Suchergebnisse

This paper summarizes the most important results of the PhD Thesis presented by M. M-V. and directed by M.A. Díaz-García. Thin film organic lasers have demonstrated its applicability at laboratory scale, spectroscopy, optical communications, chemical sensing or biosensing. To bring optically-pumped solution processed thin film organic lasers to the real market the active material must be: able to emit at low pump excitation (low threshold), photostable to ensure a long operational lifetime; capable of emitting at various wavelengths or colours, processable by low-cost solution-based methods and mechanically flexible. We show all these properties amalgamated in a novel organic active materials: carbon-bridged oligo(p-phenylenevinylene)s (COPVn) dispersed in thermoplastic polymer films and a COPV-polymer prepared as a neat film. Novel devices by using different architectures have been optimized and studied. The high performance achieved with these laser devices has been demonstrated by pumping them with an inexpensive laser diode. The sensing applicability of thin film organic lasers has been also demonstrated by preparing and characterizing bulk refractive index sensors and biosensors. ; Este documento resume los resultados más importantes de la tesis doctoral presentada por M. M-V. y dirigida por M.A. Díaz-García. Los láseres orgánicos de película delgada se aplican a escala de laboratorio, espectroscopía, comunicaciones ópticas, detección química o biodetección. Para conseguir llevar este tipo de láseres de manera eficiente al mercado, el material activo ha de cumplir las siguientes características: capacidad de emitir al ser bombeando a baja energía, alta fotoestabilidad para garantizar una larga vida útil; capacidad de emitir a diferentes longitudes de onda o colores, procesabilidad por métodos de bajo coste y que el dispositivo sea mecánicamente flexible. Todas estas propiedades están presentes en un novedoso material orgánico activo basado en oligómeros con puente de carbono (COPVn) disperso en películas de polímero termoplástico. Se han optimizado y estudiado nuevos dispositivos mediante el uso de diferentes geometrías y resonadores, observando un alto rendimiento y logrando bombearlos con un simple diodo láser. Algunas aplicaciones de detección con estos dispositivos han sido demostradas: sensores de índice de refracción y biosensores. ; The PhD thesis described in this paper, has been supported by the Spanish Government, through projects: MAT2008-06648-C02-01 and MAT-2011-28167-C02-01, and FPI grant (BES-2009-020747). MMV also acknowledges support from the European Community (FEDER) and Junta de Castilla y León (JCYL) through Postdoctoral Fellowship (no. SA046U16), as well as, under a Postdoctoral project CDEIGENT/2018/024 (Generalitat Valenciana, Spain).

Solution-processed polymer films are used in multiple technological applications. The presence of residual solvent in the film, as a consequence of the preparation method, affects the material properties, so films are typically subjected to post-deposition thermal annealing treatments aiming at its elimination. Monitoring the amount of solvent eliminated as a function of the annealing parameters is important to design a proper treatment to ensure complete solvent elimination, crucial to obtain reproducible and stable material properties and therefore, device performance. Here we demonstrate, for the first time to our knowledge, the use of an organic distributed feedback (DFB) laser to monitor with high precision the amount of solvent extracted from a spin-coated polymer film as a function of the thermal annealing time. The polymer film of interest, polystyrene in the present work, is doped with a small amount of a laser dye as to constitute the active layer of the laser device and deposited over a reusable DFB resonator. It is shown that solvent elimination translates into shifts in the DFB laser wavelength, as a consequence of changes in film thickness and refractive index. The proposed method is expected to be applicable to other types of annealing treatments, polymer-solvent combinations or film deposition methods, thus constituting a valuable tool to accurately control the quality and reproducibility of solution-processed polymer thin films. ; The work was supported by the Spanish Government (MINECO) and the European Community (FEDER) through grant No. MAT-2011-28167-C02-01. M.M.-V. has been partly supported by a MINECO FPI fellowship (No. BES-2009-020747).

Distributed feedback (DFB) laser sensors with active films consisting of a highly efficient and photostable perylenediimide dye (perylene orange, PDI-O) dispersed in polysytrene (PS), used as passive matrix, are reported. PDIdoped- PS DFB lasers show an excellent operational durability under ambient conditions, superior to those of previously reported DFBs used for sensing purposes. Their bulk refractive index sensing capabilities, under exposure to liquids of different refractive index, have been determined from changes in their emission wavelength. The role of the active film thickness on both, the laser and the sensing performance, has been explored. The use of a thick active film (850 nm) allows obtaining the lowest possible threshold and highest operational lifetime for this type of device although the sensor sensitivity is lower than that achievable with a thin film (160 nm). It is also shown that the inclusion of a high refractive index TiO2 layer on top of the sensor structure allows improving the sensor sensitivity by around two times. ; This work was supported by the Spanish Government (MINECO) and the European Community (FEDER) through grant no. MAT-2011–28167-C02. M.M-V. has been partly supported by a MINECO FPI fellowship (no. BES-2009-020747).

