RESUMEN
In the present paper colloidal PbSe nanocrystals were prepared with the particle size of 3.8 and 5.8 nm, and the temperature- dependent optical properties of colloidal PbSe nanocrystals were investigated. The experimental data show that the band gap, photoluminescence peak wavelength, photoluminescence intensity and full width at half-maximum of colloidal PbSe nanocrystals will change with variations in temperature and size at room temperature. The band gap of colloidal PbSe nanocrystals with the particle size of 3.8 nm shifts towards red when the temperature increases. However, the blue shift occurs when the particle size is 5.8 nm. The photoluminescence intensity of colloidal PbSe nanocrystals drops and the full width at half-maximum will increases with the increase in temperature.
RESUMEN
In the present paper ZnCuInS/ZnS core/shell quantum dots were prepared with the particle size of 3.2 nm. Its radiation is based on the donoracceptor pair transitions, not the band edge emission. According to the measurement of photoluminescence spectrum emitted by ZnCuInS/ZnS core/shell quantum dots, the emitting peak of 620 nm and the full width at half-maximum of 95 nm were achieved as red emitter; meanwhile, organic poly(N, N'-bis(4-butylphenyl)-N, N'-bis(phenyl) benzidine) (Poly-TPD) film was deposited and used as cyan-emitter with the peak of 480 nm. Two structures of Poly-TPD were analyzed and discussed according to the photoluminescence spectrum. Two wavelengths are complementary color. Therefore, two films were deposited one by one as bilayer emitter to obtain the complementary emission. After the suitable bias was applied on the films, the white emission was achieved with the Commission Internationale de l' Eclairage (CIE) chromaticity coordinates of (0.336, 0.339) and color rendering index of 92. Therefore, the bilayer-structure is a promising candidate for white light emitting diodes fabrication.