Modified Absorption and Emission Properties Leading to Intriguing Applications in Plasmonic–Excitonic Nanostructures

Abstract

years, great advances have been made to grow various shaped semiconductor nanocrystals (SNCs) like quantum dots, [7] nanowires, [8] nanorods (NR), [9] and other advanced shaped nanostructures, [10-12] with great precision. However, these semiconductor nanostructures have small extinction cross-sections (even smaller than geometric cross-section), leading to limited absorbance and emission quantum yields. This hinders the progress of semiconductor nanostructures in several areas ranging from clean energy production to various sensing applications. Among many promising solutions, integrating plasmonic nanoparticles (PNPs) with semiconductor nanostructures emerges as the most prominent way to alleviate aforementioned issue. The PNPs have greater extinction cross-section than SNCs (even greater than geometric cross-section), owing to light absorption and scattering by collective and coherent electron oscillations. [13,14] Moreover, these coherent oscillations can couple with electromagnetic wavelengths far greater than particle size, enabling them to guide light to subwavelength scales, thus overcoming diffraction limit. [15] Besides this, proper control over size and shape of plasmonic nanostructures enables engineering of their intrinsic properties to meet the criteria of required application. [16] For instance, by changing the aspect ratio (length to diameter ratio) of nanorods, one can cover wide spectral regions ranging from visible to near-infrared (NIR) regimes. [17] Thus, the integration of plasmonic and semiconductor nanostructures to obtain greater extinction cross-sections and modified properties in these hybrid nanostructures has received great attention from the research community over the past years. The properties of these hybrid nanostructures can be very different from the two nanoconstituents (metal and semiconductor nanostructures), owing to plasmon-exciton interactions. [18-20] Various configurations of metal/semiconductor nanostructures have been synthesized like metallic core/semiconductor shell, [21] semiconductor NR/metal nanoparticles (MNPs), [22] Janus metal/ semiconductor nanostructures, [23] and many others have been reported, [24-26] with varying absorption and emissive properties, targeting high performance applications. The energy transfer between metal-semiconductor nanostructures resulting from integration of PNPs and SNCs Hybrid nanostructures composed of metal and semiconducting nanocrystals have drawn tremendous attention owing to their extraordinary absorption and emission properties. The energy transfer in metal-semiconductor hybrids as a result of synergetic plasmon-exciton interactions leads to numerous applications in the field of solar energy harvesting, photocatalytic reactions, imaging, photonics, sensing, and many more. Various breakthroughs in advanced characterization techniques over the past decade have disclosed several factors affecting the energy transfer processes leading to modified absorption and emission properties in metal-semiconductor hybrids. Herein, various ...

Template-assisted self-assembly of achiral plasmonic nanoparticles into chiral structures

“…Alternative to multi-step assemblies, more straightforward approaches could be designed for the wide variety of herein reviewed templates, employing hybrid plasmonic–excitonic NPs. 130 …”

Luminescence Enhancement, Encapsulation, and Patterning of Quantum Dots Toward Display Applications

“…The underlying energy transfer mechanism is complex and has been discussed in several reviews. [53][54][55][56][57] LSPR is sensitive to many factors, such as the plasmonic metal type, distance, and spacer properties between QDs and the plasmonic metal, size, shape, excitation wavelength, and match of absorption and emission spectra. [55] Usually noble metal NPs (gold (Au) and silver (Ag)) are used to produce localized surface plasmons in the shapes of nanosphere, nanostar, nanoporous films, nanodisk, and so on.…”

“…[35,36,38,58] The distance can be controlled by the spacer of the polymer, polypeptide, DNA, or the shell and ligands of the QDs. [37,53,[59][60][61] When the size varies, the wavelength shifts and excitation wavelengths need to be adjusted.…”

“…The collective oscillation of the conduction electrons can enhance the local electromagnetic field and the coupling between the surface plasmon and the molecular dipole of a fluorophore, thereby promoting the energy transfer process. [ 53 ] Basically, the coupling mechanisms can be categorized as far‐field scattering, near‐field resonant energy transfer, and hot electron energy transfer. The far‐field scattering effect can efficiently increase the optical path of the electromagnetic wave leading to enhanced absorption and emission of QDs.…”

Engineered tunneling layer with enhanced impact ionization for detection improvement in graphene/silicon heterojunction photodetectors

“…With the aim to address these issues, interface engineering, such as using the tunneling heterostructures 17 – 19 , introducing the passivation layer 20 – 22 , or modification with quantum dots/nanoparticles 23 , 24 , has been adopted to improve the photo-detection in the GS heterojunction photodetectors. In addition, the integrating of plasmonic nanostructures also has been demonstrated to be an effective strategy to improve the detecting performance via the modified absorption and internal photoemission process 25 , 26 . While for the tunneling structure, which is usually constructed by inserting an insulating layer into metal-semiconductor (MS) interface, it has been considered to be the most attractive method to obviously increase the detectivity with the much easily constructed device structures 27 , 28 .…”