Electroluminescent device with modified thin film luminescent zone

An organic electroluminescent device comprising in sequence, an anode, an organic luminescent medium, and a cathode,

• characterized in that
• said organic luminescent medium is less than 5000 Angstroms in thickness and is comprised of
• an electron injecting and transporting layer containing
• an organic host material capable of sustaining both hole and electron injection and
• located in said layer as a fluorescent material a dye chosen to provide favored sites for light emission having a bandgap no greater than that of said host material and a reduction potential less negative than that of said host material.

An organic electroluminescent device comprising in sequence

• an anode formed of one or more metals having a work function of greater than 4 eV,
• a cathode formed of a combination of metals, with one or more metals other than alkali metals having a work function of less than 4 eV accounting for greater than 50 percent on an atomic basis of the total cathode metals, and, interposed between said anode and cathode,
• an organic luminescent medium consisting of an organic hole injecting zone and a luminescent zone, said organic luminescent medium being less than 5000 Angstroms in thickness and comprised of
• an electron injecting and transporting layer containing
• an organic host material capable of sustaining both hole and electron injection and
• located in said layer as an optically coupled fluorescent material chosen to provide favored sites for light emission a dye having a bandgap no greater than that of said host material and a reduction potential less negative than that of said host material and
• a hole injecting and transporting zone comprised of
• a tetraphenyldiamine layer contacting said electron injecting and transporting zone,
• a hole injecting porphyrinic compound containing layer contacting said anode, and
• a triphenylamine layer interposed between said tetraphenyldiamine layer and porphyrinic compound.

An organic electroluminescent device comprising in sequence

• an anode,
• a cathode containing magnesium and a minor amount of another metal chosen from the class consisting of aluminum, copper, silver, gold, tin, lead, bismuth, tellurium, indium, and antimony,
• at least one of said anode and said cathode being light transmissive, and, interposed between said anode and said cathode,
• an organic luminescent medium consisting of an organic hole injecting zone and a luminescent zone, said organic luminescent medium being less than 5000 Angstroms in thickness and comprised of
• a hole injecting layer containing a phthalocyanine in contact with said anode,
• a first hole transporting layer containing a bis-triphenylamine,
• a second hole transporting layer containing a tetraphenyldiamine, and
• a luminescent zone containing a metal chelated 8-hydroxyquinoline host material and a fluorescent dye capable of absorbing light at the emission wavelength of said metal chelated 8-hydroxyquinoline, having a lower bandgap and a less negative reduction potential than said chelated 8-hydroxyquinoline.