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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.

In recent years, substantial progress has been made in improving the power conversion efficiency of perovskite solar cells (PSCs). However, persistent defects continue to impede their further advancement. Although ionic liquids (ILs) have been extensively utilized for perovskite defect passivation, their application, particularly in two-step methods, remains limited. In this study, we introduced formamidine acetate (FAAc) as a liquid additive, incorporated into the PbI2 precursor solution to finely regulate perovskite crystal growth. Utilizing a two-step method, we meticulously investigated the interaction of FAAc with perovskite components, laying the groundwork for effective defect passivation. Our systematic exploration delved into the nuanced influence of ILs on perovskite solar cells, including thin film morphology, optical properties, defect density, and overall device performance. Importantly, ILs facilitated the conversion of PbI2 into a perovskite material while reducing residual PbI2 during the perovskite crystallization process, thereby significantly improving the performance of PSCs, including device stability. Though defect passivation during perovskite formation facilitated the conversion of PbI2 and the modulation of thin film morphology, the photoelectric conversion efficiency of the treated PSCs approached an impressive 24.41%. Even after undergoing 2000 hours of aging in dry air, the efficiency remained at above 96% of the initial level. This research marks a pivotal step forward in the realm of PSCs. Our findings not only showcase the potential of ionic liquids in the two-step preparation of PSCs but also highlight their pivotal role in enhancing the efficiency and stability. [ABSTRACT FROM AUTHOR]

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]

Ionic liquids (ILs) are extensively utilized for the manipulation of crystallization kinetics of perovskite, morphology optimization, and defect passivation for the fabrication of highly efficient and stable devices. However, comparing ILs with different chemical structures and selecting the appropriate ILs from the many types available to enhance perovskite device performance remains a challenge. In this study, a range of ILs containing different sizes of anions are introduced as additives for assisting in film formation in perovskite photovoltaics. Specifically, ILs with various sizes significantly affects the strength of chemical interaction between ILs and perovskite composition, inducing varying degrees of conversion of lead iodide to perovskite as well as the formation of perovskite films with markedly disparate grain sizes and morphology. Theoretical calculations in conjunction with experimental measurements revealed that small‐sized anion can more effectively reduce defect density by filling halide vacancies within perovskite bulk materials, resulting in suppression of charge‐carrier recombination, an extended photoluminescence lifetime, and significantly improved device performance. Boosted by ILs with appropriate size, the champion power conversion efficiency of 24.09% for the ILs‐treated device is obtained, and the unencapsulated devices retain 89.3% of its original efficiency under ambient conditions for 2000 h. [ABSTRACT FROM AUTHOR]

Due to the low cost and better security, aqueous zinc-ion batteries (AZIBs) are receiving a great deal of attention for large-scale energy storage. Vanadium-based materials have immense potential as AZIB cathode materials. Herein, the KxVO2 (KVO) cathode materials synthesized by the hydrothermal method. The morphology and structure of KVO were characterized by X-ray diffraction (XRD), Fourier infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). FESEM demonstrated that sample displayed sheet morphology. The electrochemical performance of KVO electrode in aqueous zinc ion battery was determined by cyclic voltammetry and galvanostatic charge–discharge test after assembly of Zn-KVO button cell using 3 M ZnSO4 aqueous electrolyte. The Zn-KVO battery has a capacity of 435.8 mAh⋅g−1 at 0.2 A g−1. After 1000 cycles at 4 A g−1, the cycle reversible capacitance retention rate was 78% of the original capacity. Compared with V2O5 electrode, the capacity and cycle stability of KVO electrode have been significantly improved. [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]