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The explosive decomposition of heavy metal azides initiated by a laser pulse was studied experimentally over a broad range of action levels (from the threshold values to those exceeding the threshold ignition energy by a factor of 100) and in the time interval including the induction period, and rapid explosive decomposition, and the expansion of detonation products. The explosive glow and expansion dynamics of the decomposition products in air and vacuum were investigated, and the velocities of the explosive decomposition front, the compression pulse, and the expansion of the explosion products were measured. Based on the results obtained, the possibility of the occurrence of preexplosion phenomena is discussed and the mechanism of laser initiation of heavy metal azides is analyzed.

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Accordingly, phosphor-converted (pc) NIR light-emitting diodes (LEDs) have received extensive scientific attention as lighting sources, owing to their conspicuous characteristics and range of applications. [8] The integration of blue InGaN LED chips with NIR phosphors is considered a promising strategy for yielding novel high-performance NIR light sources with broadband spectra. [9][10][11][12] Since NIR phosphors are key parts of these devices, affecting their overall luminescence performance and emission spectrum, selecting the appropriate phosphor is paramount. In this regard, for the design of efficient broadband NIR phosphors, applying a suitable activator as an ideal luminescence center is of vital importance.Chromium (Cr) exhibits a broadband absorption in the visible spectral range stemming from its distinctive 3d 3 electronic configuration. Besides, Cr 3+ ions can display a tunable narrowband or broadband spectrum (from deep red to the NIR region) depending on whether they are in a strong or weak crystal field environment, respectively. [9][10][11] Correspondingly, garnets possess a stable cubic crystal structure with a complex arrangement of different cations in the unit cell and exhibit several advantages, including a high thermal stability and long distances between alkali ions. The specific physicochemical Broadband near-infrared (NIR) luminescent materials have received notable attention due to their distinct photophysical properties for designing NIR light-emitting diodes (NIR LEDs). Here, a series of Ca 3−x Lu x Ga 2+x Ge 3−x O 12 :Cr 3+ (CLGGG:Cr 3+ ) (x = 0-1) NIR-emitting garnet phosphors with an emission range of 660-1200 nm are successfully developed and their lattice parameters are structurally analyzed. Upon 460 nm blue light excitation, the NIR phosphors exhibit both a substantial spectral broadening (FWHM: 129→267 nm) and a redshift of 37 nm (766→803 nm) with cosubstitution of [Lu 3+ -Ga 3+ ] pairs for [Ca 2+ -Ge 4+ ] sites. Furthermore, their luminescence thermal stability is substantially improved, maintaining ≈90% of the original photoluminescence intensity at 150 °C, owing to shrinkage of the second coordination sphere and rigid lattice, which are strongly associated with Cr 3+ trade-off occupancy and local structure evolutions. The relation between the trade-off site occupation of Cr 3+ in GaO 6 /CaO 8 polyhedrons and the NIR emission is also clarified by evaluating the decay and electron paramagnetic resonance behavior of Cr 3+ at different sites. The broadband NIR phosphors investigated here can serve as auspicious luminescent converters for phosphor-converted NIR LEDs and can provide an inspiring platform for future studies.

Light is a fuel for photosynthesis and plays an irreplaceable role in seed germination, stem elongation, leaf expansion, flowering induction, and accumulation of nutrients.