Polaron states of the full-configuration defects in metal halide perovskites

Abstract

The systematical analysis for varieties of defects with different depths and lattice relaxation strengths in metal halide perovskites (MHPs) is a challenging task. Here, we study the energy shifts of the full-configuration defects due to the polaron effect based on the all-coupling variational method in MHPs, where these polaron states are formed stemming from different defect species coupling with the longitudinal optical phonon modes via Fröhlich mechanism. We find that the polaron effect results in defect levels varying from tens to several hundreds of meV, which are very close to the correction of defect levels due to the defect-polaron effect, especially for these migration defects proved in the recent experiments in MHPs. These results provide the significant enlightenment not only for analyzing the radiation and non-radiation processes of carriers mediated by defects, but also for optimizing defect effect in the photovoltaic and photoelectric devices based on MHPs materials.

Enhancing the energetic and magnetic stability of atomic hydrogen chemisorbed on graphene using (non)compensated B–N pairs

“…DFT-D3 method of Grimme vdW correction is employed to deal with the vdW interactions between the adsorbates and graphene as well as the graphene interlayers, 58 whose validity in a nonmetal atom adsorbed system has been confirmed in our previous work. 14…”

“…[1][2][3][4][5][6][7][8][9] Integrating the high mobility and underlying magnetism of Dirac electrons into graphene becomes unprecedently desirable because magnetic/ magnetized graphene is considered a highly promising candidate for future spintronic devices. [10][11][12][13][14] Nevertheless, intrinsic graphene is nonmagnetic owing to the p-conjugated electron system. 15 A well-known paradigm that needs to remove different numbers of p z orbitals from different triangular sublattices of graphene has been proposed by Lieb.…”

“…51,52 In both magnetic systems, characteristic splits of resonance peaks were clearly substantiated in the vicinity of the Fermi level, giving rise to sizable 1.0m B and higher 3.0m B for H and B atoms, respectively. However, for the B adsorbate, both high and weak spin polarizations are highly possible due to different functionals and van der Waals (vdW) interactions as well as different adsorbates, 14,53 while for the atomic H, the induced atomic scale magnetic moment is robust. Despite all these great advantages, the corresponding adsorption energy (E a ) of H atoms chemisorbed on pristine graphene (H/G) is somewhat relatively small, À0.8 to À0.9 eV per atom.…”