Visible electroluminescence from hybrid colloidal silicon quantum dot-organic light-emitting diodes

Abstract

We demonstrate hybrid colloidal silicon quantum dot (SiQD)-organic light-emitting diodes with electroluminescence (EL) in the visible wavelengths. The device using blue photoluminescence (PL) SiQDs as emitters shows multiple EL peaks which are attributed to carrier recombination in the core quantum confinement states, the hole-transport-layer and the surface trap states, respectively. However, the red PL SiQD device shows a single EL peak consistent with the PL peak. These findings are in agreement with the previous report that large Stokes shift were observed for oxidized blue emission SiQDs due to oxide states while red emission SiQDs show negligible PL shift after oxidation.

Electroluminescence of CdSe/CdS quantum dots and the transfer of the exciton excitation energy in an organic light-emitting diode

“…The maximum external quan tum yield of the light emitting diode based on CdSe/CdS quantum dots reached under our condi tions was 0.3-0.5%. It is comparable with the existing results for QD OLEDs [7,8,10] based on CdSe/ZnS quantum dots and on Si nanocrystals.…”

“…This is due to the unique optical properties of colloidal quantum dots, including a high luminescence efficiency and the possibility of varying the radiation wavelength in a wide spectral range. Most created QD OLEDs are based on CdSe/ZnS quantum dots [8] and silicon nanocrystals [10].In this work, an organic light emitting diode is developed and created with an active emitting element in the form of a layer of CdSe/CdS colloidal quantum dots, which have a high luminescence quantum yield and significant photostability [6]. The scheme of the device is shown in Fig.…”

“…This is due to the unique optical properties of colloidal quantum dots, including a high luminescence efficiency and the possibility of varying the radiation wavelength in a wide spectral range. Most created QD OLEDs are based on CdSe/ZnS quantum dots [8] and silicon nanocrystals [10].…”

White-blue electroluminescence from a Si quantum dot hybrid light-emitting diode

“…13 In addition, a Si NC hybrid LED exhibiting an EQE as high as 8.6% at 853 nm has been reported. 14 17 Tu et al fabricated a hybrid LED using blue-emitting Si QDs, 18 and noted that the majority of the EL spectral component was obtained not from the Si QDs layer but from the organic layers. Thus, a hybrid LED with effective visible region emission from Si QDs has not been reported thus far.…”

“…The measured current and optical densities were 280 and 350 times greater than those, respectively, at the same voltage to the one previously reported in the literature. 18 Si QDs were synthesized by PLA, using 1-octyne (Tokyo Chemical Industry Co., LTD) as the solvent (10 ml) and applying the second harmonic of a Nd:YAG laser with an excitation wavelength of 532 nm, a repetition rate of 10 Hz, and a fluence of 0.8 J cm À2 . A Si(111) wafer was used as the ablation target and was placed in the bottom of a glass vial along with the solvent.…”