Exciton-Plasmon Interactions in Quantum Well Structures Near Silver Nanoparticles

Abstract

The chapter reports photoluminescence (PL) and an energy transfer dynamic in a hybrid heterostructure consisting of an Ag nanoparticle (NP) layer and Cd 0.08 Zn 0.92 O/ZnO quantum well (QW). The observed PL quenching was closely related to electronic states of excitons confined in the QW. The PL quenching of the QW emission was only observed at low temperatures which excited carriers were radiatively recombined due to excitonic localization derived from fluctuated energy potentials in the QW. In contrast, delocalization of excitons from the QW with increasing temperature resulted in disappearance of the PL quenching. Time-resolved PL measurements revealed a decay rate of PL from the QW emission through the presence of energy transfer from the QW to Ag NP layer. The temperature-dependent energy-transfer rate was similar to that of the radiative recombination rate. The Ag NP layer surface showed a visible light absorption caused by localized surface plasmons (LSPs), which was very close to the PL peak energy of the QW. These results indicated that the excitonic recombination energy in the QW was nonradiatively transferred to Ag NP layer owing to energy resonance between the LSP and the QW. These phenomena could be explained by a surface energy transfer mechanism.

Diagnosis and Treatment of Tuberculosis using Nanotechnology

“…Some of the current diagnostic tools used for the detection of tuberculosis are acid fast bacilli (AFB), loop mediated isothermal ampli cation diagnosis of pulmonary TB, gene Xpert MTB/RIF assay, lipoarabinomannan urine test for TB diagnosis in HIV infected patients, culture for TB diagnosis, molecular line probe assays diagnosis of TB, TB skin test for diagnosis of latent TB infection, etc. 3 These diagnostic techniques show low sensitivity towards bacterial infection and may provide false conclusion. The major problem DOI: https://doi.org/10.36503/chcmj in the treatment of tuberculosis is the diagnosis at its early stage.…”

“…The major problem DOI: https://doi.org/10.36503/chcmj in the treatment of tuberculosis is the diagnosis at its early stage. 3 Using nanotechnology-based sensing devices, the detection of Mycobacterium tuberculosis at early stage can be performed. 4 In the eld of nanomedicine, nanoparticles (Nps) are considered to be e ective carriers.…”

“…However, this method has limited speci city and low sensitivity. 3 To give a complete diagnosis without any false con rmation, quantum dots are used. Kim et al 6 developed a sandwich-based assay to detect TB by antigen-antibody interaction using silica coated QDs.…”