On the adsorption mechanism of caffeine on MAPbI3 perovskite surfaces: a combined UMC-DFT study

Recently, it was experimentally shown that the performance and thermal stability of the perovskite MAPbI3 were improved upon the adsorption of a molecular layer of caffeine. In this work, we used a hybrid methodology that combines uncoupled monte carlo (UMC) and density functional theory (DFT) simul...

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Bibliographic Details
Published in:Physical chemistry chemical physics : PCCP 2021-01, Vol.23 (18), p.10807-10813
Main Authors: Ribeiro Junior, Luiz A, Tromer, Raphael M, dos Santos, Ramiro M, Galvão, Douglas S
Format: Article
Language:English
Subjects:
Adsorption
Caffeine
Conduction bands
Density functional theory
Energy bands
Perovskites
Surface chemistry
Thermal stability
Valence band
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Summary:Recently, it was experimentally shown that the performance and thermal stability of the perovskite MAPbI3 were improved upon the adsorption of a molecular layer of caffeine. In this work, we used a hybrid methodology that combines uncoupled monte carlo (UMC) and density functional theory (DFT) simulations to carry out a detailed and comprehensive study of the adsorption mechanism of a caffeine molecule on the surface of MAPbI3. Our results showed that the adsorption distance and energy of a caffeine molecule on the MAPbI3 surface are 2.0 Å and −0.3 eV, respectively. The caffeine/MAPbI3 complex presents a direct bandgap of 2.38 eV with two flat intragap bands distanced 1.15 and 2.18 eV from the top of valence bands. Although the energy band levels are not significantly shifted by the presence of caffeine, the interaction MAPbI3/perovskite is enough to affect the bands’ dispersion, particularly the conduction bands.
ISSN:1463-9076
1463-9084
DOI:10.1039/d0cp04308g