CrystEngComm最新文献

Lead halide perovskites have multiple optoelectronic functions because of their intriguing photophysical properties. Unfortunately, their extensive application prospects are limited by their high toxicity and instability. For these reasons, it is significant to assemble novel lead-free halides with high-performance luminescence properties. Environment-friendly In³⁺-based halides are gaining increasing interest because of their high stabilities and photoluminescence quantum yields (PLQYs). In this research work, we synthesized a zero-dimensional (0D) hybrid indium chloride single crystal of [1-Me-Pipz]₂[InCl₆]Cl·H₂O (1-Me-Pipz = protonated 1-methylpiperazine) that demonstrated strong self-trapped exciton (STE)-associated broadband yellow light emission with a sufficient PLQY of 51.58%. Moreover, [1-Me-Pipz]₂[InCl₆]Cl·H₂O exhibits extremely excellent structural and spectral stability in a variety of harsh environments. Importantly, the outstanding optoelectronic characteristics allow indium perovskite to be used for the successful fabrication of white light-emitting diodes (WLEDs) with a high color rendering index of 86.4. This work enriches the literature on indium halide perovskites and provides a novel viewpoint for the possible applications of 0D In³⁺ perovskite-based luminescent materials.

The Ca-based fluorinated MOF, named UoC-9 (UoC = University of Cologne), was previously published, crystallising in an orthorhombic crystal system with a 2nd order phase transition (Ima2 to Pna2₁) between room temperature and 100 K. Herein, this MOF was used as a crystalline sponge to embed a selection of six different small guest molecules inside its pores by liquid exchange. After confirming that the guest molecules were successfully loaded into the pores of UoC-9, the resulting host–guest systems were extensively analysed via single crystal X-ray diffraction. The different crystal structures allowed us to investigate the structural behaviour of UoC-9 in response to the embedded guest molecules. The lattice parameters as well as the phase transition are influenced differently by the various guests, which is described in detail by supplementary Hirshfeld surface analyses enabling us to examine the underlying host–guest interactions. The NMP@UoC-9 (NMP = N-methyl-2-pyrrolidone) system exhibits superstructure reflections with a tripled b-axis, which was also elucidated within this work.

Targeted development of crystalline materials for the CO₂ reduction reaction (CO₂RR) is currently a hot topic. Copper is a common electrocatalyst for the reduction of CO₂ to CH₄. In this study, two new MOFs [Cu(TIPE)_0.5](ClO₄) (Cu-MOF) and [Co(TIPE)(TFA)₂]·2DMF (Co-MOF) (TIPE = 1,1,2,2-tetrakis(4-(imidazole-1-yl)phenyl)ethene, TFA = trifluoroacetate and DMF = N,N-dimethylformamide) were synthesized. Crystallographic analysis shows that Cu-MOF and Co-MOF are different 2D networks. Interestingly, Cu-MOF can serve as an efficient electrocatalyst for CO₂ conversion to CH₄, while the Co-MOF is not suitable for the electrocatalytic CO₂RR due to its low stability. In 1 M KOH electrolyte, Cu-MOF exhibits high performance for the electrocatalytic reduction of CO₂ to CH₄ with a faradaic efficiency (FE) of 41.53% at a potential of −1.28 V vs. RHE. The high performance and stability may be caused by the framework structure leading to a large electrochemically active surface area and fast charge transfer kinetics. This work offers an approach to design and construct CO₂ electroreduction catalysts and viable solutions to energy and environmental issues caused by excessive CO₂ emission.

The construction of semiconductor van der Waals (vdW) heterostructures has emerged as a promising approach to enhance the performance of photocatalysts for water splitting. In this study, a PtS₂/HfGe₂N₄ vdW heterojunction was designed, and its photocatalytic properties were investigated using first-principles calculations. The results indicate that the heterojunction exhibits strong light absorption and features a type-II band alignment. Charge transfer within the heterojunction creates an internal electric field, enabling its action as a direct Z-scheme photocatalyst. Additionally, its well-suited band edge position facilitates the redox reactions required for water splitting. Notably, the heterojunction demonstrates a high-intensity light absorption coefficient of 3.8 × 10⁵ cm⁻¹ at 2.3 eV corresponding to the green light in the visible spectrum, highlighting the heterojunction's potential for photocatalytic water splitting applications.

