Light-emitting diode , maximum emission

Organic Light-Emitting Diodes Using Low-Molar-Mass Materials (LMMMs) 167 Table 5.7 Emission maximum (nm) and colour for the metal chelates (27-31)... 

Bright ultraviolet light emitting diodes based on -ZnO// -Aloi2Gao ssN heterojunctions were formed for the first time. EL emission was obtained from these heterostructures with a maximum at 389 nm. CL spectra, obtained from the ZnO layer, consisted of an intense emission with a maximum at 387 nm. Hence, we suggest that the dominant EL emission was observed from the ZnO layer. The dominant device current was a hole injection from /j-Alo Gao ssN into the -type ZnO active region of the heterojunction. The lattice mismatch between ZnO and p-AlonGao ssN was estimated to be 2.2 %. 

Rare earth compounds are excellent chromophores that exhibit intense emission with a narrow spectral bandwidth (full width at half-maximum of 5-20 nm) and relatively long decay lifetime (10 2-10 6 s) [58]. Since the emission from rare earth ions originates from transitions between the f levels of rare earth atom that are well protected from environmental perturbations by the filled 5s2 and 5p6 orbitals, the resulting emission spectra are expected to be sharp and narrow. They are the most widely used materials in inorganic light-emitting diodes [59]. A great deal of effort has also been devoted... 

For TRFM of lanthanides light sources providing UV or near UV have been applied, either in pulsed form (xenon flash lamps) or as continuous radiation [xenon and mercury lamps, argon lasers, or light emitting diodes (LEDs)] in combination with light chopping modules. Importantly, for maximum emission the excitation... 

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