Ladder-type poly(indenofluorene-co-benzothiadiazole)s as efficient gain media for organic lasers: design, synthesis, optical gain properties, and stabilized lasing properties

Abstract

A novel set of ladder-type poly(indenofluorene-co-benzothiadiazole)s were designed, synthesized, and explored as efficient gain media for organic lasers.

Determination of the Best Empiric Method to Quantify the Amplified Spontaneous Emission Threshold in Polymeric Active Waveguides

“…To date, optical gain and optically pumped lasing have been demonstrated in many families of conjugated molecules and with a wide range on different resonators [ 20 , 21 ] and a first indication of lasing effect under electrical pumping has been recently reported [ 22 ]. In particular the organic systems showing optical gain can be divided in the two big families of neat films or blends of active molecules [ 2 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 , 55 , 56 , 57 , 58 , 59 , 60 ,…”

“…A different approach exploits the lineshape variation due to the appearance of the ASE band, identifying the ASE threshold as the minimum excitation density at which the ASE band becomes visible [ 49 , 50 , 51 , 52 , 53 , 54 , 55 , 56 ] (Visual, 4.7%).…”

Laser Systems and Networks with Organic Nanowires and Nanofibers

“…F8BT compounds are well known for their effective charge‐carrier transport, large optical gain coefficients (e.g., 22 < g < 66 cm −1 ) and low threshold for stimulated emission . An ASE threshold as low as 6.04 µJ cm −2 , with g values up to 84 cm −1 and thermal stability up to 280 °C has been obtained for the modified polymers with long chains . Changes in the refractive index of poly(9,9‐dioctylfluorene) (PFO, Figure h) films occur when β‐phase chains (i.e., extended planar and rigid chains) are induced in the amorphous phase by postdeposition treatments.…”

“…Hence, the emission and optical gain of conjugated polymers result from complex photophysical processes, including light absorption, interchain, and intrachain energy transfer across chromophores in close proximity, and radiative and nonradiative recombinations . For layers and nanostructures, photophysical properties are strictly dependent on chain formation and packing, which can be tailored by both chemical modification and nanostructuring . For example, benzothiadiazole modified with indenofluorene chains ( s LF‐BT, s = 2–4) shows optical properties enhanced with respect to the well‐known poly[(9,9‐dioctylfluorenyl‐2,7‐diyl)‐ co ‐(1,4‐benzo‐{2,1′,3}‐thiadiazole)] (F8BT, Figure g).…”

Pendant conjugated molecules based on a heterogeneous core structure with enhanced morphological and emissive properties for organic semiconductor lasing

“…9 With the aim to realize electrically pumped OSLs, great attention has been paid to the exploration of novel organic gain media with excellent carrier mobilities, superior optical gains and high thermal stability. [10][11][12][13][14][15][16] However, developing efficient gain media simultaneously with improved electrical properties, high luminous efficiency and low lasing thresholds is quite challenging. It is critical to elucidate the structurefunction relationships with the aim to establish a rational molecular design strategy for exploring robust organic gain media for OSLs.…”