Nonclassical Mechanism of Metal-Enhanced Photoluminescence of Quantum Dots.

Metal-enhanced photoluminescence is able to provide a robust signal even from a single emitter and is promising in applications in biosensors and optoelectronic devices. However, its realization with semiconductor nanocrystals (e.g.

Engineering of the Photon Local Density of States: Strong Inhibition of Spontaneous Emission near the Resonant and High-Refractive Index Dielectric Nano-objects.

Metallic or dielectric nano-objects change the photon local density of states of closely placed emitters, particularly when plasmon or Mie resonances are present. Depending on the shape and material of these nano-objects, they may induce either a decrease or an increase in decay rates of the excited states of the emitter. In this work, we consider the reduction of the probability of optical transitions in emitters near high-refractive index dielectric (silicon and zinc selenide) nanoparticles.

Plasmon-enhanced fluorescence in gold nanorod-quantum dot coupled systems.

Plasmon-exciton coupling is of great importance to many optical devices and applications. One of the coupling manifestations is plasmon-enhanced fluorescence. Although this effect is demonstrated in numerous experimental and theoretical works, there are different particle shapes for which this effect is not fully investigated.

Spontaneous Self-Assembly of Cesium Lead Halide Perovskite Nanoplatelets into Cuboid Crystals with High Intensity Blue Emission.

Colloidal all-inorganic perovskite nanocrystals have gained significant attention as a promising material for both fundamental and applied research due to their excellent emission properties. However, reported photoluminescence quantum yields (PL QYs) of blue-emitting perovskite nanocrystals are rather low, mostly due to the fact that the high energy excitons for such wide bandgap materials are easily captured by interband traps, and then decay nonradiatively. In this work, it is demonstrated how to tackle this issue, performing self-assembly of 2D perovskite nanoplatelets into larger size (≈50 nm × 50 nm × 20 nm) cuboid crystals.

Possible nanoantenna control of chlorophyll dynamics for bioinspired photovoltaics.

In the context of using portions of a photosynthetic apparatus of green plants and photosynthesizing bacteria in bioinspired photovoltaic systems, we consider possible control of the chlorophyll excited state decay rate using nanoantennas in the form of a single metal and semiconductor nanoparticle. Since chlorophyll luminescence competes with electron delivery for chemical reactions chain and also to an external circuit, we examine possible excited state decay inhibition contrary to radiative rate enhancement. Both metal and semiconductor nanoparticles enable inhibition of radiative decay rate by one order of the magnitude as compared to that in vacuum, whereas a metal nanosphere cannot perform the overall decay inhibition since slowing down of radiative decay occurs only along with the similar growth of its nonradiative counterpart whereas a semiconductor nanoantenna is lossless.

Colloidal nanophotonics: the emerging technology platform.

Dating back to decades or even centuries ago, colloidal nanophotonics during the last ten years rapidly extends towards light emitting devices, lasers, sensors and photonic circuitry to manifest itself as an emerging technology platform rather than an entirely academic research field.

Electroabsorption by 0D, 1D, and 2D nanocrystals: a comparative study of CdSe colloidal quantum dots, nanorods, and nanoplatelets.

This work presents a comprehensive study of electroabsorption in CdSe colloidal quantum dots, nanorods, and nanoplatelets. We experimentally demonstrate that the exposure of the nanoplatelets to a dc electric field leads to strong broadening of their lowest-energy heavy-hole absorption band and drastically reduces the absorption efficiency within the band. These are results of the quantum-confined Stark and Franz–Keldysh effects.

Vibrational spectroscopy of N'-(Adamantan-2-ylidene)thiophene-2-carbohydrazide, a potential antibacterial agent.

Vibrational states of the newly synthesized molecule N'-(Adamantan-2-ylidene)thiophene-2-carbohydrazide, a potential antibacterial agent, are examined experimentally for the crystalline phase and analyzed based on quantum chemical modelling of the solitary molecule and of the dimer, and assignment of the observed vibrational frequencies is proposed. Modelling of the title molecule dimer is found to describe better the experimentally observed vibration frequencies for the crystalline phase than calculations performed for a solitary molecule. Contributions from adamantane and thiophene parts within the molecule are identified.

Nonresonant surface-enhanced Raman scattering of ZnO quantum dots with Au and Ag nanoparticles.

Pronounced 10(4)-fold enhancement of Raman scattering has been obtained for ZnO nanocrystals on substrates coated with 50 nm Ag nanoparticles under nonresonant excitation with a commercial red-emitting laser. This makes feasible beyond 10(-18) mole detection of ZnO nanocrystals with a commercial setup using a 0.1 mW continuous wave laser and can be purposefully used in analytical applications where conjugated nanocrystals serve as Raman markers.

Anisotropic emission from multilayered plasmon resonator nanocomposites of isotropic semiconductor quantum dots.

We propose and demonstrate a nanocomposite localized surface plasmon resonator embedded into an artificial three-dimensional construction. Colloidal semiconductor quantum dots are assembled between layers of metal nanoparticles to create a highly strong plasmon-exciton interaction in the plasmonic cavity. In such a multilayered plasmonic resonator architecture of isotropic CdTe quantum dots, we observed polarized light emission of 80% in the vertical polarization with an enhancement factor of 4.