Correlation of Photodegradation Efficiency with Surface Potential of Silver-TiO₂ Nanocomposite Thin Films

Abstract

The present work focuses on photocatalytic performance of Ag-TiO2 systems. Nanocrystalline thin films of TiO2-and Ag-doped TiO2 are grown by sol–gel method, followed by spin-coating technique on Si ⟨100⟩ surface. The crystallinity and crystal size were measured from X-ray diffraction and transmission electron microscopy studies. Lateral distribution of work function (WF) was examined through contact potential difference measurement done by scanning Kelvin probe microscopy. Local WFs of Ag-TiO2 thin films were found to be smaller than that of TiO2, and the minimum WF expected from the polynomial curve fitting was that of pure Ag. The photocatalytic efficiency of these thin films is estimated from photodegradation of methyl orange analyzed by UV–vis spectrophotometer. The photodegradation efficiency of Ag-TiO2 nanocrystalline thin films increases up to a certain dopant concentration of silver, beyond which it decreases. The changes in the photodegradation efficiency of these films are correlated with variation in contact potential difference.

Evolution of damage fraction due to dense ionizing irradiation on TiO2 film

“…5(a)]. Thus WF of pristine TiO 2 thin film was estimated to be 5.035 eV corresponding to WF of reference Au tip as 5.1 eV [3]. The CPD value for 100 MeV Ag ion irradiated thin films increases from 113 mV to 460 mV for fluence varying from 1 × 10 12 ions cm −2 to 5 × 10 13 ions cm −2 .…”

“…The measurement of CPD is carried out in terms of work function (WF) measurement using scanning Kelvin probe technique. The relation between WF and CPD (V CPD ) can be expressed as [3,27,28],…”

“…Titanium dioxide (TiO 2 ) is most widely used material because of its excellent optoelectronic properties [1][2][3][4][5]. Swift heavy ion (SHI) irradiation causes dense ionization and induces modification in its structural, morphological and electronic properties [6][7][8].…”

Enhanced photoelectrochemical and sensing performance of novel TiO2 arrays to H2O2 detection

“…Thanks to its high carrier transfer rate and plasmonic effect, Ag deposited on a TiO 2 surface successfully acts as a transfer intermediate for photogenerated electrons and holes, promoting charge carrier separation [15,16]. With a view toward controlling Ag particle size and dispersion, methods of sol-gel [17][18][19][20] and photodeposition [21,22] can be used since photocatalytic activity closely depends on content, crystal size, and morphology [23][24][25][26]. Specifically, Ag quantum dots and/or nanoclusters can effectively promote the separation of the photo-generated electrons and holes [23].…”

Silver metalized mixed phase manganese-doped titania: Variation of electric field and band bending within the space charge region with respect to the silver content

“…Among the semiconductors employed, TiO 2 is most widely used because of its suitable flat band potential, chemical state, non-toxicity, strong oxidation capacity and also its high photocatalytic activity. However the use of TiO 2 is impaired by its wide band gap (∼3.2 eV), which requires UV light for photoactivation, and its major limitation is higher recombination rate of the photogenerated charge carriers resulting in lower quantum yield [2][3][4][5][6][7][8]. In this regard our research group had previously reported the incorporation of the paramagnetic Mn 2+ ions in anatase lattice at Ti 4+ substitution site [9].…”