Defect passivation with potassium trifluoroborate for efficient spray-coated perovskite solar cells in air

Defects as non-radiative recombination centers hinder the further efficiency improvements of perovskite solar cells(PSCs).Additive engineering has been demonstrated to be an effective method for defect passivation in perovskite films.Here,we employed(4-methoxyphenyl)potassium trifluoroborate(C_(7)H_(7)BF_(3)KO)with and K+functional groups to passivate spray-coated(FAPbI_(3))_(x)(MAPbBr_(3))_(1-x) perovskite and eliminate hysteresis.It is shown that the F of can form hydrogen bonds with the H atom in the amino group of MA+/FA+ions of perovskite,thus reducing the generation of MA+/FA+vacancies and improving device efficiency.Meanwhile,K+and reduced MA+/FA+vacancies can inhibit ion migration,thereby eliminating hysteresis.With the aid of C_(7)H_(7)BF_(3)KO,we obtained hysteresis-free PSCs with the maximum efficiency of 19.5%by spray-coating in air.Our work demonstrates that additive engineering is promising to improve the performance of spray-coated PSCs.

Design and optical performance investigation of all-sprayable ultrablack coating

Although ultrablack surfaces are urgently needed in wide applications owing to their extremely low reflectance over a broadband wavelength,obtaining simultaneously the ultrablackness and mechanical robustness by simple process technique is still a great challenge.Herein,by decoupling different light extinction effects to different layers of coating,we design an ultrablack coating that is all-sprayable in whole process.This coating presents low reflectance over visible–mid-infrared(VIS–MIR)wavelength(av.R≈1%in VIS),low multi-angle scattering(bidirectional reflection distribution function(BRDF)=10-2–10-3 sr-1),together with good substrate adhesion grade and self-cleaning ability,which are superior to most reported sprayable ultrablack surfaces.The light extinction effects of each layer are discussed.This method is also applicable in other material systems.

Construction of mechanically robust superamphiphobic surfaces on fiber using large particles

Superamphiphobic surfaces have attracted the attention of researchers because of their broad application prospects.Currently,superamphiphobicity is primarily achieved by minimizing the solid-liquid contact area.Over the past few decades,researchers have primarily focused on using physical deposition methods to construct superamphiphobic surfaces using fine-sized nanoparticles(<100 nm).However,porous hollow SiO_(2)particles(PH-SiO_(2)),which aretypically large spheres,have a highly hierarchical structure and can provide lower solid-liquid contact fractions than those provided byfine-sized particles.In this study,we used PH-SiO_(2)as building blocks and combined them with poly(dimethylsiloxane)to construct a mechanically robust coating on fiber by spray-coating.After chemical vapordeposition treatment,the coating exhibited excellent superamphiphobicity and could repel various liquids,covering a wide rangeof surfacetensions(27.4-72.0mN-m^(-1)).

Fabrication of fluoroalkylsilane/zeolitic imidazolate framework composites for highly efficient superhydrophobic coating

Superhydrophobic bagasse paper was successfully engineered by facile spray coating with a zeolitic imidazolate framework composite modified by 3,3,3-trifluoropropyltrimethoxysilane(FAS)and used as a filter membrane with special wettability for oil/water separation.Surface characteristics such as surface morphology,surface moieties,roughness,and wettability were observed.The addition of FAS decreased the apparent surface energy between solid surfaces and liquids with a polar contribution of surface free energy as low as 0 mN m−1.The formation of the FAS layer was confirmed by transmission electron microscopy and X-ray photoelectron spectroscopy core-level spectra.Three-dimensional surface topography revealed an increase in the spray coating cycle that enhanced the hydrophobicity of the coated paper.The results confirmed that not only microstructures but also the presence of functional groups with low surface energy(such as FAS)can promote surface hydrophobicity.The spray-coated paper with FAS/ZIF in the presence of a small amount of nanocellulose provided a superhydrophobic surface after the first spray cycle.The separation efficiency was up to 85%and was slightly affected by oil viscosity.Moreover,this can be used as a filter membrane for water-in-oil emulsions.In the present work,simple spray-coated paper is a promising candidate material for gravity-driven oil/water separation and water repellent coating.