Optical Properties of Oligo(9,9-diarylfluorene) Derivatives in Thin Films and Their Application for Organic Light-Emitting Field-Effect Transistors

Abstract

We demonstrated that oligo(9,9-diarylfluorene) derivatives have high potential for optoelectronic applications such as organic lasers and light-emitting organic field-effect transistors (LE-OFETs). The oligo(9,9diarylfluorene) derivatives have high photoluminescence quantum efficiencies up to Φ PL ≈ 70-75% and very low amplified spontaneous emission thresholds (E th ) down to 0.5 µJ/cm 2 in their vacuum-deposited neat films. In particular, the trimer derivatives (B3 and T3) show higher Φ PL and lower E th than those of the dimers (B2 and T2). Efficient deep-blue LE-OFETs with the electroluminescence (EL) peaking at λ peak ) 429 nm were demonstrated using the ter(9,9-diarylfluorene) as the active layer. Rather high luminance up to L ≈ 150 cd/m 2 and EL quantum efficiency up to η ext ≈ 0.60% were achieved with the optimum source-drain channel length, indicating bipolar carrier injection in the terfluorene layer under the FET operation.

Maximizing Field‐Effect Mobility and Solid‐State Luminescence in Organic Semiconductors

“…We note that only a few blue-emitting OLETs have been reported to date; [26] the highest mobility, which was measured for 4,4'-distyrylbiphenyl, was 0.01 cm 2 V À1 s À1 (PLQY = 20 %). We note that only a few blue-emitting OLETs have been reported to date; [26] the highest mobility, which was measured for 4,4'-distyrylbiphenyl, was 0.01 cm 2 V À1 s À1 (PLQY = 20 %).…”

Organic Light Emitting Field Effect Transistors: Advances and Perspectives

“…[52] Previous observations indicated that oligo(9,9-diarylfluorene)s exhibit high PL efficiencies from deep blue to near Ultra Violet, exhibit reasonably high mobilities for both holes and electrons (about 10 -3 cm 2 V -1 s -1 ) and are thermally stable. [53] Vacuum sublimed films of oligo(9,9-diarylfluorene) derivatives exhibit transistor behavior (unipolar p-type) and high PL quantum efficiencies.…”

Gate‐Controlled Light Emitting Diodes

“…This is a significant improvement in terms of light emission performance compared to that recently reported for LETs fabricated with vapor deposited small molecules and spin coated light emitting polymers. [6,10,14,15] Note that the EQE remains constant at high currents; EQE % 0.5% even at current densities up to 50 A cm…”