In this comprehensive review, we have introduced two distinct types of multinuclear zinc sulfide superpolyhedral molecular clusters and zinc sulfide quantum dots. Two distinct categories of hyper polyhedral zinc sulfide clusters are identified: Zn10, categorized under T3 symmetry, and Zn8, classified under P1 symmetry. Both Zn10 and Zn8 clusters feature not only μ₁-S and μ₂-S species, which are attached to ligands, but also μ₃-S and μ₄-S species that remain unattached to ligands. Furthermore, the zinc and sulfur atoms within these cluster molecules possess the versatility to be substituted by alternative cations or anions, leading to the formation of corresponding derivatives. By comparing synthetic methodologies, structural attributes, and potential applications of the multinuclear zinc sulfide superpolyhedral molecular clusters and zinc sulfide quantum dots, we have delved into the intricate relationship between zinc sulfide quantum dots and these two classes of zinc sulfide clusters, offering a fresh perspective. From a synthetic standpoint, the preparation of zinc sulfide quantum dots often shares similarities with the synthesis of Zn10 clusters, while some methods also mirror the synthesis of Zn8 clusters utilizing reactors. Quantum dots typically exhibit larger sizes compared to cluster molecules, and their growth is characterized by rapid and continuous expansion, accompanied by a continuous red-shift of the edge band peaks in their UV-vis absorption spectra. In contrast, cluster molecules display discrete and heterogeneous growth patterns, with abrupt transitions from one discrete size to another larger discrete size, mirrored by individual sharp peaks in their UV-vis absorption spectra. Regarding applications, both entities share similar domains of utilization, albeit with distinct underlying mechanisms. By elucidating these differences and similarities, we aim to foster further advancements in the field of zinc sulfide-based materials.

In this study, a crystalline material CuPMTT was synthesized via coordination self-assembly strategy. The surfaces of CuPMTT are densely populated with thiol groups that effectively capture Hg²⁺ ions, achieving an adsorption rate nearing 90% and a separation coefficient of 4.51 against Cu²⁺, thus outperforming conventional adsorbents and presenting a significant advancement in environmental protection chemistry.

Metal–organic frameworks (MOFs), self-assembled by metal ions and organic ligands, have been utilized as active layers in resistive random-access memory (RRAM) devices due to their tunable composition and structure advantages, high porosity, and diverse interactions between guest molecules and host frameworks. As one kind of special MOF, MOF nanosheets not only inherit the benefits of MOFs but also present unique two-dimensional nanoscale thicknesses. Their special properties make them beneficial for fabricating MOF films. Thus, they could be promising materials for RRAM devices. Herein, we synthesized two porphyrin MOF nanosheets and then fabricated MOF films by spin-coating. After that, we used the films for resistive switching (RS) layers in memory devices. The as-fabricated RRAM devices exhibit write-once-read-many-times memory characteristics and good nonvolatile stability. Furthermore, due to the unique luminescence of the porphyrin linker, we investigated the light-induced resistive switching characteristics. The result shows that these porphyrin-based MOF nanosheet films exhibited ternary memory properties. This RS modulation is likely related to the photoinduced electrons and holes forming along channels consisting of porphyrin molecules. This MOF-based light-mediated memory device can be a candidate for achieving environment-responsive devices and has applications in information storage devices.

