Ruggedized luminescent nanoparticle tracers have luminescent nanoparticle cores coupled to a luminescent substrate. The substrate is a large-particle size phosphor, while the nanoparticles are photoluminescent quantum dots (QDs) whose emission spectra can be tuned based on their chemical composition, size, and fabrication (e.g., dopants). The QDs are encapsulated by a protective layer to form a nanoparticle core. The protective layer can shield the QDs from external environments that would otherwise damage the delicate QDs. The substrate is also encapsulated by a protective layer, and the protective layer of the nanoparticle core is coupled to the protective layer of the substrate via a molecular linker to form a tracer particle complex. The tracer particle complexes can be disposed in a silicate suspension for subsequent use.

Ruggedized luminescent nanoparticle tracers have luminescent nanoparticle cores coupled to a luminescent substrate. The substrate is a large-particle size phosphor, while the nanoparticles are photoluminescent quantum dots (QDs) whose emission spectra can be tuned based on their chemical composition, size, and fabrication (e.g., dopants). The QDs are encapsulated by a protective layer to form a nanoparticle core. The protective layer can shield the QDs from external environments that would otherwise damage the delicate QDs. The substrate is also encapsulated by a protective layer, and the protective layer of the nanoparticle core is coupled to the protective layer of the substrate via a molecular linker to form a tracer particle complex. The tracer particle complexes can be disposed in a silicate suspension for subsequent use.

An inorganic thin film electroluminescent display element having a layer structure comprising: a first dielectric layer, a luminescent layer, comprising a luminescent material, on the first dielectric layer, and a second dielectric layer on the luminescent layer. Each of the first and the second dielectric layers comprises nanolaminate with alternating aluminum oxide Al.sub.2O.sub.3 and hafnium oxide HfO.sub.2 sub-layers, the nanolaminate having at least two sub-layers of both types and a thickness of less than or equal to 300 nm.