The refractive index sensing capabilitity of distributed feedback (DFB) lasers based on highly photostable (under ambient conditions) perylenediimide-based active films, are reported. The sensor bulk sensitivity is determined from changes in the laser emission wavelength upon exposure to different liquids. The role of the active film thickness (hf) on the sensor sensitivity and on the laser parameters is studied. Sensors based on very thin films (hf = 160 nm) show the highest sensitivities, but their laser thresholds are relatively high and their operational durabilities moderate. The use of thicker films (hf = 850 nm) allows reducing the laser threshold and increasing the durability by two orders of magnitude. In this case, a higher sensitivity is achieved when the sensor operates at the wavelength corresponding to the first-order TE1 mode, instead of at the TE0 one. Finally, it is also shown that the inclusion of a high refractive index TiO2 layer on top of the sensor structure improves the sensitivity by around two times. ; This work was supported by the Spanish Government (MINECO) and the European Community (FEDER) through grant no. MAT-2011–28167-C02. This work was partially funded by the Basque Government within the framework of the Etortek Program (Grant No. IE13-360). M. Morales-Vidal has been partly supported by a MINECO FPI fellowship (no. BES-2009-020747).

Two-dimensional (2D) distributed feedback (DFB) lasers with gratings imprinted by thermal nanoimprint lithography on the active film are reported. They show thresholds for lasing of ∼10 kW/cm2, similar to the most efficient imprinted DFB lasers reported; and long operational lifetimes (under ambient conditions) of ∼12 × 104 pump pulses. The key for their successful operation has been the selection of a highly efficient and stable dye, perylene orange (PDI-O), and a proper matrix to host it, the fluoro-modified thermoplastic resist mr-I7030R, which has enabled 2D imprinting while preserving the dye optical properties. The use of the UV-curable resist SU8 as an alternative matrix for PDI-O to be imprinted by combined nanoimprint and photolithography was also investigated, and was concluded to be unsuccessful due to severe photoluminescence quenching. By replacing PDI-O with Rhodamine 6G, lasers with reasonable thresholds, but with significantly inferior operational lifetimes in comparison to PDI-O/mr-I7030R devices, were obtained. ; We thank support from the Spanish Government (MINECO) and the European Community (FEDER) through Grants MAT2011-28167-C02 and MAT2015-66586-R, as well as to the University of Alicante. M.M-V. has been partly supported by a MINECO FPI fellowship (no. BES-2009-020747) and by a Junta de Castilla y León grant (no. SA046U16).

The human epidermal growth factor receptor 2 (ErbB2) protein plays an important role in human malignancies. Its overexpression has been recognized as a feature of a malignant cancerous phenotype in breast cancer cell lines, and has become one of the most widely investigated clinical indicators of breast, ovarian, gastrointestinal and lung cancers. In this work a vertically emitting organic distributed feedback (DFB) laser has been used to detect the ErbB2 protein. This DFB laser consists of a polystyrene (PS) film containing a perylenediimide laser dye, deposited over a second-order one dimensional grating fabricated on fused silica by thermal-nanoimprint lithography and subsequent reactive ion etching processes. Specificity of the system to ErbB2 protein biomarker, achieved by functionalizing the PS with anti-ErbB2 monoclonal antibodies, is demonstrated. A concentration limit of detection for ErbB2 protein of 14 ng/mL has been obtained, and no cross-reactivity has been observed with bovine serum albumin (BSA) and tumor necrosis factor alpha (TNFα) proteins. These findings open the possibility of using this type of biosensors in clinical applications. ; This work was supported by the Spanish Government (MINECO) and the European Community (FEDER) through grant no. MAT-2011–28167-C02. This work was partially funded by the Basque Government within the framework of the Etortek Program (Grant No. IE13-360). M. Morales-Vidal has been partly supported by a MINECO FPI fellowship (no. BES-2009-020747).

Thin film organic lasers (TFOLs) represent a new generation of inexpensive, mechanically flexible devices with demonstrated applicability in numerous applications in the fields of spectroscopy, optical communications and sensing requiring an organic, efficient, stable, wavelength-tunable and solution-processable laser material. A distributed feedback (DFB) laser is a particularly attractive TFOL because it shows single mode emission, low pump energy, easy integration with other devices, mechanical flexibility and potentially low production cost. Here, amplified spontaneous emission (ASE) and DFB laser applications of novel high performing perylene dyes and p-phenylenevinylene (PV) oligomers, both dispersed in thermoplastic polymers, used as passive matrixes, are reported. Second-order DFB lasers based on these materials show single mode emission, wavelength tunability across the visible spectrum, operational lifetimes of >105 pump pulses, larger than previously reported PV oligomers or polymers, and thresholds close to pumping requirements with light-emitting diodes. ; This work was supported by the Spanish Government (MINECO) and the European Community (FEDER) through grant no. MAT-2011–28167-C02. M. Morales-Vidal has been partly supported by a MINECO FPI fellowship (no. BES-2009-020747).

