IRG 2: Organic Optoelectronic Interfaces

Charge transport along and across interfaces is central to the operation of all organic electronic and optoelectronic devices, including organic light-emitting diodes (OLEDs), field effect transistors (OFETs), and photovoltaic cells (OPVs). The efficiency of OLEDs, for example, relies on both charge transport across multiple organic/organic (O/O) heterojunctions, and confinement of excited states at interfaces. These processes are now sufficiently optimized that commercialization of OLEDs is underway. Continued expansion of organic optoelectronics in displays, solid-state lighting, flexible electronics, and solar energy conversion requires performance improvements in other key devices. The goal of the IRG is to determine structure-property relationships at organic optoelectronic interfaces, and to employ this knowledge to improve the performance of OFETs and OPVs. To achieve this goal we have assembled a team with complementary expertise spanning materials synthesis, structure characterization, spectroscopy, charge transport, computation, device fabrication and modeling. A principal theme is the use of cutting-edge spectroscopy to understand materials performance in OFETs and OPVs. These experiments are motivated by the need for advanced techniques to address the complexity of carrier dynamics and excited states relevant to these devices. The IRG also leverages its established expertise in computational chemistry to guide the synthesis of new organic semiconductors and to determine the role of crystal packing in electronic coupling. The proposed research program is unique within the organic optoelectronics community with respect to its comprehensive integration of state-of-the-art spectroscopy and computation with materials synthesis, structure characterization, and devices.

IRG 2 research areas
Structure-Transport Relationships at Organic-Insulator Interfaces
Materials and Architectures for Organic Photovoltaics

The principal investigators and their primary areas of expertise are:

• David A. Blank- ultrafast spectroscopy
• Jean-Luc Brédas - computational quantum chemistry
• Christopher Douglas - organic synthesis
• C. Daniel Frisbie- organic transistors, scanning probe microscopy
• Russell Holmes - organic optoelectronic devices, film growth
• Paul Ruden - computational modeling of devices, theory
• Xiaoyang Zhu - photoelectron spectroscopy, IR spectroscopy