In:
Acta Physica Sinica, Acta Physica Sinica, Chinese Physical Society and Institute of Physics, Chinese Academy of Sciences, Vol. 70, No. 3 ( 2021), p. 037101-
Abstract:
The 〈i〉h〈/i〉-LuFeO〈sub〉3〈/sub〉 is a kind of narrow band gap hexagonal ferrite material, with a good application prospect in the field of ferroelectric photovoltaic. However, the low polarization intensity of 〈i〉h〈/i〉-LuFeO〈sub〉3〈/sub〉 makes the recombination rate of photogenerated electrons and holes large, which is not conducive to the improvement of the efficiency of 〈i〉h〈/i〉-LuFeO〈sub〉3〈/sub〉-based ferroelectric photovoltaic cells. In order to improve the ferroelectricity and optical absorption properties of 〈i〉h〈/i〉-LuFeO〈sub〉3〈/sub〉, the first principles method is used to calculate the doping formation energy values of In atom at different positions of 〈i〉h〈/i〉-LuFeO〈sub〉3〈/sub〉, and the most stable doping position is determined. The comparisons of band gap, optical absorption performance and polarization intensity among 〈i〉h〈/i〉-Lu〈sub〉1-〈/sub〉〈i〉〈sub〉x〈/sub〉〈/i〉In〈i〉〈sub〉x〈/sub〉〈/i〉FeO〈sub〉3〈/sub〉 (〈i〉x〈/i〉 = 0, 0.167, 0.333, 0.667) are made. With the increase of In doping, the cells of 〈i〉h〈/i〉-Lu〈sub〉1–〈/sub〉〈i〉〈sub〉x〈/sub〉〈/i〉In〈i〉〈sub〉x〈/sub〉〈/i〉FeO〈sub〉3〈/sub〉 stretch along the 〈i〉c〈/i〉-axis. The ratio of the lattice constant 〈i〉c〈/i〉/〈i〉a〈/i〉 increases from 1.94 at 〈i〉x〈/i〉 = 0 to 2.04 at 〈i〉x〈/i〉 = 0.667 when all the positions of In replace P1 position. Using the qualitative calculation of Berne effective charge, the results show that the ferroelectric polarization intensity of 〈i〉h〈/i〉-LuFeO〈sub〉3〈/sub〉, 〈i〉h〈/i〉-Lu〈sub〉0.833〈/sub〉In〈sub〉0.167〈/sub〉FeO〈sub〉3〈/sub〉, 〈i〉h〈/i〉-Lu〈sub〉0.667〈/sub〉In〈sub〉0.333〈/sub〉FeO〈sub〉3〈/sub〉 and 〈i〉h〈/i〉-Lu〈sub〉0.333〈/sub〉In〈sub〉0.667〈/sub〉FeO〈sub〉3〈/sub〉 along the 〈i〉c〈/i〉-axis are 3.93, 5.91, 7.92, and 11.02 μC·cm〈sup〉–2〈/sup〉, respectively. Therefore, with the increase of the number of In atoms replacing Lu atoms, the lattice constant 〈i〉c〈/i〉/〈i〉a〈/i〉 ratio of 〈i〉h〈/i〉-Lu〈sub〉1–〈/sub〉〈i〉〈sub〉x〈/sub〉〈/i〉In〈i〉〈sub〉x〈/sub〉〈/i〉FeO〈sub〉3〈/sub〉 increases, which can improve the ferroelectric polarization strength of the material. By analyzing the density of states of 〈i〉h〈/i〉-LuFeO〈sub〉3〈/sub〉 and 〈i〉h〈/i〉-Lu〈sub〉0.333〈/sub〉In〈sub〉0.667〈/sub〉FeO〈sub〉3〈/sub〉, we can see that In doping enhances the Fe-O orbital hybridization in 〈i〉h〈/i〉-Lu〈sub〉0.333〈/sub〉In〈sub〉0.667〈/sub〉FeO〈sub〉3〈/sub〉, and makes the optical absorption coefficient of 〈i〉h〈/i〉-Lu〈sub〉0.333〈/sub〉In〈sub〉0.667〈/sub〉FeO〈sub〉3〈/sub〉 in the solar light range larger. In summary, In doped 〈i〉h〈/i〉-LuFeO〈sub〉3〈/sub〉 is an effective method to improve its polarization intensity and optical absorption coefficient, which is of great significance for improving the performance of ferroelectric photovoltaic.
Type of Medium:
Online Resource
ISSN:
1000-3290
,
1000-3290
DOI:
10.7498/aps.70.20201287
Language:
Unknown
Publisher:
Acta Physica Sinica, Chinese Physical Society and Institute of Physics, Chinese Academy of Sciences
Publication Date:
2021
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