An organic cationic salt, hexamethylenediamine diiodide (HDADI), is introduced into formamidinium tin iodide (FASnI 3 ) perovskite solar cells (PSCs) by consideration of amino group passivation of HDA 2+ to iodide of SnI 6 4− and assisted links of amino groups at both ends of HDA 2+ to the perovskite unit cell to form the Dion−Jacobson (DJ) layered two-dimensional (2D) perovskite. X-ray diffraction and grazing-incidence wide-angle Xray scattering characteristics exclude the formation of the DJ layered 2D perovskite. A decent power conversion efficiency (PCE) and stability are derived from the high-quality perovskite films with large coverage, high crystallinity, and disappeared pinholes as well as increased radiative recombination and a prolonged carrier lifetime, which are associated with the interaction of NH 3 + and SnI 6 4− octahedra via a hydrogen bond. The interaction not only neutralizes charged defects or dangling bonds of perovskites but also forms a shield to retard the oxidation of Sn 2+ to Sn 4+ and reduce Sn vacancies. Applications of the HDADI-treated FASnI 3 films into PSCs acquire a champion PCE of 7.6% and an outstanding long-term stability of over 550 h to retain 80% of the initial efficiency in a glovebox with a N 2 environment. This work may guide the design of highly stable and efficient Sn-based PSCs.

Despite a higher power conversion efficiency (PCE) than other lead‐free perovskite solar cells (PSCs) due to intrinsically excellent optoelectronic properties and suitable bandgaps of tin (Sn) perovskites, Sn‐based PSCs still suffer from issues of stability and efficiency for practical applications. Herein, a novel strategy of tuning perovskite crystal orientation toward ≈45° with respect to the substrate by doping 2,3‐diaminopropionic acid monohydrochloride (2,3‐DAPAC) into formamidinium tin iodide (FASnI3) is proposed, which facilitates charge transport in the perovskite film and consequent device performances. In addition, the incorporation of 2,3‐DAPAC into FASnI3 enables dense and smooth high‐quality perovskite films with less Sn vacancies. Applications of the 2,3‐DAPAC‐treated FASnI3 films into PSCs acquire a champion PCE of 7.23%, showing 37.2% enhancement compared with 5.27% of the control device. Moreover, the storage stabilities of both perovskite films and PSCs are significantly prolonged with improved film quality.

No abstract

Formamidinium tin iodide (FASnI 3 ) perovskite is a promising light harvester for lead-free perovskite solar cells (PSCs). However, the poor quality of the solution-processed FASnI 3 film always leads to an inferior efficiency and poor stability. Herein, we demonstrate a mixed-cation strategy by trace-doping of highly hydrophobic cations to construct high-quality threedimensional (3D) perovskite films. Tin halide perovskites with FA and 3,3diphenylpropylammonium (DPPA) hybrid cations were fabricated, and the trace-doping of DPPA cations can greatly enhance the stability of 3D perovskites by suppressing the oxidation of Sn 2+ to Sn 4+ . After optimization of DPPAI/FAI ratios, the DPPA 0.02 FA 0.98 SnI 3 perovskite achieves better film crystallinity and morphology. Our champion device based on DPPA 0.02 FA 0.98 SnI 3 perovskite shows the highest power conversion efficiency of 6.75% with all improved device parameters. Moreover, the corresponding unencapsulated device retains 70% of its initial efficiency after aging over 600 h in N 2 environment. This work provides a feasible approach to fabricate high-quality 3D perovskites for lead-free PSCs applications.

Double-perovskite oxides that contain both 3d and 5d transition metal elements have attracted growing interest as they provide a model system to study the interplay of strong electron interaction and large spin-orbit coupling (SOC). Here, we report on experimental and theoretical studies of the magnetic and electronic properties of double-perovskites ( La 1−x Sr x ) 2 CuIrO 6 (x = 0.0, 0.1, 0.2, and 0.3). The undoped La 2 CuIrO 6 undergoes a magnetic phase transition from paramagnetism to antiferromagnetism at T N ∼ 74 K and exhibits a weak ferromagnetic behavior below T C ∼ 52 K. Two-dimensional magnetism that was observed in many other Cu-based double-perovskites is absent in our samples, which may be due to the existence of weak Cu-Ir exchange interaction. Firstprinciple density-functional theory (DFT) calculations show canted antiferromagnetic (AFM) order in both Cu 2+ and Ir 4+ sublattices, which gives rise to weak ferromagnetism. Electronic structure calculations suggest that La 2 CuIrO 6 is an SOC-driven Mott insulator with an energy gap of ∼ 0.3 eV. Sr-doping decreases the magnetic ordering temperatures (T N and T C ) and suppresses the electrical resistivity. The high temperatures resistivity can be fitted using a variable-range-hopping model, consistent with the existence of disorders in these double-pervoskite compounds.

