A Theoretical Approach to the Impulsive Excitation of Mechanoluminescence in Crystals

Abstract

Considering the linear dependence of the total intensity of mechanoluminescence (ML) on the area of newly created surfaces, an equation is derived which can explain several parameters of ML. The theory suggests that after pulse excitation of ML, initially the ML intensity increases ex‐ponentially with time, attains a maximum value, and then it decreases exponentially. The peak of the ML intensity versus time curve increases linearly with the strain rate of the crystals and the total intensity of ML initially increases and then attains a saturation value for higher values of the strain rate of the crystals. The total intensity of ML increases linearly with the mass of the crystals and the peak of the ML intensity versus time curves increases linearly with the cross‐section of the crystals. The temperature dependence of ML can also be understood from the theory proposed.

Characterisation and Mechanoluminescence studies of Sr2MgSi2O7: Eu2+, Dy3+

“…Due to the impact sample gets fractured and the creation new surfaces give rise to local and piezoelectricity, may be a reason for ML emission. This fracto-mechanoluminescent material can be helpful in designing the fracto-ML based devices such as fracture sensor, impact sensor, damage sensors, safety management monitoring system, fuse system for army warheads, etc (Chandra, 2011(Chandra, , 2012.…”

“…Sugar crystal produces a glow of light when it is crushed or fractured in dark. Such phenomenon of light emission induced by fracture of solids is known as fracto Mechanoluminescence (FML) (Chandra, 1998(Chandra, , 2012. The fracto ML induced by impulsive deformation of crystals may be useful in providing scientific background to the damage sensors; impact sensors; fuse system for army warhead; fracture produced by milling machines, crushers, hammers, etc.…”

“…They are often used as an example material when presenting afterglow mechanisms and they are the most widely studied persistent luminescent silicates (Chandra, 1998(Chandra, , 2011(Chandra, , 2012Kim, Kwon, & Sohn, 2013). It has been already reported that light emission takes place during the elastic deformation, plastic deformation and fracture of solids.…”

Preparation and characterization of gold doped (Zn, Cd)S mixed phosphors for mechano-optical transducers

“…Therefore there is a possibility to describe phenomenologically the time dependence of the ML produced during impact of a piston on the crystal in terms of newly created surfaces. Considering the phosphors as a collection of crystallites, the equation of the ML may be expressed as (Chandra et al 1986) 2r lV2/3(MO)l/3 ~213…”

“…The total intensity of ML is given by (Chandra et al 1986) lr=6rlV2/3M~/ao~-t/3exP(3--~fl~ ). 7The value of 1/fil is related to the maximum compression at a particular velocity (Mott 1952).…”