Owing to power conversion efficiencies of as high as 22.1%, hybrid organic–inorganic lead halide perovskites have become the fastest growing solar technology, competing with the conventional thin-film technology. Though unique and exceptional, long-term stability issue and toxic behavior caused by the lead content in the perovskites hamper large-scale commercial production. With this motivation toward achieving a stable and reduced toxic perovskite, we have investigated the structural, electronic, and optical properties of mixed MAGe x Pb(1–x)I3 perovskites with the generalized gradient approximation–Perdew, Burke, Ernzerhof exchange–correlation functional within the framework of density functional theory. Under structural properties, we have calculated the lattice constants, bond lengths, tolerance factors, enthalpies of formation, bulk moduli, and their derivatives for x = 0.0, 0.125, 0.375, 0.625, and 0.875. We found that mixed MAGe x Pb(1–x)I3 perovskites are stable except at x = 0. The electronic properties such as band gaps, energy band level, and effective masses have been predicted for all combinations of x. We have also analyzed the projected and total density of states in detail. Optical properties like imaginary and real parts of dielectric function, refractive index, and extinction coefficient have been discussed. Further, to understand the light trapping capacity, we have examined the absorption coefficients for x = 0.0, 0.125, 0.375, 0.625, and 0.875, and interband transitions are well estimated. The calculated values of all parameters were compared with the available experimental and theoretical values. A fairly good agreement has been obtained between them.

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Purpose The purpose of this paper is to analyze various properties of anatase titanium dioxide (TiO2) nanoparticles. Further, it proposes to implement Linear Combinations of Atomic Orbitals (LCAO) basis set under the framework of density functional theory and outline how LCAO is able to provide improved results in terms of various mechanical properties rather than plane wave and other theoretical results. Design/methodology/approach This paper provides an exploratory study on anatase TiO2 by implementing OLCAO–DFT–LDA–LBFGS–EOS–PZ algorithms to find out various ground-level properties. The data so obtained are complemented by various analysis using mathematical expressions, description of internal processes occurred and comparison to others’ analytical results. Findings The paper provides some empirical insights on how mechanical properties of anatase TiO2 improved by implementing LCAO methodology. From the analysis of electronic properties, it is seen that the anatase TiO2 supports the inter band indirect transition from O-2p in valence region to Ti-3d in the conduction region. Research limitations/implications Most of the electronic properties are underestimated because a single exchange-correlation potential is not continuous across the gap. This gap can be enhanced by implementing Green’s function in place of DFT and the other way is to implement self-interaction correction. Practical implications The use of anatase TiO2 is primarily used for catalytic applications. This is also used to enhance the quality of paper in the paper industry. Additionally, this is used as a prime ingredient in cosmetic industry. Originality/value This paper fulfills an identified need to study how LCAO, another basis set, plays an important role in improving material properties.