Showing their true colors? Full emission color tuning in the visible region can be achieved with salen-aluminum complexes that are electronically modulated at C5 of the phenoxide ring in the salen moiety. Emission spectra for various substituents R(5) are shown (EWG: electron-withdrawing group, EDG: electron-donating group).A series of salen-aluminum complexes, [{(R(5))(2)-salen(3-tBu)(2)}Al(OC(6)H(4)-p-C(6)H(5))] (salen=N,N'-bis(salicylidene)ethylenediamine; R(5)=H (1), tBu (2), Br (3), Ph (4), OMe (5), NMe(2) (6)) and [{5,5'-(NMe(3))(2)-salen(3-tBu)(2)}Al(OC(6)H(4)-p-C(6)H(5))][OTf](2) (7; OTf=CF(3)SO(3)) that are electronically modulated directly at C5 of the phenoxide ring in the salen moiety has been prepared. The crystal structures of 1, 4, 6, and 7 determined by X-ray diffraction reveal distorted square-pyramidal geometries around the Al atoms. Complexes 1-7 are all air-stable in both the solid and solution states and have high thermal stability (decomp 313-338 degrees C). Differential scanning calorimetric analyses show that they can form amorphous glasses with glass transition temperatures of 95-132 degrees C depending on the C5 substituent. UV/Vis absorption spectra of the complexes exhibit major bands at lambda=338-413 nm assignable to salen-centered pi-pi* transitions with a gradual red shift of the absorption maximum wavelengths as the substituent is varied from an electron-withdrawing (NMe(3)) to an electron-donating group (NMe(2)). The maxima in the emission spectra of 1-7 occur over the entire visible region, ranging from lambda=438 nm for 7 to lambda=599 nm for 6, with high fluorescence quantum efficiencies of up to Phi=0.40 for 4 in solution. DFT calculations suggest that the low-energy electronic transitions in 1-7 are characterized by HOMO(-i)-LUMO(+1) (i=1 for 1-6 or i=4 for 7) transitions localized on the salen moiety, with much involvement of the C5 position in the HOMO(-i). Thus, the electronic alteration at the C5 position of the phenoxide ring, which mainly affects the HOMO(-i) energy levels of salen-Al luminophores, is responsible for the observed emission color-tuning properties over the entire visible region.

This paper presents a new polydimethylsiloxane (PDMS) dry-etching method that uses microwave plasma. The applicability of the method for fabricating microstructures and removing residual PDMS is also verified. The etch rate of PDMS was dominantly influenced by the gas flux ratio of CF 4 /O 2 and the microwave power. While the PDMS etch rate increased as the flux ratio of CF 4 was increased, the etch rate decreased as the flux ratio of O 2 was increased. The maximum etch rate of 4.31 μm min −1 was achieved when mixing oxygen (O 2 ) and tetrafluoromethane (CF 4 ) at a 1:2 ratio at 800 W power. The PDMS etch rate almost linearly increased with the microwave power. The ratio of the vertical etch rate to the lateral etch rate was in a range of 1.14-1.64 and varied with the gas fluxes. In consideration of potential applications of the proposed PDMS etching method, array-type PDMS microwells and network-type microprotrusion structures were fabricated. The contact angle was dramatically increased from 104 • (non-etched PDMS surface) to 148 • (etched PDMS surface) and the surface was thereby modified to be superhydrophobic. In addition, a thin PDMS skin that blocked holes and PDMS residues affixed in nickel microstructures was successively removed.

The excellent contrast ratio, visibility, and advantages in producing thin and light displays let organic light emitting diodes change the paradigm of the display industry. To improve future display technologies, higher electroluminescence efficiency is needed. Herein, the detailed study of the non-radiative decay mechanism employing density functional theory calculations is carried out and a simple, general strategy for the design of the ancillary ligand is formulated. It is shown that steric bulk properly directed towards the phenylisoquinoline ligands can significantly reduce the non-radiative decay rate.

A novel bacterial DNA sample preparation device for molecular diagnostics has been developed. On the basis of optimized conditions for bacterial adhesion, surface-modified silicon pillar arrays for bacterial cell capture were fabricated, and their ability to capture bacterial cells was demonstrated. The capture efficiency for bacterial cells such as Escherichia coli, Staphylococcus epidermidis, and Streptococcus mutans in buffer solution was over 75% with a flow rate of 400 microL/min. Moreover, the proposed method captured E. coli cells present in 50% whole blood effectively. The captured cells from whole blood were then in- situ lyzed on the surface of the microchip, and the eluted DNA was successfully amplified by qPCR. These results demonstrate that the full process of pathogen capture to DNA isolation from whole blood could be automated in a single microchip.

We present the replication of polyethylene (PE) nano-micro hierarchical structures and their application for superhydrophobic surfaces. A commercial ultrasonic welding system was used to apply ultrasonic vibration energy to the forming of nano-micro hierarchical structures. To evaluate ultrasonic formability, Ni nanomold and nano-micro hierarchical mold were designed and fabricated. The optimal weld times were 1.5 s and 3.0 s for PE nanoprotrusions and nano-micro hierarchical structures, respectively. The forming process was conducted at atmospheric pressure. The PE structures were well replicated without a vacuum. The trapped air in the microcavity of the nano-micromold was dispersed and absorbed into the molten PE. Ultrasonic nano-microreplication technology showed an extremely short processing time and did not require a vacuum environment. To investigate the applicability of ultrasonic forming, the fabricated nanoprotrusions and nano-micro hierarchical structures were coated with plasma polymerized fluorocarbon (PPFC) of a hydrophobic nature and were applied to modify superhydrophobic surfaces. The contact angle was increased from 106 • (smooth surface) to 125 • (nanostructured surface) and finally to 160 • (nano-microstructured surface) so that the surface became superhydrophobic.