). The devices were electrically characterized at three-terminal measurements and were operated in common-base and common-emitter modes, revealing a permeable- base characteristic. The base thickness was varied in order to investigate the influence on the device performance. High current gain (~1) was obtained in common-base mode, and in common-emitter mode a current gain of 120 was achieved for a base thickness of 23 nm.

Hybrid Permeable‐Base Transistors Based on an Indenofluorene Derivative

Hybrid transistor highs! Hybrid permeable-base transistors are demonstrated (schematic circuit in Figure), which are based on an indenofluorene derivative (structure shown) and which operate by positive-charge-carrier transport. When the base/collector junction is reverse biased, the base transport factor of these devices saturates at nearly 100 %. They can be operated at current densities of the order of 1 mA mm−2.

A General Synthetic Route to Indenofluorene Derivatives as New Organic Semiconductors.

AbstractFor Abstract see ChemInform Abstract in Full Text.

A General Synthetic Route to Indenofluorene Derivatives as New Organic Semiconductors

A series of 2,6-disubstituted indenofluorene derivatives were obtained in high purity via a general route involving the Suzuki coupling reaction. The potential of these conjugated indenofluorenes as new organic semiconductors was demonstrated by the light-emitting diode reaching a high luminance of 1400 Cd/m(2) below 10 V. [structure: see text]