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Metal-organic frameworks (MOFs) have been investigated recently in perovskite photovoltaics owing to their potential to boost optoelectronic performance and device stability. However, the impact of variations in the MOF side chain on perovskite characteristics and the mechanism of MOF/perovskite film formation remains unclear. In this study, three nanoscale thiol-functionalized UiO-66-type Zr-based MOFs (UiO-66-(SH)2 , UiO-66-MSA, and UiO-66-DMSA) are systematically employed and examined in perovskite solar cells (PSCs). Among these MOFs, UiO-66-(SH)2 , with its rigid organic ligands, exhibited a strong interaction with perovskite materials with more efficient suppression of perovskite vacancy defects. More importantly, A detailed and in-depth discussion is provided on the formation mechanism of UiO-66-(SH)2 -assisted perovskite film upon in situ GIWAXS performed during the annealing process. The incorporation of UiO-66-(SH)2 additives substantially facilitates the conversion of PbI2 into the perovskite phase, prolongs the duration of stage I, and induces a delayed phase transformation pathway. Consequently, the UiO-66-(SH)2 -assisted device demonstrates reduced defect density and superior optoelectronic properties with optimized power conversion efficiency of 24.09% and enhanced long-term stability under ambient environment and continuous light illumination conditions. This study acts as a helpful design guide for desired MOF/perovskite structures, enabling further advancements in MOF/perovskite optoelectronic devices.

Electrochromism (EC) is a color control technique for providing visual information, in which vanadium pentoxide (V2O5) is a promising material for electrochromic applications due to its excellent ionic intercalation/deintercalation properties and cathodic/anodic color-changing properties. However, its poor cycling stability and color change response rate limit its practical application. Metal–organic frameworks (MOFs) combine the rigidity and flexibility of inorganic–organic materials and can meet the requirements of EC materials such as cycle stability, electrical conductivity, and stress-interference resistance. We report here a strategy to modify V2O5 with Cu-MOF. Cu-doped V2O5 and carbon skeleton (Cu2V2O7@C) composites were prepared for electrochromism. In this scheme, Cu doping can facilitate lithium ion migration by broadening and stabilizing the structure of V2O5, and the distribution of the carbon skeleton can broaden the contact of the active material with the electrolyte and improve the electron conduction. Combining these merits, it exhibits excellent long-term cycle stability (the capacity retention rate reaches 91.78% after 2000 cycles), the light transmission modulation is greatly improved compared with V2O5 (ΔT = 69%, doubled), and the response time is reduced by 30.43%. This study provides a new perspective for improving the light modulation ability and long-term use stability of vanadium oxide EC materials and promotes the development of MOF materials in the field of electrochromism. [ABSTRACT FROM AUTHOR]

Mixed‐dimensional engineering of perovskite material has been demonstrated as a facile and promising strategy to improve both photovoltaic performance and long‐term stability of perovskite solar cells (PSCs). In this study, we report an in‐plane preferred orientation of 1D perovskite induced by an ionic liquid (IL) of 1‐(3‐cyanopropyl)‐3‐methylimidazolium chloride (CPMIMCl) for the first time via sequential deposition approach, leading to a mixed dimensional perovskite thin films. The generated one‐dimensional (1D) CPMIMPbI3 with in‐plane orientation resides at the grain boundaries of three‐dimensional (3D) perovskite can be appreciably observed from the morphology level, leading to creation of high‐quality films with large grain size with more efficient defect passivation. Moreover, the dispersion of IL in the bulk phase of perovskite material allows for the formation of 1D perovskite for multiple level passivation to inhibit non‐radiative recombination and optimize carrier transport. This IL engineering strategy not only yields a mixed‐dimensional perovskite heterostructure with in‐plane orientation 1D perovskite nano‐rods but also significantly improves the opto‐electronic property with suppressed trap states. As a result, the CPMIMCl‐treated PSCs show an enhanced photovoltaic performance with a champion power conversion efficiency (PCE) up to 24.13%. More importantly, benefiting from the hydrophobicity of formed 1D perovskite and defects suppression, the corresponding PSC demonstrates an excellent long‐term stability and maintain 97.1% of its pristine PCE at 25°C under 50% RH condition over 1000 h. This research provides an innovative perspective for employing the low dimensional engineering to optimize the performance and stability of photovoltaic devices. [ABSTRACT FROM AUTHOR]

Vanadium-based material has great potential for the cathode of aqueous Zn-ion batteries (ZIBs). Herein, the Ni0.22V2O5·nH2O cathode materials were fabricated by a hydrothermal method. The morphologies and structures of materials were characterized by XRD, SEM, and TEM. The results indicated that the Ni0.22V2O5·nH2O nanobelts appear a typical layered structure, and Ni2+ was embedded in the layer. The electrochemical performance was measured by the galvanostatic charge–discharge test and cyclic voltammetry. The Zn-Ni0.22V2O5 battery represents a capacity of 320.2 mAh g−1 at 0.2 A g−1. The cycle reversible capacity retention rate was 93.9% of the initial capacitance after 2000 cycles at 5 A g−1. Meanwhile, the transmutation of the structure was characterized by in situ and ex situ XRD. The main peak corresponding to the Ni0.22V2O5 electrode at 34.7° slightly shifts to higher 2θ values and then shifts to the initial state during the charge and discharge process. The reversibility of structure improves the electrochemical stability of the Ni0.22V2O5 electrode. [ABSTRACT FROM AUTHOR]

Vanadium pentoxide (VO) with various nanostructures has been investigated during the past decades. Notably, two-dimensional VO nanosheets had attracted most attentions due to the large mass density. Here, the VO nanosheets doped by MoO (MoVO) have been synthesized by sol-gel method combined with freezing-drying process. The structures and morphology of MoVO were characterized by XRD, FTIR, TEM, and FESEM analysis. The MoVO show a two-dimensional layered structure and the XRD can be indexed to an orthorhombic VO phase. Meanwhile, the doping of MoO was confirmed by the XPS and TEM analysis. The electrochemical behaviors of the nanocomposites were investigated by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and galvanostatic charge-discharge test. As a result, the interlayer spacing of the Mo V O nanosheets were inlarged by VMoO. The improvment of electrochemical properties was due to defects and the layer structure. [ABSTRACT FROM AUTHOR]