Electroluminescence from Organic Materials

The electrons and holes flowing between the cathode and the anode in opposite directions may collide on route and then form an excited state, i.e. an exciton. Upon relaxation of the excited state to the ground state, light is emitted, if the excited state is a singlet. In the singlet excited state the spin states of the 

Some authors claim that in polymers, recombination occurs between free charged polarons, so that the maximum efficiency corresponds to the internal quantum efficiency, ri t the number of photons emitted for every electron injected), as given by 

It is evident from the above discussion that the threshold voltage, current density, power efficiency, luminous efficiency and, to some extent, device lifetime of OLEDs using organic low-molar-mass compounds, oligomers and polymers depends on intrinsic molecular properties, such as HOMO and LUMO energy levels, efficiency of hole and electron injection and subsequent transport, efficiency of singlet formation and fluorescence efficiency. The 

The efficiency of injection of holes and electrons into the organic material in an OLED is dependent on the nature of the cathode and anode and how closely they match their work functions with the LUMO and HOMO, respectively, of the organic material in the centre of the device. There is some degree of flexibility of device design with respect to matching these parameters by judicious choice of electrode materials and organic compounds. 

ANODE CONTACT + ITTL TFT PROTECTION PDCELS LAYER 

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The first observations of electroluminescence from organic materials were made in the 1950s [1]. Interest in this phenomenon was fueled by the work of Pope et al. [2], who observed electroluminescence from single crystals of anthracene. A voltage was applied between silver paste electrodes that were placed on the opposite sides of an anthracene... 

Electroluminescence from organic materials was first discovered using solid anthracene crystals immersed in a liquid electrolyte. " Very high voltages, e.g. 400-2000 V, were necessary in order to observe electroluminescence partly due... 

Photo luminescence and Electroluminescence from Organic Materials... 

Polarized luminescence from oriented molecular materials 1999 Ladder-type materials 1999 Electroluminescence in organics... 

A.N. Krasnov, ELDs rise on organic wings electroluminescent-display technology is being rescued from its industrial niche by implementations using organic materials, Inf. Display, 18 18-21, 2002. 

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