Amplified spontaneous emissions from π‐conjugate conductive polymer film: evanescent‐field modulation by a 1‐D photonic crystal substrate

Abstract

One‐dimensional photonic crystal (PC) with alternating layers of TiO2 and SiO2 was fabricated with spin coating and low temperature baking, resulting in a successful tuning of the PC stop band so as to block the amplified spontaneous emission (ASE) of a π‐conjugate polymer film. Single PC as a substrate, not a cavity with two PC's, of the polymer film was sufficient to shift the tangential ASE to the energy at PC stop band edge, indicating that the tangential ASE propagating along the interface was modulated by its evanescent‐field tail in the PC, which opens a possibility for wide tuning of the coherent luminescence from an ultrathin π‐conjugate polymer film with ultimate mode volume. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Amplified spontaneous edge‐ emissions from π‐conjugated polymer ultrathin films: Discrete or continuous energy detuning

“…This emission was ascribed to ASE, based on the two observations: (1) the peak height was proportional to the excitation power subtracted by a threshold 3 μJ/mm 2 , and (2) the linewidth decreased abruptly at the same threshold. This emission at 0-1 transition may not the only one allowed, but was selected as the most efficient emission among other higher vibrational transitions: with the use of a photonic crystal (PC) substrate whose stopband covered the 0-1 transition energy region, the ASE energy was demonstrated to be partially detuned to the 0-4 transition near the PC stopband edge [1]. This partial detuning was due to the imperfect stopband of the PC that was fabricated through a combination of solution spincoating and sol-gel chemical reaction.…”

“…Based on the successful demonstration of the material's versatility, luminescence energy tuning of the same polymer film [1] will be the next challenge. Although organic materials generally have advantage of chemical modification to attain different physical properties, optoelectrical applications welcome optical detuning using the same specimen without chemical modifications.…”