Adjusting the photoconductive properties of LaCoO3 thin films by epitaxial strain
TL;DR: In this article, the tetragonal distortion of CoO6 octahedra results in a decrease of ΔCF as well as Eg, enhancing the photoconductive performance of LaCoO3 thin films.
About: This article is published in Optical Materials.The article was published on 2021-11-01. It has received 1 citations till now. The article focuses on the topics: Tetragonal crystal system & Thin film.
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TL;DR: In this article , the bending state of LSCO thin film was changed by directly applying mechanical bending, and the curvature diameter of the catalytic electrode was directly controlled, which showed that the OER activity of the LSCo thin film electrode considerably improved under an in situ strain of only ∼ 0.24%.
Abstract: Cobaltate has multiple valence states of 3d orbitals, and its oxygen evolution reaction (OER) performance can be adjusted by adjusting the oxygen concentration, internal electronic structure and connection between the lattice to afford superior OER activity. Therefore, cobaltate is considered a promising OER catalyst in alkaline media. Herein, the bending state of LSCO thin film was changed by directly applying mechanical bending, and the curvature diameter of the catalytic electrode was directly controlled. The results show that the OER activity of the LSCO thin film electrode considerably improved under an in situ strain of only ∼0.24%. It also showed that the volcanic trend in OER performance involves two parameters: the tolerance factor of Co and activation energy of oxygen.
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TL;DR: N nanoscale phase stabilization of CsPbI3 quantum dots (QDs) to low temperatures that can be used as the active component of efficient optoelectronic devices and describe the formation of α-CsP bI3 QD films that are phase-stable for months in ambient air.
Abstract: We show nanoscale phase stabilization of CsPbI 3 quantum dots (QDs) to low temperatures that can be used as the active component of efficient optoelectronic devices. CsPbI 3 is an all-inorganic analog to the hybrid organic cation halide perovskites, but the cubic phase of bulk CsPbI 3 (α-CsPbI 3 )—the variant with desirable band gap—is only stable at high temperatures. We describe the formation of α-CsPbI 3 QD films that are phase-stable for months in ambient air. The films exhibit long-range electronic transport and were used to fabricate colloidal perovskite QD photovoltaic cells with an open-circuit voltage of 1.23 volts and efficiency of 10.77%. These devices also function as light-emitting diodes with low turn-on voltage and tunable emission.
2,103 citations
TL;DR: In this paper, the ABO3-based photocatalysts for water splitting were systematically reviewed in detail and divided into four groups based on the employed modification strategies, i.e., chemical component adjustment, micro-/nano-structure adjustment, local lattice structure adjustment, and application of the modification strategy of ABO 3 in designing AxByOz photocatalyst.
223 citations
TL;DR: In this paper, it was shown that the magnetic properties can be "tuned" by epitaxial strain imposed on LCO thin films by the epitaxia growth on various substrate materials.
