Berlin 2012 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 6: Poster: Structural Ordering and Electronic Transport (joint focus with HL)

CPP 6.21: Poster

Monday, March 26, 2012, 17:30–19:30, Poster A

Immobilization of quantum dots via conjugated SAMs and their application as a light-controlled sensor for the detection of hydrogen peroxide — •Waqas Khalid¹, Mira El Helou¹, Tobias Murböck¹, Zhao Yue¹, Jose-Maria Montenegro¹, Kirsten Schubert², Gero Göbel², Fred Lisdat², Gregor Witte¹, and Wolfgang Parak¹ — ¹Fachbereich Physik and WZMW, Philipps-Universität Marburg, Marburg, Germany — ²Biosystems Technology, Technical University of Applied Sciences Wildau, Germany

A light-addressable gold electrode modified with CdS and FePt or with CdS@FePt nanoparticles (NPs) via an interfacial dithiol layer is presented. High-resolution synchrotron-based XPS measurements reveal that trans-stilbenedithiol (StDT) provides high quality self-assembled monolayers compared to benzenedithiol, biphenyldithiol (capped, uncapped) and capped StDT, in case they are formed at elevated temperatures. This alternative preparation evokes a discernible enhancement of lateral dithiol packing. The CdS NPs well immobilized on the dithiol layer allow for current generation under illumination and appropriate polarization. High quality of SAMs and the enhanced conductivity of their fully conjugated backbones impair a refinement in photocurrents and device performance by an order of magnitude. Moreover, FePt NPs serve as catalytic sites for the reduction of hydrogen peroxide to water. Advantageously, both NP properties can be combined by the use of hybrid NPs fixed on the electrode by means of the optimized StDT layer. This allows a light controlled analysis of different peroxide concentrations.[1] [1] W. Khalid et al. ACS Nano, 2011 (in print).