Alkali Postdeposition Treatment-Induced Changes of the Chemical and Electronic Structure of Cu(In,Ga)Se2 Thin-Film Solar Cell Absorbers: A First-Principle Perspective
Loading...
Access rights
openAccess
publishedVersion
URL
Journal Title
Journal ISSN
Volume Title
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
This publication is imported from Aalto University research portal.
View publication in the Research portal (opens in new window)
View/Open full text file from the Research portal (opens in new window)
Other link related to publication (opens in new window)
View publication in the Research portal (opens in new window)
View/Open full text file from the Research portal (opens in new window)
Other link related to publication (opens in new window)
Date
2019-01-23
Department
Major/Subject
Mcode
Degree programme
Language
en
Pages
10
Series
ACS Applied Materials and Interfaces, Volume 11, issue 3, pp. 3024-3033
Abstract
The effects of alkali postdeposition treatment (PDT) on the valence band structure of Cu(In,Ga)Se2 (CIGSe) thin-film solar cell absorbers are addressed from a first-principles perspective. In detail, experimentally derived hard X-ray photoelectron spectroscopy (HAXPES) data [ Handick, E.; et al. ACS Appl. Mater. Interfaces 2015, 7, 27414-27420 ] of the valence band structure of alkali-free and NaF/KF-PDT CIGSe are directly compared and fit by calculated density of states (DOS) of CuInSe2, its Cu-deficient counterpart CuIn5Se8, and different potentially formed secondary phases, such as KInSe2, InSe, and In2Se3. The DOSs are based on first-principles electronic structure calculations and weighted according to element-, symmetry-, and energy-dependent photoionization cross sections for the comparison to experimental data. The HAXPES spectra were recorded using photon energies ranging from 2 to 8 keV, allowing extraction of information from different sample depths. The analysis of the alkali-free CIGSe valence band structure reveals that it can best be described by a mixture of the DOS of CuInSe2 and CuIn5Se8, resulting in a stoichiometry slightly more Cu-rich than that of CuIn3Se5. The NaF/KF-PDT-induced changes in the HAXPES spectra for different alkali exposures are best reproduced by additional contributions from KInSe2, with some indications that the formation of a pronounced K-In-Se-type surface species might crucially depend on the amount of K available during PDT.Description
| openaire: EC/H2020/641004/EU//Sharc25
Keywords
chalcopyrite thin-film solar cells, DFT, HAXPES, KF-PDT, KInSe
Other note
Citation
Malitckaya, M, Kunze, T, Komsa, H P, Havu, V, Handick, E, Wilks, R G, Bär, M & Puska, M J 2019, ' Alkali Postdeposition Treatment-Induced Changes of the Chemical and Electronic Structure of Cu(In,Ga)Se 2 Thin-Film Solar Cell Absorbers : A First-Principle Perspective ', ACS Applied Materials and Interfaces, vol. 11, no. 3, pp. 3024-3033 . https://doi.org/10.1021/acsami.8b18216