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heterostructures shows how different effects can be tuned to tailor the bandgap
and the variation can be understood with simple physical arguments. Since the
analysis is quite general, therefore, it can be applied to other heterostructures
as well.
5.6 Conclusion
In this chapter a pool of 2400 materials is explored which can absorb solar
light for photoelectrochemical water splitting. The criteria imposed for the
bandgap, band edge positions and the stability in aqueous solution in neutral
pH for a certain potential range gives a handful of candidates which can serve
as good photoabsorber for the water splitting reaction. The careful comparison
of the bandgap with different methods involving hybrid functionals and many
body perturbation theory methods assures credibility to the method that is
used for the bandgap calculation of a large number of materials. A literature
survey for the materials in the list of candidates found which can act as good
photoabsorbers suggests Ca2PbO4, Cu2PbO2 AgGaO2, AgIn2 and NaBiO3 as
potential candidates.
Additionally, a strategy to engineer the bandgap is also explored via layering
of different lattice matched structures. For the model systems explored
i.e BaSnO3 and BaTaO2N the calculations suggest that the variations in the
bandgap of the structure can be understood with the simple arguments of confinement
and tunneling effects. This strategy can be applied to other lattice
matched systems for bandgap engineering.