The geometric and electronic structure of condensed phase organic conducting polymer PEDOT:PSS blends has been investigated by periodic density functional theory (DFT) calculations with a generalized-gradient approximation (GGA) functional, and a plane wave basis set. The influence of the degree of doping of the PEDOT polymer on structural and optical parameters such as the reflectivity, absorbance, conductivity, dielectric function, refractive index and the energy-loss function is studied. A flip from the benzoid to the quinoid structure is observed in the calculations when the neutral PEDOT is doped by negatively charged PSS. Also the optical properties are affected by the doping. In particular, the reflectivity was found to be very sensitive to the degree of doping, where higher doping implies higher reflectivity. The reflectivity is highly anisotropic, with the dominant contribution stemming from the direction parallel to the PEDOT polymer chain.

We embedded IR-resonant microparticles as visible scatterers and thermal emitters in a transparent nanocellulose composite, to form a metamaterial that provides radiative cooling while simultaneously functioning as an optical diffuser.

A combination of analytical techniques was used to examine monolayers of 1-(2-thioethyl)pyrrole (1-TEP) and 3-(2-thioethyl)pyrrole (3-TEP) adsorbed on gold, including infrared, UV-vis-NIR, mass spectroscopy, ellipsometry, wetting, and X-ray photoelectron spectroscopy. Both monolayers were found to undergo adsorption-catalyzed reactions. Monolayers of 1-TEP were disordered even after long deposition times, with an isotropic distribution (orientation) of the tails, from perpendicular to parallel to the substrate, as expected for a short chain thiolate with a relatively bulky tail group. Vapor and solution deposition methods produced the same results. The 1-TEP monolayers were quite sensitive to oxygen, and exposure to air resulted in the rapid formation of carbonyl species. In the bulk, 1-TEP did not react in this manner. Solution-deposited 3-TEP monolayers consisted predominantly of short-chain alkanethiolates and/or disulfides that had lost the pyrrole moiety, together with ca. 30% of intact, bound 3-TEP. The cleavage was not reflected in the ethanolic solutions, nor did the amount of intact 3-TEP on the surface decrease with deposition time, so cleavage probably occurred upon adsorption. The intact 3-TEP molecules assumed a conformation with the pyrrole rings essentially parallel to the substrate. A large carbonyl peak indicated that the 3-TEP oxidized even more quickly than 1-TEP when exposed to air.

Radiative cooling passively removes heat from objects via emission of thermal radiation to cold space. Suitable radiative cooling materials absorb infrared light while they avoid solar heating by either reflecting or transmitting solar radiation, depending on the application. Here, we demonstrate a reflective radiative cooler and a transparent radiative cooler solely based on cellulose derivatives manufactured via electrospinning and casting, respectively. By modifying the microstructure of cellulose materials, we control the solar light interaction from highly reflective (> 90%, porous structure) to highly transparent (≈ 90%, homogenous structure). Both cellulose materials show high thermal emissivity and minimal solar absorption, making them suitable for daytime radiative cooling. Used as coatings on silicon samples exposed to sun light at daytime, the reflective and transparent cellulose coolers could passively reduce sample temperatures by up to 15 °C and 5 °C, respectively.

The electrochemical oxidation of 1-(2-thioethyl)pyrrole (1-TEP) and 3-(2-thioethyl)pyrrole (3-TEP) monolayers on gold was studied. Their cyclic voltammograms were different, with, for example, 1-TEP having three oxidation peaks and 3-TEP just one. Moreover, the cyclic voltammetry of both TEP monolayers was unusual and did not follow the expected behavior for simple electron transfer from an adsorbed monolayer. The chronoamperometry for 1-TEP was also surprising, showing nucleation-like peaks; this was not seen for 3-TEP. Air exposure left the 1-TEP, but not the 3-TEP, surface electrochemically inert. Spectroscopic data on the oxidation products of surface-bound pyrroles are presented for the first time. IRAS, XPS, and UV-vis-NIR showed that, after electrochemical cycling, all the pyrrole rings were absent. This demonstration that the molecules decompose calls into question the generality of the grafting mechanism of adhesion promotion for this type of compound.