Porous Semiconductor Chalcogenide Aerogels

Abstract

Chalcogenide aerogels based entirely on semiconducting II-VI or IV-VI frameworks have been prepared from a general strategy that involves oxidative aggregation of metal chalcogenide nanoparticle building blocks followed by supercritical solvent removal. The resultant materials are mesoporous, exhibit high surface areas, can be prepared as monoliths, and demonstrate the characteristic quantum-confined optical properties of their nanoparticle components. These materials can be synthesized from a variety of building blocks by chemical or photochemical oxidation, and the properties can be further tuned by heat treatment. Aerogel formation represents a powerful yet facile method for metal chalcogenide nanoparticle assembly and the creation of mesoporous semiconductors.

Diffusion- and reaction-limited cluster aggregation revisited

“…At high dilutions, the fractal structure of the aggregates is independent of the initial concentration of the aggregating particles, but starts to increase when the density becomes sufficient to form percolating networks with a fractal dimension of d perc f = 2.5. In principle, the model provides a reasonable scenario of nanoparticle aggregation emerging, for instance, as one a) Electronic mail: swetlana.jungblut@tu-dresden.de of the steps in the aerogel production [14][15][16][17][18][19][20][21] , in which the destabilization of nanoparticles suspended in a solution induces their aggregation into disordered networks. The recent advances in nanotechnology and the expansion of the research associated with the topic of nanoparticle aggregation revealed, however, some deficiencies of the model.…”

Gelation of plasmonic metal oxide nanocrystals by polymer-induced depletion attractions

“…ions or molecules). The former has been adapted across noble metal (16,(18)(19)(20)(21) , metal chalcogenide (22)(23)(24)(25)(26) , and metal oxide (27)(28)(29)(30)(31) systems, but this method is prone to fuse NCs during assembly and consequently limits the realization of size and shape-dependent NC optical properties (i.e., PL and LSPR) within the gels. While gelation via chemical bridging is a viable strategy to mitigate NC fusing, translating this approach across NC materials requires customizing surface functional groups for specific NC compositions, so far limited to metal chalcogenide NCs (32,33) and Au NPs (17) .…”

Colloidal Nanocrystals: A Toolbox for Materials Chemistry

“…[88] Nowadays, a wide range of inorganic materials can be processed into nanoparticle-based aerogels including metal chalcogenides (CdS, CdSe, CdTe, PbS, ZnS, etc. ), [84,[88][89][90][91][92][93][94][95][96] metals (Pd, Pt, Au, Ag, etc. ), [97][98][99][100][101] their oxides (TiO 2 , [102][103][104][105][106] Y 2 O 3 , [81] BaTiO 3 , [82] InTaO 4 , [107] SrTiO 3 , [87] Y 3 Al 5 O 12 , [108] etc.…”

“…Controlled destabilization can be accomplished by means of additives such as acids, bases, electrolytes, [99,110] complexing agents, [96,[114][115][116] ligand strippers, [85,88,97] or non-solvents. [82,[102][103][104][105]108] Another possibility is the use of non-additive triggers such as temperature, [82,83,100,[102][103][104][105] irradiation, [84,106] mechanical methods such as centrifugation, [81,107,117] ultrasonic treatment, [82] or electrochemical methods. [118] The choice of trigger depends primarily on the type of stabilization (electrostatic or steric).…”