Investigations On Preparation And Application Of ZnS-based Mechanoluminescent Materials

Mechanoluminescence?ML?is a luminous phenomenon produced by a solid material under external mechanical action?compression,stretching,bending,impact,etc.?.According to the mechanical characteristics of ML,it can be divided into two categories:the tribo-ML and the deformation-ML.Due to the high repeatability,the linear dependence of light emission intensity on the mechanical stress,and the ability to achieve force-light conversion without electrical power supply characteristics of the elastic-deformation-ML,it have attracted increasing attention in recent years for their wide potential applications in stress sensing and imaging,structural damage monitoring,wearable illuminating devices,self-powered display,mechanical energy collection and conversion.However,their low ML intensity greatly hinders its practical applications.Aiming at the problem of weak ML of materials and application,typical Zn S-based ML materials are selected in this paper,and the following parts are mainly carried out:?1?Three kinds of elastic-ML powder materials,Zn S:Mn²⁺and Zn S:Cu,were prepared by high-temperature solid-phase sintering.X-ray powder diffractometer?XRD?,scanning electron microscope?SEM?,X-ray photoelectron spectrometer?XPS?,Raman spectrometer and other instruments are used to characterize the basic properties of materials such as morphology,crystal structure and element content.?2?With enhanced ML of Zn S:Mn²⁺by Li⁺co-doping,the effects of Li⁺doping concentration on the morphology,crystal structure,photoluminescence?PL?,ML performance,and quantum efficiency of Zn S:Mn²⁺were systematically studied.It was determined that the incorporation of Li⁺at a certain concentration can effectively improve the optical properties of Zn S:Mn²⁺.The current PL and ML intensity of Zn S:Mn²⁺,Li⁺materials reached the strongest when the current precursor materials introduced Li⁺concentrations of 4 at.%and 5 at.%,respectively.Compared with Zn S:Mn²⁺samples without undoped Li⁺,PL and ML of Zn S:Mn²⁺,Li⁺by 4 at.%and 5at.%of Li⁺concentrations were enhanced by 338%and 610%,respectively.At the same time,the electron paramagnetic resonance spectroscopy was used to study the change trend of sulfur vacancy concentration of samples with different Li⁺doping concentrations.It was found that the enhanced is related to effect of sulfur vacancy concentration by co-doping with Li⁺.?3?High-brightness Zn S:Cu/PDMS ML composite thin-film devices were prepared by combining polydimethylsilane?PDMS?with zinc sulfide?Zn S?ML powder.Three factors?ML powder concentration in the film,tensile deformation,stretching frequency?affecting the luminescent intensity of Zn S:Cu/PDMS ML composite film devices were studied,and the optimal light-emitting conditions of Zn S:Cu/PDMS ML composite film devices are:70%of Zn S:Cu particle concentration,40%of tensile deformation,and 30 Hz of tensile frequency.The ML of Zn S:Cu/PDMS ML composite film is very stable.Under 25200 stretching,the ML intensity of Zn S:Cu/PDMS ML composite film was hardly reduced.?4?Developed a display device based on Zn S:Cu/PDMS ML film,used in water-speed sensors,lighting/display systems,wearable light-emitting devices and other fields,realizing the application of self-driven energy devices for luminous conduction.