Afternoon Keynote Lecture
1:40 – 2:35 p.m
"Alternative Transparent Electrode Technologies for Organic Photovoltaics"
As the performance of organic photovoltaics continues to improve and pilot production gains momentum, technological challenges beyond the PCE records continue to gain attention. Looking at the total costs or the percentage of embedded energy of a hypothetical OPV product, the transparent electrode and the encapsulation take up a large share.
In the last years, we have studied a number of materials and technologies for transparent electrodes which will be presented here. The performance, growth and stability of thin metal films (Rs=27.3 Ω /sq. and T= 84.3% at 580 nm including the substrate) were investigated; metal nanowire percolation type electrodes of silver (10.5 Ω /sq. and T= 84.8% at 550 nm) and copper nanowires (14.2 Ω /sq. and T= 79.1% at 550 nm) have been manufactured and integrated into efficient organic PV cells. In addition, cells with highly conductive PEDOT:PSS, Carbon nanotubes and doped small molecules (n-C60) have been studied.
To study encapsulation, we have established the electrical calcium test method to study barrier and encapsulation technologies. We have investigated thin-film barriers deposited by ALD, sputtering and the barrier performance of standard, opaque Al back-electrodes. Using the latter ones in combination with simple pin cells, we have determined a T50-dose (required to reach 50% of the initial efficiency) of around 20 mg/m² and acceleration factors for different climate conditions.
Dr.-Ing. Lars Müller-Meskamp is heading a research group for alternative transparent electrodes and encapsulation for organic optoelectronic devices at IAPP, TU Dresden (Prof. Dr. K. Leo). Before joining the IAPP, he worked at Qimonda Dresden in the development of flash memory technology. During his Ph.D. he worked on the characterization of charge transfer of individual molecules and self-assembled monolayers at the FZ-Juelich (Prof. Dr. R. Waser). He graduated from the RWTH Aachen, Germany, where he received his diploma and Ph.D. after studying electrical engineering and information technology.