Self consistent hybrid functionals What we ve learned so far

These are exciting times for computational materials science. We are witnessing a wide spread availability of high performance computing facilities, a huge increase in accessible computational resources, and an accompanying development of new exchange correlation functionals within density functional theory. All this contributes to the establishment of density functional theory as an indispensable tool for materials science investigations in general. Here, we want to highlight some examples utilising a recently developed self consistent hybrid functional, proposed by Shimazaki and Asai J Chem Phys 130 164702, 2009 [3] and Skone et al. Phys Rev B 89 195112, 2014 [4] , allowing for the calculation of accurate material properties using a fully ab initio procedure. The obtained structural and electronic properties of a range of oxide semiconductors will be critically discussed with respect to experimental results, and pave the way towards open questions in the fiel

Cluster Approach To Model Titanium Dioxide as Isolated or Organic Dye Sensitized Nanoobjects

International audienceThis paper proposes the cluster approach methodology to simulate electronic properties of semiconducting isolated nanocrystalline materials as well as functionalized by organic dye molecules. The proposed cluster approach considers the nanoobject construction with the crystal structure in the internal part while the surface is modified according to the environmental interaction. In this aim, the (TiO2)n clusters with n = 2-140, indoline dye molecule D102, and their hybrid composites were investigated. The electronic properties of (TiO2)n were computed thanks to different DFT potentials, considering the nanobject sizes evaluation, their environmental surface modification and saturation, and the interface effects occurring between the cluster and sensitizer. The studies prove that the electronic features of (TiO2)n nanoparticles with surface being altered by the external environment may be coherently computed using DFT methodology with LC-BLYP potential by modifying the long-range separation parameter μ. The values of μ depend on the composition of the investigated system, whereas the surface saturation of the studied clusters possessing suitable size did not have any critical impact on their electronic properties. It is shown that the developed methodology is also relevant to characterize the charge transfer involved in the hybrid forms associating dye molecules and (TiO2)n clusters. The mentioned process is crucial in the efficiency of photovoltaic devices based on the hybrid systems