The cover photo describes the ring topological structure of carbon nucleus (using vortex-fractal-ring theory), which consists from two globules with 3 protons globule substructures. As discussed by, this vortex-fractal-ring theory is a new and original view of elementary particles and the structure of atomic nuclei, atoms, and molecules. Its basics are simple for understanding through the comprehensive topological structure that does not need description by complicated mathematical formulas. This theory together with grammatical evolution can design new models of nanostructures and allows us to understand the fundamental physical and chemical reasons for the stability and reactivity of atoms and molecules.
Bi-doped CH3NH3PbI3 effective masses and electronic properties research: A theoretical study using VASP
School of Mathematics and Physics, Huanggang Normal University, Newport NO.2 Road, Hubei, Huanggang, 438000, P. R. China
Adv. Mater. Lett., 2019, 10 (4), pp 275-278
Publication Date (Web): Jan 10, 2019
Copyright © 2019 VBRI Press
We calculated the effective masses and electronic properties of Bi-doped CH3NH3PbI3 perovskites as a thermoelectric material using the VASP functional. The Bismuth doping concentration of 11.1%, 20%, 33.3% corresponding band gaps are 1.46. 0.75, 0.56 eV, respectively. The effective masses of carriers and the band gaps decrease with the doping concentration addition. We found that the structure of Bi as an interstitial atom doped MAPbI3 were much more stable than undoped one by the crystal systemic energy, and the Bi doping made the Fermi Level shift close to the bottom of conduction band, leading to charge carrier close to the Fermi level, resulted in the higher electrical conductivity. Moreover, Bi doping produced a smaller electron effective mass with doping concentration addition, increasing the MAPbI3’s mobility. As a result, the Bi-doped MAPbI3 could simultaneously enhance the electrical conductivity and Seebeck coefficient. Our results showed that Bi doped MAPbI3 is a promising approach to develop thermoelectric and photovoltaic properties in organic-inorganic hybrid perovskite materials.
Bi-doped MAPbI3, effective masses, electrical conductivity, seebeck coefficient, fermi level.