Synthesis and characterization of thin film electroluminescent devices all-prepared by ultrasonic spray pyrolysis

• Thin film electroluminescent devices were fabricated by ultrasonic spray pyrolysis at 450 °C.
• The electroluminescent devices were fabricated on glass substrates.
• ZnO:Al was used as transparent conductive layer.
• ZnS:Mn and Al2O3 were used as phosphor and insulating layers, respectively.
• The electroluminescent devices have a low threshold operation voltage.

Alternating current thin film electroluminescent devices have been fabricated using aluminum-doped zinc oxide (ZnO:Al) as transparent conducting layer, aluminum oxide (Al2O3) as insulating layers, and manganese-doped zinc sulfide (ZnS:Mn) as electroluminescent layer. All these films were deposited by the ultrasonic spray pyrolysis technique at the same temperature (450°) on glass substrates, forming a standard MISIM (metal–insulator–semiconductor–insulator–metal) configuration. The electroluminescence of MISIM devices with a total thickness of ~ 1330 nm was investigated by applying a sinusoidal voltage with a frequency of 10 kHz. The devices showed orange-emission spectra centered at approximately 570 nm, characteristic of 4T1 → 6A1 radiative transitions of Mn2 + ions in the ZnS host, with a sharp intensity increase upon increasing the root mean square voltage above a threshold of 25 V and a rapid saturation for voltages higher than 38 V. The electroluminescent emission of these MISIM structures can be observed with the naked eye under ambient illumination.