Abstract: Ferromagnetic order can be induced in $\mathrm{La}\mathrm{Co}{\mathrm{O}}_{3}$ (LCO) thin films by epitaxial strain. Here, we show that the magnetic properties can be ``tuned'' by epitaxial strain imposed on LCO thin films by the epitaxial growth on various substrate materials, i.e., (001) oriented $\mathrm{Sr}\mathrm{La}\mathrm{Al}{\mathrm{O}}_{4}$, $\mathrm{La}\mathrm{Al}{\mathrm{O}}_{3}$, $\mathrm{Sr}\mathrm{La}\mathrm{Ga}{\mathrm{O}}_{4}$, ${(\mathrm{La}\mathrm{Al}{\mathrm{O}}_{3})}_{0.3}{({\mathrm{Sr}}_{2}\mathrm{Al}\mathrm{Ta}{\mathrm{O}}_{6})}_{0.7}$, and $\mathrm{Sr}\mathrm{Ti}{\mathrm{O}}_{3}$. The lattice mismatch at room temperature of the in-plane lattice parameters between the substrate, ${a}_{s}$, and bulk LCO, ${a}_{b}$, ranges from $\ensuremath{-}1.31%$ to $+2.63%$. Single-phase, ⟨001⟩ oriented LCO thin films were grown by pulsed laser deposition on all these substrates. Due to the difference of the thermal-expansion coefficients between LCO and the substrates, the films experience an additional tensile strain of about $+0.3%$ during the cooling process after the deposition at ${T}_{s}=650\phantom{\rule{0.2em}{0ex}}\ifmmode^\circ\else\textdegree\fi{}\mathrm{C}$. The film lattice parameters display an elastic behavior, i.e., an increase of the in-plane film lattice parameter with increasing ${a}_{s}$. From the ratio between the out-of-plane and in-plane strain, we obtain a Poisson ratio of $\ensuremath{
u}\ensuremath{\approx}1∕3$. All films show a ferromagnetic transition as determined from magnetization measurements. The magnetization increases strongly with increasing tensile strain, whereas the transition temperature ${T}_{C}$ after a rapid initial rise appears to saturate at ${T}_{C}\ensuremath{\approx}85\phantom{\rule{0.3em}{0ex}}\mathrm{K}$ above $a=3.86\phantom{\rule{0.3em}{0ex}}\mathrm{\AA{}}$. The effective magnetic moment ${\ensuremath{\mu}}_{\mathrm{eff}}$ in the paramagnetic state increases almost linearly as a function of the mean lattice parameter $⟨a⟩$, indicating an enhanced population of higher spin states, i.e., intermediate- or high-spin states. The experimental results are discussed in terms of a decrease of the octahedral-site rotation with increasing tensile strain.
182 citations
01 Jan 2012
TL;DR: In this paper, the ABO3-based photocatalysts for water splitting were systematically reviewed in detail and divided into four groups based on the employed modification strategies, i.e., chemical component adjustment, micro-/nano-structure adjustment, local lattice structure adjustment, and application of the modification strategy of ABO 3 photocatalyst in designing AxByOz photocatylsts.
Abstract: Abstract ABO3-based photocatalysts for water splitting were systematically reviewed in this manuscript. Crystal structure and chemical composition characteristics of ABO3 materials were briefly introduced to guide the modification of ABO3-based photocatalysts. The ABO3-based photocatalysts were then reviewed in detail and divided into four groups based on the employed modification strategies, i.e., chemical component adjustment, micro-/nano-structure adjustment, local lattice structure adjustment, and application of the modification strategy of ABO3 photocatalysts in designing AxByOz photocatalysts. In this section, the recent research works on ABO3-based photocatalysts in our group were presented. Finally, application of ABO3 photocatalysts in Z-scheme systems for overall water splitting was introduced. This review summarized the development of ABO3-based photocatalysts and showed the values and possible direction of future research, thereby offering a guide for photocatalytic water splitting.
174 citations
TL;DR: In this article, the authors present an understanding of important aspects of the growth of the parent perovskite compound via pulsed laser deposition on SrTiO3 (001) substrates and the subsequent topotactic reduction.
Abstract: The recent observation of superconductivity in Nd0.8Sr0.2NiO2 calls for further investigation and optimization of the synthesis of this infinite-layer nickelate structure. Here, we present our current understanding of important aspects of the growth of the parent perovskite compound via pulsed laser deposition on SrTiO3 (001) substrates and the subsequent topotactic reduction. We find that to achieve single-crystalline, single-phase superconducting Nd0.8Sr0.2NiO2, it is essential that the precursor perovskite Nd0.8Sr0.2NiO3 thin film is stabilized with no visible impurity phases; in particular, a Ruddlesden–Popper-type secondary phase is often observed. We have further investigated the evolution of the soft-chemistry topotactic reduction conditions to realize full transformation to the infinite-layer structure with no film decomposition or formation of other phases. We find that capping the nickelate film with a subsequent SrTiO3 layer provides an epitaxial template to the top region of the nickelate film, much like the substrate. Thus, for currently optimized growth conditions, we can stabilize superconducting single-phase Nd0.8Sr0.2NiO2 (001) epitaxial thin films up to ∼10 nm.
115 citations