Conference Papers Year : 2025

Electronic and Photocatalytic Properties of Sn1−xTixO2 Alloys and (SnO2)n/(TiO2)m Superlattices under Biaxial Strain: A First-Principles and Evolutionary Algorithm Study.

Abstract

The aim of this study is to develop more efficient semiconductor materials for photocatalytic water splitting by integrating superlattice structures and metal oxide substitutions. While metal oxides such as TiO₂ and SnO₂ show promise for water splitting, their large band gaps and rapid carrier recombination limit their effectiveness in harnessing sunlight. To overcome these challenges, the influence of biaxial tensile and compressive strains on the stability, structural , electronic properties, and photocatalytic efficiency of (SnO₂)n/(TiO₂)m superlattices and Sn1-xTixO₂ alloys are investigated using first-principles and evolutionary algorithm calculations. As a result, the variable composition evolutionary algorithm allowed us to predict four different configurations of substitution in tin dioxide by titanium atoms (Sn1−xTixO2, Sn-Ti-O). It was observed that the band gap decreases with increasing biaxial strain, along with a corresponding decrease in titanium concentration. Superlattice configurations were investigated using different stacking arrangements of nSnO2 layers and mTiO2 layers, such as (n=m), (n,1), and (1, m). The results show that the (1, m) stacking arrangement achieves the highest values for bulk modulus, Poisson's ratio, and Debye temperature. Exceptional stability was confirmed through phonon dispersion analysis for the 3(SnO2​)/1(TiO2)​)1superlattice under both tensile and compressive strains (-5% to 5%), with other superlattices maintaining stability between -3% and 4%. Furthermore, the electronic analysis demonstrated a decrease in the band gap with increasing tensile strain, achieving a tunable band gap from 3.34 eV to 2.54 eV for 1(SnO2​)/3(TiO2​) using the HSE06 functional, with high carrier mobility. These superlattices exhibit favorable band edge alignments at pH = 0, 7, and 14, showcasing their potential as efficient photocatalysts.

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Dates and versions

hal-05098600 , version 1 (05-06-2025)

Identifiers

  • HAL Id : hal-05098600 , version 1

Cite

Najwa Harrati, Adlane Sayede. Electronic and Photocatalytic Properties of Sn1−xTixO2 Alloys and (SnO2)n/(TiO2)m Superlattices under Biaxial Strain: A First-Principles and Evolutionary Algorithm Study.. European Materials Research Society (E-MRS), May 2025, Strasbourg, France. ⟨hal-05098600⟩
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