eprintid: 1395992 rev_number: 28 eprint_status: archive userid: 608 dir: disk0/01/39/59/92 datestamp: 2013-06-11 19:37:44 lastmod: 2021-09-19 23:43:23 status_changed: 2013-06-11 19:37:44 type: article metadata_visibility: show item_issues_count: 0 creators_name: Scanlon, DO creators_name: Kehoe, AB creators_name: Watson, GW creators_name: Jones, MO creators_name: David, WI creators_name: Payne, DJ creators_name: Egdell, RG creators_name: Edwards, PP creators_name: Walsh, A title: Nature of the band gap and origin of the conductivity of PbO2 revealed by theory and experiment. ispublished: pub divisions: UCL divisions: B04 divisions: C06 divisions: F56 note: © 2011 American Physical Society abstract: Lead dioxide has been used for over a century in the lead-acid battery. Many fundamental questions concerning PbO2 remain unanswered, principally: (i) is the bulk material a metal or a semiconductor, and (ii) what is the source of the high levels of conductivity? We calculate the electronic structure and defect physics of PbO2, using a hybrid density functional, and show that it is an n-type semiconductor with a small indirect band gap of ∼0.2 eV. The origin of electron carriers in the undoped material is found to be oxygen vacancies, which forms a donor state resonant in the conduction band. A dipole-forbidden band gap combined with a large carrier induced Moss-Burstein shift results in a large effective optical band gap. The model is supported by neutron diffraction, which reveals that the oxygen sublattice is only 98.4% occupied, thus confirming oxygen substoichiometry as the electron source. date: 2011-12-09 official_url: http://dx.doi.org/10.1103/PhysRevLett.107.246402 vfaculties: VMPS oa_status: green language: eng primo: open primo_central: open_green article_type_text: Journal Article verified: verified_manual elements_source: PubMed elements_id: 875729 doi: 10.1103/PhysRevLett.107.246402 lyricists_name: Scanlon, David lyricists_id: DSCAN57 full_text_status: public publication: Physical Review Letters volume: 107 number: 24 article_number: 246402 event_location: US issn: 0031-9007 citation: Scanlon, DO; Kehoe, AB; Watson, GW; Jones, MO; David, WI; Payne, DJ; Egdell, RG; ... Walsh, A; + view all <#> Scanlon, DO; Kehoe, AB; Watson, GW; Jones, MO; David, WI; Payne, DJ; Egdell, RG; Edwards, PP; Walsh, A; - view fewer <#> (2011) Nature of the band gap and origin of the conductivity of PbO2 revealed by theory and experiment. Physical Review Letters , 107 (24) , Article 246402. 10.1103/PhysRevLett.107.246402 <https://doi.org/10.1103/PhysRevLett.107.246402>. Green open access document_url: https://discovery.ucl.ac.uk/id/eprint/1395992/1/1395992.pdf