Electrically driven light emission from single colloidal quantum dots at room temperature

Abstract

Light emission from single colloidal CdSe/ ZnS ͑core/shell͒ nanocrystals embedded in electrically driven organic light emitting devices is demonstrated at room temperature. Spectral diffusion and blinking from individual quantum dots were observed both in electro-and photoluminescence. The authors propose a model in which the nanocrystals act as seeds for the formation of current channels that lead to enhanced exciton recombination in the vicinity of the quantum dots. This work demonstrates that individual semiconductor nanocrystals can serve as emissive probes in organic light emitting devices and that they can be used to manipulate device structure and properties at the nanometer scale.

CdS/ZnS core–shell nanoparticles in arachidic acid LB films

“…High luminescence efficiency and stability have been demonstrated for core-shell nanoparticles [6,7]. Coreshell nanocrystals have potential applications in light emitting devices based on quantum dots of CdSe/ZnS [8,9], nanowires of Si/CdS [10] and quantum rods of CdSe/CdS [11].…”

Recent advances on single photon sources based on single colloidal nanocrystals

“…Based on the same approach, the only evidence of electroluminescence from a single colloidal quantum dot is reported in Ref. 87, where no evidence of photon antibunching is reported, however.…”

Single‐Molecule Electroluminescence of a Phosphorescent Organometallic Complex

“…[12][13][14][15] The heavy metals in organometallic complexes cause shortening of the triplet excitedstate lifetime to a few microseconds and an increase in the phosphorescence quantum efficiency, [16] enabling the PL study of several organometallic complexes at the single-molecule level. [17][18][19][20] The EL process on the level of a single dopant entity has been observed for colloidal quantum dots, [21,22] silver clusters [23] and carbon nanotubes.[24] Also, electric-field-induced chemiluminescence in single conjugated polymer nanoparticles has been reported recently.[25] Herein, we have succeeded in detecting the EL signal from single molecules of an organic dye doped at a very low concentration in a non-conjugated polymer host matrix. The single-molecule EL detection was possible because 1) charge recombination in the host is localized in distinct sites, 2) the onset voltage for EL of the dopant molecules is lower than that for the host and 3) the dopant molecules could be separated from the host EL background spectrally.…”