Structure and Band-Gap Design of a New Series of Light-Emitting Poly(cyanofluorene-alt-o/m/p-phenylenevinylene)-Based Copolymers for Light-Emitting Diodes

Abstract

A new series of 2,2‘-(9,9-dioctyl-9H-fluorene-2,7-diyl)diacetonitrile-based alternating polyfluorene copolymers (P12 - FL, P13 - FL, P14 - FL) containing ortho-, meta-, and para-substituted phenylene derivatives have been designed, synthesized, and characterized. These polymers were synthesized using a Knoevenagel condensation polymerization reaction and were found to be predominantly in the trans configuration. The resulting polymers were found to be thermally stable and readily soluble in common organic solvents. The structural, configurational, and conformational changes in the backbone caused a wide variation in the absorption and emission maxima of the polymers. The fabricated light-emitting devices showed very good performance in terms of turn-on voltage, electroluminescence, and lifetime properties.

Synthesis of New Conjugated CNPPV Derivatives Containing Different Lengths of Oligothiophene Units for Organic Solar Cells

“…[25] 1,4-Bis(cyanomethyl)-2,5-bis(dodecyloxy)benzene (1) was obtained by a three-step synthetic path from hydroquinone as described elsewhere. [23,26] …”

“…The starting material, 1,4-bis(cyanomethyl)-2,5-bis(dodecyloxy)benzene (1), was obtained by a three-step synthetic path from hydroquinone as described elsewhere. [23,26] Diformylterthiophene (2), diformylquinquethiophene (3), and diformylseptithiophene (4) were prepared according to the literature procedures. [25] The polymers CNPPV-3T, CNPPV-5T, and CNPPV-7T were obtained by Knoevenagel polycondensation of 1 with the corresponding dialdehydes.…”

Grafting Hole-Transport Precursor Polymer Brushes on ITO Electrodes: Surface-Initiated Polymerization and Conjugated Polymer Network Formation of PVK

“…The substrates were cleaned by Soxhlet extraction for 24 h to ensure the complete removal of any physically adsorbed PVK. The substrates were taken from the Soxhlet apparatus and immediately transferred to the spincoater, and a solution of the electroluminescent polymer (P14-FL) 37 (1.9 mg/mL) in freshly distilled toluene was cast at 1000 rpm, giving a ca. 90 nm electroluminescent layer.…”

“…The device structure consisted of the PVK SIPmodified ITO (45 nm), spin-coated poly(cyanofluorene-alt-pphenylenevinylene) or PCNPV electroluminescent layer and evaporated Al layer for cathode. The PCNPV has been previously reported to have a LUMO of 3.07 and HOMO of 5.42 or a band gap of 2.35 V. 37 The forward bias current was obtained when the ITO electrode was positively biased and the aluminum was negatively biased. The device showed a relatively low turnon voltage of 4.0 V in both the I-V and L-V measurements in air with current and luminance reaching 3000 mA/cm 2 (7.7 V) and 2000 Cd/m 2 (5.0 V) (Figure 7).…”

The GRACE of staged revascularization after primary angioplasty st‐elevation myocardial infarction

“…Various comonomers like benzothiadiazole,1 pyridine,2 bithiazole,3 naphthoselenadiazole,4 indenofluorene,5 quinoxaline,6 or perylene7 might act as electron acceptors 6, 8–16. Out of these, recently, quinoxalines,6 2,1,3‐benzothiadiazoles,1 and thieno[3,4‐ b ]‐pyrazines17 received much attention as acceptor units because of their physical properties.…”