The storage of time-stable holographic gratings in hydrogel matrices when the material is immersed in aqueous media is a real challenge at present. The optimization of the storage stages of the holograms must be properly investigated to identify the most suitable development processes. For this reason, this work is focused on the study of the optimization of the washing stages of the hydrogels based on acrylamide and N,N'-methylenebis(acrylamide) once unslanted transmission holograms have been stored. High-performance liquid chromatography and UV-visible measurements have been employed in our system to analyze the composition of the washing solutions. PBST and DMSO:H2O are used as solvents in the washing stages. The diffraction efficiencies are measured during the washing stages and after the storing of the holograms during several days in PBST. Maximum diffraction efficiencies of 38 and 27.6% are reached when PBST and DMSO:H2O are employed, respectively, for the washing process. Holograms show temporal stability after being stored immersed in PBST at 4 °C for 4 days. ; This research was funded by Ministerio de Ciencia, Innovación y Universidades, Spain, under project PID2019-106601RB-I00 and AdBiHol-PID2019-110713RB-I00 funded by MCIN/AEI/10.13039/501100011033 and by "ERDF A way of making Europe"; Generalitat Valenciana, Spain, under projects CDEIGENT/2018/024, GRISOLIAP/2019/143, PROMETEO/2021/006, PROMETEO/2020/094 and IDIFEDER/2021/014 (co-funded by European Union through the FEDER Program). M. I. Lucío acknowledges her Juan de la Cierva Incorporación grant (IJC 2018-035355-I) funded by MCIN/AEI/10.13039/501100011033. M. I. Lucío and A. Beléndez acknowledge the Programa Propio para el fomento de la I + D + I del Vicerrectorado de Investigación y Transferencia de Conocimiento of the Universidad de Alicante for the grant "Ayudas para estancias de personal investigador invitado" (INVA20-02). K. Berramdane thanks to the government of Algeria for her scholarship offered to develop her thesis in the Holography and ...

Two-dimensional (2D) distributed feedback (DFB) lasers with gratings imprinted by thermal nanoimprint lithography on the active film are reported. They show thresholds for lasing of ∼10 kW/cm2, similar to the most efficient imprinted DFB lasers reported; and long operational lifetimes (under ambient conditions) of ∼12 × 104 pump pulses. The key for their successful operation has been the selection of a highly efficient and stable dye, perylene orange (PDI-O), and a proper matrix to host it, the fluoro-modified thermoplastic resist mr-I7030R, which has enabled 2D imprinting while preserving the dye optical properties. The use of the UV-curable resist SU8 as an alternative matrix for PDI-O to be imprinted by combined nanoimprint and photolithography was also investigated, and was concluded to be unsuccessful due to severe photoluminescence quenching. By replacing PDI-O with Rhodamine 6G, lasers with reasonable thresholds, but with significantly inferior operational lifetimes in comparison to PDI-O/mr-I7030R devices, were obtained. ; We thank support from the Spanish Government (MINECO) and the European Community (FEDER) through Grants MAT2011-28167-C02 and MAT2015-66586-R, as well as to the University of Alicante. M.M-V. has been partly supported by a MINECO FPI fellowship (no. BES-2009-020747) and by a Junta de Castilla y León grant (no. SA046U16).

The aim of this work was to improve the laser performance, in terms of threshold and operational lifetime, of lasers based on polymer films doped with perylenediimide (PDI) derivatives as active media. For such purpose, we first investigated the amplified spontaneous emission (ASE) properties of perylene orange (PDI-O), when doped into polystyrene (PS) films. Lower ASE thresholds and larger photostabilities than those of similar films containing another PDI derivative (PDI-C6), recently reported in the literature, have been measured. Results have been interpreted in terms of the photoluminescence efficiency of the films, which depends on the type of molecular arrangement, inferred with the help of nuclear magnetic resonance experiments. We also show that PS films have a better ASE performance, i.e. lower thresholds and larger photostabilities, than those based on poly(methyl methacrylate), which was recently highlighted as one of the best matrixes for PDI-O. Finally, a one-dimensional second-order distributed feedback laser using PS doped with PDI-O was fabricated and characterized. This device has shown a threshold significantly lower (by around one order of magnitude) than that of a similar laser based on PDI-C6-doped PS. ; We thank support from the Spanish Government (MECC) and the European Community (FEDER) through grants MAT2008-06648-C02 and MAT-2011-28167-C02, as well as from the University of Alicante. MGR and MM are supported respectively by a CSIC fellowship within the program JAE and by MEC through a FPI fellowship.

