Experimental evidence was provided by the fact that the intensity of 498 nm luminescence shows a quadratic dependence on excitation power, and the intensity of blue luminescence increased with the increase in Yb ion concentration.
As an important wide band-gap Ⅱ-Ⅵ semiconductor, ZnSe has attracted much attention for their various applications in photoelectronic deⅥces such as blue light-emitting diodes and blue-green diode lasers.
1,4-distyryl benzene (DSB) is the oligomer of PPV that is researched the most extensively. It is a blue light-emitting material and it has highfluorescent quantum efficiency in solution. In solid, however, the fluorescence quantum efficiency of DSB is very low because there is very strong π-πstacking effect among the conjugated molecules, which limits its application in the light-emitting diodes.
IR transmition spectra show that the blue emitting PS almost only exists Si-O-Si peaks, but the red emitting PS not only mainly has Si-O-Si peaks and also has several obvious peaks of SiH x . It is suggested that the blue emission of PS comes from some defect centers in SiO 2.
Polychrome luminescence was observed in the UV irradiation of an aerated anthrone solution in ethanol or isopropanol: the initially blue luminescence of the solution changed to indigo blue and then to green.
Crystals of divalent tungstates are characterized by two main luminescence spectral ranges: a short-wavelength (blue) luminescence band in the range 390-420 nm and a group (often two groups) of longer wavelength (green) bands in the range 480-520 nm.
The position of the blue luminescence band is the same (in the range 510-530 nm) for crystals with different divalent cations.
Variation of the blue luminescence intensity at a wavelength of 472 nm (the 1G4 → 3H6 transition) with the pump power and ytterbium concentration is analyzed.
Intense blue luminescence of anodic aluminum oxide
It is found that the spectral contour of dual luminescence also depends on the excitation wavelength and the blue emission band is cut off at a sufficiently long-wavelength excitation in the region of 390 nm.
Assumptions are made about the types of intrinsic and impurity defects involved in the formation of various centers in GaN as sources of blue emission.
A violet peak at about 380 nm and a blue band at about 430 nm were observed in the room temperature photoluminescence spectra, and the origin of blue emission was investigated.
Poly(9,9-dioctylfluorene) (PFO) shows highly efficient blue emission with photo excitation occurring between 340-400 nm.
We have designed a new structure blue emission device with doped Alq3 of 3% in hole transmission layers of NPB.