Influence of Ag doping on structural, optical, and photoluminescence properties of nanostructured AZO films by sol–gel technique

•The optical band gap of the Ag–AZO film is tuned with Ag doping.•The PL intensity of the Ag–AZO film in visible region is increased with Ag doping.•The PL positions of these peaks were blue shifted with increased Ag content.•The increase in IB and IG is due to the charge difference between Ag+ and Zn2+.•The shifting of the PL positions is due to the size of Ag+ and Zn2+ ions.

The effects of Ag doping on the structural, electrical, optical, and photoluminescence properties of sol-gel derived Al rich zinc oxide (Ag–AZO) films are studied. The Al/Zn atomic ratio was constant (∼20%) in all the films, whereas the Ag/Zn atomic ratio varied from 0% to 3%. All the films were highly transparent in the 400–1200 nm wavelength range. The XRD results and surface morphologies of the films confirmed that the grain size increased with Ag doping. The optical band gap (Eg) of the Ag–AZO film first decreased to a value of ∼3.31 eV for a 1% Ag/Zn atomic ratio from a value of ∼3.69 for undoped AZO film. For higher values (beyond a 1% Ag/Zn atomic ratio) of Ag doping, the values of Eg started to increase and finally attained a value of ∼3.66 eV for an Ag/Zn 3% atomic ratio. The photoluminescence (PL) studies showed that the relative PL intensity of the Ag–AZO films in blue (IB) and green (IG) regions increased with Ag doping. The PL positions of these peaks were blue shifted with increased Ag content up to an Ag/Zn atomic ratio of 3%. The increase in IB and IG is due to the charge difference between Ag+ and Zn2+, whereas shifting of the PL positions is due to the size of Ag+ and Zn2+ ions.

Graphical abstractThe optical band gap of the Ag–AZO film first decreased to a value of ∼3.31 eV for a 1% Ag/Zn atomic ratio from a value of ∼3.69 for undoped AZO film. For higher values (beyond a 1% Ag/Zn atomic ratio) of Ag doping, the values of Eg started to increase and finally attained a value of ∼3.66 eV for an Ag/Zn 3% atomic ratio. The photoluminescence (PL) studies showed that the relative PL intensity of the Ag–AZO films in blue (IB) and green (IG) regions increased with Ag doping. The PL positions of these peaks were blue shifted with increased Ag content up to an Ag/Zn atomic ratio of 3%. The increase in IB and IG is due to the charge difference between Ag+ and Zn2+, whereas shifting of the PL positions is due to the size of Ag+ and Zn2+ ions.Figure optionsDownload full-size imageDownload as PowerPoint slide