Temperature Tuning of Nonlinear Exciton Processes in Self‐Assembled Oligophenyl Nanofibers under Laser Action

Organic solid‐state integrated amplifiers and lasers

“…Lasing by optical pumping has been demonstrated in nanofibers based on conjugated polymers [313] and oligomers [309], dye-doped polymers [304], and small semiconducting molecules doped with dyes [308], exhibiting performance metrics such as laser linewidths and thresholds that are comparable with those of their macroscopic counterparts. There are also reports on coherent random lasing in nanofibers of organic crystalline conjugated oligomers, in particular para-sexiphenyl (p-6P) [314][315][316][317] for high sensitivity nonlinear optical nanosensors. It is also worth pointing out at the significant activity on doping of nanofibers with semiconducting nanocrystals (quantum dots or rods) as well as on suitably aligning the resultant emitting structures mainly for addressing applications in sensing [318][319][320][321][322][323].The atomically smooth surface of the end faces of the PNFs can provide sufficient resonant feedback to allow for these structures to act as Fabry-Pérot cavities with high-Q factor and produce light amplification at low threshold values.…”

Multiband Laser Action from Organic-Organic Heteroepitaxial Nanofibers

“…These epitaxial nanofibers exhibit important optical properties, such as highly polarized blue luminescence and laser action [5][6][7][8][9], which could be exploited for applications in photonic and sensing technologies. Recent advances in the field include the achievement of highly polarized, red-green-blue (RGB) emission from epitaxially aligned bilayer nanofibers obtained upon deposition of sexithiophene (6T) on p6P/muscovite templates, and the development of a roll-printing technique for high-yield and massive transfer of nanofibers from the native substrate to a receiving substrate for device applications [10].…”

Photophysics and Photonics of Heteroepitaxial Organic Nanofibers

“…Fluorescence decay traces taken at 80 K are drawn in the inset of Fig. 7 (Quochi et al, 2008). At high pump fluences, the excited-state decay dynamics is dominated by nonradiative, density-dependent processes ascribed to singlet-singlet (bimolecular) annihilations.…”

“…The spectral profile (right panel) shows evidence of lasing emission on top of the 0-1 spontaneous emission band. The time profile analysis (bottom panel) demonstrates that at 80 K prompt laser emission decays rapidly, leaving the system with a population of singlet excitons undergoing monomolecular recombination with ~1 ns decay time (Quochi et al, 2008).…”

“…A relevant example of organic epitaxy on inorganic substrates is represented by high-vacuum deposition of para-sexiphenyl (p-6P) on (001)-oriented muscovite mica (Simbrunner et al, 2011), which yields large domains of parallel and crystalline nanofibers with extremely high surface-tovolume ratios, sub-wavelength cross-sectional dimensions, and lengths up to the millimeter scale (Yanagi et al, 1999;Andreev et al, 2000;Balzer & Rubahn, 2001). These nanofibers exhibit excellent photonic and optoelectronic properties: high blue photoluminescence efficiency (Stampfl et al, 1995), high in-fiber carrier mobility (Birendra-Singh et al, 2006;Kjelstrup-Hansen et al, 2006), luminescence guidance (Balzer et al, 2003), in-fiber amplification of spontaneous emission with large gain factors Cordella et al, 2007), and optically-induced laser action (Quochi et al, 2004(Quochi et al, , 2005(Quochi et al, , 2008. Very recently, organic-organic heteroepitaxy of mixed p-6P/alpha-sexithiophene (6T) nanofibers with highly polarized blue, green and red emission has been successfully demonstrated (Simbrunner et al, 2010), further broadening the range of potential applications of organic epitaxial nanofibers in photonics and optoelectronics.…”