Oxygen vacancy dominant strong visible photoluminescence from BiFeO₃ nanotubes

Abstract

In this Letter, we report oxygen vacancy dominant strong visible photoluminescence (PL) from multiferroic BiFeO3(BFO) nanotubes (NTs) prepared by sol–gel template method. Abundant oxygen vacancies present in BFO NTs provide alternate paths for the photo‐induced carrier generation and recombination thus affecting the PL and photoabsorption characteristics. This study not only assists in understanding the optoelectronic characteristics of BFO NTs at nanoscale but also suggests BFO nanostructures as potential candidates for future photonic and sensing applications. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Surface State‐Induced Anomalous Negative Thermal Quenching of Multiferroic BiFeO3 Nanowires

“…These oxygen vacancies exist in three charged states: singly charged (V O+ ), doubly charged (V O++ ), and neutral (V O ). It should be noted that the emission wavelength closely matches with our previously reported results . However, the variation in relative intensity and slight shift of the defect emission is probably due to sample‐to‐sample variations in the depth of defect states (energy of defect sites) due to small size and shape variation of BFO nanostructures.…”

“…It should be noted that the emission wavelength closely matches with our previously reported results. [8,10,33] However, the variation in relative intensity and slight shift of the defect emission is probably due to sample-to-sample variations in the depth of defect states (energy of defect sites) due to small size and shape variation of BFO nanostructures. Different depths of defect states (energies of defect states) are reflected through small difference in the spectral positions of emission maximums.…”

The effect of gadolinium doping on the structural, magnetic and photoluminescence properties of electrospun bismuth ferrite nanofibers

“…It has a bandgap varying from 2.5 eV to 2.8 eV [5][6][7]. It has been investigated as a potential candidate for optoelectronic applications such as photovoltaics [8][9][10], photonic and optoelectronic devices [11,12]. Studies have shown that the photoluminescence properties of BFO can even be manipulated through the use of electric fields [13].…”

“…Studies have shown that the photoluminescence properties of BFO can even be manipulated through the use of electric fields [13]. Further, the optoelectronic properties of BFO have been found to be enhanced in one dimensional nanostructures such as nanofibers [11] and nanotubes [12] when compared to bulk samples, due to strong surface level interactions and large surface to volume ratio [14]. Electrospun nanofibers have added advantages over other one dimensional nanostructures such as high aspect ratios, large surface areas [15][16][17] and enhanced optical properties [11,18].…”

“…Both BFO nanofilms and wires showed strong DLE bands when annealed under O 2 , whereas nanowires annealed under H 2 atmospheres exhibited weaker DLE bands. Recent studies on BFO nanotubes [12] synthesized via a sol-gel technique showed the presence of abundant oxygen vacancies, which affected the PL and photo absorption properties of the BFO nanotubes. Similarly reports on transition metal doping such as Nickel on the photoluminescence properties of BFO showed an increase in oxygen vacancies for higher levels of Nickel doping [19,20].…”