[en] Over the past decade, perovskite remains the most sought-after photoluminescent nanomaterial for record breaking photoelectric conversion efficiency (PCE). All- inorganic cesium lead halide perovskite (CsPbX₃, X =Cl, Br, I) NCs have been considered as the most promising nanomaterials due to their unique optoelectronic properties- bright photoluminescence (PL), narrow spectral widths, and band gap tunability over the entire visible spectrum. The inherent challenges with these nanomaterials are poor aqueous stability, high cost associated with anion exchange for colour tunability, and extreme sensitivity towards reaction conditions leading to feeble photoluminescence. properties. (author)

[en] In this study, composites composed of all-inorganic perovskite quantum dots (QDs) of CsPbBr₃ encapsulated in a metal-organic framework of ZIF-8 (CsPbBr₃(at)ZIF-8) were prepared using an in situ chemical reduction method. For the first time, the CsPbBr₃(at)ZIF-8 composites were used for surface-enhanced Raman scattering (SERS). The CsPbBr₃(at)ZIF-8 composites remained effective and emitted normal luminescence under UV illumination after 200 days of storage at room temperature, indicating that they were able to overcome the instability of perovskite QDs at room temperature and that they can be stored for long-term use. The enhancement factor value is 1.17 x 10⁵. The adsorption behavior of 4-mercaptopyridine (4-MPY) on the CsPbBr₃(at)ZIF-8 composites was studied using typical SERS spectral bands, and these were contrasted with the SERS spectra on silver films. The enhancement mechanism is attributed to a charge transfer contribution. The results indicate that CsPbBr₃(at)ZIF-8 composites have potential application in SERS detection

[en] The development of a new kind of self-powered vibration sensor (SPVS) with cantilever structure made with polymeric piezoelectric material for low frequency vibrations detection is demonstrated. Methylammonium lead bromide (MAPB) particles incorporated poly(vinylidene fluoride) (PVDF) composite film exhibiting significant yield of piezoelectric β-phase and outstanding flexibility that resulting superior mechanical energy harvesting behaviour. The composite films also possess relatively increased dielectric constant than PVDF film. The resonance frequency and amplitude of damping vibrations have been determined utilizing the output voltage of the SPVS without any power source. Thus, SPVS might be useful in detecting low frequency vibrations in self-powered mode. (paper)

[en] Results of investigation of glass formation in double systems limiting the ternary system HgBr₂-PbBr₂-CsBr, and series of samples with composition close to ternary eutectic points of the ternary system are represented. Conditions of preparation of glass are determined. Characteristic temperatures are determined using differential thermal analysis, T_g/T_m ratios and H_R factor of glass-like samples are calculated

[en] Highlights: • The V_Br of CsPbBr₃ NCs can be effectively reduced by adding 1,9-DN in the solution. • The CsPbBr₃ NCs prepared with 1,9-DN have a good ethanol tolerance. • The illumination and thermal stability of CsPbBr₃ NCs was obviously improved. -- Abstract: Despite colloidal CsPbBr₃ nanocrystals (NCs) exhibit an excellent optoelectronic characteristics, the stability greatly restricts their potential applications due to the ionic nature. The CsPbBr₃ NCs were synthesized in a Br-rich strategy by adding 1,9-DN. The PL intensity of CsPbBr₃ NCs was increased and the average PL decay lifetime was reduced due to the decrease of defects. The chemical, illumination and thermal stability of CsPbBr₃ NCs were obviously improved, which may be caused by the increase of ligand and the decrease of V_Br on the surface of CsPbBr₃ NCs as adding 1,9-DN. The results provide a novel strategy to prepare emissive materials with environmental stability, implying great promise in optoelectronic applications.

[en] A CsPbBr₃/Cs₄PbBr₆ perovskite composite, which exhibits highly efficient pure green luminescence and better long-term stability than CsPbBr₃ nanocrystals, has emerged for wide color gamut displays and various optoelectronic applications. While many reports have been made on the optoelectronic properties of perovskite materials, the study of the rapid mass synthesis of this material remains challenging. In addition, more case studies are still needed to optimize the conditions such as the differences in raw materials or addition of ligands, and to clarify these changes. Here, a new synthesis strategy is reported that enables rapid mass synthesis of green-emitting perovskite composites by forming ultrafine reverse microemulsions by hydraulic shear. Furthermore, in this synthesis method, the oleylamine (OLA)/oleic acid (OA) ratio plays an important role in the improvement of photoluminescence quantum yields (PLQYs), which is ascribed to the increase of luminescent CsPbBr₃ in the Cs₄PbBr₆ matrix. This high color purity green-emitting perovskite composite exhibits excellent optical properties of a high PLQY of 50.6%, an emission wavelength of 519 nm, and a narrow full-width at half-maximum of 22.4 nm

