Browsing by Subject "Hybrid platform"

Filter results by typing the first few letters
Now showing 1 - 2 of 2
  • Thumbnail Image
    ItemOpen Access
    Excitonically driven quantum dot light-emitting diodes: exLEDs
    (Optical Society of America, 2013) Güzeltürk, Burak; Hernandez-Martinez, Pedro Ludwig; Sharma, Vijay Kumar; Coşkun, Yasemin; Ibrahimova, Vusala; Sun, X.W.; Tuncel, Donus; Demir, Hilmi Volkan
    A hybrid platform of colloidal quantum dots integrated into conjugated polymers is eported for excitonically driven light-emitting diodes having pure quantum dot emission in the electroluminescence spectrum with substantially enhanced efficiency.
  • Thumbnail Image
    ItemOpen Access
    Phonon-assisted nonradiative energy transfer from colloidal quantum dots to monocrystalline bulk silicon
    (IEEE, 2012) Yeltik, Aydan; Güzeltürk, Burak; Hernandez-Martinez, Pedro L.; Demir, Volkan Demir
    Silicon is one of the most dominant materials in photovoltaics. To increase optical absorption of silicon solar cells, colloidal quantum dots (QDs) have been proposed as a good sensitizer candidate owing to their favorably high absorption cross-section and tunable emission and absorption properties. To this end, QD sensitization of silicon has previously been studied by mostly facilitating radiative energy transfer (RET) [1,2]. Although RET based sensitization has achieved a considerable increase in conversion efficiencies in silicon photovoltaics, RET is fundamentally limited due to the effective coupling problem of emitted photons to silicon. Alternatively, nonradiative energy transfer (NRET), which relies on near field dipole-dipole coupling [3], has been shown to be feasible in sensitizer-silicon hybrid systems [4-8]. Although colloidal QDs as a sensitizer have been used to facilitate NRET into silicon, the detailed mechanisms of NRET to an indirect bandgap nonluminecent material, together with the role of phonon assistance and temperature activation, have not been fully understood to date. In this study, we propose a QD-silicon nanostructure hybrid platform to study the NRET dynamics as a function of temperature for distinct separation thicknesses between the donor QDs and the acceptor silicon plane. Here, we show NRET from colloidal QDs to bulk Si using phonon assisted absorption, developing its physical model to explain temperature-dependent lifetime dynamics of NRET in these QD-Si hybrids. © 2012 IEEE.