Dresden 2014 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 29: Poster: Organic semiconductors and hybrid organic-inorganic heterostructures / Organic photovoltaics
HL 29.5: Poster
Monday, March 31, 2014, 17:00–20:00, P2
External Quantum Efficiency of novel PTCDA derivatives — •Robin Döring, Nils Rosemann, Eduard Baal, Jörg Sundermeyer, and Sangam Chatterjee — Philipps-Universität Marburg, Marburg, Germany
3,4,9,10 perylene tetracarboxylic dianhydride (PTCDA) is a well-studied and widely commercially available dye and n-channel organic semiconductor. A major disadvantage of PTCDA is its low solubility in organic solvents. We studied the optical properties of novel PTCDA derivatives featuring high solubility in organic solvents such as CH2Cl2 and C7H8. A “flourophore-spacer-receptor” configuration based photoinduced electron transfer (PET) is assumed. If the PET between the receptor (amine group) and fluorophore (perylene core) within the molecule is suppressed, the PL intensity is expected to increase significantly. Hence, protonation of the amine functional group should disallow PET. This, in turn, makes applications like non-contact sensing of pH possible. The experimental setup features an integrating sphere which allows measurements of the absolute photoluminescence. These measurements then yield the external quantum efficiency η of the samples. In combination with time resolved photoluminescence measurements this enables us to determine the true radiative (τr) and non-radiative (τnr) decay times of the excited states. Our results confirm a strong dependency of the quantum efficiency on the fact whether or not PET is enabled.