Antonio Facchetti

CHAPTER 4:Self-Assembled Mono- and Multilayers for Functional Opto-Electronic Devices

Organic electronics pursues the fabrication of low cost, lightweight, mechanical flexible opto-electronic devices on plastic substrates eventually fabricated using roll-to-roll printing methodologies. Since opto-electronic device performance and lifetime strongly depends on the device functional interfaces, great effort has been devoted in their optimization and/or functionalization. Such functional interfaces affect charge exchange, control light confinement, enable efficient adhesion among the different layers as well as determine rheological parameters (viscosity, surface energy, wettability) for device fabrication if carried out from solution. In this chapter we describe the utilization of self-assembled monolayers (SAMs) and multilayers (SAMTs) as key elements for the realization of opto-electronic devices such as organic field-effect transistors (OFETs), organic photovoltaic cells (OPVs), organic light-emitting diodes (OLEDs), and organic nonlinear optical devices such as electro-optic (EO) modulators.

Relating microstructure to transport in organic semiconductor transistors

As organic semiconductors approach commercialization, there is a need to better understand the relationship between charge transport and microstructure, in particular to identify the inherent bottlenecks to charge transport. The highest field-effect mobility is found in semicrystalline polymers and in solubilized small molecules that crystallize readily. No consistent correlation however is found between grain size and mobility. This observation suggests the importance of the role of intergrain charge transport in semicrystalline and polycrystalline organic thin films.