@article{HeydariFlehrStumpe2013, author = {Heydari, Esmaeil and Flehr, Roman and Stumpe, Joachim}, title = {Influence of spacer layer on enhancement of nanoplasmon-assisted random lasing}, series = {Applied physics letters}, volume = {102}, journal = {Applied physics letters}, number = {13}, publisher = {American Institute of Physics}, address = {Melville}, issn = {0003-6951}, doi = {10.1063/1.4800776}, pages = {4}, year = {2013}, abstract = {Threshold reduction and emission enhancement are reported for a gold nanoparticle-based waveguided random laser, exploiting the localized surface plasmon resonance excitation. It was experimentally found that a proper thickness of the spacer layer between the gold nanoparticles and the gain layer enhances the random laser performance. It tunes the coupling between the gain polymer and the gold nanoparticles and avoids the quenching of emission in close contact to the gold nanoparticles which is considered as one of the main sources of loss in the current laser system. (C) 2013 American Institute of Physics. [http://dx.doi.org/10.1063/1.4800776]}, language = {en} } @article{HeydariPastorizaSantosFlehretal.2013, author = {Heydari, Esmaeil and Pastoriza-Santos, Isabel and Flehr, Roman and Liz-Marzan, Luis M. and Stumpe, Joachim}, title = {Nanoplasmonic enhancement of the emission of semiconductor polymer composites}, series = {The journal of physical chemistry : C, Nanomaterials and interfaces}, volume = {117}, journal = {The journal of physical chemistry : C, Nanomaterials and interfaces}, number = {32}, publisher = {American Chemical Society}, address = {Washington}, issn = {1932-7447}, doi = {10.1021/jp404068m}, pages = {16577 -- 16583}, year = {2013}, abstract = {We report on the influence of localized surface plasmon resonance excitation of Au@SiO2 core-shell nanoparticles on the amplified spontaneous emission of a semiconductor polymer composite (F8BT/MEH-PPV). Au@SiO2 nanoparticles are compatible with the donor-acceptor polymer matrix and get uniformly distributed within the whole polymer film. The plasmon resonance band of the nanoparticles correlates with both the emission and excitation spectra of the polymer composite, as well as with the donor emission and acceptor excitation spectra. We demonstrate that resonantly excited Au@SiO2 nanoparticles enhance the amplified spontaneous emission and the modal gain of the polymer films. The measurement of influential factors reveals that the emission is enhanced predominantly by the increase of acceptor excitation rate, which is accompanied by depletion of the FRET efficiency and increase of quantum yield. The enhancement factor is increased by both introducing a higher loading of plasmonic nanoparticles in the polymer film and increasing the excitation energy. This work shows that these plasmonic nanoantennas are able to enhance the stimulated emission of semiconductor polymers by improving the size mismatch between the excitation light and the emitting polymer.}, language = {en} }