Research

26 pages, 63495 KiB

Open AccessEditor’s ChoiceArticle

Improving the Performance of BaMnO₃ Perovskite as Soot Oxidation Catalyst Using Carbon Black during Sol-Gel Synthesis

by Verónica Torregrosa-Rivero, María-Salvadora Sánchez-Adsuar and María-José Illán-Gómez

Nanomaterials 2022, 12(2), 219; https://doi.org/10.3390/nano12020219 - 10 Jan 2022

Cited by 9 | Viewed by 2019

A series of BaMnO₃ solids (BM-CX) were prepared by a modified sol-gel method in which a carbon black (VULCAN XC-72R), and different calcination temperatures (600–850 °C) were used. The fresh and used catalysts were characterized by ICP-OES, XRD, XPS, FESEM, TEM, O [...] Read more.

A series of BaMnO₃ solids (BM-CX) were prepared by a modified sol-gel method in which a carbon black (VULCAN XC-72R), and different calcination temperatures (600–850 °C) were used. The fresh and used catalysts were characterized by ICP-OES, XRD, XPS, FESEM, TEM, O_2-TPD and H_2- TPR-. The characterization results indicate that the use of low calcination temperatures in the presence of carbon black allows decreasing the sintering effects and achieving some improvements regarding BM reference catalyst: (i) smaller average crystal and particles size, (ii) a slight increase in the BET surface area, (iii) a decrease in the macropores diameter range and, (iv) a lower temperature for the reduction of manganese. The hydrogen consumption confirms Mn(III) and Mn(IV) are presented in the samples, Mn(III) being the main oxidation state. The BM-CX catalysts series shows an improved catalytic performance regarding BM reference catalyst for oxidation processes (NO to NO₂ and NO₂-assisted soot oxidation), promoting higher stability and higher CO₂ selectivity. BM-C700 shows the best catalytic performance, i.e., the highest thermal stability and a high initial soot oxidation rate, which decreases the accumulation of soot during the soot oxidation and, consequently, minimizes the catalyst deactivation. Full article

(This article belongs to the Special Issue Synthesis and Applications of Nanomaterials Based on Perovskites)

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13 pages, 2167 KiB

Open AccessEditor’s ChoiceArticle

Lead-Free Cesium Titanium Bromide Double Perovskite Nanocrystals

by G. Krishnamurthy Grandhi, Anastasia Matuhina, Maning Liu, Shambhavee Annurakshita, Harri Ali-Löytty, Godofredo Bautista and Paola Vivo

Nanomaterials 2021, 11(6), 1458; https://doi.org/10.3390/nano11061458 - 31 May 2021

Cited by 33 | Viewed by 5687

Abstract

Double perovskites are a promising family of lead-free materials that not only replace lead but also enable new optoelectronic applications beyond photovoltaics. Recently, a titanium (Ti)-based vacancy-ordered double perovskite, Cs₂TiBr₆, has been reported as an example of truly sustainable [...] Read more.

Double perovskites are a promising family of lead-free materials that not only replace lead but also enable new optoelectronic applications beyond photovoltaics. Recently, a titanium (Ti)-based vacancy-ordered double perovskite, Cs₂TiBr₆, has been reported as an example of truly sustainable and earth-abundant perovskite with controversial results in terms of photoluminescence and environmental stability. Our work looks at this material from a new perspective, i.e., at the nanoscale. We demonstrate the first colloidal synthesis of Cs₂TiX₆ nanocrystals (X = Br, Cl) and observe tunable morphology and size of the nanocrystals according to the set reaction temperature. The Cs₂TiBr₆ nanocrystals synthesized at 185 °C show a bandgap of 1.9 eV and are relatively stable up to 8 weeks in suspensions. However, they do not display notable photoluminescence. The centrosymmetric crystal structure of Cs₂TiBr₆ suggests that this material could enable third-harmonic generation (THG) responses. Indeed, we provide a clear evidence of THG signals detected by the THG microscopy technique. As only a few THG-active halide perovskite materials are known to date and they are all lead-based, our findings promote future research on Cs₂TiBr₆ as well as on other lead-free double perovskites, with stronger focus on currently unexplored nonlinear optical applications. Full article

(This article belongs to the Special Issue Synthesis and Applications of Nanomaterials Based on Perovskites)

