Non-fullerene Organic N-Type Conductors with Tunable Properties for Optoelectronics

Principal Investigator: Samson Jenekhe

Electrically conductive organic compounds offer potential for flexible low-cost electronic and optoelectronic devices such as organic field effect transistors (OFETS), photovoltaics (OPV), and light-emitting diodes (OLEDs). For such devices, electron conducting (n-type) materials are required; however, most conductive organic compounds are p-type, with fullerene (C60 and C70) derived compounds being the most widely used n-type materials. These materials suffer from drawbacks such as high cost, poor yield, and poor solubility and interlayer miscibility. Thus, there is a need for low cost n-type organic compounds with tunable structures to optimize solubility/miscibility, 3D conformation, optical properties, and electron mobility.

Dr. Sam Jenekhe’s lab is a leader in the development of non-fullerene n-type organic conductors, ranging from single molecules to oligomers and polymers. These materials feature high electron mobilities (up to 0.3 cm2/V-1s-1) competitive with the incumbent fullerene-based compounds. Large pi-conjugated chromophore groups offer enhanced optical absorbance and quantum efficiency. Pendant functional groups impart solubility for solution processing of active layers, while specialized linking groups enable precise control of the 3D structure and interlayer miscibility. Bulk heterojunction OPV devices produced using these materials have reached efficiencies of 6.4%, competitive with the best non-fullerene organic solar cells. Further applications include phosphorescent OLEDS (PhOLEDS) produced by solution deposition methods, rather than costly vacuum evaporation. Blue PhOLEDs have been produced with the highest performance (brightness of 2790 cd/m2 and external quantum efficiency of 15.5%) observed to date in polymer-based blue PhOLEDs, exceeding even the performance of many vacuum-processed devices.

Applications

• Organic photovoltaics (OPV)

• Phosphorescent organic light emitting diodes (PhOLEDs) 

• Organic electronics


Advantages

• Tunable structures for optimization of solubility, miscibility, optical properties, and 3D structure 

• High electron mobilities which meet or exceed state-of-the-art fullerene layers 

• Lower cost of materials and processing over incumbents

For more info, contact: Forest Bohrer