Strongly Iridescent Hybrid Photonic Sensors Based on Self-Assembled Nanoparticles for Hazardous Solvent Detection

Abstract

Facile detection and the identification of hazardous organic solvents are essential for ensuring global safety and avoiding harm to the environment caused by industrial wastes. Here, we present a simple method for the fabrication of silver-coated monodisperse polystyrene nanoparticle photonic structures that are embedded into a polydimethylsiloxane (PDMS) matrix. These hybrid materials exhibit a strong green iridescence with a reflectance peak at 550 nm that originates from the close-packed arrangement of the nanoparticles. This reflectance peak measured under Wulff-Bragg conditions displays a 20 to 50 nm red shift when the photonic sensors are exposed to five commonly employed and highly hazardous organic solvents. These red-shifts correlate well with PDMS swelling ratios using the various solvents, which suggests that the observable color variations result from an increase in the photonic crystal lattice parameter with a similar mechanism to the color modulation of the chameleon skin. Dynamic reflectance measurements enable the possibility of clearly identifying each of the tested solvents. Furthermore, as small amounts of hazardous solvents such as tetrahydrofuran can be detected even when mixed with water, the nanostructured solvent sensors we introduce here could have a major impact on global safety measures as innovative photonic technology for easily visualizing and identifying the presence of contaminants in water.

A photonic crystal material for the online detection of nonpolar hydrocarbon vapors

“…where m is the order of a diffraction maximum, λ is the wavelength of the reflectance maximum, d 111 is the interplanar distance between crystallographic (111) planes, n eff is the effec- tive refractive index of the CCA, n air is the refractive index of the medium (in our case air) from which light falls in and θ is the incidence angle [8,9,36]. The incidence angle was varied from 8° to 65° in the experiments.…”

“…Photonic crystals (PhCs) used for chemical sensors can be divided into three groups depending upon their structure, that is, one-dimensional (1D), two-dimensional (2D), and three-dimen-sional (3D) [1][2][3][4][5][6][7][8][9][10]. 2D and 3D structures used as chemical sensors are studied in most projects.…”

“…2D structures consist of a monolayer of spherical particles placed on a substrate. 3D struc- 3D PhC (CCA) polystyrene redshift (<50 nm) methanol vapors 5% (V methane /V 0 ) [7] 3D PhC (PCCA) a polystyrene-Ag/ polydimethylsiloxane redshift (<50 nm) chloroform, chlorobenzene, tetrahydrofuran, dichloromethane and dimethoxyethane liquids 5 µL (5 nm) [8] 3D PhC (CCA) polystyrene redshift (<40 nm) methanol, ethanol, isopropanol, 1-propanol and n-butanol vapors 2% (V ethane /V) [9] 3D PhC (PCCA) polymethylmethacrylate/ methyl cellulose redshift (<80 nm) ethanol, n-propanol, isopropanol and n-butanol liquids and vapors NA [15] 3D PhC (CCA) polystyrene redshift methanol and ethanol NA [16] 3D PhC (PCCA) polystyrene/ polydimethylsiloxane redshift (<150 nm) benzene, toluene, p-xylene, n-pentane, n-heptane, n-octane and n-decane vapors 0.3 mg/m 3 (toluene) this work a Polymerized crystalline colloidal array.…”

“…Organic solvents are usually detected by using polymer matrix sensors (Table 1) through matrix interaction [7][8][9]15,16]. The impregnation and immobilization methods are rather close; they are used for the determination of inorganic ions (Cu 2+ , Pb 2+ , Hg 2+ , Ni 2+ and Cd 2+ ) [2,11,[17][18][19] and organic molecules of simple and complex structure (glucose, organophosphates, urea, creatinine, ciprofloxacin and sarin) [5,6,[20][21][22][23][24][25][26][27].…”

Eco-Friendly Push-Coated Polymer Solar Cells with No Active Material Wastes Yield Power Conversion Efficiencies over 5.5%

“…Although PSCs have a fairly simple device architecture, several key aspects such as the formation of flat and uniform interfaces or phase separation in the active layer can considerably influence their photovoltaic characteristics. − Unlike spin-coating during which the thin films are rapidly formed owing to centrifugal forces, push-coating is a two-step process in which the solution quickly spreads laterally through capillary forces, followed by solvent diffusion into PDMS in the vertical direction (Figure ). In our previous attempts to fabricated PC films for functional optoelectronic devices, we selected relatively long push-coating times to ensure that all the solvent diffused into PDMS before its removal. , However, previous studies on PDMS also suggest that small volumes (<5 μL) of chlorinated solvents such as DCB should diffuse relatively rapidly into PDMS. , In fact, when push-coating 3 μL of PCDTBT:PC 71 BM solution in DCB onto a ZnO-coated glass substrate, we found that over 90% of the solvent has already diffused into PDMS after 1 min (Table S1). On the other hand, the amount of DCB remaining in the PCDTBT:PC 71 BM is lower than 3% of the deposited solvent volume (lower than 0.08 μL).…”