Solution-processed Fabrication and Characterization of Light-Emitting Electrochemical Cells with Silver Nanowirde Electrodes

Conclusion and Outlook: The focus of this thesis was to investigate LEC architectures that can be fabricated by solution processing. In particular, the aim wa to replace the ITO electrode with silver nanowires.

It was shown that AZO and additional buffer layers as ETLs couldn't be successful to inject electrons into the organic semiconductor and therefore the inefficient injection cannot provide electrons and holes for radiative recombination and the light output from the device is low.

In the normal structure of LECs, we applied a new structure design which didn't utilize any ETLs. Equally interesting are the results of the performance optimization of the different HTL and active layer thicknesses and it was demonstrated how to utilize thick active material layers.

In the last step, both ITO and the evaporated silver top electrode were successfully replaced with silver nanowire as anode and cathode, respectively.

In conclusion, this thesis has demonstrated LEC fabrication and operation under ambient conditions, and fully solution-processed devices that feature silver nanowire electrodes.

Successful implementation of solution processing methods could allow LECs to become an ultra-low-cost lighting alternative for various large area fabrications, using roll to roll coating and slot die casting.

 

The gap between LECs and currently available lighting technology has become smaller indicating the potentials of LECs in future’s technology. Nevertheless, further development could primarily address the limited lifetime of LECs by increasing ionic conductivity of active layer ink, and also improve efficiency using solution processed reflector bottom electrode like silver ink in order to increase the light emission.