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- Garcia-Ben, Javier, et al.
(författare)
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Narrowing the tolerance factor limits for hybrid organic-inorganic dicyanamide-perovskites
- 2022
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Ingår i: Journal of Solid State Chemistry. - : Elsevier BV. - 0022-4596 .- 1095-726X. ; 316, s. 123635-
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Tidskriftsartikel (refereegranskat)abstract
- In this work we focus in setting the limits of the tolerance factor and the size of the A-cations that stabilize the perovskite structure in hybrid dicyanamide compounds [A][Mn(dca)3]. For this purpose, we propose an alter-native, simple approach to calculate a more realistic effective ionic radius for the large and anisotropic A-cations often present in these type of compounds. We test the proposed procedure by analysing the crystal structures of [A][Mn(dca)3] dicyanamide hybrids reported in the literature and recalculating the tolerance factors of such compounds, as well as by preparing five new [A][Mn(dca)3] members, discussing also the influence of the A -cation shape in the stability limits of the perovskite structure. Interestingly, such methodology is not only useful to develop new compounds of the emerging family of (multi)functional multi(stimuli)-responsive dicyanamide materials but can also be applied to other hybrid organic-inorganic perovskites and related materials.
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| 2. |
- García-Ben, Javier, et al.
(författare)
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Structure and thermal property relationships in the thermomaterial di-n-butylammonium tetrafluoroborate for multipurpose cooling and cold-storage
- 2023
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Ingår i: Journal of Materials Chemistry A. - : Royal Society of Chemistry (RSC). - 2050-7488 .- 2050-7496. ; 11:41, s. 22232-22247
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Tidskriftsartikel (refereegranskat)abstract
- Nowadays around 46% of food production around the world requires refrigeration, which is generally provided either by active vapour-compression (based on refrigerants with liquid-gas transitions) or passive cold-storage (based on solid-to-liquid phase change materials, SL-PCMs). However, in order to avoid fluid losses during the transitions, new thermomaterials with solid-solid transitions are desired for both applications. In this work, we find that [DBA][BF4] (DBA = di-n-butylammonium) is a promising thermomaterial with solid-solid phase transitions. This compound presents thermal properties of great interest not only for active barocaloric refrigeration, but also for passive cold-storage, which make this a unique multipurpose thermomaterial. The observed cold-storage capacity is very close to that of commercial SL-PCMs (E ∼ 135 kJ kg−1), while the pressure-induced thermal changes (ΔS ∼ [200-270] J K−1 kg−1) are superior to those of most barocaloric materials, operating under lower pressures (p ∼ [500-1000] bar). Moreover, the operating temperature range of this material is very adequate for food preservation (250-310 K), which is a great advantage over most barocaloric materials. Beyond the thermal properties, we perform deep structural characterization, which reveals a progressive structural disorder of the [DBA]+ cations and [BF4]− anions as the origin of such thermal properties, which will help the future rational design of enhanced thermomaterials.
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| 3. |
- Cuquejo-Cid, Alberto, et al.
(författare)
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Photoluminescent and vapochromic properties of the Mn(II)-doped (C6H11NH3)(2)PbBr4 layered organic-inorganic hybrid perovskite
- 2021
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Ingår i: Polyhedron. - : Elsevier BV. - 0277-5387 .- 1873-3719. ; 193
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Tidskriftsartikel (refereegranskat)abstract
- By a wet-chemistry route we have been able to effectively dope the CHA(2)PbBr(4) compound, a ferroelectric compound with photovoltaic effect, with different amounts of Mn2+ obtaining three pure compounds CHA(2)Pb(1-x)Mn(x)Br(4) with x = 0.05, 0.07 and 0.11. At room temperature the crystal structure of these new Mn-doped compounds present an orthorhombic symmetric with polar space group Cmc2(1), as in the case of the undoped compoud (x = 0). Very interestingly, the doped compounds exhibit a broad PL emissions at room temperature, with a maximum around 605 nm and a long PL lifetime (similar to 0.55 ms), whose intensity increases further upon cooling. The observed PL emission is induced from an energy transfer from host semiconductor to the d-orbitals of Mn2+ cation. In addition, we have explored the capability of these materials to act as chemical sensors for volatile organic compounds and report the selective luminescence vapochromic response in this family of compounds. Therefore, the here presented Mn-doped CHA(2)Pb(1-x)MnxBr4 compounds belong to the scarce and desirable group of multifunctional materials, where not only ferroelectric and photovoltaic properties can coexist but also photoluminescence and vapochromic properties, rendering them extremely interesting for a large number of potential practical applications.
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