Dendrimer light-emitting diodes
Abstract
The electronics industry today is one that stands as a multi-billion dollar industry that is increasingly
incorporating more and more products that have ever escalating applications in our everyday life. One of
the main sectors of this industry, and one that is likely to continue expanding for a considerable number
of years are flat-panel displays. Traditionally, the displays market has been dominated by cathode ray
tube (CRT) and liquid crystal displays (LCDs) display types. The drawback of such display displays is
that they can be bulky, heavy and/or expensive and so there is considerable room for an alternative and superior
technology. One possibility is organic semiconductor displays where light-emitting molecules can
be dissolved in common solvents before being inkjet printed, spin-coated or even painted onto any surface
giving the benefits of simple and cost effective processing. Organic light-emitting diodes (OLEDs)
have recently become ever more evident as a major display type.
This thesis focuses on the advancement of light-emitting dendrimers towards flat-panel display applications.
The particular interest in dendrimers arises because it has been found they are capable of giving
solution-processed phosphorescent devices with high efficiency. Throughout the thesis the benefits of
the dendrimer concept are repeatedly shown revealing why this could become the ideal organic material
for display applications.
The thesis introduces various techniques of electroluminescence and photoluminescence measurements
before applying such methods to study a large number of light-emitting dendrimers in order to
explore the role of intermolecular interactions, how they are related to molecular structure, and how this
determines photophysical and charge transporting properties of the dendrimers. By such studies a number
of highly efficient solution-processed phosphorescent light-emitting dendrimers have been identified
while the efficiency of devices made from these dendrimers has been improved. This has been demonstrated
in each of the three primary display colours of red, green and blue. The work detailed thus brings
closer the prospect of dendrimer light-emitting diodes being the future flat-panel display type of choice.
Type
Thesis, PhD Doctor of Philosophy
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