title: p-n Heterojunction of doped graphene films obtained by pyrolysis of biomass precursors.
abstract: Nitrogen-doped graphene [(N)G] obtained by pyrolysis at 900 °C of nanometric chitosan films exhibits a Hall effect characteristic of n-type semiconductors. In contrast, boron-doped graphene [(B)G] obtained by pyrolysis of borate ester of alginate behaves as a p-type semiconductor based also on the Hall effect. A p-n heterojunction of (B)G-(N)G films is built by stepwise coating of a quartz plate using a mask. The heterojunction is created by the partial overlapping of the (B)G-(N)G films. Upon irradiation with a xenon lamp of aqueous solutions of H(2) PtCl(6) and MnCl(2) in contact with the heterojunction, preferential electron migration from (B)G to (N)G with preferential location of positive holes on (B)G is established by observation in scanning electron microscopy of the formation of Pt nanoparticles (NP) on (N)G and MnO(2) NP on (B)G. The benefits of the heterojunction with respect to the devices having one individual component as a consequence of the electron migration through the p-n heterojunction are illustrated by measuring the photocurrent in the (B)G-(N)G heterojunction (180% current enhancement with respect to the dark current) and compared it to the photocurrent of the individual (B)G (15% enhancement) and (N)G (55% enhancement) components.
authors.affiliation: Instituto Universitario de Tecnología Química, Univ. Politécnica de Valencia, Av. De los Naranjos s/n, 46022, Valencia, Spain.
authors.forename: Marcos
authors.initials: M
authors.lastname: Latorre-Sánchez
authors.forename: Ana
authors.initials: A
authors.lastname: Primo
authors.forename: Pedro
authors.initials: P
authors.lastname: Atienzar
authors.forename: Amparo
authors.initials: A
authors.lastname: Forneli
authors.forename: Hermenegildo
authors.initials: H
authors.lastname: García
mesh_terms: D000464:Alginates / Q000737:chemistry; D018533:Biomass; D001881:Borates / Q000737:chemistry; D001895:Boron / Q000737:chemistry; D002384:Catalysis; D048271:Chitosan / Q000737:chemistry*; D004583:Electrons; D004952:Esters; D006108:Graphite / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning; D049329:Nanostructures / Q000737:chemistry; D009584:Nitrogen / Q000737:chemistry; D055095:Optics and Photonics; D010777:Photochemistry; D012666:Semiconductors; D013059:Spectrum Analysis, Raman; D013696:Temperature; D014867:Water / Q000737:chemistry; D014978:Xenon
chemical_list: D000464:Alginates; D001881:Borates; D004952:Esters; D014867:Water; D014978:Xenon; D006108:Graphite; D048271:Chitosan; D009584:Nitrogen; D001895:Boron
keywords: doped graphene; graphene; graphene films; p-n heterojunctions; photocurrents