Search results for " perovskite"
showing 10 items of 63 documents
Tendencies in ABO3 Perovskite and SrF2, BaF2 and CaF2 Bulk and Surface F-Center Ab Initio Computations at High Symmetry Cubic Structure
2021
This research was partly funded by the Latvian Council of Science project No. LZP‐ 2020/2‐0009 (for R. Eglitis), as well as the ERAF Project No. 1.1.1.1/18/A/073. We express our gratitude for the financial support from Latvian–Ukraine cooperation Project No. Latvia–Ukraine LV‐ UA/2021/5. The Institute of Solid State Physics, University of Latvia (Latvia), as the Centre of Excellence has received funding from the European Unions Horizon 2020 Framework Pro‐ gramme H2020‐WIDESPREAD01‐2016‐2017‐Teaming Phase2 under Grant Agreement No. 739508, project CAMART2.
Fabrication and Characterisation of Titania Photonic Nanostructures
2015
In this work, we report about the preparation and morphological characterization of photonic nanopatterned titania films (~ 200 nm).
Polystyrene nanoparticle-templated hollow titania nanosphere monolayers as ordered scaffolds
2018
We report a novel multi-step method for the preparation of ordered mesoporous titania scaffolds and show an illustrative example of their application to solar cells. The method is based on (monolayer) colloidal nanosphere lithography that makes use of polystyrene nanoparticles organised at a water–air interface and subsequently transferred onto a solid substrate. A titania precursor solution (titanium(IV) isopropoxide in ethanol) is then drop-cast onto the monolayer and left to “incubate” overnight. Surprisingly, instead of the expected inverse monolayer-structure, a subsequent calcination step of the precursor yields an ordered monolayer of hollow titania nanospheres with a wall thickness …
Proton Dynamics in In:BaZrO3: Insights on the Atomic and Electronic Structure from X-ray Absorption Spectroscopy
2009
The local structure of Ba2+, Zr4+, and In3+ in In:BaZrO3 is investigated with EXAFS for samples having 0 to 75% In3+ content. It is found that indium can be inserted in any ratio in the host matrix oxide and that the oxygen coordination shell displays an In-O distance very similar to the Zr-O length. In the Zr-rich compositions, there is a preferred dopant-vacancy association that, however, does not give rise to dopant-proton interaction in the hydrated samples. The tendency of Ba2+ to be attracted toward the dopant site is attributed to the electrostatic interaction with the dopant and to the structural rearrangement around the In3+ site. Third cumulant analysis at high temperatures (up to…
Doping induced stable room temperature dual emission from gadolinium doped vacancy ordered double halide perovskite, Gd:Cs2SnCl6
2022
The recent advancement in bandgap engineering through controlled doping has widen the prospectof vacancy ordered double halide perovskites (VO DHPs) by conferring them with designableoptoelectronic properties. Here, we report synthesis of Gd doped Cs2SnCl6 via a simplesolvothermal method. Gd3+ ions doping lowers the band gap from 3.8 eV to 2.8 eV and facilitatesstable room temperature dual PL emission centered at 440 nm and 610 nm. The macroscopicemission process is well supported by the confocal PL emission studies on isolated crystallites.Both the pristine (Cs2SnCl6) and Gd:Cs2SnCl6 exhibit crystalline cubic structure with Fm3m spacegroup. Rietveld refinement correlates well with the cubi…
Modeling bismuth insertion in 1D hybrid lead halide TMSO(Pb x Bi y )I3 pseudo-perovskites
2022
Abstract The structures of the disordered 1D (pseudo-)perovskites of general TMSO(Pb x Bi y )I3 formulation [TMSO = (CH3)3SO+], obtained by doping the TMSOPbI3 species with Bi3+ ions, are investigated through the formulation of a statistical model of correlated disorder, which addresses the sequences of differently occupied BI6 face-sharing octahedra (B = Pb, Bi or vacant site) within ideally infinite [(BI3)−] n chains. The x-ray diffraction patterns simulated on the basis of the model are matched to the experimental traces, which show many broad peaks with awkward (nearly trapezoidal) shapes, under the assumption that the charge balance is fully accomplished within each chain. The analysis…
State of the art and prospects for halide perovskite nanocrystals
2021
Financiado para publicación en acceso aberto: Universidade de Vigo/CISUG Metal-halide perovskites have rapidly emerged as one of the most promising materials of the 21st century, with many exciting properties and great potential for a broad range of applications, from photovoltaics to optoelectronics and photocatalysis. The ease with which metal-halide perovskites can be synthesized in the form of brightly luminescent colloidal nanocrystals, as well as their tunable and intriguing optical and electronic properties, has attracted researchers from different disciplines of science and technology. In the last few years, there has been a significant progress in the shape-controlled synthesis of …
Purcell Enhancement and Wavelength Shift of Emitted Light by CsPbI3 Perovskite Nanocrystals Coupled to Hyperbolic Metamaterials
2020
Manipulation of the exciton emission rate in nanocrystals of lead halide perovskites (LHPs) was demonstrated by means of coupling of excitons with a hyperbolic metamaterial (HMM) consisting of alternating thin metal (Ag) and dielectric (LiF) layers. Such a coupling is found to induce an increase of the exciton radiative recombination rate by more than a factor of three due to the Purcell effect when the distance between the quantum emitter and HMM is nominally as small as 10 nm, which coincides well with the results of our theoretical analysis. Besides, an effect of the coupling-induced long wavelength shift of the exciton emission spectrum is detected and modeled. These results can be of i…
On the Way to Optoionics
2020
Discussions with Michael Grätzel, Ursula Röthlisberger, Robert A. Evarestov and Bettina V. Lotsch are gratefully acknowledged.
Optoelectronic devices based on caesium lead halide perovskite nanocrystals
2020
Tradicionalmente, la implementación de materiales activos en circuitos fotónicos integrados se ha basado en la utilización de semiconductores III-V y vidrios y materiales ferroeléctricos dopados con iones de tierras raras. Sin embargo, en la actualidad existe una alternativa basada en (nano) materiales sintetizados por técnicas de química coloidal. La posibilidad de procesar nanomateriales en solución permite fabricar semiconductores con propiedades ópticas (emisión, absorción, dispersión de luz) que pueden diseñarse durante la síntesis. Además, su naturaleza coloidal permite integrarlas en cualquier arquitectura óptica mediante sencillas técnicas de impresión en tinta. En este contexto, lo…