PROCESS AND DEVICE OF REFRIGERATION INDUCED BY AN EXTERNAL STIMULUS ON A CALORIC ORGANIC-INORGANIC- HYBRID MATERIAL

Abstract

Process of refrigeration induced by an external stimulus comprising the application of an external stimulus selected among hydrostatic pressure, uniaxial pressure, electric field and illumination with light, to an organic-inorganic hybrid material of crystalline structure with hexagonal packing, of formula ABX.sub.3 (I), where A is a given monovalent organic cation or a given mixture of monovalent organic cations or a given mixture of monovalent organic cations and monovalent inorganic cations, B is a given divalent metal cation, a given mixture of divalent metal cations, or a given 50/50% atomic mixture of a monovalent cation and a trivalent cation, and X is a halide anion or a mixture thereof. A device with cooling capacity induced by an external stimulus, comprising the above organic-inorganic hybrid material.

Claims

1. A refrigeration process which comprises applying an external stimulus selected from hydrostatic pressure, uniaxial pressure, electric field, and illumination with light to an organic-inorganic hybrid material of hexagonal packing crystal structure of general formula:
ABX.sub.3(I) where: A is selected from the group consisting of a monovalent organic cation, a mixture of monovalent organic cations, and a mixture of monovalent organic cations and monovalent inorganic cations; the monovalent organic cation is selected from the group consisting of [NH.sub.3NH.sub.2].sup.+, [NH.sub.3OH].sup.+, [CH(NH.sub.2).sub.2].sup.+, [C(NH.sub.2).sub.3].sup.+, [C.sub.3NH.sub.8].sup.+, [(CH.sub.3).sub.2NH.sub.2].sup.+, [CH.sub.3CH.sub.2NH.sub.3].sup.+, [CH.sub.3C(NH.sub.2).sub.2].sup.+, [(CH.sub.3).sub.4N].sup.+, [C.sub.3N.sub.2H.sub.5].sup.+, [(CH.sub.3).sub.3NH].sup.+, [(CH.sub.3).sub.2CNH.sub.3].sup.+, [(C.sub.4H.sub.4)NH.sub.2].sup.+, [(CH.sub.3).sub.2CH.sub.3).sub.2N].sup.+, [(CH.sub.3CH.sub.2).sub.2NH.sub.2].sup.+, and [(C.sub.6H.sub.5)NH.sub.3].sup.+; and the monovalent organic cation mixture is a mixture of any of the organic cations mentioned, including [CH.sub.3NH.sub.3].sup.+; and the mixture of organic cations and monovalent inorganic cations is a mixture of any of the aforementioned organic cations with one or more inorganic cations selected from the group consisting of Cs.sup.+, Rb.sup.+, and NH.sub.4.sup.+; B is selected from the group consisting of: a divalent metal cation, a mixture of divalent metal cations, and a 50/50% atomic mixture of a monovalent cation and a trivalent cation, where: the divalent metal cation is selected from the group consisting of: Mg.sup.2+, Ca.sup.2+, Sr.sup.2+, Mn.sup.2+, Fe.sup.2+, Co.sup.2+, Ni.sup.2+, zn.sup.2+, Pb.sup.2+, sn.sup.2+, and Sb.sup.2+; the monovalent metal cation is selected from the group consisting of: Ag.sup.+, Na.sup.+, K.sup.+, Tl.sup.+, and Cu.sup.+; the trivalent cation is selected from the group consisting of: Cr.sup.3+, Fe.sup.3+, Bi.sup.3+, In.sup.3+; Y.sup.3+, Lu.sup.3+, La.sup.3+, Ce.sup.3+, Pr.sup.3+, Nd.sup.3+, Pm.sup.3+, Sm.sup.3+, Eu.sup.3+, Gd.sup.3+, Tb.sup.3+, Dy.sup.3+, Ho.sup.3+, Er.sup.3+, Tm.sup.3+ and Yb.sup.3+; X is a halide anion selected from the group consisting of F.sup., Cl.sup., Br.sup., I.sup., and a mixture thereof.