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19 pages, 4872 KiB

Open AccessArticle

Design of Novel Perovskite-Based Polymeric Poly(l-Lactide-Co-Glycolide) Nanofibers with Anti-Microbial Properties for Tissue Engineering

by Aleksander Góra, Lingling Tian, Seeram Ramakrishna and Shayanti Mukherjee

Nanomaterials 2020, 10(6), 1127; https://doi.org/10.3390/nano10061127 - 07 Jun 2020

Cited by 19 | Viewed by 3018

Abstract

There is a growing need for anti-microbial materials in several biomedical application areas, such are hernia, skin grafts as well as gynecological products, owing to the complications caused by infection due to surgical biomaterials. The anti-microbial effects of silver in the form of [...] Read more.

There is a growing need for anti-microbial materials in several biomedical application areas, such are hernia, skin grafts as well as gynecological products, owing to the complications caused by infection due to surgical biomaterials. The anti-microbial effects of silver in the form of nanoparticles, although effective, can be toxic to surrounding cells. In this study, we report, for the first time, a novel biomedical application of Ag_0.3Na_1.7La₂Ti₃O₁₀-layered perovskite particles, blended with poly(L-lactide-co-glycolide) (PLGA), aimed at designing anti-microbial and tissue engineering scaffolds. The perovskite was incorporated in three concentrations of 1, 5, 10 and 15 w/w% and electrospun using dimethylformamide (DMF) and chloroform. The morphology of the resultant nanofibers revealed fiber diameters in the range of 408 to 610 nm by scanning electron microscopy. Mechanical properties of perovskite-based nanofibers also matched similar mechanical properties to human skin. We observed impressive anti-microbial activity, against Gram-negative, Gram-positive bacteria and even fungi, to Ag_0.3Na_1.7La₂Ti₃O₁₀ in powder as well as nanofiber-incorporated forms. Furthermore, cytotoxicity assay and immunocytochemistry revealed that perovskite-based nanofibers promoted the proliferation of human dermal fibroblasts whist maintaining normal cellular protein expression. Our study shows that perovskite-nanofibers have potential as scaffolds for biomedical applications with anti-microbial needs. Full article

(This article belongs to the Special Issue Synthesis and Applications of Nanomaterials Based on Perovskites)

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14 pages, 2490 KiB

Open AccessArticle

Vapor-Phase Photocatalytic Overall Water Splitting Using Hybrid Methylammonium Copper and Lead Perovskites

by Teresa García, Rocío García-Aboal, Josep Albero, Pedro Atienzar and Hermenegildo García

Nanomaterials 2020, 10(5), 960; https://doi.org/10.3390/nano10050960 - 18 May 2020

Cited by 12 | Viewed by 3362

Abstract

Films or powders of hybrid methylammonium copper halide perovskite exhibit photocatalytic activity for overall water splitting in the vapor phase in the absence of any sacrificial agent, resulting in the generation of H₂ and O₂, reaching a maximum production rate [...] Read more.

Films or powders of hybrid methylammonium copper halide perovskite exhibit photocatalytic activity for overall water splitting in the vapor phase in the absence of any sacrificial agent, resulting in the generation of H₂ and O₂, reaching a maximum production rate of 6 μmol H₂ × g cat⁻¹h⁻¹ efficiency. The photocatalytic activity depends on the composition, degreasing all inorganic Cs₂CuCl₂Br₂ perovskite and other Cl/Br proportions in the methylammonium hybrids. XRD indicates that MA₂CuCl₂Br₂ is stable under irradiation conditions in agreement with the linear H₂ production with the irradiation time. Similar to copper analogue, hybrid methylammonium lead halide perovskites also promote the overall photocatalytic water splitting, but with four times less efficiency than the Cu analogues. The present results show that, although moisture is strongly detrimental to the photovoltaic applications of hybrid perovskites, it is still possible to use these materials as photocatalysts for processes requiring moisture due to the lack of relevance in the photocatalytic processes of interparticle charge migration. Full article

(This article belongs to the Special Issue Synthesis and Applications of Nanomaterials Based on Perovskites)

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6 pages, 1368 KiB

Open AccessCommunication

Facile Synthesis of FAPbI₃ Nanorods

by He Huang, Linzhong Wu, Yiou Wang, Alexander F. Richter, Markus Döblinger and Jochen Feldmann

Nanomaterials 2020, 10(1), 72; https://doi.org/10.3390/nano10010072 - 29 Dec 2019

Cited by 6 | Viewed by 5689

Abstract

Metal halide perovskites are promising materials for a range of applications. The synthesis of light-emitting perovskite nanorods has become popular recently. Thus far, the facile synthesis of perovskite nanorods remains elusive. In this work, we have developed a facile synthesis to fabricate FAPbI [...] Read more.

