Runli Tang

New fluorescent and colorimetric probe for cyanide: direct reactivity, high selectivity, and bioimaging application.

Taking advantage of the special nucleophilicity of cyanide, a new ratiometric fluorescent and colorimetric probe (Coum-1) was designed by tuning the π-conjugated bridge to affect the intramolecular charge transfer efficiency. Upon the addition of CN(-) anion, the probe displayed very large blue-shift in both fluorescence (90 nm) and absorption (90 nm) spectra, with the detection limit of 800 nM. Other anions gave nearly no interference. Furthermore, Coum-1 was successfully applied to the fluorescent microscopic imaging for the detection of CN(-) in HeLa cells.

Benzene-cored fluorophors with TPE peripheries: facile synthesis, crystallization-induced blue-shifted emission, and efficient blue luminogens for non-doped OLEDs

In this paper, three benzene-cored fluorophors with TPE moiety peripheries (PhTPE, Ph2TPE and Ph3TPE), are synthesized and their thermal, optical and electronic properties are investigated. All of them are nearly non-emissive when readily dissolved in solution but become highly emissive in the aggregate state, making them promising candidates for optoelectronic materials. Non-doped OLEDs with these luminogens as emissive layers exhibit sky-blue to deep blue emissions from 488 to 457 nm with Lmax, ηC, max and ηP, max up to 3966 cd m−2, 5.0 cd A−1 and 3.87 lm W−1, respectively, owing to the twisted conformation between the benzene core and TPE units.

High performance organic sensitizers based on 11,12-bis(hexyloxy) dibenzo[a,c]phenazine for dye-sensitized solar cells

Three new metal-free organic sensitizers containing 11,12-bis(hexyloxy) dibenzo[a,c]phenazine (BPz) units were synthesized and used for dye-sensitized solar cells (DSSCs). The broad absorption spectra indicate that the light harvesting abilities were enhanced by the introduction of the BPz unit in the π-conjugated space, which can also cause an anti-aggregation effect and the suppression of charge recombination. Among these sensitizers, LI-39 showed the best photovoltaic performance: a short-circuit photocurrent density (Jsc) of 14.40 mA cm−2, an open-circuit photovoltage (Voc) of 0.74 V, and a fill factor (ff) of 0.67, corresponding to an overall conversion efficiency of 7.18% under standard global AM 1.5 solar light conditions. The result shows that the organic sensitizers based on this bulky fused aromatic rings as well as the auxiliary acceptor are the promising candidates for improvement of the performance of DSSCs.

Construction of efficient blue AIE emitters with triphenylamine and TPE moieties for non-doped OLEDs

In this paper, by merging the hole-dominated triphenylamine (TPA) and tetraphenylethene (TPE) moieties together with different linkage positions, four derivatives of 1,2-bis[4′-(diphenylamino)biphenyl-4-yl]-1,2-diphenylethene (2TPATPE) were successfully synthesized with confirmed structures, and their thermal, optical and electronic properties were fully investigated. Thanks to the introduction of the meta-linkage mode on the TPE core, their π-conjugation length could be effectively restricted to ensure blue emission. The non-doped OLEDs based on these four emitters exhibit blue emissions from 443–466 nm, largely blue-shifted with respect to the green emission of 2TPATPE (514 nm). Meanwhile, good electroluminescence efficiencies with Lmax, ηC,max, and ηP,max of up to 8160 cd m−2, 3.79 cd A−1, and 2.94 Im W−1 respectively, have also been obtained, further validating our rational design of blue AIE fluorophores.

A New Approach to Prepare Efficient Blue AIE Emitters for Undoped OLEDs

Two aggregation-induced emission active luminogens (TPE-pTPA and TPE-mTPA) were successfully synthesized. For comparison, another six similar compounds were prepared. Because of the introduced hole-dominated triphenylamine (TPA), fluorene groups with high luminous efficiency, and unconjugated linkages, the π conjugation length of the obtained luminogens is effectively restricted to ensure their blue emission. The undoped organic light-emitting diodes based on TPE-pTPA and TPE-mTPA exhibited blue or deep-blue emissions, low turn-on voltages (3 V), and high electroluminescence efficiencies with Lmax, ηC,max, and ηP,max values of up to 26,697 cd m(-2), 3.37 cd A(-1), and 2.40 Lm W(-1).

How the linkage positions affect the performance of bulk-heterojunction polymer solar cells

Two new alternating copolymers. PCT-10,13-BPz (P1) and PCT-2,7-BPz (P2), which were constructed from the same monomers and only different in the connecting points, were synthesized via Suzuki coupling reaction. The UV-vis absorptions, thermal stability, energy levels, field-effect carrier mobility and photovoltaic characteristics of the two copolymers were systematically evaluated to understand the relationships between the polymer structure at the molecular level and the photovoltaic performances. Photovoltaic cells based on the two copolymers with a structure of ITO/PEDOT : PSS/Polymer : PC71BM/PFN/Al exhibited PCEs of 4.31% and 0.64%, respectively, under one sun of AM 1.5 solar simulator illumination (100 mW cm−2).

Second-order nonlinear optical dendrimers containing different types of isolation groups: convenient synthesis through powerful “click chemistry” and large NLO effects

In this paper, two series of dendrimers, which contain normal phenyl or pentafluorophenyl as the end-capped group, were conveniently prepared with high purity and satisfactory yields, through the combination of divergent and convergent approaches, coupled with the utilization of the powerful Sharpless “click” reaction. Due to the Ar–ArF self-assembly effect, as well as their perfect 3D structure and the isolation effects of the interior triazole rings, G4-PFPh-TB exhibited a very large d33 value of 252 pm V−1, which should be one of the highest values for simple azo chromophore moieties.

New second-order nonlinear optical (NLO) hyperbranched polymers containing isolation chromophore moieties derived from one-pot “A2 + B4” approach via Suzuki coupling reaction

In this paper, a facile synthetic route was designed to prepare two new hyperbranched polymers HP1 and HP2 useful as second-order nonlinear optical (NLO) materials through a one-pot “A2 + B4” approach via a simple Suzuki coupling reaction. Thanks to the effect of the isolation chromophores to the main chromophore and the three-dimensional spatial isolation effect of the hyperbranched structure, these hyperbranched polymers demonstrated high second-harmonic generation coefficients (up to 73.6 pm V−1) and good optical transparency (with the maximum absorption as 466 nm in film).

Synthesis, characterization and photovoltaic performances of D–A copolymers based on BDT and DBPz: the largely improved performance caused by additional thiophene blocks

Two new low bandgap copolymers, PBDT-DBPz and PBDT-DTDBPz, were prepared, in which the only difference was the additional added thiophene bridge between the BDT donor unit and DBPz acceptor unit for PBDT-DTDBPz. In addition to the improvements of UV-vis absorption and hole mobility, the PSC based on PBDT-DTDBPz:PC71BM demonstrated a power conversion efficiency of 4.75%, much higher than that of the device based on PBDT-DBPz:PC71BM (0.46%), under the same experimental conditions.

New triphenylamine-based sensitizers bearing double anchoring units for dye-sensitized solar cells

Two organic sensitizers (LI-33 and LI-34) with double anchoring units were synthesized and utilized for dye sensitized solar cells (DSSCs), which contained thiophene or vinyl thiophene as π-bridge. The introduction of double anchoring units can change their absorption spectra and energy levels in a large degree, thus, the better light-harvesting ability and the convenient electron transfer along the whole molecule can be obtained. The solar cell based on LI-34 exhibited a broad incident photon-to-current conversion efficiency (IPCE) spectrum and high conversion efficiency (η=6.05%) with coadsorbent CDCA.