Publications

@article{,
title = {Directing Single-Molecule Emission with DNA Origami-Assembled Optical Antennas},
author = {K H\"{u}bner and M Pilo-Pais and F Selbach and T Liedl and P Tinnefeld and F D Stefani and G P Acuna},
url = {https://doi.org/10.1021/acs.nanolett.9b02886},
doi = {10.1021/acs.nanolett.9b02886},
issn = {1530-6984},
year = {2019},
date = {2019-09-11},
journal = {Nano Letters},
volume = {19},
number = {9},
pages = {6629-6634},
abstract = {Abstract Conventional surface enhanced Raman scattering (SERS) substrates are well known for their supreme electromagnetic enhancements and ultrahigh sensitivity in detecting molecules at low concentrations. However, large-area quasi-uniform SERS substrates are difficult to achieve by standard top-down nanofabrication techniques, resulting in fluctuant SERS responses and unwanted fluorescence interferences, which severely limit their performances in practical applications. To tackle these challenges, a large-scale quasi-uniform hybrid graphene fragmented-gold substrate with stable and reproducible SERS readouts as well as large enhancement factors over an ultrawideband spectrum is developed. The hybrid substrate is fabricated via cold-etching through a controllable break up of a thin gold film followed by a graphene transfer. The stimulated localized surface plasmons interact strongly with the graphene layer, leading to spectrally and spatially modified graphene-mediated surface enhanced Raman scattering (GSERS) responses. The perfect monolayer graphene of the GSERS substrate prevents adsorbates from the atmosphere and direct contact between bonded molecules and gold, thus reducing the catalytic activity of gold and producing clean, stable, and reproducible molecular Raman signals. The easy-fabricated hybrid GSERS substrate not only provides a powerful platform to collect robust molecular Raman spectra but also shows great potentials for future mass production of high-performance nanophotonic devices.},
keywords = {Molecularly-Functionalized},
pubstate = {published},
tppubtype = {article}
}

@article{,
title = {From Optical to Chemical Hot Spots in Plasmonics},
author = {J Gargiulo and R Bert\'{e} and Y Li and S A Maier and E Cort\'{e}s},
url = {https://doi.org/10.1021/acs.accounts.9b00234},
doi = {10.1021/acs.accounts.9b00234},
issn = {0001-4842},
year = {2019},
date = {2019-08-20},
journal = {Accounts of Chemical Research},
keywords = {Molecularly-Functionalized},
pubstate = {published},
tppubtype = {article}
}

@article{,
title = {Distance Dependence of Single-Molecule Energy Transfer to Graphene Measured with DNA Origami Nanopositioners},
author = {I Kaminska and J Bohlen and S Rocchetti and F Selbach and G P Acuna and P Tinnefeld},
url = {https://doi.org/10.1021/acs.nanolett.9b00172},
doi = {10.1021/acs.nanolett.9b00172},
issn = {1530-6984},
year = {2019},
date = {2019-07-10},
journal = {Nano Letters},
volume = {19},
number = {7},
pages = {4257-4262},
abstract = {Despite the thorough investigation of graphene since 2004, altering its surface chemistry and reproducible functionalization remain challenging. This hinders fabrication of more complex hybrid materials with controlled architectures, and as a consequence the development of sensitive and reliable sensors and biological assays. In this contribution, we introduce DNA origami structures as nanopositioners for placing single dye molecules at controlled distances from graphene. The measurements of fluorescence intensity and lifetime of single emitters carried out for distances ranging from 3 to 58 nm confirmed the d\textendash4 dependence of the excitation energy transfer to graphene. Moreover, we determined the characteristic distance for 50% efficiency of the energy transfer from single dyes to graphene to be 17.7 nm. Using pyrene molecules as a glue to immobilize DNA origami nanostructures of various shape on graphene opens new possibilities to develop graphene-based biophysics and biosensing.},
keywords = {Molecularly-Functionalized},
pubstate = {published},
tppubtype = {article}
}

@article{,
title = {Interchromophoric Interactions Determine the Maximum Brightness Density in DNA Origami Structures},
author = {T Schr\"{o}der and M B Scheible and F Steiner and J Vogelsang and P Tinnefeld},
url = {https://doi.org/10.1021/acs.nanolett.8b04845},
doi = {10.1021/acs.nanolett.8b04845},
issn = {1530-6984},
year = {2019},
date = {2019-02-13},
journal = {Nano Letters},
volume = {19},
number = {2},
pages = {1275-1281},
abstract = {An ideal point light source is as small and as bright as possible. For fluorescent point light sources, homogeneity of the light sources is important as well as that the fluorescent units inside the light source maintain their photophysical properties, which is compromised by dye aggregation. Here we propose DNA origami as a rigid scaffold to arrange dye molecules in a dense pixel array with high control of stoichiometry and dye\textendashdye interactions. In order to find the highest labeling density in a DNA origami structure without influencing dye photophysics, we alter the distance of two ATTO647N dyes in single base pair steps and probe the dye\textendashdye interactions on the single-molecule level. For small distances strong quenching in terms of intensity and fluorescence lifetime is observed. With increasing distance, we observe reduced quenching and molecular dynamics. However, energy transfer processes in the weak coupling regime still have a significant impact and can lead to quenching by singlet-dark-state-annihilation. Our study fills a gap of studying the interactions of dyes relevant for superresolution microscopy with dense labeling and for single-molecule biophysics. Incorporating these findings in a 3D DNA origami object will pave the way to bright and homogeneous DNA origami nanobeads.},
keywords = {Molecularly-Functionalized},
pubstate = {published},
tppubtype = {article}
}

@article{,
title = {Cobalt-Catalyzed Electrophilic Aminations with Anthranils: An Expedient Route to Condensed Quinolines},
author = {J Li and E Tan and N Keller and Y-H Chen and P M Zehetmaier and A C Jakowetz and T Bein and P Knochel},
url = {https://doi.org/10.1021/jacs.8b11466},
doi = {10.1021/jacs.8b11466},
issn = {0002-7863},
year = {2019},
date = {2019-01-09},
journal = {Journal of the American Chemical Society},
volume = {141},
number = {1},
pages = {98-103},
abstract = {The reaction of various organozinc pivalates with anthranils provides anilines derivatives, which cyclize under acidic conditions providing condensed quinolines. Using alkenylzinc pivalates, electron-rich arylzinc pivalates or heterocyclic zinc pivalates produces directly the condensed quinolines of which several structures belong to new heterocyclic scaffolds. These N-heterocycles are of particular interest for organic light emitting diodes with their high photoluminescence quantum yields and long exciton lifetimes as well as for hole-transporting materials in methylammonium lead iodide perovskites solar cells due to an optimal band alignment for holes and a large bandgap.},
keywords = {Molecularly-Functionalized},
pubstate = {published},
tppubtype = {article}
}