AMADEus Seminar - Pr. Samson A. Jenekhe - Friday 23 june 2017 & Tuesday 27 june 2017 - 2:00 pm ENSCBP Bât A (Amphi 2)

23.06.2017: Emerging Era of Plastic Electronics: Advances in Materials, Devices and Technologies

Organic and polymer semiconductors have emerged as the foundation for a range of new technologies including organic light-emitting diodes (OLEDs) for displays and solid-state lighting, thin film transistors for printed and flexible electronics, various sensors, and low cost solar cells. Our work is focused on the molecular engineering of materials and devices, encompassing synthesis, processing, solid state structure, properties, structure-property relationships, and device applications of both p-type and n-type semiconducting organic and polymeric materials. Several examples of our recent advances in these areas will be discussed, including: (1) highly efficient multilayered OLEDs enabled by solution-processed electron transport materials; (2) high-mobility n-type polymer semiconductors for n-channel transistors, complementary circuits, and electronic memories; and (3) n-type organic semiconductors for efficient fullerene-free polymer solar cells.

27.06.2017: Organic Photovoltaics Beyond Fullerenes

Fullerene-based electron acceptors have provided the foundation for advances in fundamental understanding of charge photogeneration and practical developments in organic photovoltaics (OPVs) in the last 25 years. The use of fullerene derivatives such as [6,6]-phenyl-C70-butyric acid methyl ester (PC70BM) in combination with advances in the synthesis of narrow band gap polymer semiconductors have led to major progress in achieving power conversion efficiencies that now approach 12%. The prospects of enabling new pathways to more efficient OPVs while overcoming the small photovoltage, high cost, poor photochemical stability, and other limitations of fullerene-based OPVs have motivated efforts to discover alternative electron acceptor materials. Our recent efforts have led to the discovery of fullerene-free electron-accepting (n-type) polymers that result in all-polymer bulk heterojunction solar cells with efficiencies comparable to fullerene-based OPVs. We have also discovered small-molecule non-fullerene electron acceptors that enable highly efficient solar cells comparable to fullerene-based OPVs. In both cases higher photovoltages and increased charge photogeneration via photoinduced hole transfer were observed compared to fullerene systems. These recent advances suggest that molecular engineering of next generation non-fullerene organic photovoltaics are poised to move the field beyond the limitations of fullerenes.