Polymer composites of carbon nitride (g-C(3)N(4)) and poly(3-hexylthiophene) (P3HT) resulted in enhanced H(2) production from water-containing Na(2)S and Na(2)SO(3) as electron donors, showing a H(2) evolution rate 300 times the yield achieved using g-C(3)N(4).

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H 2 S plays important physiological and pathological roles in cardiovascular system and nervous system. But recent evidences imply that hydrogen polysulfides (H 2 S n ) are the actual signaling molecules in cells. Although H 2 S n have been demonstrated to be responsible for mediating tumor suppressors, ion channels, and transcription factors, more of their biological effects are still need to be elaborated. On one hand, H 2 S n have been suggested to be generated from endogenous H 2 S upon reaction with reactive oxygen species (ROS). On the other hand, H 2 S n derivatives are proposed to be a kind of direct antioxidant against intracellular oxidative stress. This conflicting results should be attributed to the regulation of redox homeostasis between ROS and H 2 S n . Superoxide anion (O 2 •− ) is undoubtedly the primary ROS existing in mitochondria. We reason that the balance of O 2•− and H 2 S n are pivotal in physiological and pathological processes. Herein, we report two near-infrared fluorescent probes Hcy-Mito and Hcy-Biot for the detection of O 2•− and H 2 S n in cells and in vivo. Hcy-Mito is conceived to be applied in mitochondria, and Hcy-Biot is designed to target tumor tissue. Both of the probes were successfully applied for visualizing exogenous and endogenous O 2•− and H 2 S n in living cells and in tumor mice models. The results demonstrate that H 2 S n can be promptly produced by mitochondrial oxidative stress. Flow cytometry assays for apoptosis suggest that H 2 S n play critical roles in antioxidant systems.

Owing to the difficulty in acquiring compounds with combined high energy bandgaps and lower‐lying intramolecular charge‐transfer excited states, the development of ultraviolet (UV) thermally activated delayed fluorescence (TADF) materials is quite challenging. Herein, through interlocking of the diphenylsulfone (PS) acceptor unit of a reported deep‐blue TADF emitter (CZ‐PS) by a dimethylmethylene bridge, CZ‐MPS, a UV‐emissive TADF compound bearing a shallower LUMO energy level and a more rigid structure than those of CZ‐PS is achieved. This represents the first example of a UV‐emissive TADF compound. Organic light‐emitting diode (OLED) using CZ‐MPS as the guest material can emit efficient UV light with emission maximum of 389 nm and maximum total external quantum efficiency (EQEmax) of 9.3%. Note that this EQEmax value is twice as high as the current record EQEmax (4.6%) for UV‐OLEDs. This finding may shed light on the molecular design strategy for high‐performance UV‐OLED materials.

A novel series of red-light-emitting copolymers derived from fluorene and 2-pyran-4-ylidenemalononitrile (PM) have been synthesized through a palladium-catalyzed Suzuki coupling reaction. The polymers were characterized by FT-IR, NMR, and elemental analysis. All these polymers are completely soluble in common organic solvents, such as THF, CH 2Cl2, CHCl3, and toluene, and they have good thermal stability with onset decomposition temperature (Td) of 406-407 °C and glass-transition temperature (Tg) of 73-186 °C. Cyclic voltanmetry studies reveal that these copolymers have low-lying LUMO energy levels ranging from -3.53 to -3.57 eV and HOMO energy levels ranging from -5.77 to -5.79 eV, which indicated that they may be promising candidates for electron-transporting or hole-blocking materials in light-emitting diodes. These polymers in thin films can emit strong red photoluminescence (PL) around 641-662 nm with the corresponding additional peaks in the range 704-712 nm upon photoexcitation. Double-layer LEDs fabricated with the configuration of ITO/PEDOT/polymer/Ba/Al can emit red light with external quantum efficiencies of 0.21-0.38%. Preliminary electroluminescent (EL) results show that these polymers are novel promising candidates for red emissive materials in polymer light-emitting diodes.

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A dual-channel naphthalimide-based chemosensor for rapid and sensitive detection of fluoride ion has been developed. Upon addition of F(-), it undergoes deprotonation reaction through H-bonding interactions, and its maximum absorption wavelength is red-shifted for 214 nm to the far-red region, together with drastically quenched fluorescence. In addition, it shows high selectivity toward F(-) anion, thus could be used for practical applications to detecting F(-) in both solution and solid state. Furthermore, the fluorescence of NIM could be enhanced in protein-containing acidic environments, hence NIM could act as lysosome marker to differentiate cancer cells from normal ones in cell imaging.

A charge-transfer-featured naphthalimide derivative with a small exchange energy but a lower lying (3)ππ* state than (3)CT state is found to contribute to triplet harvesting through a P-type rather than an E-type delayed fluorescence, and could act as a quite promising host to achieve highly efficient OLEDs.