Low-Voltage Cathodoluminescent Phosphors

Abstract

Phosphors have been used for the display of information since the invention of the cathode-ray tube (CRT) by Karl Ferdinand Braun in 1897. With the development of color television, an effort spanning approximately 30 years, came the most significant advances in phosphor technology. The most noteworthy was the shift to the all-sulfide system, and discovery of the red, rare-earth oxysulfide phosphors.

Suppression of photocatalysis and long-lasting luminescence in ZnGa2O4by Cr3+doping

“…4 As a type of wide band gap (4.5 eV) semiconductor, ZnGa 2 O 4 phosphor has attracted enormous attentions due to its many possible applications for eld emission displays and electroluminescent devices due to its chemically and mechanically stable structure, which may be sustained under harsh environments. 5,6 ZnGa 2 O 4 phosphor has a cubic normal AB 2 O 4 spinel crystal structure with an Fd3m space group 7 in which Zn 2+ ions, surrounded by 4 oxygen atoms, occupy the tetrahedral A sites and Ga 3+ ions, surrounded by 6 oxygen atoms, occupy the octahedral B sites. With this spinel structure, ZnGa 2 O 4 can be described in terms of a close packed cubic arrangement of 32 oxygen anions.…”

Synthesis and properties of Sr2CeO4 blue emission powder phosphor for field emission displays

“…2,3 Currently some of the new phosphor candidates being developed for FEDs are green SrGa 2 S 4 :Eu 2ϩ , and blue SrGa 2 S 4 :Ce 3ϩ . 4 Unfortunately, sulfide phosphors emit and decompose sulfide gases during electron excitation, subsequently causing the cathode to deteriorate and the luminous efficiency of phosphors to decrease. 5 In order to avoid these problems, new coating techniques are being developed for sulfide phosphors, such as coating with conductive oxides.…”

Photoluminescence and cathodoluminescence properties of Na2MgGeO4:Mn2+ green phosphors

“…Under 297 nm excitation, the as-prepared Na 2 MgGeO 4 :0.03Mn 2+ phosphor shows a strong green emission band ranging from 475 nm to 550 nm centered at 521 nm, which can be ascribed to the 4 T 1 ( 4 G)-6 A 1 ( 6 S) transition of the Mn 2+ ions. 38 When monitoring the emission at 521 nm, there is a broad strong excitation band ranging from 240 nm to 350 nm with a maximum at 297 nm and several weak sharp peaks at 363 nm, 384 nm, 431 nm and 451 nm, which were attributed to the transitions from 6 A 1 ( 6 S) to 4 E( 4 D), 4 T 2 ( 4 D), [ 4 A 1 ( 4 G), 4 E( 4 G)] and 4 T 2 ( 4 G) respectively. As the d-d transitions are spin and parity forbidden, the excitation bands in the wavelength range of 350-500 nm were very weak, which correlates well with the emission spectrum (10Â magnied emission spectrum).…”

“…However FEDs have no deection coils, so they can be very thin and should work with low voltage electrons (<5 kV). 3,5,6 As we know, a low voltage will decrease the CL intensity of a phosphor, and in order to solve this problem a high current density (10-100 mA cm À2 ) can be adopted. [7][8][9] Thus, it is important to develop FED phosphors with high luminescent efficiencies and excellent conductivities under low-voltage electrons and high current densities.…”