Regensburg 2019 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 12: HL Poster I
HL 12.37: Poster
Monday, April 1, 2019, 17:30–20:00, Poster E
Rydberg-like states in organic semiconductor rods — •Aswin Asaithambi1, Daichi Okada2, Guenther Prinz1, Yohei Yamamoto2, and Axel Lorke1 — 1Lotharstrasse 1, Faculty of Physics, CENIDE, University of Duisburg-Essen, 47057 Duisburg, Germany — 2Division of Material Science, Faculty of Pure and Applied Sciences, University of Tsukuba, Tsukuba, Japan
The Organic semiconductor Borondipyrromethene (BODIPY) drawn much attention in recent years due to their advantageous photo-physical properties. BODIPY molecules, under certain conditions, can be grown into crystalline rods [1]. Different growth methods result in BODIPY rods with different photo-emission wavelengths, for example green, orange or red [1].
In this contribution we show photo-luminescence (PL) spectra of green rods under 405nm laser excitation. The PL spectrum shows, besides a broad luminescence band, a set of peaks with energies that follows E(n)=Eg-E0/n2. Eg is the band gap and E0 is the effective Rydberg constant that varies between different rods. Interestingly, PL line scans reveal that E0 is constant within a single green rod and even in a serendipitously grown striped rods containing both red and green emitting regions.A slight decrease in the line width without a change in peak position was observed when lowering the temperature to 83K. The findings will be discussed using different models such as Rydberg excitons or charge complexes in the crystal.
A. Asaithambi et al., JPC C DOI: 10.1021/acs.jpcc.8b09202