2. The refrigeration process according to claim 1, wherein A is a monovalent organic cation selected from the group consisting of: [(CH.sub.3).sub.2NH.sub.2].sup.+, [CH.sub.3CH.sub.2NH.sub.3].sup.+, [(CH.sub.3).sub.4N].sup.+, [(CH.sub.3).sub.3NH].sup.+, [(CH.sub.3).sub.2CNH.sub.3].sup.+, [(CH.sub.3).sub.2CH.sub.3).sub.2N].sup.+, and [(CH.sub.3CH.sub.2).sub.2NH.sub.2].sup.+.

3. The refrigeration process according to claim 2, wherein A is [(CH.sub.3).sub.2NH.sub.2].sup.+.

4. The refrigeration process according to claim 1, wherein A is a 60/40% atomic mixture of [(CH.sub.3).sub.2NH.sub.2].sup.+/[(CH.sub.3).sub.2CH.sub.3).sub.2N].sup.+ or a 75/25% atomic mixture of [(CH.sub.3).sub.2NH.sub.2].sup.+/Cs.sup.+.

5. The refrigeration process according to claim 1, wherein the trivalent cation is selected from the group consisting of: Cr.sup.3+, Fe.sup.3+, Bi.sup.3+, In.sup.3+, and Y.sup.3+.

6. The refrigeration process according to claim 1, wherein the trivalent cation is selected from the group consisting of: Lu.sup.3+, La.sup.3+, Ce.sup.3+, Pr.sup.3+, Nd.sup.3+, Pm.sup.3+, Sm.sup.3+, Eu.sup.3+, Gd.sup.3+, Tb.sup.3+, Dy.sup.3+, Ho.sup.3+, Er.sup.3+, Tm.sup.3+, and Yb.sup.3+.

7. The refrigeration process according to claim 1, wherein B is selected from the group consisting of a divalent metal cation.

8. The refrigeration process according to claim 1, wherein B is selected from the group consisting of: Pb.sup.2+, Mn.sup.2+, a 60/40% atomic mixture of Mn.sup.2+/Co.sup.2+, and a 50/50% atomic mixture of Ag.sup.+/Bi.sup.3+.

9. The refrigeration process according to claim 1, wherein X is Cl.sup..

10. The refrigeration process according to claim 1, wherein X is a 60/40% atomic mixture of Cl.sup./I.sup., or a 30/50/20% atomic mixture of I/Cl.sup./Br.sup..

11. The refrigeration process according to claim 1, wherein the organic-organic hybrid material is [(CH.sub.3).sub.2NH.sub.2]PbCl.sub.3.

12. The refrigeration process according to claim 1, wherein the external stimulus is hydrostatic pressure.

13. The refrigeration process according to claim 1, which is a continuous cyclic process and wherein each cycle comprises: a) applying and maintaining the stimulus for a certain period of time, with which the material gives off heat that is conducted outside the device; b) removing the stimulus with which the material cools; and c) using the cooled material to absorb heat from inside the device to be cooled.

14. (canceled)

