Giant barocaloric effect in the ferroic organic-inorganic hybrid [TPrA][Mn(dca)3] perovskite under easily accessible pressures

Abstract

The fast growing family of organic–inorganic hybrid compounds has recently been attracting increased attention owing to the remarkable functional properties (magnetic, multiferroic, optoelectronic, photovoltaic) displayed by some of its members. Here we show that these compounds can also have great potential in the until now unexplored field of solid-state cooling by presenting giant barocaloric effects near room temperature already under easily accessible pressures in the hybrid perovskite [TPrA][Mn(dca)3] (TPrA: tetrapropylammonium, dca: dicyanamide). Moreover, we propose that this will not be an isolated example for such an extraordinary behaviour as many other organic–inorganic hybrids (metal-organic frameworks and coordination polymers) exhibit the basic ingredients to display large caloric effects which can be very sensitive to pressure and other external stimuli. These findings open up new horizons and great opportunities for both organic–inorganic hybrids and for solid-state cooling technologies.

Giant barocaloric effects over a wide temperature range in superionic conductor AgI

“…To date, giant BC effects have only been experimentally demonstrated near room temperature in a polymer 10 , a small number of relatively expensive magnetic materials 11 – 16 , a number of fluorites 17 – 20 , a hybrid perovskite 21 and a small number of ferro/ferrielectric materials 22 , 23 . Following the recent prediction of giant BC effects in fluoride-based superionic conductors at very high temperatures 24 , we demonstrate here giant BC effects nearer to room temperature in a powder of AgI, which is the prototypical solid electrolyte that was shown to display fast ionic conduction over one century ago 25 , 26 .…”

Raman Spectroscopy Studies on the Barocaloric Hybrid Perovskite [(CH3)4N][Cd(N3)3]

“…Compounds that combine simultaneously organic and inorganic chemical groups are of great interest since they enlarge the range of structural possibilities that allow the coexistence and modulation of fundamental physical properties, increasing their multifunctional potential [ 1 ]. These hybrid inorganic-organic compounds have attracted great attention in the last years in view of their high technological potential in the areas of optoelectronics [ 2 ], photovoltaics [ 3 ], ferroelectrics [ 4 ], multiferroics [ 5 , 6 ], and, very recently, also in the field of barocaloric materials for solid-state cooling [ 7 , 8 ].…”

“…A very prominent member of this family is the manganese azide with A: [(CH 3 ) 4 N] + (n = 4), (TMA), (TMAMnN 3 ), the first azide reported to have a three-dimensional framework structure [ 17 ], which is now known to show coexistence of three ferroic orders (antiferroelectric, ferroelastic and magnetic bistability) [ 6 , 16 ]. In addition, in view of its very large entropy change at the ferroelastic phase transition (two times larger than in the case of the giant barocaloric hybrid perovskite [TPrA][Mn(dca) 3 ] (TPrA = (CH 3 CH 2 CH 2 ) 4 N + , dca = [N(CN) 2 ] − ) [ 8 ]), it has been first proposed [ 6 ] and recently experimentally proved that this material is a very promising barocaloric material [ 18 ].…”

Comparative studies of vibrational properties and phase transitions in perovskite‐like frameworks of [(C3H7)4N][M(N(CN)2)3] with MMn, Co, Ni

“…[1][2][3][4][5][6][7][8] Most extensively studied perovskite-type compounds contained HCOO − ligands but recently those with dicyanamide (N(CN) 2 −, dca) ligands also gained significant interest due to their complicated sequence of phase transitions as well as dielectric, barocaloric, and non-linear optical properties. [9][10][11][12][13][14] In this respect, former studies of tetrapropylammonium manganese dicyanamide (TPrAMn) showed that this compound exhibits only one structural phase transition at 330 K. [10] Further studies of Fe, Ni, and Co analogues revealed that these compounds undergo three structural phase transformations of the same character. [11] It is also worth noting that TPrAMn and TPrACo exhibit very strong pressure dependence of the phase transition temperatures and large phase transition entropies.…”

“…[10,12] Thus, these compounds were shown to exhibit a large barocaloric effect. [12,14] TPrAM (M¼Mn, Fe, Co, Ni) compounds were studied using X-ray diffraction, thermal, and dielectric methods. [9][10][11] In spite of these studies, phase transition mechanisms of Mn, Fe, Co, and Ni analogues are still not well understood.…”