TY - JOUR A1 - Heydari, Esmaeil A1 - Pastoriza-Santos, Isabel A1 - Liz-Marzan, Luis M. A1 - Stumpe, Joachim T1 - Nanoplasmonically-engineered random lasing in organic semiconductor thin films JF - Nanoscale horizons N2 - We demonstrate plasmonically nano-engineered coherent random lasing and stimulated emission enhancement in a hybrid gainmedium of organic semiconductors doped with core-shell plasmonic nanoparticles. The gain medium is composed of a 300 +/- 2 nm thin waveguide of an organic semiconductor, doped with 53 nm gold nanoparticle cores, isolated within silica shells. Upon loading the nanoparticles, the threshold of amplified spontaneous emission is reduced from 1.75 mu J cm(-2) x 10(2) for an undoped gain medium, to 0.35 mu J cm(-2) x 10(2) for a highly concentrated gain medium, and lasing spikes narrower than 0.1 nm are obtained. Most importantly, selection of silica shells with thicknesses of 10, 17 and 21 nm enables engineering of the plasmon-exciton energy coupling and consequently tuning of the laser slope efficiency. With this approach, the slope efficiency is increased by two times by decreasing the silica shell from 21 nm down to 10 nm, due to the enhancement of the localized electric field. Y1 - 2017 U6 - https://doi.org/10.1039/c7nh00054e SN - 2055-6756 SN - 2055-6764 VL - 2 SP - 261 EP - 266 PB - Royal Society of Chemistry CY - Cambridge ER - TY - JOUR A1 - Heydari, Esmaeil A1 - Pastoriza-Santos, Isabel A1 - Flehr, Roman A1 - Liz-Marzan, Luis M. A1 - Stumpe, Joachim T1 - Nanoplasmonic enhancement of the emission of semiconductor polymer composites JF - The journal of physical chemistry : C, Nanomaterials and interfaces N2 - 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. Y1 - 2013 U6 - https://doi.org/10.1021/jp404068m SN - 1932-7447 VL - 117 IS - 32 SP - 16577 EP - 16583 PB - American Chemical Society CY - Washington ER - TY - JOUR A1 - Heydari, Esmaeil A1 - Flehr, Roman A1 - Stumpe, Joachim T1 - Influence of spacer layer on enhancement of nanoplasmon-assisted random lasing JF - Applied physics letters N2 - 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] Y1 - 2013 U6 - https://doi.org/10.1063/1.4800776 SN - 0003-6951 VL - 102 IS - 13 PB - American Institute of Physics CY - Melville ER - TY - JOUR A1 - Heydari, Esmaeil A1 - Buller, Jens A1 - Wischerhoff, Erik A1 - Laschewsky, André A1 - Döring, Sebastian A1 - Stumpe, Joachim T1 - Label-Free biosensor based on an all-polymer DFB laser JF - Advanced optical materials KW - label-free biosensors KW - DFB lasers KW - active optical resonators KW - hydrogels KW - semiconducting polymers Y1 - 2014 U6 - https://doi.org/10.1002/adom.201300454 SN - 2195-1071 VL - 2 IS - 2 SP - 137 EP - 141 PB - Wiley-VCH CY - Weinheim ER -