The chemical synthesis of nanographene molecules constitutes the bottom-up approach toward graphene, simultaneously providing rational chemical design, structure-property control and exploitation of their semiconducting and luminescence properties. Here, we report nanographene-based lasers from three zigzag-edged polycyclic aromatics. The devices consist of a passive polymer film hosting the nanographenes and a top-layer polymeric distributed feedback resonator. Both the active material and the laser resonator are processed from solution, key for the purpose of obtaining low-cost devices with mechanical flexibility. The prepared lasers show narrow linewidth ( < 0.13 nm) emission at different spectral regions covering a large segment of the visible spectrum, and up to the vicinity of the near-infrared. They show outstandingly long operational lifetimes (above 105 pump pulses) and very low thresholds. These results represent a significant step forward in the field of graphene and broaden its versatility in low-cost devices implying light emission, such as lasers. ; The Alicante team acknowledges support from the Spanish Government (MINECO) and the European Community (FEDER) through grant no. MAT2015-66586-R. The researcher R.M.-M. has been partly supported by a MINECO FPI fellowship (no. BES-2016-077681). The work at the University of Málaga is supported by MINECO FEDER project reference CTQ2015-69391. J.W. acknowledges financial support from the MOE Tier 3 program (MOE2014-T3-1-004) and NRF Investigatorship Award (NRF-NRFI05-2019-0005).

Thin-film organic lasers are attractive light sources for a variety of applications. Recently, it is reported that carbon-bridged oligo(p-phenylenevinylene)s (COPVn with repeating unit n = 1–6) function as unique laser dyes which combine high fluorescence efficiency, wavelength tunability, and both thermal and photostability, making them ideal for use in organic semiconductor lasers. However, in order to obtain such excellent properties, COPVn require blending in a matrix, such as a thermoplastic polymer, thus leading to miscibility issues, limited absorption, and charge transporting properties. Here, high-performance lasers with a novel active polymer poly-COPV1, based on the basic unit of COPV1 and prepared as a high-quality neat film, are reported which overcome the trade-off between the device performance and durability. The prepared lasers show thresholds 30 times lower and operational lifetimes 300 times longer than devices based on COPV1 dispersed in polystyrene. The low threshold operation allows the poly-COPV1 lasers to be pumped by a nitride diode laser. ; Spanish Government (MINECO). Grant Numbers: MAT2011-28167-C02-01, MAT2015-66586-R European Community (FEDER) MINECO FPI Fellowship. Grant Number: BES-2009-020747 Junta de Castilla y León (JCYL) Postdoctoral Fellowship. Grant Number: SA046U16 MEXT. Grant Numbers: 16H04106, 15H05754 Engineering and Physical Sciences Research Council. Grant Numbers: EP/K503162/1, EP/J009016/1 Royal Society Wolfson Research

Thin film organic lasers represent a new generation of inexpensive, mechanically flexible devices for spectroscopy, optical communications and sensing. For this purpose, it is desired to develop highly efficient, stable, wavelength-tunable and solution-processable organic laser materials. Here we report that carbon-bridged oligo(p-phenylenevinylene)s serve as optimal materials combining all these properties simultaneously at the level required for applications by demonstrating amplified spontaneous emission and distributed feedback laser devices. A series of six compounds, with the repeating unit from 1 to 6, doped into polystyrene films undergo amplified spontaneous emission from 385 to 585 nm with remarkably low threshold and high net gain coefficients, as well as high photostability. The fabricated lasers show narrow linewidth (105 pump pulses for oligomers with three to six repeating units) and wavelength tunability across the visible spectrum (408–591 nm). ; The work in Spain was supported by the Spanish Government (MINECO) and the European Community (FEDER) through grant nos. MAT-2011–28167-C02-01 and CTQ2012-33733 and from the Junta de Andalucía through research project P09-FQM-4708. M.M.-V. has been partly supported by a MINECO FPI fellowship (no. BES-2009-020747). Dr Merino and Dr Retolaza, at Tekniker (Spain), are acknowledged for supplying the NIL fabricated resonators. We also thank I. Garcés for technical assistance. The work in Tokyo was supported by MEXT, Japan (for KAKENHI 15H05754 to E.N. and JST-PRESTO 'New Materials Science and Element Strategy' to H.T.).