Chlorine‑Rich Substitution Enabled 2D3D Hybrid Perovskites for High Efficiency and Stability in Sn‑Based Fiber‑Shaped Perovskite Solar Cells

Despite the impressive power conversion efficiency(PCE)beyond 25.5%,perovskite solar cells,especially the Sn-based variants,are poorly stable under normal operating conditions compared with the market-dominant silicon solar cells that can last for over 25 years.2D3D hybrid perovskite materials are one of the best options to overcome the instability chal-lenge without compromising efficiency.Indeed,a record performance of 1 year was reported in Pb-based 2D3D planar per-ovskite devices.However,the reaction between 2 and 3D perovskite molecules requires high temperatures(-300°C)and increased reaction time(-24 h)to achieve high-quality 2D3D hybrid perovskites.Herein,we base on the ability of chlorine to displace iodine from its ionic compounds in solutions to utilize chloride ions as catalysts for speeding up the reaction between iodine-based 2D and 3D perovskite molecules.The approach reduces the reaction time to-20 min and the reaction temperature to-100°C with the formation of high-quality 2D3D hybrid perovskites,free from pure 2D traces.Integrating the synthesized 2D3D hybrid perovskite material with 50%chlorine doping in a fiber-shaped solar cell architecture yielded the highest reported PCE of 11.96%in Sn-based fiber-shaped perovskite solar cells.The unencapsulated and encapsulated fiber-shaped solar cells could maintain 75%and 95.5%of their original PCE,respectively,after 3 months under room light and relative humidity of 35–40%,revealing the champion stability in Sn-based perovskite solar devices.The solar yarn also demonstrated constant energy output under changing light incident angles(0–180°).

Crumpled,high-power,and safe wearable Lithium-Ion Battery enabled by nanostructured metallic textiles

Textile-based flexible Lithium-Ion Batteries(LIBs)show promising mechanical flexibility that is appealing for a wide variety of wearable and flexible electronic applications.The flexibility of flexible LIBs nowadays is still limited.In addition,their power performance is too low to enable high-speed charging,due to the low conductivity of the textiles.Here,we develop highly electrically conductive metallic fabrics,which are fabricated by coating nanostructured Ni or Cu(nano-reliefs)on woven cotton fabrics,as current collectors to enable crumpled,high-power,and safe wearable LIBs.The nanostructured metal coating not only effectively increases the contact area between current collectors and active materials,but also shortens the charge carrier transport paths,so that LIBs constructed on these nanostructured metallic cotton fabrics exhibit a high power density of 439 W/L and superior electrochemical stability under various mechanical deformations including folding,twisting,squeezing,and impacting.This type of nanostructured metallic textile is highly desirable for portable and wearable electronic applications.

Protection against Chemical Warfare Agents and Biological Threats Using Metal−Organic Frameworks as Active Layers

The SARS-CoV-2 pandemic outbreak and the unfortunate misuse of toxic chemical warfare agents(CWAs)highlight the importance of developing functional materials to protect against these chemical and pathogen threats.Metal−organic frameworks(MOFs),which comprise a tunable class of crystalline porous materials built from inorganic nodes and organic linkers,have emerged as a class of heterogeneous catalysts capable of rapid detoxification of multiple classes of these harmful chemical or biological hazards.In particular,zirconium-based MOFs(Zr-MOFs)feature Lewis acidic nodes that serve as active sites for a wide range of catalytic reactions,including the hydrolysis of organophosphorus nerve agents within seconds in basic aqueous solutions.In addition,postsynthetic modification of Zr-MOFs enables the release of active species capable of reacting with and deactivating harmful pathogens.Despite this impressive performance,utilizing Zr-MOFs in powder form is not practical for application in masks or protective uniforms.To address this challenge,our team sought to develop MOF/fiber composite systems that could be adapted for use under realistic operating conditions to protect civilians,military personnel,and first responders from harmful pathogens and chemical warfare agents.Over the last several years,our group has designed and fabricated reactive and biocidal MOF/fiber composites that effectively capture and deactivate these toxic species.In this Account,we describe the evolution of these porous and reactive MOF/fiber composites and focus on key design challenges and considerations.First,we devised a scalable method for the integration of Zr-MOFs onto textile substrates using aqueous precursor solutions and without using pretreated textiles,highlighting the potential scalability of this method.Moving beyond standard textiles,we also developed a microbial synthesis strategy to prepare hierarchically porous MOF/bacterial cellulose nanofiber composite sponges that can both capture and detoxify nerve agents when exposed to contaminated gas flows.The mass loading of the MOF in the nanofibrous composite sponge is up to 90%,affording higher work capacities compared to those of textile-fiber-based composites with relatively lower MOF loadings.Next,we demonstrated that heterogeneous polymeric bases are suitable replacements for volatile liquid bases typically used in solution-phase reactions,and we showed that these composite systems are capable of effectively hydrolyzing nerve agents in the solid state by using only water that is present as humidity.Moreover,incorporating a reactive dye precursor into the composite affords a dual function sensing and detoxifying material that changes color from white to orange upon reaction with the byproduct following nerve agent hydrolysis,demonstrating the versatility of this platform for use in decontamination applications.We then created chlorine-loaded MOF/fiber composites that act as biocidal and reactive textiles that are capable of not only detoxifying sulfur-mustard-based chemical warfare agents and simulants but also deactivating both bacteria and the SARS-CoV-2 virus within minutes of exposure.Finally,we synthesized a mixed-metal Ti/Zr-MOF coating on cotton fibers to afford a photoactive biocidal cloth that shows fast and broad-spectrum biocidal performance against viruses and Gram-positive and Gram-negative bacteria under visible light irradiation.Given the tunable,multifunctional nature of these MOF/fiber composites,we believe that this Account will offer new insights for the rational design and preparation of functional MOF/fiber composites and pave the way toward the development of next-generation reactive and protective textiles.