Discovering High Intensity Room Temperature Visible Spectrum Piezoluminescence in Self-Assembled Grain-Oriented Hierarchical Multilayers
Abstract
Piezoluminescence (PL) implies generation of luminescence in the visible spectrum by mechanical action. The effect allows direct conversion of mechanical stress into light and has been observed in compounds with suitable crystallographic symmetry modified with activator ion. The mechanism behind the emission has been proposed to be as follows: (i) application of stress produces local electric field in the material due to the piezoelectric effect and the magnitude of field is significantly high in the vicinity of the activator ion due to local structural distortion; (ii) local field due to piezoelectric effect may result in reducing the trap-depth of the carriers or it may cause the band bending; (iii) next thermal detrapping or charge tunnel can occur; and (iv) lastly, generation of the excitor ions and their de-excitations results in the PL effect. The underlying basis for the effect thus lies in the presence of the local piezoelectricity and energy states available from the suitable activator ion. In this program, we utilized the advances made in the understanding of ceramic nanocomposites and coupled it with the fundamentalsbehind the PL emission to realize a hierarchical structure with high intensity room temperature emission. The focus in this effort was on establishing the structure property performance relationships governing the interactions between the stress, crystallography, microstructure and light emission. PL can be utilized in various scenarios where mechanical energy is continuously available surfaces of the aircrafts, automobiles and ships; roadways and pedestrian walkways; high deformation structures such as windmills and flexible rooftops, etc. New sensing technologies for stress, impact, and damage could be designed based on the PL effect. The effect could also be used for visualization of stress propagation in structures such as pipes and mounts.
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 31, 2016
- Accession Number
- AD1068359
Entities
People
- Yongke Yan
Organizations
- Virginia Tech