Formation mechanism of core-shell nanocrystals obtained via dehydration of coprecipitated hydroxides at hydrothermal conditions

This review analyzes and summarizes the research results for oxide material synthesis by combustion of organic-inorganic mixtures. We have outlined the range of physical and chemical factors influencing the precursor processes and the oxide material synthesis itself, as well as have shown the ways and options to control these processes and nanoscale materials' properties. We have highlighted several issues concerning the analysis methods for the resulting materials and processes. We have exemplified the practical implementation of the methods under discussion.

Section: Oxide Materials Production By Scsmentioning

confidence: 99%

Oxide material synthesis by combustion of organic-inorganic compositions

Ostroushko¹,

Русских²

2017

“…As a rule, the conditions of hydrothermal synthesis (HTS), significantly affect the composition, structure, and size of particles and crystallites of the synthesized products [1][2][3][4][5][6][7]. Important factors in this case are the sequence and rate of reagents mixing and the pH of the hydrothermal fluid [8,9]. Changes in pH usually significantly affect the state and composition of phases resulting from hydrothermal treatment [10,11].…”

Section: Introductionmentioning

confidence: 99%

Influence of hydrothermal synthesis conditions on the composition of the pyrochlore phase in the Bi2O3-Fe2O3-WO3 system

Lomakin¹,

Проскурина²,

Гусаров³

2020

Self Cite

The paper deals with a study of the effect which the hydrothermal fluid pH has on the formation of a pyrochlore-structured phase in the Bi 2 O 3-Fe 2 O 3-WO 3 system. It was shown that at pH of 1 and 8, the formation of pyrochlore-structured phase particles with crystallite sizes of 38 and 118 nm, respectively, is accompanied by the formation of the Bi 2 WO 6 compound with the Aurivillius phase structure. At pH values from 2 to 7, only pyrochlore-structured nanocrystalline particles with a variable composition are formed. Under these conditions, the dependence of the average size of crystallites of the pyrochlore-structured phase particles on pH is extreme, as the size increases from ∼ 67 nm at pH 2 up to ∼ 126 nm at pH 5 and then decreases to ∼ 102 nm at pH 7. The samples obtained at pH 3-4 have a composition that is the closest to that specified for the synthesis. When pH increases up to 10, there forms a non-single-phase product that contains the Bi 2 WO 6 phase and δ-Bi 2 O 3-based phase.

“…A significant advantage of ZrO 2 material is its ability to be doped with yttrium oxide (Y 2 O 3 ), which allows one to vary the optoelectronic characteristics of ZrO 2 -Y 2 O 3 -based nanostructured systems. Doping with rare-earth metals or niobium (Nb) allows to significantly improve the transport characteristics of the photoelectode and to increase the PCE of the PSCs [12,13]. Previously reports of PSCs fabricated using undoped ZrO 2 -based photoelectode have been made [14].…”

Section: Introductionmentioning

confidence: 99%

Very wide-bandgap nanostructured metal oxide materials for perovskite solar cells

Larina¹,

Alexeeva²,

Almjasheva³

et al. 2019

Self Cite

Very wide-bandgap undoped and Y 2 O 3-doped ZrO 2 nanoparticles were synthesized and their structural, optical, morphological and energy characteristics were investigated. It was found that the bandgap value in ZrO 2 decreases with Y 2 O 3 doping. The developed materials were used for fabrication of nanostructured photoelectrodes for perovskite solar cells (PSCs) with the architecture of glass/FTO/ZrO 2-Y 2 O 3 /CH 3 NH 3 PbI 3 /spiro-MeOTAD/Au. The power conversion efficiency in the PSCs based on ZrO 2-Y 2 O 3 photoelectrodes was significantly higher than that for undoped ZrO 2 photoelectrodes. We have found that nanostructured layers, based on very wide-bandgap materials could efficiently transfer the injected electrons via a hopping transport mechanism.