Ph.D Thesis

Ph.D StudentAvnon Eran
SubjectElectronic Organic Devices Made by Self Assembly Based
DepartmentDepartment of Nanoscience and Nanotechnology
Supervisor PROF. Nir Tessler
Full Thesis textFull thesis text - English Version


Electronic devices that are based on semiconducting organic materials are attractive to use in a growing number of applications. Flexible displays, solar cells and more are all examples where the possibility for solution processing, cost-effectiveness, flexibility, and tuneability of electronic and optical properties via chemical synthesis, offered by organic materials are highly desired.

In order for organic-based electronic devices to fulfill their potential, fabrications procedures that maintain the advantages of organic materials are required. Conventional fabrication procedures and especially patterning or lithography techniques employed in the microelectronic industry are not always compatible with organic materials, and moreover, do not allow the ease of processing associated with such materials.

Therefore, it is clear that in the field of organic electronics alternative fabrication and patterning techniques have to be employed. Almost two decades of intensive research have led to the development of a variety of alternative patterning techniques that are capable of micrometer and nanometer resolution. However, only in recent years some of those methods were employed in the fabrication scheme of organic devices.

The main goal of this dissertation is to demonstrate how alternative patterning technique, and especially those involving self-assembly, can be successfully employed in the fabrication of organic devices. We aimed not only to fabricate devices but also addressing unresolved issued in either the fabrication or operation of such devices.

We first demonstrate how self assembled monolayers and the photocatalytic effect of titanium dioxide can be exploited to form a micrometer-scale templates that allow self localization of an organic conducting material. These templates serve as the source and drain electrodes of an organic field effect transistor. 

Nanometer-scale patterning is demonstrated as part of the fabrication scheme of organic photovoltaic devices. In this case self-assembly of block copolymers is exploited to fabricate devices with controlled interpenetrating heterojunction.  We show that devices with this highly desired architecture can present up to two fold increase in device efficiency.   

The final chapter of this thesis addresses a different subject. We experimentally and theoretically show the existence of a long range resonant energy transfer mechanism. We present experimental evidence for resonant energy transfer in the range of 100 nm in a specific materials system, which far exceed the range predicated by known resonant energy transfer mechanisms. Such process can have important implications on the way we understand organic solar cells operation and provide new guidelines for organic solar cells architectures and optimization.