Spectral emission modification using localized surface plasmon of metallic nanoparticles

Abstract

A method for engineering a line shape of emission spectrum of an organic emissive material in an electroluminescent device is disclosed in which a layer of plasmonic metallic nanostructures having a localized surface plasmonic resonance (LSPR) is provided in proximity to the emissive layer and the layer of plasmonic metallic nanostructures is greater than 2 nm but less than 100 nm from the emissive layer and the LSPR of the plasmonic metallic nanostructures matches the emission wavelength of the organic emissive material. An electroluminescent device incorporating the plasmonic metallic nanostructures is also disclosed.

1 . A method for engineering a line shape of emission spectrum of an organic emissive material in an electroluminescent device, wherein the electroluminescent device comprises an anode layer, a cathode layer, and an emissive layer disposed in between the anode and the cathode layers, wherein an organic emissive material is provided in the emissive layer, the method comprising:
 providing a layer of plasmonic metallic nanostructures having a localized surface plasmonic resonance (LSPR), wherein the layer of plasmonic metallic nanostructures is greater than 2 nm from but less than 100 nm from the emissive layer and the LSPR of the layer of plasmonic metallic nanostructures is within ±10 nm of the peak emission wavelength of the organic emissive material.   
     
     
         2 . The method of  claim 1 , wherein the LSPR of the layer of plasmonic metallic nanostructures is within ±5 nm of the peak emission wavelength of the organic emissive material 
     
     
         3 . An electroluminescent device, comprising:
 an anode layer;   a cathode layer: and   a stack of layers disposed between the anode layer and the cathode layer, said stack of layers including:
 an emissive layer comprising an organic emissive material, the organic emissive material having an emission wavelength; and 
 a first layer of plasmonic metal nanostructures having a localized surface plasmonic resonance (LSPR), wherein the layer of plasmonic metal nanostructures is at a distance greater than 2 nm from but less than 100 nm from the emissive layer and the LSPR of the layer of plasmonic metal nanostructures is tuned to be within ±10 nm of the peak emission wavelength of the organic emissive material. 
   
     
     
         4 . The device of  claim 3 , wherein the LSPR of the layer of plasmonic metal nanostructures is tuned to be within ±5 nm of the peak emission wavelength of the organic emissive material. 
     
     
         5 . The device of  claim 3 , wherein the stack of layers comprising a hole transporting layer (HTL) disposed between the emissive layer and the anode layer, and
 wherein the first layer of plasmonic metal nanostructures is disposed between the HTL and the anode layer.   
     
     
         6 . The device of  claim 5 , wherein the first layer of plasmonic metal nanostructures has a thickness and the thickness is selected to result in the LSPR of the first layer of plasmonic metal nanostructures be within ±10 nm of the peak emission wavelength of the organic emissive material. 
     
     
         7 . The device of  claim 6 , wherein the LSPR of the first layer of plasmonic metal nanostructures is within ±5 nm of the peak emission wavelength of the organic emissive material. 
     
     
         8 . The device of  claim 5 , wherein the first layer of plasmonic metal nanostructures has a thickness and comprises a plurality of plasmonic metal nanostructures having a particle size wherein the particle size is selected to result in the LSPR of the first layer of plasmonic metal nanostructures is within ±10 nm of the peak emission wavelength of the organic emissive material. 
     
     
         9 . The device of  claim 8 , wherein the LSPR of the first layer of plasmonic metal nanostructures is within ±5 nm of the peak emission wavelength of the organic emissive material. 
     
     
         10 . The device of  claim 3 , wherein the stack of layers comprising an electron transporting layer (ETL) disposed between the emissive layer and the cathode layer,
 wherein the first layer of plasmonic metal nanostructures is disposed between the ETL and the cathode layer.   
     
     
         11 . The device of  claim 10 , wherein the first layer of plasmonic metal nanostructures has a thickness and the thickness is selected to result in the LSPR of the first layer of plasmonic metal nanostructures being within ±10 nm of the peak emission wavelength of the organic emissive material. 
     
     
         12 . The device of  claim 11 , wherein the LSPR of the first layer of plasmonic metal nanostructures is within ±5 nm of the peak emission wavelength of the organic emissive material. 
     
     
         13 . The device of  claim 10 , wherein the first layer of plasmonic metal nanostructuress has a thickness and comprises a plurality of plasmonic metal nanostructures having a particle size, wherein the particle size is selected to result in the LSPR of the first layer of plasmonic metal nanostructures being within ±10 nm of the peak emission wavelength of the organic emissive material. 
     
