Studies on the Orientation of ACEL ZnS:Cu Particles in Applied AC Fields

Abstract

In the last sixty years the understanding of the mechanisms of alternating current electroluminescence (ACEL) in transition metal-doped zinc sulfides, in particular ZnS:Cu particles has been the goal of all workers in the field. An in depth understanding of the crystallography and uncommon hemimorphic nature of these particles has lead to some understanding as to mechanism of light emission under an alternating current field. Hydrochloric acid etching of ZnS:Cu particles has allowed an intimate study of the hemimorphic nature and high density of planar stacking faults present in the particles that are critical for ACEL to occur. This work using complimentary field emission scanning electron microscopy and digital optical microscopy shows that the alignment of the planar stacking faults of these particles relative to the applied electric field is critical for light emission. Perpendicular alignment of the stacking faults results in no emission of light; as the alignment gradually approaches parallel emission increases and at parallel reaches a maximum. Thus, for devices using these materials alignment of the particles with the electric field is most important to maximize light output.

AC electroluminescent lamps: shedding some light on their mysteries

“…This model is in agreement with the observation from microscopic studies [23] that light emission occurs from discrete areas near to the surface of the particles. It also agrees with the observation [24] that unconfined ACEL particles rotate until their long axes are parallel to the field (in order that their positive and negative space charges can get as close to the appropriate electrode as possible).…”

Recent Progress of Fiber Shaped Lighting Devices for Smart Display Applications—A Fibertronic Perspective

“…Over the past three decades, a wide range of applications using ACEL device have been permeated into modern technological devices. Their decent brightness, large area illumination, low power consumption, and resistance to weathering enables ACEL devices to be applied in the backlights of watches, computer screens, and automotive and aeronautical instrument panels . Recently, however, with growing demand for more comfortable and convenient devices, wearable electronics based on flexible and stretchable technologies have become highly desirable .…”

Dispenser printed electroluminescent lamps on textiles for smart fabric applications

“…A proposed solution to incorporate light emitting displays into smart fabrics utilises electroluminescent (EL) displays. EL lamps are visible in mobile phone keypads, watches, aeronautical and automotive instrumentation, and advertising panels [2]. Since the initial discovery of electroluminescence in 1936 [3] electroluminescent devices have been developed based on inorganic thin-film alternating-current EL (TFACEL) [4], inorganic semiconductor based EL (such as light emitting diodes) [5], and organic semiconductor EL (such as organic light emitting diodes) [6].…”