Quasiparticle band structure and optical properties of NH < inf > 3 < /inf > BH < inf > 3 < /inf >

Abstract

The quasiparticle band structure of the low temperature orthorhombic phase of NH3BH3 is studied by using the GW approximation. It is found that NH3BH3 is an insulator with a value of the band gap of 5.90 eV with GGA and of 9.60 eV with the GW approximation. Then, the optical properties of NH3BH3 are obtained by the calculation of the dielectric function, corrected by a scissor shift operation corresponding to the GW correction on the band gap. Also, the optical anisotropy in NH3BH3 is analyzed through the refractive index and static dielectric constants along the different crystallographic directions. Finally, it is found that the energy loss function has a prominent peak at 22.26 eV; at these frequencies (above 22.26 eV) NH3BH3 becomes transparent. (© 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)Ammonia borane (NH3BH3) is currently investigated as a potential material for reversible hydrogen storage. While the focus was mostly on phase transitions and ground state properties to date, this Letter presents the quasiparticle band structure of the low temperature orthorhombic phase of NH3BH3 obtained by using the GW approximation. The authors calculate the corresponding optical properties. It is found that NH3BH3 is a large band gap insulator, and shows a strong optical anisotropy. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.