PbS quantum dot light-emitting diodes (QLEDs) emitting
around 1550
nm promise important applications in optical communications. However,
due to insufficient suppression of surface traps for large-size PbS
quantum dots (QDs), their performance under large driving current
density was not satisfactory. In this work, octanethiol surfactant
was added into a PbS QD solution and adsorbed onto the dot surface.
As a result, the surface traps and the continuous oxidation of the
unprotected (100) facets in PbS QDs were greatly suppressed. Therefore,
the PbS QDs with octanethiol doubled their photoluminescence efficiency
and showed outstanding stability. The PbS-based QLEDs with benchmark
device structure showed a breakthrough high radiance of 18.3 W sr–1 m–2 with >2000 mA/cm2 driving current density. The efficient passivation of surface
traps with octanethiol surfactant and the suppressed coupling between
excitons and surface states under large working current were the main
reasons for achieving the breakthrough high radiance.
The quantum dot up-conversion device combines an infrared photodetector (PD) and a visible quantum-dot light-emitting diode (QLED) to directly convert infrared target to visible image. However, large efficiency loss is...
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