We present the experimental evidence of the collisionless electron bounce resonance heating (BRH) in low-pressure dual-frequency capacitively coupled plasmas. In capacitively coupled plasmas at low pressures when the discharge frequency and gap satisfy a certain resonant condition, the high energy beamlike electrons can be generated by fast sheath expansion, and heated by the two sheaths coherently, thus the BRH occurs. By using a combined measurement of a floating double probe and optical emission spectroscopy, we demonstrate the effect of BRH on plasma properties, such as plasma density and light emission, especially in dual-frequency discharges.

PODIPY and aza-PODIPY have been successfully prepared by the treatment of dipyrromethene and azadipyrromethene with POCl3 in the presence of Et3 N. The new PODIPY and aza-PODIPY dyes are found to have photophysical properties. PODIPY and aza-PODIPY are water-soluble, and aza-PODIPY is suited for labeling living Hep-2 cells for imaging assays in the near-infrared region. Molecular orbital calculations show that the increase in the HOMO-LUMO band gap for the lowest energy absorption bands is observed in the new phosphorus-containing aza-PODIPY, and the HOMO and LUMO energies of aza-PODIPY are found to be higher than those of aza-BODIPY.

We have developed a new method for the synthesis of CdTe and PbTe nanocrystals by using TeO2 with trioctylphosphine oxide as Te precursor. Using this method, uniform-sized CdTe nanocrystals are successfully synthesized without the use of any air-sensitive alkylphosphine. The monodispersity, size, and shape of as-synthesized CdTe nanocrystals are well-controlled using “green” chemicals at elevated temperatures; the photoluminescence emission of CdTe nanocrystals covers a wide range from 510 to 750 nm. Oleic acid has been chosen as the only ligand to achieve controllable synthesis of CdTe nanocrystals with not only different sizes covering from green to red emissions but also different crystal structures (wurtzite and zinc blende) and shapes (including spherical, tetrapod, dendrimer, and flower) by simply adjusting the injection and/or growth temperatures. PbTe nanocrystals with spherical and cubic shapes have also been synthesized successfully with this new tellurium precursor and they can easily self-assemble into two-dimensional ordered structures. Special attention has also been paid to the studies of the new molecular mechanisms involved in the formation of metal telluride nanocrystals.

A selective and sensitive turn-on fluorescent NIR probe for cysteine has been developed. Cleavage of 2,4-dinitrobenzenesulfonyl (DNBS) with thiols switches the weakly fluorescent aza-BODIPY dye (λ(em) = 734 nm, Φ(f) = 0.03) to a strongly fluorescent species in the NIR region (λ(em) = 755 nm, Φ(f) = 0.14).