[Seminar] "Unconventionally low donor content in efficient polymer solar cells and photocatalytic nanoparticles" by Prof. Mats Andersson

Date

Monday, April 1, 2024 - 13:30 to 14:30

Location

Seminar Room L5D23

Description

 
Speaker: 
Flinders Institute for Nanoscale Science and Technology, College of Science and Engineering, 
Flinders University, Adelaide, SA, Australia  
 
Abstract: 
Polymer solar cells have gained considerable interest during the last decades. Over the last years the photovoltaic performance has increased rapidly with high power conversion for lab-scale devices. Our efforts have mainly been focused on design and synthesis of new materials but also on morphology control and printing of solar cells.

The thermal stability of solar cell materials and interfaces are important prerequisites, as solar cells are often exposed to elevated temperatures during fabrication and operation. Glass transition temperature is a critical parameter that determines the kinetics of molecular reorganization of polymer semiconductors during thermal treatments. Our work includes morphology studied by dynamic mechanical thermal analysis (DMA). Compared to normal DMA measurements the materials are deposited onto a supporting substrate. The technique is a highly sensitive method for determining the Tg of materials, including sub-Tg transitions and melting points.[1]

A completely amorphous indacenodithiophene based polymer was synthesized and used in solar cells combined with the Y6 acceptor material. In contrast to conventional donor:acceptor (D:A) systems, the charge generation is mainly driven by Y6, allowing a high performance even at a low D:A mass ratio of 1:50. Low ratios are generally believed to yield lower efficiency than the more conventional 1:1.2 ratio. However, the solar cells exhibit a peak performance over 11% PCE at a D:A ratio of 1:5.[2] Unexpectedly, as the polymer proportion increases, a reduced photovoltaic performance is observed. Similarly, nanoparticles made of the materials and used for photocatalytic hydrogen evolution show an analogous trend with a peak performance at a D:A ratio of 1:6.7.

References:
[1] A. Sharma et al., Chem. Mater., 31(17), 6740 (2019).
[2] A. Dolan et al., Adv. Mater., 2309672 (2024).
 
Short-bio: 
Mats Andersson performed a joint PhD-work at the Departments of Organic Chemistry and Polymer Technology, Chalmers University of Technology, Gothenburg, Sweden, and he received his PhD degree in Organic Chemistry in 1995. He was appointed Professor in Polymer Chemistry in 2004 and he held a chair in Polymer Chemistry 2007-2015. In 2012 he was elected as a member of the Royal Swedish Academy of Engineering Sciences. In 2013 he was awarded a South Australian Chair in Energy and in 2014 Mats moved to Adelaide, Australia, to join University of South Australia as a Research Professor. In 2017 he moved to Flinders University, Adelaide, as a Matthew Flinders Professor and he is currently director of Flinders Institute for Nanoscale Science and Technology. His research interests are focused on structure – property relationships of different types of functional materials. Currently his research includes printed polymer solar cells, new antifouling coatings and single atom electrochemical catalysis. 

 

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