Rare earth phosphors in semiconducting light emitting diodes

Rare earth phosphors in semiconducting light emitting diodes 

The major drawback of the system YAG Ce is the decrease in overall efficiency upon lowering the colour temperature. 

Some of the conditions to be satisfied by phosphor material are (i) the phosphor should absorb at the emission wavelength of the diode, (ii) the quantum yield should be high and (iii) the full width at half maximum of the emission band should be small to achieve high luminous output. Some of the promising phosphor systems containing Eu3+ and Tb3+ 

The role of rare earths in electroluminescent and field emission display phosphors has been of much interest and activity [134]. Flat panel displays unite all non-cathode ray tube (CRT) direct view displays. 

The structure of an AC-TEFL device is shown in Fig. 12.23. AC-TFEL devices  

---