Suchergebnisse

All‐solution processed surface‐emitting organic distributed feedback lasers are attractive devices for low‐cost applications. Here, lasers emitting in the spectral region between 375 and 475 nm, in which both active material and resonator (1D relief gratings) are based on solution‐processable polymer films, are reported. Ten different organic compounds dispersed in polystyrene are used as active layers of the prepared devices. They include various carbon‐bridged oligo(p‐phenylenevinylene) (COPVn, with n = 1,2) derivatives and two terfluorene compounds. The synthesis and complete optical and amplified spontaneous emission properties of one of the COPV1 compounds, COPV1(Me)‐t‐Bu, designed for deep‐blue emission, are also included. The feasibility of the resonator fabrication, performed by holographic lithography with a dichromated gelatine photoresist over the active film, is successfully demonstrated for all devices. Remarkably, no resolution limitations are found even for the lowest grating period (235 nm) required for the fabrication of the laser based on COPV1(Me)‐t‐Bu. It is also demonstrated that the rectangular grating profile with duty cycle 0.75:0.25 (hill:valley) is very convenient to optimize the resonator efficacy. ; The Spanish team acknowledges support from the Spanish Government (MINECO) and the European Community (FEDER) through Grant No. MAT2015-66586-R. H.T. and E.N. thank the financial support from MEXT (JP19H05716 for H.T. and JP19H0549 for E.N.).

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.).