EL emission enhancement in powder electroluminescent device via insertion of receptive layer. Issue 3 (1st February 2020)

• Record Type: Journal Article
• Authors: Takeda, N.; Tsuneyasu, S.; Satoh, T.
• Is Part Of: Electronics letters. Volume 56:Issue 3(2020)
• Page Start: 144
• Page End: 147
• Publication Date: 2020-02-01
• Subjects: dielectric losses -- electrodes -- electroluminescent devices -- permittivity -- electroluminescence -- powders -- brightness; current luminance -- loss tangent tan -- receptive layer -- EL properties -- electrical energy losses -- dielectric loss -- frequency‐dependence -- device efficiency -- powder EL devices -- EL emission enhancement -- powder electroluminescent device -- letter substrate -- transparent electrode -- uniform electric field -- device capacitance -- emission‐enhancement mechanism -- frequency dependence; Electronics -- Periodicals; 621.381
• DOI: 10.1049/el.2019.3085
• Languages: English
• ISSNs: 0013-5194

Abstract

Abstract : A method to enhance the electroluminescence (EL) of powder electroluminescent devices via the insertion of a receptive layer between the letter substrate and the transparent electrode is proposed. This approach affords uniformity of distance between the substrate and electrode, which ensures a more uniform electric field on application of a voltage to the device. Both the current and luminance are observed to increase, and the device capacitance and capacitive reactance improve on introduction of the receptive layer, which enhances the EL properties. The emission‐enhancement mechanism is examined via measurements of the frequency dependence of the current, luminance, and loss tangent tan δ . Regardless of the receptive layer, the current decreases in the frequency regime over which tan δ increases, which indicates that the EL properties are affected by electrical energy losses due to dielectric loss. The frequency‐dependence behaviours of tan δ and temperature are found to be different because of heat production due to both dielectric loss and radiationless deactivation, which means that dielectric loss must be reduced to improve device efficiency. Their approach can form an integral aspect of the evaluation of powder electroluminescent devices.