Thin Layer of Semiconductor Plasmonic Nanocrystals for the Enhancement of NIR Fluorophores

Abstract

Semiconductor plasmonic nanocrystals (PNCs) are a novel class of materials for near-infrared (NIR) plasmonics possessing strong and tunable localized surface plasmon resonances (LSPRs). In this work, we used PNCs to fabricate an active substrate for the enhancement of optical responses from near-infrared emitters: a thin film of PNCs in poly­(vinyl alcohol). This film supports LSPR and can be utilized to enhance the optical absorption, emission, and scattering in the NIR spectral region. PbS quantum dots deposited onto the fabricated active substrate demonstrate a 3-fold amplification of the integrated photoluminescence (PL) intensity. The possible mechanisms leading to the change in the PL parameters are discussed.

Photoluminescence Decay of Colloidal Quantum Dots: Reversible Trapping and the Nature of the Relevant Trap States

“…Since the first studies reporting the observation and interpretation of size-dependent absorption and emission in nanometer-sized colloidal semiconductor crystals (colloidal quantum dots, QDs), − these materials have been intensively investigated theoretical and experimentally due to fundamental scientific interest and bearing in mind their potential applications: imaging and sensing, − light harvesting and photovoltaics, − lasing, , photocatalysis, , optoelectronics, optical limiters, and infrared emitters and detectors. − Interfaces are crucial factors in the majority of these applications, since the chemical and physical properties of QDs (and assemblies of QDs), like those of any other colloidal particle, − are naturally conditioned by the nature of their surface (composition, geometry), surrounding environment, and the interactions between the two, in ways that are often not fully understood. For the most commonly studied type of QDs, that is, those consisting of the inorganic semiconductor nanocrystal proper covered by surfactant molecules (ligands), this means the interactions between (i) the surface of the inorganic core, − (ii) the ligands coating that surface, ,,,,− and (iii) the surrounding medium (solvent, polymer matrix, etc., including ions and other species, as well as the ligand molecules nonbonded to the surface of the inorganic core). ,− …”

Ternary Composites with PbS Quantum Dots for Hybrid Photovoltaics

“…In can be seen that, after the ligand exchange, the PL intensity decreases and the average PL lifetime increases. An increase in the decay time can be the result of damage of the QD surface because of the treatment which causes more efficient recombination involving carrier traps, which is characterized by longer decay times …”

“…An increase in the decay time can be the result of damage of the QD surface because of the treatment which causes more efficient recombination involving carrier traps, which is characterized by longer decay times. 46 Liquid-Phase Ligand Exchange. To perform the liquidphase ligand exchange, the as-synthesized OA-capped PbS QDs were treated with PbI 2 in a methanol/DMF mixture.…”

Thickness-Dependent NIR LSPR of Curved Ag/TiS2 Bilayer Film

“…The mono-disperse polystyrene (PS) colloid with size 200 nm and the density 1.05 g/cm 3 was purchased from the Duke Scientific Corporation. NH 4 OH (25%) and H 2 O 2 (30%) were purchased from Sigma-Aldrich Co. Ltd. (Beijing, China) and the Sino-Pharm Chemical Reagent Co. Ltd. (Shanghai, China).…”

“…For nanostructured noble metals, the collective resonances of the free carriers of the sufficient density leads to localized surface plasmon resonances (LSPR) [ 1 , 2 , 3 ]. LSPR had been reported in noble metals for decades, which is widely used in catalysis, information storages, biosensors and surface-enhanced Raman scattering [ 4 , 5 , 6 , 7 , 8 ].…”