Research Overview

The goal of our research group centers on understanding the materials science necessary to make viable optoelectronic devices from organic materials. These include, for example, light-emitting diodes, thin-film transistors, photodetectors, Xerographic photoreceptors, biological sensors and electrooptic modulators. The promise of organic materials is that they are amenable to processing and device fabrication schemes which can make them significantly less expensive than conventional alternatives. The first research mission involves study of the fundamental photophysics and charge transport properties of several classes of organic materials including conjugated polymers and oligomers, molecularly doped polymers and molecular crystals. Specifically, measurements of transient excited state spectroscopy, photoconductivity and photoluminescence are of import to determine the fundamental performance limits for organic electronics. The second line of research is the fabrication and characterization of organic devices. The purpose of these studies, in conjunction with the fundamental studies, is to understand the mechanism by which these devices work and to ascertain the practical limits on them. These are deduced from electrical and spectroscopic measurements on functioning devices. The final area of experimentation is aimed at developing new ways to make these devices and systems based upon them which take advantage of the processibility of organics. This involves research into the workings of various patterning and layering schemes such as "self-assembly" to create useful supramolecular structures. The ultimate vision motivating this avenue of investigation would be to make circuitry or displays on plastic using simple process technology which could bypass the need for expensive lithography and vacuum deposition.

Research Interests

• Polymer electronics
• Optoelectronic devices
• Light-emitting diodes
• Thin-film transistors
• Photodetectors
• Xerographic photoreceptors
• Biological sensors
• Electrooptic modulators

Selected Publications

• Xu, L.S.; Tang, C.W.; Rothberg, L.J., "High Efficiency Phosphorescent White Organic Light-Emitting Diodes with an Ultra-Thin Red and Green Co-Doped Layer and Dual Blue Emitting Layers," Organic Electronics, 2016, 32, 54-58.
• Chakrsborty, R.: Rothberg, L,J,. "Role of Aggregates in the Luminescence Decay Dynamics of Conjugated Polymers," Journal of Physical Chemistry A, 2016, 120, 4-511-555.
• Chang, C.S.; Rothberg, L.J., "Plasmon-Enhanced Photoconductivity in Amorphous Silicon Thin Films by Use of Thermally Stable Silica-Coate Gold Nanorods," Chemistry of Materials, 2015, 27, 9-3211-3215.
• Winans, J.D.; Hungerford, C.; Shome, K.; Rothberg, L.J.; Fauchet, P.M., "Plamonic Effects in Ultrathin Amorphous Silicon Solar Cells,: Performance Improvements with Ag Nanoparticles on the Front, the Back and Both," Optics Express, 2015, 23, 3-A92-A105.
• Klubek, K.P.; Dong, S.C.; Liao, L.S.; Tang, C.W.; Rothberg, L.J., "Investigation Blue Phosphorescent Iridium Cyclometalated Dopant with Phenyl-Imidazold Ligands," Organic Electronics,2014, 15, 11-3127-3136.