Nanocomposites of Carbon Nanotubes and Semiconductor Nanocrystals as Advanced Functional Material with Novel Optoelectronic Properties

Abstract

Semiconductor nanoparticles of very small size, or quantum dots, exhibit fascinating physical properties, completely different from their bulk varieties, mostly because of the quantum confinement effect. Due to their modified band structure, they particularly show attractive optoelectronic characteristics. Carbon nanotubes are a class of nanomaterials, which also possess wonderful optoelectronic properties and can revolutionize modern semiconductor technology to a great extent. Carbon nanotube fieldeffect transistors (CNTFETs) can replace standard MOSFETs in an array of devices and can function in a more effective way. When these two optoelectronic components combine together in nanocomposites, one may get advanced optoelectronic devices for widespread application in sensors, solar cells, energy storage devices, light-emitting diodes, electrocatalysts, etc.

Semiconductor Nanoparticle Anchored Single-Walled Carbon Nanotubes for a Bolometer

“…Such structures enhance the efficiency of charge separation and greatly reduce the exciton recombination. , Functionalization of semiconductor nanoparticles (NPs) with a varying band gap on the SWCNT surface will produce a new class of functional materials with remarkable properties by combining characteristics of individual components. These nanocomposites are potentially useful in a wide range of advanced applications, in the field of chemical sensors, biosensors, and nanoelectronics …”

“…Two mechanisms are proposed to explain the photo-interaction in SWCNTs: (I) The interband transition model is associated with a series of van Hove singularities in the one-dimensional (1D) electronic density of states. Electron–hole pairs are produced upon photoexcitation, and the lifetime of these carriers is long with spectral features in absorption and photoconductivity that match the optical transitions associated with the van Hove singularities. , (II) In the exciton model, photogenerated electron–hole pairs at energies lower than the direct band gap give rise to charge-neutral species that cannot contribute directly to photoconductivity unless a charge separation mechanism, such as a large bias, is provided . Instead, the excitons interact with the CNT lattice and dissociate thermally, thus enhancing the photoresponse of SWCNTs.…”

“…These nanocomposites are potentially useful in a wide range of advanced applications, in the field of chemical sensors, biosensors, and nanoelectronics. 10 The work thus focuses on understanding the effect of semiconductor NPs on the bolometric performance of the SWCNTs. The anchored SWCNT bolometer with semiconducting NPs, such as zinc oxide (ZnO, wurtzite structure, with an energy band gap of ∼3.4 eV), stannous disulfide (SnS 2 , hexagonal structure, with an energy band gap of ∼2.0 eV), and cadmium sulfide (CdS, cubic structure, with an energy band gap of ∼2.4 eV), displays an enhanced bolometric response for near-infrared (NIR) and wide wavelength source (200−1200 nm) illuminations.…”

Dynamics of light-induced charge transfer between carbon nanotube and CdSe/CdS core/shell nanocrystals

“…For example, seeded nanorods (sNRs) in photovoltaic devices and photodetectors have exhibited a highly efficient charge separation [7][8][9][10][11]. The combination of the high charge transport capabilities of CNTs with the optoelectronic flexibility of single component symmetric quantum dots (QDs) was studied for light-harvesting applications such as photovoltaic cells [12][13][14][15][16][17][18], photocatalysis [19,20], and light sensors [21][22][23][24][25][26][27][28][29][30]. Equivalently, Konstantatos et al [31] reported a large responsivity ∼10 7 A W −1 and photoconductive gain ∼10 8 in an analogous hybrid device comprised graphene and colloidal QDs.…”