15. A device with cooling capacity induced by an external stimulus, comprising: (1) an organic-organic hybrid material of general formula ABX.sub.3 (I) and hexagonal packing crystalline structure, (2) means to cyclically exercise the stimulus during a certain period of time on the organic-inorganic hybrid material and then remove it, where the external stimulus is selected from the group consisting of hydrostatic pressure, uniaxial pressure, electric field and illumination with light, wherein: A is selected from the group consisting of a monovalent organic cation, a mixture of monovalent organic cations, and a mixture of monovalent organic cations and monovalent inorganic cations; the monovalent organic cation is selected from the group consisting of [NH.sub.3NH.sub.2].sup.+, [NH.sub.3OH].sup.+, [CH(NH.sub.2).sub.2].sup.+, [C(NH.sub.2).sub.3].sup.+, [C.sub.3NH.sub.8].sup.+, [(CH.sub.3).sub.2NH.sub.2].sup.+, [CH.sub.3CH.sub.2NH.sub.3].sup.+, [CH.sub.3C(NH.sub.2).sub.2].sup.+, [(CH.sub.3).sub.4N].sub.+, [C.sub.3N.sub.2H.sub.5].sup.+, [(CH.sub.3).sub.3NH].sup.+, [(CH.sub.3).sub.2CNH.sub.3].sup.+, [C.sub.4H.sub.4)NH.sub.2].sup.+, [(CH.sub.3).sub.2CH.sub.3)N].sup.+, [(CH.sub.3CH.sub.2).sub.2NH.sub.2].sup.+, and [(C.sub.6H.sub.5)NH.sub.3].sup.+; and the monovalent organic cation mixture is a mixture of any of the organic cations mentioned, including [CH.sub.3NH.sub.3].sup.+; and the mixture of organic cations and monovalent inorganic cations is a mixture of any of the aforementioned organic cations with one or more inorganic cations selected from the group consisting of Cs.sup.+, Rb.sup.+, and NH.sub.4.sup.+; B is selected from the group consisting of: a divalent metal cation, a mixture of divalent metal cations, and a 50/50% atomic mixture of a monovalent cation and a trivalent cation, where: the divalent metal cation is selected from the group consisting of: Mg.sup.2+, Ca.sup.2+, Sr.sup.2+, Mn.sup.2+, Fe.sup.2+, Co.sup.2+, Ni.sup.2+, Cu.sup.2+, Zn.sup.2+, Cd.sup.2+, Pb.sup.2+, Sn.sup.2+, and Sb.sup.2+; the monovalent metal cation is selected from the group consisting of: Ag.sup.+, Na.sup.+, K.sup.+, Tl.sup.+, and Cu.sup.+; the trivalent cation is selected from the group consisting of: Cr.sup.3+, Fe.sup.3+, Bi.sup.3+, In.sup.3+; Y.sup.3+, Lu.sup.3+, La.sup.3+, Ce.sup.3+, Pr.sup.3+, Nd.sup.3+, Pm.sup.3+, Sm.sup.3+, Eu.sup.3+, Gd.sup.3+, Tb.sup.3+, Dy.sup.3+, Ho.sup.3+, Er.sup.3+, Tm.sup.3+ and Yb.sup.3+; and X is a halide anion selected from the group consisting of F.sup., Cl.sup., Br.sup., I.sup., and a mixture thereof.

16. The device according to claim 15, wherein the organic-inorganic hybrid material is in powder form, suspended in a fluid, suspended in a solid matrix, or in the form of a thin film.

17. The refrigeration process according to claim 1, wherein A is a monovalent organic cation selected from the group consisting of: [(CH.sub.3).sub.2NH.sub.2].sup.+, [CH.sub.3CH.sub.2NH.sub.3].sup.+, [(CH.sub.3).sub.4N].sup.+, [(CH.sub.3).sub.3NH].sup.+, [(CH.sub.3).sub.2CNH.sub.3].sup.+, [(CH.sub.3).sub.2CH.sub.3).sub.2NH].sup.+, and [(CH.sub.3CH.sub.2).sub.2NH.sub.2].sup.+, and B is selected from the group consisting of a divalent metal cation.

18. The refrigeration process according to claim 1, wherein A is a monovalent organic cation selected from the group consisting of: [(CH.sub.3).sub.2NH.sub.2].sup.+, [CH.sub.3CH.sub.2NH.sub.3].sup.+, [(CH.sub.3).sub.4N].sup.+, [(CH.sub.3).sub.3NH].sup.+, [(CH.sub.3).sub.2CNH.sub.3].sup.+, [(CH.sub.3).sub.2CH.sub.3).sub.2N].sup.+, and [(CH.sub.3CH.sub.2).sub.2NH.sub.2].sup.+, B is selected from the group consisting of a divalent metal cation; and X is Cl.sup..