To achieve high-performance optoelectronic devices and thermoelectric behaviour, non-stoichiometric compositions have been utilised in ternary transition metal dichalcogenides. This study marks the first report on the growth of Cu_xSb_1−xSe₂ (x = 0.2, 0.4, 0.6, 0.8) crystals using the Bridgman technique. We investigated the impact on their structural, optical, thermal and electrical properties in comparison with pure CuSbSe₂. Powder X-ray diffraction confirmed the presence of the dominant orthorhombic CuSbSe₂ phase along with minor secondary phases and this result was well supported by Raman spectroscopy. The crystallite size increases from 12 nm to 27 nm while the lattice strain decreases from 0.0116 to 0.0054 with Cu content in the crystal. Elemental analysis carried out by EDAX has reflected the desired stoichiometry of each crystal. FESEM images have shown flat as well as layer growth on their surfaces, thereby giving an indication that the growth of crystals occurred by a layer-by-layer growth mechanism. Raman spectra indicated the red shift in the A_g vibrational mode of CuSbSe₂ with increasing Cu proportion. The direct bandgap of each crystal is reduced from 1.55 eV to 1.42 eV with higher Cu percentage which is determined from the Kubelka–Munk function using the recorded reflectance spectrum which shows that these crystals can be promising candidates for optoelectronic applications. The positive value of the Seebeck coefficient (S) demonstrates the p-type semiconducting nature of each crystal measured in the temperature range of 323 K to 593 K. Among the grown crystals, P3 (Cu_0.6Sb_0.4Se₂) exhibited the superior power factor and ZT values of 0.0182 μW cm⁻¹ K⁻² and 0.935 × 10⁻⁴ at 595 K, respectively. The TGA of each crystal demonstrated single step decomposition, showcasing a maximum weight loss of 18.07% for the P4 crystal, which is confirmed by DTG. To assess the photodetection properties of each crystal, I–V curves and pulse photoresponses are recorded in parallel to plane configuration. Among all grown crystals, the P3 (Cu_0.6Sb_0.4Se₂) crystal based photodetector exhibits superior responsivity and detectivity of 0.014 mA W⁻¹ and 5.656 × 10⁸ Jones, respectively. These findings show that these crystals can be considered as a choice for thermoelectric as well as photodetection applications.

Cerium oxide-supported platinum nanoparticles are widely used in the CO-PROX reaction. Due to expense and rarity, developing synthetic routes that reduce the platinum load and improve the performance of catalysts is essential. A rod-shaped ceria was used as the support, and a series of PtCo_x/CeO₂-r catalysts with constant low Pt loading of 0.21 wt% were prepared by a co-impregnation method. Combined with the performance using different atomic ratios and characterizations, the catalysts presented strong interaction among Pt, Co and Ce at Co/Pt = 9 and showed the best catalytic performance, making a CO conversion increase of 18.0% at 80 °C but a decrease in the best conversion temperature of 90 °C to 80 °C, as compared with the Pt/CeO₂-r catalysts. The enhanced activity of PtCo₉/CeO₂-r was attributed to the synergistic effect of Pt–Co–Ce and reducing the Pt–O–Ce bond energy, which promoted the redox cycle via the Mars–van Krevelen mechanism. It is helpful in reducing the reaction temperature, widening the temperature window and improving the selectivity of CO₂. When the concentration of CO was 10 000 ppm, and the WHSV was 30 000 mL g⁻¹ h⁻¹, the optimal conversion of the catalyst could reach 96.6%, and the optimal conversion temperature was 80 °C.

In this study, a Pr/CDs/SSS/PbO₂ electrode with good electrocatalytic activity and superior stability was successfully prepared by an electrodeposition process. XRD results showed that the doping of the Pr element inhibited the PbO₂ crystal growth, resulting in the complete disappearance of the α-PbO₂ diffraction peaks. Compared with the pure PbO₂ electrode, the Pr/CDs/SSS/PbO₂ electrode possesses a smaller grain size and a more compact electrode surface structure. In addition, the results of XRD and XPS confirmed that Pr³⁺ and Pr⁴⁺ existed simultaneously in the electrode, which increased the oxygen precipitation over potential (1.96 V) and reduced the interfacial resistance (5.01 Ω) of the Pr/CDs/SSS/PbO₂ electrode. Significantly, the prepared Pr/CDs/SSS/PbO₂ electrode showed the highest catalytic activity when the electrode was prepared in 5 mmol L⁻¹ of Pr-containing solution, and the degradation of MB by the Pr/CDs/SSS/PbO₂ electrode was 98.2% after 180 min of degradation under the conditions: 50 mg L⁻¹ of MB, pH = 5, and 30 mA cm⁻² of current density. The removal rate of TOC was 58%, which was much higher than that of the pure PbO₂ electrode (3.44%). In general, the Pr/CDs/SSS/PbO₂ electrode can be considered an efficient and low-cost anode material for the electrochemical treatment of organic wastewater.