Performance improvement of dye-sensitized solar cells with Ag nanoparticles

Light absorption by photovoltaic (PV) devices is shown to improve with the use of plasmonic silver nanoparticles (100 nm size) added to the active layer of dye-sensitized solar cell (DSSCs). The electrolyte containing 2 wt. silver nanoparticles exhibits the highest conductivity of 1.27 × 10−2 S cm−1. The DSSC using this electrolyte exhibits the highest efficiency of (6.99 ± 0.15) . The Jsc is (14.25 ± 0.71) mA cm−2, Voc is (0.70 ± 0.01) V and FF is (69.94 ± 3.80) . The same DSSC also exhibits the shortest electron transport time, τtr of (7.00 ± 0.41) ms and long recombination time, τrec of (87.22 ± 9.17) ms

Unraveling the surface properties of PMMA/azobenzene blends as coating films with photoreversible surface polarity

A repeated trans–cis isomerisation led to the random reorientation and arrangement of chromophores in PMMA/azobenzene blends as coating films.</p

Localized Deep and Shallow Traps of α-Peaks from Thermally Stimulated Current (TSC) Measurement on Thermoplastic Polymers

In this paper, trap levels around the glass transition temperature (Tg) of polymers have been characterized using Thermally Stimulated Current (TSC) technique. Deconvolution on α-peaks of the Tg for PE (-104 °C), plasticized PVC (-35 °C), PMMA (90 °C) and PET (96 °C) were carried out based on the first-order kinetic theory for non-Debye relaxation. Using temperature, T from TSC experimental data, we have successfully separated the α-peaks of the thermoplastic polymers. It is found that the complex curve of α-peaks can composed of four (4) to eight (8) sub peaks. Dominant sub peaks were identified at Tmax = -105 °C, -34 °C, 89 °C and 92 °C for PE, pPVC, PMMA and PET, respectively. These peaks show activation energy, Ea of shallow and deep trap centers ranged from 0.3 eV to 4.6 Ev where they represent the depolarization of localized dipoles and space charges relaxations in the polymers.</jats:p

Correction: White light employing luminescent engineered large (mega) Stokes shift molecules: a review

Correction for ‘White light employing luminescent engineered large (mega) Stokes shift molecules: a review’ by Nadia Nabihah Mohd Yusof Chan et al., RSC Adv., 2021, 11, 13409–13445, DOI: 10.1039/D1RA00129A.</p

White light employing luminescent engineered large (mega) Stokes shift molecules: a review

Illustration of white light designated with the 1931-CIE coordinate of (0.33, 0.33), and photophysical mechanisms that contribute to large Stoke shift molecules.</p

Colour analysis of organic synthetic dye coating paint films consisting 4-hydroxycoumarin derivatives after exposed to UV-A

This work investigates the visible optical stability of coating paint film consisting organic synthetic dye, 4-hydroxycoumarin derivatives to the exposure to ultraviolet A (UV-A) light. An azo dye was synthesized by coupling diazonium salt of aniline derivative (obtained by diazonation of 4-chloroaniline in presence of sodium nitrite and hydrochloric acid) with 4-hydroxycoumarin in the presence of sodium hydroxide. The azo dye was mixed with xylene before using it as a pigment in the coating composition. The mixture of poly(methyl methacrylate) (PMMA) and acrylic polyol was used as the coating binder. The synthesized dye and binder were then mixed at specific ratio to form a complete coating solution. Two coating solutions with PMMA having different molecular weights (Mw: 350,000 gmol-1 and Mw: 996,000 gmol-1) were used in this study. Each of them was labelled as 350 K and 996 K indicating its molecular weight. Both mixtures were applied as coating paint films on glass substrates were exposed to UV-A for fast photo-degradation process. The visible optical stability of the coating paint films was measured and recorded at an interval of eight-hours exposure for 35 days using the Commission Internationale de l'Eclairage (CIE) L∗a∗b∗ colour coordinate system. The obtained datas were analysed using standard deviation (STD). In this study, both coating samples showed low standard deviation for hue angle, namely 0.206 for 996 K and 0.258 for 350 K which indicates a high colour stability. However, the 350 K possesses a smaller colour difference (ΔE) of 0.798 compared to 1.418 for 996 K. © 2019 IOP Publishing Ltd

The visible reflectance spectrum stability and water content resistivity of natural dye coating paint film consisting chlorophyll

Purpose: The purpose of this paper is to study the colour stability and water content resistivity of the green colour coating paint film (consisting of chlorophyll) during exposure to ultraviolet A (UV-A). Design/methodology/approach: The natural green dye was prepared by immersing Cassia alata L. leaves in absolute ethanol. The extract was prepared in two batches of dye samples where one of it was a pure dye and the other was added with 3 Wt. % Cu(NO3)2 as an additive. Polymer blend as a binder was prepared by mixing poly(methyl methacrylate) (PMMA) and commercial acrylic polyol. The blended polymer was mixed with the natural dye in a specific ratio and applied as coating paint film on glass panel surfaces. The visible spectrum stability (colour stability) and water content resistivity of the coating paint films during exposure to UV-A were monitored. Findings: Addition of Cu(NO3)2 had improved the colour stability of the coating paint film. Fourier transform infrared spectroscopy analysis showed that both coating paint films do not absorb water and are resistive to water content. Research limitations/implications: The ability of Cu(NO3)2 as an colour stability additive to the natural green dye applied in the coating paint film. Practical implications: The coating paint film developed in this work is suitable to be applied on glass substrates. Originality/value: The colour stability of the coating paint film was analysed by using the reflectance spectrum

Comparative Study of Chemical and Mechanical Treatment Effects on Bacterial Cellulose from Nata de Coco

In this work, bacterial cellulose was obtained from nata de coco. Initially, the samples were subjected to three types of different condition which were raw, chemical treatment and mechanical treatment. Bacterial cellulose was characterized by Fourier Transform Infrared Spectroscopy (FTIR), X-Ray Diffractometer (XRD) and Field Emission Scanning Electron Microscopy (FESEM). Bacterial cellulose met the specifications of pure cellulose either using chemical or mechanical treatments proved by IR spectra reading. XRD results indicated that the crystallinity of chemical treatment bacterial cellulose is higher than the mechanical treatment bacterial cellulose which was 68.6% and 59.5% respectively. The FESEM analysis shows that the size of the bacterial cellulose that obtained from chemical treatment is smaller than mechanical treatments which were 19.42μm and 50.35μm.</jats:p