19. The refrigeration process according to claim 1, wherein A is a monovalent organic cation selected from the group consisting of: [(CH.sub.3).sub.2NH.sub.2].sup.+, [CH.sub.3CH.sub.2NH.sub.3].sup.+, [(CH.sub.3).sub.4N].sup.+, [(CH.sub.3).sub.3NH].sup.+, [(CH.sub.3).sub.2CNH.sub.3].sup.+, [(CH.sub.3).sub.2CH.sub.3).sub.2N].sup.+, and [(CH.sub.3CH.sub.2).sub.2NH.sub.2].sup.+, B is selected from the group consisting of: Pb.sup.2+, Mn.sup.2+, a 60/40% atomic mixture of Mn.sup.2+/Co.sup.2+, and a 50/50% atomic mixture of Ag.sup.+/Bi.sup.+.

20. The refrigeration process according to claim 1, wherein A is a monovalent organic cation selected from the group consisting of: [(CH.sub.3).sub.2NH.sub.2].sup.+, [CH.sub.3CH.sub.2NH.sub.3].sup.+, [(CH.sub.3).sub.4N].sup.+, [(CH.sub.3).sub.3NH].sup.+, [(CH.sub.3).sub.2CNH.sub.3].sup.+, [(CH.sub.3).sub.2CH.sub.3).sub.2N].sup.+, and [(CH.sub.3CH.sub.2).sub.2NH.sub.2].sup.+, B is selected from the group consisting of: Pb.sup.2+, Mn.sup.2+, a 60/40% atomic mixture of Mn.sup.2+/Co.sup.2+, and a 50/50% atomic mixture of Ag.sup.+/Bi.sup.3+; and X is Cl.sup..

Description

BRIEF DESCRIPTION OF THE FIGURES

[0067] FIG. 1: Crystal structure of the comparative compound [(CH.sub.3CH.sub.2CH.sub.2).sub.4N][Mn(N(CN).sub.2).sub.3] obtained by single-crystal X-ray diffraction.

[0068] FIG. 2: Crystal structure of the comparative compound [CH.sub.3NH.sub.3]PbCl.sub.3 obtained by single-crystal X-ray diffraction.

[0069] FIG. 3: Crystal structure of the compound [(CH.sub.3).sub.2NH.sub.2]PbCl.sub.3 obtained by single-crystal X-ray diffraction.

[0070] FIG. 4: Barocaloric effect of the comparative compound [(CH.sub.3CH.sub.2CH.sub.2).sub.4N][Mn(N(CN).sub.2).sub.3].

[0071] FIG. 5: Barocaloric effect of compound [(CH.sub.3).sub.2NH.sub.2]PbCl.sub.3.

EXAMPLES

Example 1: Preparation of [(CH).SUB.2.NH.SUB.2.]PbCl.SUB.3

[0072] The material [(CH.sub.3).sub.2NH.sub.2]PbCl.sub.3 was obtained by mechanochemical synthesis at room temperature using the starting compounds [(CH.sub.3).sub.2NH.sub.2]Cl and PbCl.sub.2. Equimolar amounts of [(CH.sub.3).sub.2NH.sub.2]Cl and PbCl.sub.2 were used for this purpose and ground in a mortar for 15 minutes until a homogeneous powder was visually obtained.

[0073] Compound [(CH.sub.3).sub.2NH.sub.2]Cl was previously synthesized by reaction of equimolar amounts of dimethylamine in aqueous solution (40% weight of (CH.sub.3).sub.2NH in H.sub.2O) and of hydrochloric acid in aqueous solution (37% weight of HCl in H.sub.2O). This mixture was stirred for 15 minutes in an ice bath. Crystallization of dimethylammonium chloride was carried out by evaporating the solvent in a rotary evaporator until the appearance of a white solid precipitate of microcrystals. This solid was filtered and washed with diethyl ether several times and dried under vacuum overnight.

