Stability of Anthocyanin Sensitized TiO2 Photoelectrochemical (PEC) Solar Cells Prepared by Sol Gel Process

Highly porous dye sensitized TiO2 thin film solar cells have been prepared by the sol gel process. Sensitization was achieved by use of anthocyanin pigment extracted from delphinidin purple and cyanidin 3-5 diglucose (C35D). Sensitization was also studied on ruthenium complex RuL* sensitization dye. Dye sensitized photoelectrodes have exhibited broad transmission minimum in the visible range. Solar cells fabricated from these electrodes gave overall conversion efficiencies of 3.16% for delphinidin purple and 2.97% for C35D. RuL dye sensitized solar cell gave 4.84%. The cells\' stability performance in terms of photovoltage was found to drop with time of exposure. However the cells still exhibited I-V characteristics over a long period (six months) of study. *L = bis (isthiocyanato) ruthenium (II)-bis-2,2-bipyridine-4,4\'-dicarboxylic ligand (Af. J. of Science and Technology: 2002 3(2): 56-61

An ab-initio study of P-type ZrCoY (YSb and Bi) half – Heusler semiconductors

In this study, the structural, electronic, mechanical, optical, and thermoelectric properties of the cubic half-Heusler compound ZrCoY(YSb and Bi) obtained using first-principles calculations are presented. The following exchange-correlation functionals have been employed: Generalized Gradient Approximation with Perdew-Burke-Ernzerhoff (GGA-PBE), Generalized Gradient Approximation with Perdew-Burke-Enzerhoff for solids (GGA-PBESol) and Local Density Approximation (LDA). Both ZrCoSb and ZrCoBi compounds are mechanically and dynamically stable, based on the elastic and phonon properties analysis. The calculated electronic band gaps for both compounds are about 1 eV, as predicted by all the three functionals. Since it is noted that GGA-PBE functional is most favourable for predicting structural properties and the energetic stability of ZrCoSb and ZrCoBi compounds, it is further used to calculate their thermoelectric properties. Within the energy range of 0–40 eV, the refractive index, dielectric constant, and energy loss function of ZrCoSb and ZrCoBi compounds are calculated. The possibility of electronic transition from the valence band maximum (VBM) to the conduction minimum band (CBM) is confirmed by the occurrence of absorption peaks in the visible range. For the evaluation of thermoelectric properties, the p-type and n-type doping attained Seebeck coefficients of 1800 and -1800 μVK−1 at 300 K, respectively. The maximum peak of 17 × 1011 W/m s K2 is attained in n-type doping, according to the power factor results

An ab-initio study of P-type ZrCoY (Y[dbnd]Sb and Bi) half – Heusler semiconductors

DATA AVAILABILITY STATEMENT : Data will be made available on request.Please read abstract in article.Applied Sciences, Engineering, and Technology (PASET); The Centre for High Performance Computing (CHPC); University of Pretoria.https://www.cell.com/heliyon/homePhysic

Electron Transport and Recombination in Dye Sensitized Solar Cells Fabricated from Obliquely Sputter Deposited and Thermally Annealed TiO2 Films

Dye sensitized solar cells based on annealed titanium dioxide films prepared by oblique reactive DC magnetron sputtering have been investigated in detail. Electron transport and recombination were studied using intensity-modulated photocurrent and photovoltage spectroscopy. Electron transport time as well as lifetime were found to increase upon lowering of the light intensity and to increase upon increasing the thickness of the TiO2 film. The properties are very similar to those observed for solar cells based on colloidal TiO2 films despite the morphologies being very different. In all cases, films are composed of a porous assembly of TiO2 nanocrystals. Grain boundaries with associated trap and/or energy barriers may explain the observed transport properties