Modeling the Photochrome-TiO₂ Interface with Bethe-Salpeter and Time-Dependent Density Functional Theory Methods.

Area of Science:

• Computational chemistry
• Materials science
• Solid-state physics

Background:

• Hybrid organic-inorganic semiconductors are vital for molecular electronics and photoresponsive applications.
• Characterizing interfaces and excited electronic states in these large systems is computationally challenging.
• Existing methods like time-dependent density functional theory (TD-DFT) have limitations for complex hybrid materials.

Purpose of the Study:

• To investigate photochromic molecules adsorbed on TiO2 nanoclusters using a many-body Green's function approach.
• To assess the performance of time-dependent density functional theory (TD-DFT) for these hybrid systems.
• To evaluate the photochromic properties of various organic-inorganic hybrid materials.

Main Methods:

• Many-body Green's function (MBGF) Bethe-Salpeter equation (BSE) calculations.
• Investigation of photochromic molecules (e.g., azobenzenes) adsorbed on TiO2 nanoclusters.
• Assessment of TD-DFT performance using different exchange-correlation functionals.

Main Results:

• The study presents the first MBGF BSE investigation of photochromic molecules on TiO2 nanoclusters.
• TD-DFT results for organic-inorganic interfaces are highly dependent on the chosen exchange-correlation functional.
• Significant differences in calculated photochromic properties were observed based on the functional used.

Conclusions:

• Accurate simulation of hybrid organic-inorganic interfaces requires careful selection of computational methods and functionals.
• TD-DFT can yield qualitatively different conclusions for these systems depending on the functional choice.
• This work provides a pathway towards more reliable computational simulations of advanced hybrid materials.