Prussian blue analogues (PBAs) have been considered as one kind of the most promising cathode materials for Zn-ion batteries (ZIBs) due to their low cost, high performance, high safety, and high abundance. However, owing to the low conductivity and single electron reaction, it is a great challenge to obtain a PBA cathode material with high reversible capacity, high rate capability, and good temperature adaptability. Here, a cathode material, K1.14(VO)3.33[Fe­(CN)6]2·6.8H2O (KVHCF), with a multielectron reaction and double conductive carbon framework (DCCF) is designed and synthesized by combining structure and morphology engineering. With the multielectron reaction and high electronic conductivity simultaneously, the KVHCF@DCCF cathode material delivers a high specific capacity (180 mAh·g–1 @ 400 mA·g–1) and the best rate performance (116 mAh·g–1 @ 8000 mA·g–1) of the reported PBAs. Moreover, KVHCF@DCCF presents a high specific capacity of 132 mAh·g–1 @ 400 mA·g–1 at 0 °C. Even at −10 °C, it still delivers specific capacities of 127 mAh·g–1 @ 40 mA·g–1 and 80 mAh·g–1 @ 400 mA·g–1 with a retention of 86% after 700 cycles. In situ X-ray diffraction (XRD) and ex situ X-ray photoelectron spectroscopy (XPS) are carried out to investigate the charge–discharge electrochemical reaction mechanism.

Solution-processed quasi-two-dimensional (Q-2D)/colloidal perovskite nanocrystals (PNCs) perovskite composite films are first prepared as the emitting layers of perovskite light-emitting diodes (PeLEDs). The subsequent multi-spin-coating of PNCs not only fills the gully-like fluctuations of the nanocrystal pinning-prepared Q-2D perovskite films and decreases their surface roughness but also transforms the bilayer perovskite nanosheets into multilayer ones, thus improving the charge transport and reducing the hole-injection barrier in the composite films. More importantly, the bromide vacancies and Pb defects in the Q-2D perovskites are removed via Br– supply and Pb-OOC-R interaction, in which the Br ions and COO– groups (from oleic acid) come from the PNC solution, and the radiation recombination is significantly enhanced. Based on the Q-2D/PNCs perovskite composite emitter, the PeLEDs achieve a maximum luminescence of ∼2.0 × 104 cd/m2 and a peak current efficiency of 27.5 cd/A, showing 175 and 337% enhancements compared to the control device with the pristine Q-2D perovskite emitter. The lifetime for the luminance decaying to 50% of the initial intensity increases by a factor of 13.8, demonstrating that the device stability is also improved by the Q-2D/PNCs perovskite composite film.

The aim of the study was to develop an amorphous solid dispersion of a poorly water-soluble drug with high melting point by ball milling and hot melt extrusion as a co-processing method. Solid dispersion systems were prepared by ball milling-hot melt extrusion and then compared with those prepared with hot melt extrusion. The effects of three process parameters in the co-processing method, namely, barrel temperature, screw speed, and cooling rate, were systematically studied. The physical state of prepared solid dispersion was characterized by differential scanning calorimetry, X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, phase solubility, and dissolution study.The Resveratrol-Eudragit® EPO system exhibited good miscibility and significant dissolution enhancement. Resveratrol in the amorphous solid dispersion existed in an amorphous state and had molecular interactions with Eudragit® EPO. Stability studies showed no apparent difference in the physical state of the solid dispersion after 6 months. In conclusion, combining ball milling with hot melt extrusion is a promising method for preparing the amorphous solid dispersion of a poorly water-soluble drug with high melting point. Fig. 6 The dissolution curves of RES from solid dispersions under different parameters: (a) ball milling time, (b) ball milling frequency, (c) barrel temperature, (d) screw speed, (e) cooling rate.