RESUMEN
Vacancy-ordered perovskites and derivatives represent an important subclass of hybrid metal halides with promise in applications including light emitting devices and photovoltaics. Understanding the vacancy-property relationship is crucial for designing related task-specific materials, yet research in this field remains sporadic. For the first time, we use the Connolly surface to quantitatively calculate the volume of vacancy (Vâ¡, â¡ = vacancy) in vacancy-ordered double perovskite derivatives (VDPDs). A relationship between void fraction and the structure, photoluminescent properties and humidity stability was established based on zero-dimensional (0-D) [N(alkyl)4]2Sbâ¡Cl5â¡'-type VDPDs. Compared with the more commonly studied A2M(IV)X6â¡-type double perovskite (A = cation, M = metal ion, X = halide), [N(alkyl)4]2Sbâ¡Cl5â¡' features double vacancy sites. Our results demonstrate an inverse relationship between the photoluminescent quantum yield and Vâ¡ in 0-D VDPDs. Additionally, structural transformation from A2SbCl5 to A3Sb2Cl9 was first reported, during which the novel 'gate-opening' gas adsorption phenomenon was observed in VDPDs for the first time, as evidenced by 'S'-shaped sorption isotherms for water vapor, indicating a cation-controlled water-vapor response behavior. A mixed-cation strategy was developed to modulate the humidity stability of VDPDs. Characterized by controllable water-responsive behavior and unique 'on-off-on' luminescent switching, A2M(III)â¡X5â¡'-type materials show great promise for multi-level information anti-counterfeiting applications.
RESUMEN
A new layered metal sulfide, namely (C6H15N3)1.3(NH4)1.5H1.5In3SnS8 (1, C6H15N3 = N-(2-aminoethyl) piperazine), has been solvothermally synthesized and characterized. Compound 1 crystallizes in the monoclinic space group C2/c. Its structure features a two-dimensional layer of {In3SnS8}n3n- with the (4,4) topology net, which is formed by interlinking supertetrahedral T2 clusters as secondary building units. Band structure calculations revealed that 1 had a band gap of 2.7 eV. The photoelectric response of 1 showed steady and reversible on/off cycles with an "on" state of 121.13 nA cm-2. Moreover, the activation of 1 by replacing the sluggish organic cations with harder K+ ions endowed the material with improved adsorption performances for Sr2+ ions from aqueous solutions.
RESUMEN
Recently zero-dimensional (0-D) inorganic-organic metal halides (IOMHs) have become a promising class of optoelectronic materials. Herein, we report a new photoluminescent (PL) 0-D antimony(III)-based IOMH single crystal, namely [H2BPZ][SbCl5]·H2O (BPZ = benzylpiperazine). Photophysical characterizations indicate that [H2BPZ][SbCl5]·H2O exhibits singlet/triplet dual-band emission. Density functional theory (DFT) calculations suggest that [H2BPZ][SbCl5]·H2O has the large energy difference between singlet and triplet states, which might induce the dual emission in this compound. Temperature-dependent PL spectra analyses suggest the soft lattice and strong electron-phonon coupling in this compound. Thermogravimetric analysis shows that the water molecules in the lattice of the title crystal could be removed by thermal treatment, giving rise to a dehydrated phase of [H2BPZ][SbCl5]. Interestingly, such structural transformation is accompanied by a reversible PL emission transition between red light (630 nm, dehydrated phase) and yellow light (595 nm, water-containing phase). When being exposed to an environment with 77% relative humidity, the emission color of the dehydrated phase was able to change from red to yellow within 20 s, and the red emission could be restored after reheating. The red to yellow emission switching could be achieved in acetone with water concentration as low as 0.2 vol%. The reversible PL transition phenomenon makes [H2BPZ][SbCl5]·H2O a potential material for luminescent water-sensing.