Purity conjugated polymers

Despite the scientific progress and the demonstration of novel device concepts, there was considerable skepticism that semiconducting polymers would ever reach the levels of purity required for long-lifetime commercial devices. In the context of the last 50 years of semiconductor physics, conjugated polymers were often... 

There have been numerous studies of the electrical and emission properties of conjugated polymer-, small molecule-, and molecularly doped polymer-based OLEDs. The current-voltage and radiance-voltage characteristics have been nica sured as a function of thickness of the organic layer, temperature, different metal electrodes, etc. in an attempt to understand the device physics. A major factor in hibiting progress is the purity of the organic impurities that are incorporated dur-... 

In general. Figure 9-2 b to c show strategies to make conjugated polymers more proeessible but it must be noted that the different synthetic approaches do not only result in different degrees of (a) chemical purity but also alter (b) the physical properties due lo intrinsic differences. Compared to a pure conjugated... 

As the archetypical blue emitting polymer, polyfluorene has been studied extensively using a wealth of optical techniques to elucidate its photophysical properties. Moreover, as it is a simple homopolymer that can be synthesized to very high purity, it offers a unique platform to help us understand many aspects of the excited state behavior of conjugated polymers in general. Here we address the main properties associated with excited state, i.e. exciton, behavior and the many possible interactions between excitons that can occur, although this is by no means an exhaustive review. 

Studies on conjugated polymers have recently shifted to the undoped state, predominantly as the undoped state has shown to have very interesting luminescence [27] as well as photovoltaic [28] properties. In the undoped state the number of charge carriers is small and the interest from the point of view of transport is more focussed on the mobility of charge carriers. Similar to the situation in molecular crystals, the transport properties of conjugated polymers are also strongly dependent on structural order and the purity of the samples. 

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