     
         14 . The device of  claim 13 , wherein the LSPR of the first layer of plasmonic metal nanostructures is within ±5 nm of the peak emission wavelength of the organic emissive material. 
     
     
         15 . The device of  claim 10 , wherein the stack of layers further comprising a hole transport layer (HTL) disposed between the emissive layer and the anode layer, and wherein a second layer of plasmonic metal nanostructures is disposed between the HTL and the anode layer. 
     
     
         16 . The device of  claim 15 , wherein each of the first and second layers of plasmonic metal nanostructures has a thickness and the thickness of each of the first and second layers of plasmonic metal nanostructures is selected to result in the LSPR of the first and second layers of plasmonic metal nanostructures being within ±10 nm of the peak emission wavelength of the organic emissive material. 
     
     
         17 . The device of  claim 16 , wherein the LSPR of the first and layers of plasmonic metal nanostructures is within ±5 nm of the peak emission wavelength of the organic emissive material. 
     
     
         18 . The device of  claim 15 , wherein each of the first and second layers of plasmonic metal nanostructures has a thickness and comprises a plurality of plasmonic metal nanostructures having a particle size, wherein the particle size of the plurality of plasmonic metal nanostructures is selected to result in the LSPR of the first and second layers of plasmonic metal nanostructures being within ±10 nm of the peak emission wavelength of the organic emissive material. 
     
     
         19 . The device of  claim 18 , wherein the LSPR of the first and second layers of plasmonic metal nanostructures is within ±5 nm of the peak emission wavelength of the organic emissive material. 
     
     
         20 . The device of  claim 3 , wherein the first layer of plasmonic metal nanostructures is a patterned plasmonic metal film, wherein the patterned plasmonic metal film has a feature size selected to result in the LSPR of the patterned plasmonic metal film be within ±10 nm of the peak emission wavelength of the organic emissive material. 
     
     
         21 . The device of  claim 20 , wherein the LSPR of the patterned plasmonic metal film is within ±5 nm of the peak emission wavelength of the organic emissive material. 
     
     
         22 . An electroluminescent device, comprising:
 an anode layer;   a cathode layer: and   a stack of layers disposed between the anode layer and the cathode layer, said stack of layers including:
 an emissive layer comprising an organic emissive material, the organic emissive material having an emission wavelength; 
 a hole transporting layer disposed between the emissive layer and the anode layer; and 
 an electron transporting layer disposed between the emissive layer and the cathode; 
   wherein (1) or (2) is true:
 (1) the anode layer or the cathode layer is a layer of plasmonic metal nanostructures having a localized surface plasmonic resonance (LSPR), or 
 (2) a layer of plasmonic metal nanostructures having a LSPR that is disposed either between the hole transporting layer and the anode layer or between the electron transporting layer and the cathode layer, 
   wherein the layer of plasmonic metal nanostrcutures is at a distance greater than 2 nm from but less than 100 nm from the emissive layer and the LSPR of the layer of plasmonic metal nanostructures is tuned to be within ±10 nm of the peak emission wavelength of the organic emissive material.   
     
     
         23 . The device of  claim 22 , wherein the LSPR of the layer of plasmonic metal nanostructures is within ±5 nm of the peak emission wavelength of the organic emissive material. 
     
     
         24 . The device of  claim 22 , wherein the layer of plasmonic metal nanostructures has a thickness and the thickness of the layer of plasmonic metal nanostructures is selected to result in the LSPR of the layer of plasmonic metal nanostructures is within ±10 nm of the peak emission wavelength of the organic emissive material. 
     
     
         25 . The device of  claim 24 , wherein the LSPR of the layer of plasmonic metal nanostructures is within ±5 nm of the peak emission wavelength of the organic emissive material. 
     
     
         26 . The device of  claim 22 , wherein the layer of plasmonic metal nanostructures has a thickness and comprises a plurality of plasmonic metal nanostructures having a particle size wherein the particle size is selected to result in the LSPR of the layer of plasmonic metal nanostructures be within ±10 nm of the peak emission wavelength of the organic emissive material. 
     
     
         27 . The device of  claim 26 , wherein the LSPR of the layer of plasmonic metal nanostructures is within ±5 nm of the peak emission wavelength of the organic emissive material. 
     
     
         28 . The device of  claim 22 , wherein the layer of plasmonic metal nanostructures is a patterned plasmonic metal film, wherein the patterned plasmonic metal film has a feature size selected to result in the LSPR of the patterned plasmonic metal film be within ±10 nm of the peak emission wavelength of the organic emissive material. 
     
     
         29 . The device of  claim 28 , wherein the LSPR of the patterned plasmonic metal film is within ±5 nm of the peak emission wavelength of the organic emissive material.