[en] All-inorganic perovskite solar cells (PSCs) have been demonstrated to solve the thermal instability problem of organic-inorganic hybrid PSCs. Therefore, NiO${}_x$ film is prepared by electron beam evaporation as a hole transport layer of all inorganic CsPbIBr${}_2$ PSCs. Then, the postannealing is used to promote the diffusion of NiO${}_x$ into the gold electrode, and enhance interface contact and reducing the electrical resistance of NiO${}_x$/Au. After optimizing NiO${}_x$/Au interface, the devices based on NiO${}_x$ achieved a power conversion efficiency (PCE) of 6.7%. Furthermore, the best all-inorganic CsPbIBr${}_2$ PSC free of encapsulation retains 95% of initial efficiency over 100 h at 85 °C. Herein, an effective postannealing strategy is provided for optimized NiO${}_x$/Au interface to make stable and efficient all-inorganic CsPbIBr${}_2$ PSCs. (© 2021 Wiley-VCH GmbH)

[en] Sections Cs₂CdBr₄-CsPbBr₃ (1) and CsCdBr₃-CsPbBr₃ (2) of the CdBr₂-PbBr₂-CsBr ternary system are studied by the methods of differential thermal and x-ray diffraction analyses. Both sections are quasibinary and eutectic. Compounds are not formed. Eutectics coordinates are: 40 mol. % of CsPbBr₃ at 435 Deg C (for section 1) and 20 mol. % of CsPbBr₃ at 390 Deg C (for section 2)

[en] Three-dimensional (3D) organic-inorganic hybrid perovskites (OIHPs) have achieved tremendous success in direct X-ray detection due to their high absorption coefficient and excellent carrier transport. However, owing to the centrosymmetry of classic 3D structures, these reported X-ray detectors mostly require external electrical fields to run, resulting in bulky overall circuitry, high energy consumption, and operational instability. Herein, we first report the unprecedented radiation photovoltage in 3D OIHP for efficient self-driven X-ray detection. Specifically, the 3D polar OIHP MhyPbBr${}_3$ (1, Mhy=methylhydrazine) shows an intrinsic radiation photovoltage (0.47 V) and large mobility-lifetime product (1.1×10${}^{-<!--\; ???\; -->3}$ cm${}^2$ V${}^{-<!--\; ???\; -->1}$) under X-ray irradiation. Strikingly, these excellent physical characteristics endow 1 with sensitive self-driven X-ray detection performance, showing a considerable sensitivity of 220 µC Gy${}^{-<!--\; ???\; -->1}$ cm${}^{-<!--\; ???\; -->2}$, which surpasses those of most self-driven X-ray detectors. This work first explores highly sensitive self-driven X-ray detection in 3D polar OIHPs, shedding light on future practical applications. (© 2024 Wiley‐VCH GmbH)

[en] Understanding the properties of the precursor can provide deeper insight into the crystallization and nucleation mechanisms of perovskites, which is vital for the solution-process device performance. Herein, we conducted a detailed investigation into the photophysics properties of CsPbBr${}_3$ precursors in a broad concentration and various solvents. The precursor transformed from the solution state into the colloidal state and exhibited aggregation-induced emission character as the concentration increased. The aggregative luminescence from the precursors originates from the polybromide plumbous that is formed through the coordination of solvent molecules to the lead metal center. Two adducts with monodentate (PbBr${}_2$ ⋅ solvent) and bidentate (PbBr${}_2$ ⋅ 2solvent) ligands can be obtained, accompanied by emission with photoluminescence at 610 and 565 nm, respectively. Furthermore, the aggregative luminescence intensity and color could be regulated by changing the solvent and precursor ratio. Besides, we discussed the difference between the molecular aggregate in the organic system and the ionic aggregate in the inorganic system: the ionic aggregate is composed of solvated ions rather than individual molecules as in organic systems, which could possess properties that ions do not have. The fluorescence that is sensitive to Pb${}^{2+}$ coordination reported here could be applied to screen perovskite additives and judge the precursor aging. (© 2024 The Authors. Angewandte Chemie International Edition published by Wiley-VCH GmbH)