1 research outputs found
Infrared Emitting PbS Nanocrystal Solids through Matrix Encapsulation
Colloidal
semiconductor nanocrystals (NCs) are emerging as promising
infrared-emitting materials, which exhibit spectrally tunable fluorescence,
and offer the ease of thin-film solution processing. Presently, an
important challenge facing the development of nanocrystal infrared
emitters concerns the fact that both the emission quantum yield and
the stability of colloidal nanoparticles become compromised when nanoparticle
solutions are processed into solids. Here, we address this issue by
developing an assembly technique that encapsulates infrared-emitting
PbS NCs into crystalline CdS matrices, designed to preserve NC emission
characteristics upon film processing. An important feature of the
reported approach is the heteroepitaxial passivation of nanocrystal
surfaces with a CdS semiconductor, which shields nanoparticles from
the external environment leading to a superior thermal and chemical
stability. Here, the morphology of these matrices was designed to
suppress the nonradiative carrier decay, whereby increasing the exciton
lifetime up to 1 μs, and boosting the emission quantum yield
to an unprecedented 3.7% for inorganically encapsulated PbS NC solids