Density Functional Theory Study of Optical and Electronic Properties of (TiO2)n=5,8,68 Clusters for Application in Solar Cells

Abstract

A range of solution-processed organic and hybrid organic−inorganic solar cells, such as dye-sensitized and bulk heterojunction organic solar cells have been intensely developed recently. TiO2 is widely employed as electron transporting material in nanostructured TiO2 perovskite-sensitized solar cells and semiconductor in dye-sensitized solar cells. Understanding the optical and electronic mechanisms that govern charge separation, transport and recombination in these devices will enhance their current conversion efficiencies under illumination to sunlight. In this work, density functional theory with Perdew-Burke Ernzerhof (PBE) functional approach was used to explore the optical and electronic properties of three modeled TiO2 brookite clusters, (TiO2)n=5,8,68. The simulated optical absorption spectra for (TiO2)5 and (TiO2)8 clusters show excitation around 200–400 nm, with (TiO2)8 cluster showing higher absorbance than the corresponding (TiO2)5 cluster. The density of states and the projected density of states of the clusters were computed using Grid-base Projector Augmented Wave (GPAW) and PBE exchange correlation functional in a bid to further understand their electronic structure. The density of states spectra reveal surface valence and conduction bands separated by a band gap of 1.10, 2.31, and 1.37 eV for (TiO2)5, (TiO2)8, and (TiO2)68 clusters, respectively. Adsorption of croconate dyes onto the cluster shifted the absorption peaks to higher wavelengths.

Improved Simulated-Daylight Photodynamic Therapy and Possible Mechanism of Ag-Modified TiO2 on Melanoma

“…Therefore, the change in sunlight response induced by Ag-doped TiO 2 is most likely because some Ti atoms are substituted with Ag atoms. The energy band structure, the total density of states and the partial density of states, and the optical absorption properties were determined via density functional theory using the CASTEP code [ 47 ].…”

Computational, Investigational Explorations on Structural, Electro-Optic Behavior of Pelargonidin Organic Colorant for TiO2 Based DSSCs

“…In addition, the symmetry of TiO 2 s crystalline structure is critical for tuning surface energy, binding energy, band structure, charge mobility and other parameters that improve the opto-electronic behavior of solar cells [18]. As a result, it is necessary to investigate the interconnectedness of TiO 2 symmetry with the pelargonidin organic colorant to enhance physical and chemical behavior in solar-cell applications [19]. In computational investigations, frontier molecular orbital analysis, physicochemical and electronic parameter calculation, UV-visible and DOS spectral analysis, van der Waals prediction and molecular electrostatic potential map were performed by means of Gaussian tools, and the IR symmetry response was calculated using crystal maker software.…”

Spray pyrolisis deposition and characterization of Cd-TiO2 thin film for photocatalytic and photovoltaic applications

“…The strong dye absorbance was identified at 516 nm for TO and CTO thin films. The solar power efficiency of TO [Jsc = 5.4 mA/cm 2 ] thin film is less when it is compared to CTO thin film [Jsc = 6.3 mA/cm 2 ] [[24][25][26].…”