Wenyue Dong

Aggregation induced emission and amplified explosive detection of tetraphenylethylene-substituted polycarbazoles

Novel conjugated polymers based on 3,6-carbazole repeat units were synthesized by nickel-catalyzed Yamamoto coupling under microwave heating. The resulting poly(3,6-carbazole)s contain tetraphenylethylene (TPE) units in their side chains. The resultant polymers show aggregation induced emission (AIE) behavior. Hereby, the photoluminescence (PL) intensity of PCzTPE0.5 in 90% water–THF is 35 times higher than that in pure THF, connected to the introduction of TPE side chains. The ability of polymer PCzTPE0.5 for explosive sensing was also studied. A maximum Stern–Volmer quenching constant of 1.26 × 106 M−1 was observed for PL quenching of PCzTPE0.5 aggregates by trinitrobenzene (TNB). A solid state paper strip test based on PCzTPE0.5 and PCzTPE also demonstrates effective PL quenching towards both TNB vapor and solution.

Cross‐Linked Multifunctional Conjugated Polymers Prepared by In Situ Electrochemical Deposition for a Highly‐Efficient Blue‐Emitting and Electron‐Transport Layer

An efficient and controllable approach to prepare cross-linked films from a conjugated polymer precursor by electrochemical deposition (ED) is reported for the first time. A novel polymer precursor with high solubility, high electroactivity, and electron-transport ability has been designed. The electrochemically deposited polymer film shows high thickness, smooth morphology, and high fluorescence. The single-layer pure-blue-emitting ED PLED exhibits a luminous efficiency of 3.8 cd A(-1) .

RGB Small Molecules Based on a Bipolar Molecular Design for Highly Efficient Solution-Processed Single-layer OLEDs

In this paper, we describe a bipolar molecular design for small molecule solution-processed organic light emitting diodes (OLEDs). Combining the rigidity of the conjugated emissive cores and the flexibility of the peripheral alkyl-linked carbazole groups, two series of highly efficient bipolar RGB (red, green, blue) emitters have been synthesized and characterized. The emissive cores are composed of electron-withdrawing groups; the carbazole groups endow the materials electron-donating units. Such bipolar structures are advantageous for the carrier injection and balance. Four peripheral carbazole groups are introduced in T-series materials (TCDqC, TCSoC, TCBzC, TCNzC), and another four in O-series materials (OCDqC, OCSoC, OCBzC, OCNzC). With the single-layer device configuration of ITO/PEDOT:PSS/emitting layer/CsF/Al, two green devices exhibited excellent performance with a maximum luminescence efficiency of over 6.4 cd A(-1), and a high maximum luminance of more than 6700 cd m(-2). In addition, compared with the T-series, the luminescence efficiency of blue and red devices based on O-series materials increased from 1.6 to 2.8 cd A(-1) and 0.2 to 1.3 cd A(-1), respectively. To our knowledge, the performance of the blue device based on OCSoC is among the best of the blue small-molecule solution-processed single-layer devices reported so far.

Microporous, tetraarylethylene-based polymer networks generated in a reductive polyolefination process

Microporous Polymer Networks (MPNs) that contain aggregate-induced emission (AIE) active tetraphenylethylene (TPE) or other tetraarylethylene units have been generated in a reductive polyolefination process starting from four different tris(α,α-dichlorobenzyl)arene derivatives with dicobalt octacarbonyl or chromium(II)acetate as reductive olefination agents. Microporosity with moderately high BET surface areas up to 500 m2 g−1 could be combined with high solid state photoluminescence quantum yields up to 25.3% for polymer network P4. This unique combination should be promising for applications as optical solid state sensors, especially for MPNs with electron-deficient triazine core units.

Peripheral Cyanohexyl Substituent in Wide Bandgap Polymer: Increase the Electron Injection Property for Blue Phosphorescence Light Emitting Device

Novel blue phosphor host, PCNCzSi, using 3,6-linked carbazole with δ-π tetraphenylsilane segment as the main chain modified by peripheral cyanohexyl group was designed. The Si-carbazole backbone entitles the polymer with wide bandgap, high E(T) and good hole transporting ability. The introduction of peripheral CN group with high electron affinity enhances the electron injecting property of the polymer revealed by electron-only device and UPS measurement. Highly efficient spin-coated phosphorescent polymer light-emitting device, using PCNCzSi as the host for blue iridium complex, FIrpic, was realized. The maximum luminous efficiency and maximum external quantum efficiency of the device were 15 cd/A and 6.7%, respectively, which are very high values for blue phosphorescent device using polymers as hosts as known.

Conjugated polymers containing tetraphenylethylene in the backbones and side-chains for highly sensitive TNT detection

The novel polytriphenylamines derivatives PTPA1-TPE and PTPA2-TPE with TPE as side groups and bis(tert-butyl)-TPE in the backbones have been successfully synthesized via Yamamoto-type coupling under microwave heating. The incorporation of TPE units in the backbones and side-chains endows the polymers with a distinct AIE effect and high fluorescence quantum yields in the solid state. Meanwhile, nitroaromatic explosive detection based on dispersed, electron-rich PTPA1-TPE and PTPA2-TPE nanoaggregates in THF/water was carried out. Both of them show high sensitivity towards the TNT analyte, with a maximum Stern–Volmer quenching constant Ksv of up to 8.3 × 104 M−1. In addition, the paper strip test demonstrates the promising practical application of the polymers as solid state sensors towards PL-based nitroaromatic explosive detection.