Université de Fribourg

Carbon‐assisted stable silver nanostructures

Abdollahi, S. Narjes ; Ochoa Martínez, Efraín ; Kilchoer, Cédric ; Kremer, Geoffroy ; Jaouen, Thomas ; Aebi, Philipp ; Hellmann, Tim ; Mayer, Thomas ; Gu, Yibei ; Wiesner, Ulrich B. ; Steiner, Ullrich ; Wilts, Bodo D. ; Gunkel, Ilja

In: Advanced Materials Interfaces, 2020, vol. 7, no. 23, p. 2001227

Nanostructured silver stands out among other plasmonic materials because its optical losses are the lowest of all metals. However, nanostructured silver rapidly degrades under ambient conditions, preventing its direct use in most plasmonic applications. Here, a facile and robust method for the preparation of highly stable nanostructured silver morphologies is introduced. 3D nanostructured...

Université de Fribourg

Opinion dynamics and wisdom under conformity

Buechel, Berno ; Hellmann, Tim ; Kloessner, Stefan

In: Journal of economic dynamics and control, 2015, vol. 52, p. 240-257

We study a dynamic model of opinion formation in social networks. In our model, boundedly rational agents update opinions by averaging over their neighbors’ expressed opinions, but may misrepresent their own opinion by conforming or counter-conforming with their neighbors. We show that an agent׳s social influence on the long-run group opinion is increasing in network centrality and...

Université de Fribourg

The dynamics of continuous cultural traits in social networks

Buechel, Berno ; Hellmann, Tim ; Pichler, Michael M.

In: Journal of economic theory, 2014, vol. 154, p. 274-309

We consider an overlapping generations model where continuous cultural traits are transmitted from an adult generation to the children. A weighted social network describes how children are influenced not only by their parents but also by other role models within the society. Parents can invest into the purposeful socialization of their children by strategically displaying a cultural trait...

Université de Fribourg

Under-connected and over-connected networks : the role of externalities in strategic network formation

Buechel, Berno ; Hellmann, Tim

In: Review of Economic Design, 2012, vol. 16, no. 1, p. 71–87

Since the seminal contribution of Jackson and Wolinsky (J Econ Theory 71(1):44–74, 1996) it has been widely acknowledged that the formation of social networks exhibits a general conflict between individual strategic behavior and collective outcome. What has not been studied systematically are the sources of inefficiency. We approach this omission by analyzing the role of positive and...