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The document is a contents list for the Journal of Materials Chemistry C, which is published by The Royal Society of Chemistry. It features articles on materials for optical, magnetic, and electronic devices. The list includes papers on topics such as reliability issues of amorphous oxide semiconductor-based thin film transistors, developments in perovskite photodetectors, and recent advances in small-molecule organic fluorescent semiconductors. The journal aims to connect the world with the chemical sciences and reinvest its profits back into the chemistry community. [Extracted from the article]

A series of RbEu bimetallic ammonium metal nitrate hybrid analogues, [(CH3)3NCH2X]2[RbEu(NO3)6] (X = Cl, 1; Br, 2; I, 3), have been synthesized via solvent evaporation. This series shows similar cage-like perovskite frameworks, in which the cations are confined in the spaces enclosed by the hydrogen-bonding interactions. They display structural phase transitions between 200–430 K. Detailed single-crystal structural analysis of 1–3 reveals the change of the dynamics of the cation and the distortion of the [Rb4Eu4(NO3)12] anionic framework is the driving force for the structural phase transition. Meanwhile, the thermal and dielectric anomalies are verified by differential scanning calorimetry and dielectric measurements, respectively. Interestingly, the subtle change of cation significantly affects the switching temperature and dielectric behaviors, showing the typical 'butterfly effect' in these RbEu bimetallic hybrids. Notably, they also display excellent optical properties, that is, the Eu3+ ion acts as the activator of the photoluminescence property. Meanwhile, compounds 1–3 have phosphorescent characteristics and 1 has the highest fluorescence quantum yield (FQY) of 57.82%. This finding will be evidently meaningful for exploring high-performance multifunctional switching materials for novel applications. [ABSTRACT FROM AUTHOR]

Invited for the cover of this issue are Le‐Ping Miao, Chao Shi, Yi Zhang and co‐workers at Jiangxi University of Science and Technology. The image depicts the structure diagrams of the 3D hybrid rare‐earth double perovskite compounds. The phase transition temperatures of the two compounds were indicated by the "ice and fire", respectively. It implies the increase of the phase transition temperature of the compounds. Read the full text of the article at 10.1002/chem.202103913. [ABSTRACT FROM AUTHOR]

Organic–inorganic hybrid molecular ferroelectrics have attracted broad attention in the field of research of ferroelectric materials. Following the surge of stable candidates, hybrid bimetal molecular-based materials have been recently explored to achieve excellent ferroelectricity. However, rare hybrid bimetal molecular ferroelectrics were reported. Inspired by "ferroelectrochemistry", a chiral nitrite-based hybrid bimetal molecular ferroelectric material, [(R)-3-quinuclidinol]2[LiCo(NO2)6] (1), was reported. The ferroelectric-paraelectric phase transition (C2 ↔ P321) behaviour of 1; was found at 343 K (Curie temperature, Tc) with a spontaneous electronic polarization (Ps) of 0.52 μC cm−2 and a coercive field (Ec) of 48 kV cm−1 at 298 K. Various-temperature single crystal structural analysis and dielectric constant measurements reveal that the rapid rotation of the organic cation and slight order–disorder transition of the NO2− anion are the origin of the ferroelectricity. To our knowledge, 1 is the first example of a nitrite-based hybrid bimetal molecular ferroelectric material that is triggered by an external electric field. This finding establishes a clear stimulus–structure–response relationship in advanced hybrid ferroelectric materials. [ABSTRACT FROM AUTHOR]

As a mechanical analog of ferroelectricity and ferromagnetism, ferroelasticity has made outstanding contributions in the fields of energy conversion, information processing, and mechanical switching. However, research on 2D ferroelasticity is lacking so far, and it is still a challenge to synthesize 2D perovskite ferroelastics. Here, we successfully constructed three 2D organic–inorganic hybrid ferroelastics: (PEA)2CdCl4 [PEA = phenethylamium cation, 1], (3-FPEA)2CdCl4 [3-FPEA = 3-fluorophenethylamium cation, 2] and (4-FPEA)2CdCl4 [4-FPEA = 4-fluorophenethylamium cation, 3]. These compounds undergo a structural phase transition between 379–385 K, exhibit temperature-triggered ferroelasticity, and possess a dielectric transition. The structural analysis of temperature-variable single crystals indicates that the reason for the phase transition of the ferroelastics is the order–disorder transition of cations and distortion of the anion framework. This research provides new options for a new generation of 2D perovskite ferroelastics. [ABSTRACT FROM AUTHOR]