Metal halide perovskites are promising materials for a range of applications. The synthesis of light-emitting perovskite nanorods has become popular recently. Thus far, the facile synthesis of perovskite nanorods remains elusive. In this work, we have developed a facile synthesis to fabricate FAPbI₃ nanorods for the first time, demonstrating a high photoluminescence quantum yield of 35–42%. The fabrication of the nanorods has been made possible by carefully tuning the concentration of formamidine-oleate as well as the amount of oleic acid with pre-dissolved PbI₂ in toluene with oleic acid/oleylamine. Full article

(This article belongs to the Special Issue Synthesis and Applications of Nanomaterials Based on Perovskites)

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11 pages, 2069 KiB

Open AccessArticle

Facile Synthesis of Methylammonium Lead Iodide Perovskite with Controllable Morphologies with Enhanced Luminescence Performance

by Tao Wang, Huafang Zhang, Sumin Hou, Yan Zhang, Quanjun Li, Zhenlong Zhang, Huiping Gao and Yanli Mao

Nanomaterials 2019, 9(12), 1660; https://doi.org/10.3390/nano9121660 - 21 Nov 2019

Cited by 13 | Viewed by 4822

Abstract

Organic–inorganic hybrid perovskites with well-defined morphology have attracted much attention due to their unique photophysical properties. However, controlling the morphology of nanocrystalline perovskite to improve its photoelectric application remains a challenge. In this article, using a modified solution deposition method, we successfully synthesized [...] Read more.

Organic–inorganic hybrid perovskites with well-defined morphology have attracted much attention due to their unique photophysical properties. However, controlling the morphology of nanocrystalline perovskite to improve its photoelectric application remains a challenge. In this article, using a modified solution deposition method, we successfully synthesized uniform methylammonium lead iodide (MAPbI₃) nanoplates, nanocubes, and nanorods and investigated the effect of morphology on the photoelectric properties of these materials. We found that the morphology can be controlled by regulating the amounts of reactant methylammonium iodide (MAI) and the rate at which MAPbI₃ precursor is added into toluene solution, and that the corresponding size distributions can be optimized by tuning the final vacuum-drying temperature. The morphology has an obvious effect on the bandgap optimization and fluorescence enhancement of MAPbI₃, and the nanoplates exhibit stronger photoluminescence intensity and have a longer carrier lifetime than nanocubes and nanorods. The results show that the morphologies of MAPbI₃ perovskite nanocrystals can be controlled by tuning the synthesizing conditions, and the MAPbI₃ perovskite nanocrystals with special morphology can be used in special nanosize optoelectronic devices. Full article

(This article belongs to the Special Issue Synthesis and Applications of Nanomaterials Based on Perovskites)

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12 pages, 4302 KiB

Open AccessArticle

Enhancing the Photovoltaic Performance of Perovskite Solar Cells Using Plasmonic Au@Pt@Au Core-Shell Nanoparticles

by Bao Wang, Xiangyu Zhu, Shuhan Li, Mengwei Chen, Nan Liu, Hao Yang, Meiqing Ran, Haifei Lu and Yingping Yang

Nanomaterials 2019, 9(9), 1263; https://doi.org/10.3390/nano9091263 - 05 Sep 2019

Cited by 19 | Viewed by 3499

Abstract

Au@Pt@Au core-shell nanoparticles, synthesized through chemical reduction, are utilized to improve the photoelectric performance of perovskite solar cells (PSCs) in which carbon films are used as the counter electrode, and the hole-transporting layer is not used. After a series of experiments, these Au@Pt@Au [...] Read more.

