Fabricating Transparent Multilayers with UV and Near-IR Double-Blocking Properties through Layer-by-Layer Assembly

Abstract

We have fabricated a transparent composite film with UV and near-infrared (near-IR) double-blocking properties using polyethyleneimine (PEI), indium tin oxide (ITO), and zinc oxide (ZnO) through layer-by-layer (LbL) assembly under an ultrasonic field. By applying ultrasonic-assisted LbL assembly, the aggregation of nanoparticles has been excluded, resulting in a flatter and more transparent (visible range) film than that obtained under conventional LbL assembly. Moreover, the effects of the ultrasonic field are discussed in terms of the fact that the transformation between the states of PEI/ITO films assembled with or without ultrasonic field was reversible. To enhance the UV-blocking properties in the most damaging region (290−350 nm), we incorporated ZnO nanoparticles, which can block UV rays below 350 nm, and the obtained hybrid multilayer displayed a high transparency of over 85% (visible range) and good UV-/near-IR double-blocking effects that shielded nearly 80% of the UV rays under 350 nm and 80% of the IR radiation above 1600 nm.

Facile method for preparation of superfine copper nanoparticles with high concentration of copper chloride through photoreduction

“…Metal nanoparticles have elicited considerable attention because of their high surface area-to-volume ratio, size-dependent properties, and potential applications in biomedical, optical, magnetic, electronic, and catalytic elds. [1][2][3][4][5][6][7][8][9][10][11][12][13][14] As metal nanoparticles, copper nanoparticles have been extensively studied because of their electronic, catalytic, optical, thermal conductivity, and antifungal/antibacterial properties. [15][16][17][18][19][20][21][22][23] Various methods have been used to prepare ultrane copper particles.…”

Preparation and Layer-by-Layer Solution Deposition of Cu(In,Ga)O2 Nanoparticles with Conversion to Cu(In,Ga)S2 Films

“…With regard to packing issues, the use of smaller colloidal particles, produced via jet milling or partial chemical dissolution ( e.g ., HCl in Experimental Section, vide supra ) of existing as-deposited CIGO particles (or CIGS particles prepared from them, Figure 1 , part B), is expected to provide more uniformly packed films devoid of channels. Film quality may also benefit from enhanced nanoparticle packing via gentle ultrasonic agitation during film deposition [58] and internal restructuring and smoothing of films containing polyelectrolyte components via post-deposition salt annealing. [59] .…”

Enhanced near-infrared reflectance and functional characteristics of Al-doped ZnO nano-pigments embedded PMMA coatings

“…Unfortunately, incorporation of any second phase particles hampers the transparency. It is envisioned that nano size dispersoids retain the optical quality in addition to functionality [5]. Fig.…”

“…They have a unique property of high solar reflectance in the nearinfrared (NIR) region (780 to 2500 nm) and solar energy absorbance in ultraviolet (UV) region (290 to 400 nm), which makes them ideal for multifunctional, optically transparent surface coatings. Since infrared radiation in the wavelength region 810 to 1100 nm is said to be the prime reason for the heat build-up, hence NIR reflecting white pigments have become necessary for designing thermal-control surface coatings and functional paints [1][2][3][4][5]. It is well realized that the gradual rise in the atmospheric temperatures is a net effect of CO 2 release from different sources including air-conditioning equipments.…”

“…In this context, we are investigating the role of particle size, particle morphology and dispersibility in ZnO nano-pigments to produce inorganic-polymer functional coatings that can offer high visible brightness and thermal control effect for green buildings [5,21]. In fact, low-emitting surfaces decrease radiative heat transfer by reflecting the incident infrared radiation which reduces the radiative heat emission in the near-infrared spectral region.…”