Organic–inorganic hybrid bismuth halides, as essential members of the lead-free family, have attracted much attention due to their unique properties. However, the growth of bismuth-based single crystals with potentially low defect density has encountered many challenges, such as intractable rapid crystallization, the use of toxic organic solvents, and halide oxidation caused by prolonged heating. Herein, we developed a liquid phase diffusion method to prepare large-sized one-dimensional hybrid bismuth single crystals. Adopting this method, centimeter-sized (1,5-pentanediamine)BiI5 single crystals were harvested, which possess a hole trap density as low as 1.31 × 109 cm−3 and a carrier mobility reaching 28.2 cm2 V−1 s−1. The X-ray detectors based on (1,5-pentanediamine)BiI5 single crystals exhibit a sensitivity value of 8120 μC Gyair−1 cm−2 at −80 V. This work provided a new strategy for the growth of bismuth-based perovskite single crystals and inspired the growth of other hybrid perovskite materials. [ABSTRACT FROM AUTHOR]

Molecule-based switchable dielectrics with distinct changes of dielectric constant, which enable conversion of electronic properties between different states under external stimuli, are technologically important. The crown-ether clathrate system is a highly promising class of molecule-based switchable dielectrics. Herein, by choosing yttrium nitrate to be assembled with a 15-crown-5 molecule, we synthesized a new crown-ether clathrate, namely [15-crown-5][Y(NO3)2(H2O)5][NO3] (1). One relatively small thermal anomaly peak was observed centered at 230 K (Ttr) for compound 1. Single-crystal structures obtained at various temperatures revealed its reversible phase transition to be driven by the synergistic effect of the dynamic changes of the counter [NO3]− anions from an ordered to disordered state and the relatively strong thermal vibrations of the 15-crown-5 molecules, along with the rearrangement of [Y(NO3)2(H2O)5]+ cations in the crystal. Meanwhile, compound 1 also displayed a bistable dielectric response characteristically found in different structural phases. This discovery confirmed the possibility of using compound 1 as a molecule-based dielectric switching material. [ABSTRACT FROM AUTHOR]

(HTz)[Ba(ClO4)3] (HTz=thiazolium cation, 1), a perchlorate‐based hybrid perovskite‐type single crystal undergoes sequential structural phase transitions at 143/154 K and 210/218 K. The perovskite‐type cage structure is composed of Ba2+ nodes and ClO4− linkers to form anionic cage Ba8(ClO4)12 in which the HTz resides. It is notable that the anionic framework incorporating HTz is a perovskite‐type structure with the (412 ⋅ 63) framework. Various‐temperature single‐crystal structure analyses reveal the stepwise changed dynamics of HTz, and the distortion of the anionic cage Ba8(ClO4)12 are the origin of the phase transitions. We tend to attribute the switchable dielectric constant behavior mainly to order‐disorder transition of the HTzs and the rearrangement of the Ba8(ClO4)12 framework. Furthermore, dielectric switching is recorded. Our findings may prompt investigations of new perchlorate‐based organic‐inorganic hybrid perovskites. [ABSTRACT FROM AUTHOR]

Host–guest molecular crystals are classical types of molecular materials widely applied for fluorescent sensors, absorption, separation, etc. Their significance lies in deciphering the intermolecular interactions in crystal engineering and expanding the scope of pharmaceuticals and chemical-responsive smart materials. Here, we report three flexible host–guest molecular solvate crystals, 1·CH2Cl2, 1·dioxane, and 1·DMF, that crystallize with a much lower boiling point guest dichloromethane (DCM, 313 K), and high boiling points guest dioxane (374 K) and dimethylformamide (DMF, 426 K). Surprisingly, thermogravimetric and crystallographic characterizations show that 1·CH2Cl2 has a relatively high desolvation onset temperature of 390 K, which is much higher than that of 1·dioxane (305 K) and 1·DMF (307 K). Crystal structure analysis shows that this high stability originates from the confinement and steric effects of the trapped guest solvent molecules in the crystal cavities. Powder X-ray diffraction shows that the three compounds' desolvated powder can self-trap the CH2Cl2 (DCM) molecules, returning to the 1·CH2Cl2 state. Moreover, spectroscopic characterization presents an emission redshift of about 30 nm for 1·dioxane and 1·DMF compared to that of the former. These results are attributed to the flexible host plate's dihedral angle that undergoes a drastic change of about 50° which leads to the greatly enhanced conjugation degree of the host plate. [ABSTRACT FROM AUTHOR]

Invited for the cover of this issue are Le-Ping Miao, Chao Shi, Yi Zhang and co-workers at Jiangxi University of Science and Technology. The image depicts the structure diagrams of the 3D hybrid rare-earth double perovskite compounds. The phase transition temperatures of the two compounds were indicated by the "ice and fire", respectively. It implies the increase of the phase transition temperature of the compounds. Read the full text of the article at 10.1002/chem.202103913., (© 2022 Wiley-VCH GmbH.)