Regensburg 2022 – scientific programme
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 12: Poster 1
CPP 12.38: Poster
Monday, September 5, 2022, 18:00–20:00, P1
In-situ white light, near infrared spectroscopy on thin films and photonic crystals of nanoporous silicon during liquid imbibition — •Guido Dittrich1,2, Raul Urteaga3, and Patrick Huber1,2 — 1Hamburg University of Technology, Institute of Materials and X-Ray Physics, 21073 Hamburg, Germany — 2Deutsches Elektronen-Synchrotron DESY, Centre for X-Ray and Nano Science CXNS, Hamburg, Germany — 3IFIS-Litoral (Universidad Nacional del Litoral-CONICET), Guemes 3450, 3000 Santa Fe, Argentina
Nanoporous materials offer a high specific surface area and spatial confinement. Scientists are aiming to abuse these properties for functional materials in a variety of fields, e.g. thermoelectrics, catalysis, Lab-on-a-Chip as well as energy storage and harvesting applications. Understanding the fundamental transport mechanisms on the nanoscale is required and drives the progress. We present a method to measure liquid imbibition in nanoporous silicon (np-Si) with a resolution even resolving spreading of ultra-thin precursor films in nanopore space with a time resolution of microseconds. Therefore, a photonic crystal (PC) is etched in at a chosen height during the fabrication. The PC has a specific resonance wavelength, which can be monitored with white light spectroscopy. Imbibition by fluids, in our case oligostyrenes, into the central defect of the PC changes the effective refractive index and causes a proportional shift of the resonance wavelength. This offers very localized information on the nanopore filling at the position of the PC. Producing only thin np-Si films, one can measure the shift of the thin film interference with a NIR-spectrometer simultaneously.