Author's School

Graduate School of Arts & Sciences

Author's Department/Program



English (en)

Date of Award


Degree Type


Degree Name

Doctor of Philosophy (PhD)

Chair and Committee

William Buhro


My research aims to study the formation mechanism of CdSe quantum belts: QBs) and the surface passivation of CdTe quantum wires: QWs). Investigation of QB morphology and QW passivation are fundamentally important to avoid nonradiative recombination and to increase electron-transport efficiency in semiconductor solar-cell devices. The origin of CdSe QBs is a lamellar structure of cadmium-octylamine precursor complex, with an intermediate state of stripe-like assembly of CdSe magic-sized nanoclusters. Transformation of: CdSe)13 nanoclusters to CdSe quantum belts: QBs) is conducted by higher annealing-temperature and confirmed by their optical and structural characterization. The QBs possess a thickness of 1.5-2.0 nm with a width of 7-15 nm and length of >1 micrometer. Most remarkably, the QBs have a superior morphology with noticeably high quantum efficiency: QE, 30 ± 10 %), comparable to quantum rods. High QE is explained by a delocalized exciton recombination with a lower density of defect sites. The colloidal CdTe quantum wires: QWs) are preferred for solar-cell applications due to a tunable diameter range: 5-60 nm), a long length dimensionality: > 5 micrometer), and near-IR band-gap emission energy: 1.5 eV). Successive surface passivation with Lewis acids and bases successfully passivates the QW surface. A significantly enhanced CdTe QW quantum efficiency: QE, 5-8 %) is achieved, which is two orders of magnitude larger than the previous disappointing QE: < 0.01 %). Enhanced photoluminescence: PL) emission reveals intrinsic higher and lower emission bands for CdTe QWs. Enhanced photoluminescence excitation: PLE) features consistently match previous theoretical calculations for electronic transitions. Significantly high QEs of CdSe QBs: 30 ± 10 %) and CdTe QWs: 5-8 %) promise colloidal 1D quantum structures suitable for bio-imaging and solar-cell applications.


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