Plasmon-Assisted Suppression of Surface Trap States and Enhanced Band-Edge Emission in a Bare CdTe Quantum Dot

Abstract

Colloidal quantum dots have emerged as a versatile photoluminescent and optoelectronic material. Limitations like fluorescence intermittency, non-radiative Auger recombination and surface traps are commonly addressed by growing a wide-bandgap shell. However, the shell isolates the excitonic wave function and reduces its interaction with the external environment necessary for different applications. Furthermore, their long emission lifetime hinders their use in high-speed optoelectronics.Here, we demonstrate a high degree of control on the photophysics of a bare core CdTe quantum dot solely by plasmon-coupling, showing that more than 99% of the surface defect-state emission from a trap-rich quantum dot can be quenched. Moreover, the band-edge state excitonic and biexcitonic emission rates are Purcell enhanced by 1460 and 613-fold, respectively. Our findings show how plasmon-coupling on bare quantum dots could make chemical approaches developed for improving their optical properties unnecessary, with implications for nanoscale lasers, light emitting devices, solar cells, and ultrafast singlephoton sources.Keywords: colloidal quantum dots • radiative decay rate • surface defect state • plasmonic nanostructures • hybrid quantum system

Plasmon-Induced Trap State Emission from Single Quantum Dots

“…Despite this wealth of information, there is less understanding of their influence in optical cavities, as well as the interplay with intrinsic excitons. [34] Here, we demonstrate for the first time that the carrier recombination process in QDs is significantly modified by a plasmonic nanocavity, resulting in dominant trap state emission under two-photon excitation. We use a 'nanoparticle-on-mirror' (NPoM) geometry [35], built of individual Au nanoparticles above a Au film with QDs sandwiched between the metallic surfaces (Fig.…”

Surface Plasmonic‐Assisted Photocatalysis and Optoelectronic Devices with Noble Metal Nanocrystals: Design, Synthesis, and Applications

“…Flatae et al studied the phenomena of QDs CdTe based on plasmon coupling and investigated its properties. They concluded that plasmon coupling on the QDs could increase the optical properties in different applications of electronic and optical devices . They gained about 99% of the surface defect‐state emission from a trap‐rich QD.…”

“…They concluded that plasmon coupling on the QDs could increase the optical properties in different applications of electronic and optical devices. [131] They gained about 99% of the surface defect-state emission from a trap-rich QD. Furthermore, two critical parameters and edge state excitonic and bi-excitonic emission rates are seen to be increased by ≈1460and 613-fold, respectively.…”

Люминесценция коллоидных квантовых точек Ag-=SUB=-2-=/SUB=-S/SiO-=SUB=-2-=/SUB=-, декорированных малыми наночастицами Au

“…Для КТ, обладающих дефектной люминесценцией ( " trap state luminescence"), эффекты плекситонного взаимодействия практически не изучены. В работах [14][15][16][17] продемонстрировано управление излучением ловушечных состояний одиночных КТ и их ансамблей за счет взаимодействия с плазмонными НЧ. Найдено усиление экситонной люминесценции за счет подавления дефектной люминесценции.…”