Assembly of Phosphide Nanocrystals into Porous Networks: Formation of InP Gels and Aerogels

Abstract

The applicability of sol-gel nanoparticle assembly routes, previously employed for metal chalcogenides, to phosphides is reported for the case of InP. Two different sizes (3.5 and 6.0 nm) of InP nanoparticles were synthesized by solution-phase arrested precipitation, capped with thiolate ligands, and oxidized with H₂O₂ or O₂/light to induce gel formation. The gels were aged, solvent-exchanged, and then supercritically dried to obtain aerogels with both meso- (2-50 nm) and macropores (>50 nm) and accessible surface areas of ∼200 m²/g. Aerogels showed higher band gap values relative to precursor nanoparticles, suggesting that during the process of assembling nanoparticles into 3D architectures, particle size reduction may have taken place. In contrast to metal chalcogenide gelation, InP gels did not form using tetranitromethane, a non-oxygen-transferring oxidant. The requirement of an oxygen-transferring oxidant, combined with X-ray photoelectron spectroscopy data showing oxidized phosphorus, suggests gelation is occurring due to condensation of phosphorus oxoanionic moieties generated at the interfaces. The ability to link discrete InP nanoparticles into a 3D porous network while maintaining quantum confinement is expected to facilitate exploitation of nanostructured InP in solid-state devices.

Surface of glassyGeS2: A model based on a first-principles approach

“…In this case, common synthesis methods are based on nucleation-to-growth or linker-* coasne@mit.edu driven assembly of building units where the final structures can reach a state close to equilibrium. Obtaining in a controlled way such materials, which exhibit a large surface area from ∼10 to 500 m 2 /g made up of highly polarizable atoms, can lead to breakthroughs for applications relying on the surface properties of the host compound (photocatalysis and gas separation, for instance) [14][15][16]. Recently, chalcogels have been demonstrated to be efficient sorbents for environmental remediation from gaseous and water waste media [17,18].…”

Synthesis of Inorganic–Organic 2D CdSe Slab‐Diamine Quantum Nets

“…Porous semiconductors have been recognized as a unique class of nanomaterials due to their low density, high surface area, and large open pores . Typically, these materials are formed via the sol–gel assembly of semiconductor nanoparticles into aerogel networks by chemical bridging of nanoparticles.…”

“…[12][13][14][15][16][17][18][19][20][21] In these materials, the ultrathin semiconductor inorganic 2D slabs are intercalated with organic diamines, providing not only an ideal model system for fundamental study but also free-standing quantum wells for optoelectronic applications.Porous semiconductors have been recognized as a unique class of nanomaterials due to their low density, high surface area, and large open pores. [22][23][24][25][26][27][28][29][30][31][32][33] Typically, these materials are formed via the sol-gel assembly of semiconductor nanoparticles into aerogel networks by chemical bridging of nanoparticles. For example, Arachchige and Brock reported that the thiolate ligands capping on the surfaces of nanoparticles are oxidized to network nanoparticles together.…”

“…Porous semiconductors have been recognized as a unique class of nanomaterials due to their low density, high surface area, and large open pores. [22][23][24][25][26][27][28][29][30][31][32][33] Typically, these materials are formed via the sol-gel assembly of semiconductor nanoparticles into aerogel networks by chemical bridging of nanoparticles. For example, Arachchige and Brock reported that the thiolate ligands capping on the surfaces of nanoparticles are oxidized to network nanoparticles together.…”

Encapsulating Cytochrome <em>c</em> in Silica Aerogel Nanoarchitectures without Metal Nanoparticles while Retaining Gas-phase Bioactivity

“…Aerogels are highly porous materials often formed by synthesizing sol-gel metal oxides(While metal oxide aerogels are very common, carbon and other types of aerogels have been synthesized. One example is InP aerogels) 10 and drying these sol-gels in such a way that the porous solid matrix is left unchanged [11][12][13][14] . All of the pores in solid aerogels result in much available surface area making aerogels extremely useful for any applications where surface reactions are important.…”