Au@Pt@Au core-shell nanoparticles, synthesized through chemical reduction, are utilized to improve the photoelectric performance of perovskite solar cells (PSCs) in which carbon films are used as the counter electrode, and the hole-transporting layer is not used. After a series of experiments, these Au@Pt@Au core-shell nanoparticles are optimized and demonstrate outstanding optical and electrical properties due to their local surface plasmon resonance and scattering effects. PSC devices containing 1 wt.% Au@Pt@Au core-shell nanoparticles have the highest efficiency; this is attributable to their significant light trapping and utilization capabilities, which are the result of the distinctive structure of the nanoparticles. The power conversion efficiency of PSCs, with an optimal content of plasmonic nanoparticles (1 wt.%), increased 8.1%, compared to normal PSCs, which was from 12.4% to 13.4%; their short-circuit current density also increased by 5.4%, from 20.5 mA·cm⁻² to 21.6 mA·cm⁻². The open-circuit voltages remaining are essentially unchanged. When the number of Au@Pt@Au core-shell nanoparticles in the mesoporous TiO₂ layer increases, the photovoltaic parameters of the former shows a downward trend due to the recombination of electrons and holes, as well as the decrease in electron transporting pathways. Full article

(This article belongs to the Special Issue Synthesis and Applications of Nanomaterials Based on Perovskites)

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12 pages, 3182 KiB

Open AccessArticle

MAPbI₃ Incorporated with Carboxyl Group Chelated Titania for Planar Perovskite Solar Cells in Low-Temperature Process

by Pei-Shan Li, Rathinam Balamurugan, Bo-Tau Liu, Rong-Ho Lee and Hsueh-Tao Chou

Nanomaterials 2019, 9(6), 908; https://doi.org/10.3390/nano9060908 - 23 Jun 2019

Cited by 10 | Viewed by 3460

Abstract

Low-temperature, solution-processed, highly efficient hybrid organic/inorganic perovskite planar heterojunction solar cells were fabricated by incorporating reactive crystalline titania (h-TAc) into MAPbI₃ layers. The h-TAc was prepared by the sol-gel reaction at low temperature followed by solvothermal treatment. The photoelectrical properties of the [...] Read more.

Low-temperature, solution-processed, highly efficient hybrid organic/inorganic perovskite planar heterojunction solar cells were fabricated by incorporating reactive crystalline titania (h-TAc) into MAPbI₃ layers. The h-TAc was prepared by the sol-gel reaction at low temperature followed by solvothermal treatment. The photoelectrical properties of the solar cells with h-TAc were analyzed. The incorporation with 0.85-wt% h-TAc showed the highest power conversion efficiency (PCE, 15.9%), increasing 69% compared to the pristine cell. The enhancement arose from large-grained microstructures, leading to a low rate of charge recombination. The carboxyl groups chelated on the surface of h-TAc revealed a strong attraction to lead ions, which are significantly helpful to MAPbI₃ crystal growth. Full article

(This article belongs to the Special Issue Synthesis and Applications of Nanomaterials Based on Perovskites)

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10 pages, 3408 KiB

Open AccessArticle

Facile Synthesis and Optical Properties of CsPbX₃/ZIF-8 Composites for Wide-Color-Gamut Display

by Shiliang Mei, Bobo Yang, Xian Wei, Hanqing Dai, Zhihao Chen, Zhongjie Cui, Guilin Zhang, Fengxian Xie, Wanlu Zhang and Ruiqian Guo

Nanomaterials 2019, 9(6), 832; https://doi.org/10.3390/nano9060832 - 31 May 2019

Cited by 39 | Viewed by 5274

Abstract

All-inorganic CsPbX₃ (X = Cl, Br, and I) perovskite quantum dots (QDs), an emerging type of luminescent materials, have drawn extensive attention in recent years. However, the amelioration of their stability is becoming a critical issue. Herein, we present a facile and [...] Read more.

All-inorganic CsPbX₃ (X = Cl, Br, and I) perovskite quantum dots (QDs), an emerging type of luminescent materials, have drawn extensive attention in recent years. However, the amelioration of their stability is becoming a critical issue. Herein, we present a facile and efficient approach to prepare novel perovskite QDs/metal–organic frameworks (CsPbX₃/ZIF-8) composites under ambient-atmospheric conditions. The obtained composites exhibit better properties including high photoluminescence (PL) quantum yields (QYs) (41.2% for green and 34.8% for red), narrow-band emission (20 nm for green and 31 nm for red), and enhanced stability in comparison to bare QDs. Furthermore, their application in a remote-type white-light-emitting device was explored and a wide color gamut (~137% of the National Television System Committee standard) was achieved, verifying that these novel luminescent composites have great prospect in backlight display application. Full article

(This article belongs to the Special Issue Synthesis and Applications of Nanomaterials Based on Perovskites)

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