Carrier balance is essential to obtain efficient emission in polymer light-emitting diodes (PLEDs). A new polymer 3P5O composed of alternating p-terphenyl and tetraethylene glycol ether segments is designed and synthesized by the Suzuki coupling reaction and successfully employed as hole-buffer layer to improve carrier balance. Multilayer PLEDs [ITO/ PEDOT:PSS/3P5O/SY/LiF/Al], with Super Yellow (SY) as the emitting layer and 3P5O as the hole-buffer layer, reveal maximum luminance (17,050 cd/m 2 ) and maximum current efficiency The performance enhancement has been attributed to holebuffering characteristics of 3P5O that results in improved carrier recombination ratio and wider carrier recombination region. Current results indicate that the 3P5O is a promising hole-buffer polymer to enhance the performance of optoelectronic devices.

Insulated molecular wires (IMWs) bearing noncentrosymmetric conjugated axle components were precisely synthesized via iterative cross-coupling reactions in organic solvents and subsequent intramolecular slippage transformation in aqueous solvents. This programmable synthetic procedure selectively afforded both insulated and uninsulated molecular wires bearing oligo(phenylene ethynylene)a nd permethylated a-cyclodextrins with welldefined conjugation lengths and supramolecular structures. High selectivity of this method was confirmed by NMR and mass spectroscopica nalyses. The resultant IMWs exhibited distinct opticalp roperties because of different conjugation lengthsa nd insulated structures. This synthetic strategy for structurally defined IMWs bearing non-centrosymmetric conjugated axle components could provide ap latform foro btaining diversef unctionalized materials useful in the fields of non-centrosymmetric molecular machines and molecular electronics. p-Conjugated molecules have gained significant importance because of their unique optical and electrical properties, resulting in their wide application in developing components such as light emitting diodes, [1,2] sensors, [3] bio-imaging materials, [4] and conductive materials in molecular electronics. [5] p-Conjugated molecules were endowedw ith superior physical properties, such as high conductivity,o na ccount of their delocalized p-electrons. Because of their particularly high conductivity, pconjugated molecules are also called molecular wires. However,t he strong p-p molecular interactions of their p-orbitals impart negative effects on their processabilities and material properties, resulting in decreased solubility and disordered energy/electron transfer.Ino rder to overcome these effects, in-sulatedm olecular wires (IMWs) have been proposed, [6] in which the p-conjugated cores are three-dimensionally protected by non-conductive cyclic molecules with host-guesti nteractions. As the threading supramolecular structures in IMWs, rotaxanes [7] have attracted attention of chemists because they isolate the conjugatedb ackbonesf rom surrounding molecules, resultingi na ugmented solubility and unimolecular p-conjugated properties. [8][9][10] The synthetic methodologies for IMWs are strongly governed by the host-guest interactions betweenc onjugated axles and cyclic molecules; [11] hence,t here are limited conjugated cores that are suitable fort he syntheses of IMWs. [6] The achievement of af ine control of IMWs with desired covering positions on the various p-backbones stillr emains challenging. Recently,w ereported the synthesis as well as optical [12,13] and electrical [14,15] properties of IMWs using permethylated cyclodextrinsl inked with conjugated guests. [16] We obtained af acile access to the IMWs via self-inclusion between oligo(phenylene ethynylene) (OPE) linked with permethylated a-cyclodextrins (PM a-CDs) and asubsequent fixation with palladium-catalyzed cross-coupling reactions in aqueous media, thus yieldingf unctionalized materials for molecu...

No abstract

π-Conjugated molecules have been utilized to functionalize inorganic surfaces to form organic–inorganic hybrid materials. However, the intrinsically strong π–π interaction results in undesirable aggregations on the inorganic surface, thereby disturbing the charge transfer through the organic–inorganic interface. In this study, a new strategy was developed using insulated π-conjugated molecules bearing a [1]rotaxane structure, where the π-conjugation was covered with covalently linked permethylated α-cyclodextrins. Aggregation-free immobilization was achieved on an inorganic surface by using insulated molecules to suppress intermolecular interaction. In the presence of these insulated molecules, the hybrid interface displayed excellent interfacial electrical properties. Moreover, the functionalized hybrid surface was utilized as an electrocatalyst to produce hydrogen peroxide using a Co(II)–chlorin complex, wherein the catalytic efficiency was improved dramatically by utilizing insulated molecules as bridging moieties at the interface. These results demonstrate that the insulation of π-conjugated molecules is a powerful strategy for modifying inorganic surfaces.