Search

High-density In-Al codoped ZnO (In, Al, ZnO) nanobunches are synthesized by using chemical vapor deposition method, which can be used to fabricate In, Al, ZnO nanobunches photodetectors. The ZnO nanobunches each have a hexagonal wurtzite structure. It is found that the average length of the nanobunches is ～5 m. The photoconduction mechanism and a series of photoelectric characteristics are studied including I-V characteristic measured in dark and UV illumination, responsivity and response time. The results indicate the presence of an internal gain mechanism. The response time is less than 0.5 s and decay time is about 23 s, so the fabricated device can indeed be used for light detection.

An undoped electrophosphorescent organic light-emitting diode is fabricated using a pure platinum(II) (2-phenylpyridinato-N, C2) (3-benzoyl-camphor) [(ppy)pt(bcam)] phosphorescent layer acting as the emitting layer. A maximum power efficiency ηp of 6.62 lm/W and current efficiency of 14.78 cd/A at 745cd/m2 are obtained from the device. The roll-off percentage of ηp of the pure phosphorescent phosphor layer device is reduced to 5% at a current density of 20 mA/cm2, which is about 11% for conventional phosphorescent devices. The low roll-off efficiency is attributed to the phosphorescent material, which has the molecular structure of a strong steric hindrance effect.

A new nonlinear optical material urea L-malic acid film (ULMA) was successfully prepared by physical vapour deposition (PVD) at appropriate heating temperature. XRD and FTIR measurements show that the film and the ULMA powder have the same composition and crystal structure. Furthermore, the film keeps the nonlinear properties of the ULMA crystal. Thermal analysis shows that ULMA has good thermal stability with constant melting point. Its evaporation temperature is below the decomposition temperature of its substrates urea and L-malic acid. The difference between evaporation and decomposition temperature is increased in vacuum. Therefore, it is verified that the PVD method is a practical approach to prepare ULMA film if the heating temperature is controlled between the evaporation and decomposition temperatures.