Plasmon-mediated emergence of collective emission and enhanced quantum efficiency in quantum dot films

Abstract

We present experimental and theoretical results on monolayer colloidal cadmium selenide quantum dot films embedded with tiny gold nanoparticles. By varying the density of the embedded gold nanoparticles, we were able to engineer a plasmon-mediated crossover from emission quenching to enhancement regime at interparticle distances for which only quenching of emission is expected. This crossover and a nonmonotonic variation of photoluminescence intensity and decay rate, in experiments, is explained in terms of a model for plasmonmediated collective emission of quantum emitters which points to the emergence of a new regime in plasmonexciton interactions. The presented methodology to achieve enhancement in optical quantum efficiency for optimal doping of gold nanoparticles in such ultrathin high-density quantum dot films can be beneficial for new-generation displays and photodetectors.

Large emission enhancement and emergence of strong coupling with plasmons in nanoassemblies: Role of quantum interactions and finite emitter size

“…The AuNP doped films are transferred at same area corresponding to that of ref. QD film to keep QD number density constant as disscussed earlier [8][9][10] . Typical surface pressure (Π)-surface area(A) isotherms 9 for bare QD films and a nanoparticle-doped QD monolayer is shown in h) RADIAL DISTRIBUTION FUNCTION: The radial distribution function (RDF) or pair correlation function 10 in a system of particles (atoms, molecules, colloids, etc.…”

“…The average surface separation between QDs remain comparable in both ref.QD and AuNP doped QD film. i) PHOTOLUMINESCENCE MEASUREMENT: PL measurements on our samples were performed using a WITec alpha SNOM setup in confocal mode as described earlier 8,10 . The layer of respective samples is transferred on glass substrate for spectral study.…”

“…Here we have calculated the enhancement in AuNP doped film in comparison with the reference QD film. The Enhancement factor from PL measurement 10 For the spectral study, we have accessed the higher resolution with grating of 600g/mm (spectral resolution in energy scale-3 meV). All excitations were performed with the blue line (488 nm) of an Ar ion laser using 50x objective for higher area illumination, Signal is collected in transmission mode with objective having magnification 100x (Nikon NA-1.51).…”

Plasmon‐Enhanced Photoluminescence and Photocatalysis Reactions in Metal‐Semiconductor Nanomaterials: UV‐Generated Hot Electron in Gold‐Zinc Oxide

“…The extent to which the exciton‐plasmon coupling could be cooperative is found to be distance dependence in a way that the enhanced electric field near the metal nanoparticles can fade with the junction length between the two materials . Thus, the inter‐distance between SC and metal nanoparticles was believed to manage the competition between enhancing and quenching the PL of the SC.…”

Observation of photonic spin-momentum locking due to coupling of achiral metamaterials and quantum dots

“…The experimental results are based on fabricated 2D HMM templates consisting of hexagonal arrays of silver nanowires (length 800 nm) embedded in alumina matrix prepared using methods described earlier [40]. A compact monolayer of cadmium selenide (CdSe) QDs, synthesised by well known methods [38,41,42], was placed on top of the metamaterial using the well known Langmuir-Blodgett (LB) technique as discussed earlier [43,44] as well as in supplementary materials [39]. The metamaterials prepared undergo a wavelength dependent topological transition to a phase having hyperbolic optical dispersion -hence called HMM -depending on silver nanowire filling fraction ( f = 0.15 in our study) [39].…”