[0074] The PbCl.sub.2 compound was synthesized by reacting equimolar amounts of sodium chloride (or potassium chloride) in saturated aqueous solution and lead nitrate in aqueous solution. This solution mixture was stirred for 15 minutes in an ice bath. The crystallization of PbCl.sub.2 was carried out by evaporating the solvent in a rotary evaporator until the appearance of a white solid precipitate of microcrystals. This solid was filtered and washed with diethyl ether several times and dried under vacuum overnight.

[0075] Compounds [(CH.sub.3).sub.2NH.sub.2]Cl and PbCl.sub.2 can also be obtained commercially.

[0076] To obtain single crystals of the compound and to obtain greater purity, this compound was dissolved in an organic solvent (such as N, N-dimethylformamide or dimethyl sulfoxide) in concentrations between 15%-45% by weight. Subsequently, the solvent was allowed to evaporate at room temperature for one week to obtain single crystals or to purify the compound. The obtained material was characterized by single-crystal X-ray diffraction (see FIG. 3).

Example 2: Deposition of a [(CH.SUB.2.).SUB.2.NH.SUB.2.]PbCl.SUB.3 .Thin Film on a Substrate

[0077] To deposit a [(CH.sub.3).sub.2NH.sub.2]PbCl.sub.3 thin film on a substrate, this compound was dissolved in an organic solvent (either N, N-dimethylformamide or dimethyl sulfoxide) in concentrations between 15%-45% by weight. Subsequently, the solvent was allowed to evaporate on a substrate by means of rotation at 2000 rpm for 60 seconds to obtain a thin layer of the hybrid compound.

Example 3: Barocaloric Effect

[0078] The differential scanning calorimetry technique was used to study the caloric effect of the material. To do this, samples of about 5 mg of the material are analyzed in a TA Instruments MDSC Q2000 equipped with a pressure cell. The samples were cyclically heated and cooled at speeds between 1 C. min.sup.1 and 20 C. min.sup.1, from room temperature to 150 C., under nitrogen atmosphere. These heating and cooling cycles were performed at different nitrogen pressures from 1 bar to 69 bar, with a constant flow of nitrogen of 50 ml min.sup.1. The pressure cell was calibrated for each of these pressures using an indium standard. The barocaloric effect was obtained as the difference of isobaric entropy change at the pressure of 69 bar and change of isobaric entropy at the pressure of 1 bar, in units of J kg.sup.1 K.sup.1.

TABLE-US-00002 Transition Pressure Barocaloric temper- sensi- Effect ature tivity Material (J kg.sup.1 K.sup.1) ( C.) (K kbar.sup.1) Comparative example 1 37.0 57 23.1 [(CH.sub.3CH.sub.2CH.sub.2).sub.4N][Mn(N(CN).sub.2).sub.3] (experi- mental) Comparative example 2 15.65 57 3.5 [CH.sub.3NH.sub.3]PbI.sub.3 (theoretical) Comparative example 3 23.38 124 9.6 [CH.sub.3NH.sub.3]PbBr.sub.3 (theoretical) Comparative example 4 28.93 102 5.7 [CH.sub.3NH.sub.3]PbCl.sub.3 (theoretical) Example 1 31.0 42 23.2 [(CH.sub.3).sub.2NH.sub.2]PbCl.sub.3 (experi- mental)

[0079] The barocaloric effect of the comparative example 1 and of the example 1 of the invention are illustrated in FIGS. 4 and 5 respectively.

[0080] The barocaloric effect of the [(CH.sub.3).sub.2NH.sub.2]PbCl.sub.3 compound is considerably larger than that predicted for the compounds of comparative examples 2-4 which are the chemically closest compounds. Also, the [(CH.sub.3).sub.2NH.sub.2]PbCl.sub.3 compound has a better working temperature, much closer to room temperature than that of comparative the compounds, which largely facilitates its application as cooling material.

REFERENCES

Non-Patent Literature

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