Berlin 2008 – wissenschaftliches Programm
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SYEC: Symposium Exact-exchange and hybrid functionals meet quasiparticle energy calculations
SYEC 3: Exact-exchange and hybrid functionals meet quasiparticle energy calculations III - Poster (joined by SYMS posters)
SYEC 3.3: Poster
Donnerstag, 28. Februar 2008, 18:30–19:30, Poster F
Role of emerging methods in advanced DFT study of novel compounds with high-efficiency photovoltaic applications — •Pablo Palacios1,2, Perla Wahnon1, Kefren Sanchez1, Irene Aguilera1, Julio Juan Fernandez1, and Jose Carlos Conesa2 — 1Universidad Politecnica de Madrid, Madrid, Spain — 2Consejo Superior de Investigaciones Cientificas, Cantoblanco, Spain
An exhaustive study of compounds with unusual electronic structure used as new efficient photovoltaic materials is presented. These intermediate band materials obtained by selective substitution of atoms of a host semiconductor by transition metals present a narrow, partially-filled band inside the semiconductor band-gap, separated from host valence and conduction bands. Therefore additional current carriers can be obtained from the absorption of low energy photons enabling electrons to get the conduction band through the intermediate band.
Although standard DFT is a suitable tool for our purposes, in order to enhance prediction capabilities for these new materials there are some features, i.e. host semiconductor gap, which can be improved with advanced methods let be GW, exact exchange or hybrid functionals.
Exact exchange studies have been done in several candidates for intermediate band material as well as advanced analysis of the correlation effect. Exact exchange method was implemented in our group within SIESTA. For the moment these studies have contributed to support the reliability of the prediction of intermediate band materials to such an extent that experimental samples are being grown. State-of-the-art techniques could complement the results obtained to date.