Electroluminescence emission patterns of organic light-emitting transistors based on crystallized fluorene-type polymers

Kajii, Hirotake; Ohtomo, Takahiro; Ohmori, Yutaka

doi:10.1109/am-fpd.2016.7543694

Cited by 1 publication

(2 citation statements)

References 22 publications

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“…Finally, F8BTrelated materials continue to be of strong interest for electrically pumped light emission struc tures [31,32,[41][42][43][44] including LEDs and LETs and it will be interesting to explore how beneficial the blend structure optimization performed here for SE and lasing might be in that context.…”

Section: Resultsmentioning

confidence: 99%

“…This tendency is also found in the PFO:F8BT films (Figure 4b, peak PLQE = 44% for 5 wt% F8BT) and is typically reported for other FRETcoupled host:guest systems, signaling a tradeoff between the efficiency of FRET and guest selfquenching. [43,44] However, no ASE was detected in PFO:F8BT blends when pumped at 370 nm with pulse energies up to 50 µJ (2330 µJ cm −2 ) irrespective of F8BT fraction. Figure 4c shows the corresponding DBPhFCz:F8BT ASE threshold (E th ASE ) dependence.…”

Section: Pl and Optical Gain Properties Of Host Materials And Blendsmentioning

confidence: 97%

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Host Exciton Confinement for Enhanced Förster‐Transfer‐Blend Gain Media Yielding Highly Efficient Yellow‐Green Lasers

Zhang

Liu

Wei

et al. 2018

Adv Funct Materials

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This paper reports state-of-the-art fluorene-based yellow-green conjugated polymer blend gain media using Förster resonant-energy-transfer from novel blue-emitting hosts to yield low threshold (≤7 kW cm −2 ) lasers operating between 540 and 590 nm. For poly(9,9-dioctylfluorene-co-benzothiadiazole) (F8BT) (15 wt%) blended with the newly synthesized 3,6-bis(2,7-di([1,1′-biphenyl]-4-yl)-9-phenyl-9H-fluoren-9-yl)-9-octyl-9H-carbazole (DBPhFCz) a highly desirable more than four times increase (relative to F8BT) in net optical gain to 90 cm −1 and 34 times reduction in amplified spontaneous emission threshold to 3 µJ cm −2 is achieved. Detailed transient absorption studies confirm effective exciton confinement with consequent diffusionlimited polaron-pair generation for DBPhFCz. This delays formation of host photoinduced absorption long enough to enable build-up of the spectrally overlapped, guest optical gain, and resolves a longstanding issue for conjugated polymer photonics. The comprehensive study further establishes that limiting host conjugation length is a key factor therein, with 9,9-dialkylfluorene trimers also suitable hosts for F8BT but not pentamers, heptamers, or polymers. It is additionally demonstrated that the host highest occupied and lowest unoccupied molecular orbitals can be tuned independently from the guest gain properties. This provides the tantalizing prospect of enhanced electron and hole injection and transport without endangering efficient optical gain; a scenario of great interest for electrically pumped amplifiers and lasers.

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Section: Resultsmentioning

confidence: 99%

Section: Pl and Optical Gain Properties Of Host Materials And Blendsmentioning

confidence: 97%

Host Exciton Confinement for Enhanced Förster‐Transfer‐Blend Gain Media Yielding Highly Efficient Yellow‐Green Lasers

Zhang

Liu

Wei

et al. 2018

Adv Funct Materials

View full text Add to dashboard Cite

show abstract

Electroluminescence emission patterns of organic light-emitting transistors based on crystallized fluorene-type polymers

Cited by 1 publication

References 22 publications

Host Exciton Confinement for Enhanced Förster‐Transfer‐Blend Gain Media Yielding Highly Efficient Yellow‐Green Lasers

Host Exciton Confinement for Enhanced Förster‐Transfer‐Blend Gain Media Yielding Highly Efficient Yellow‐Green Lasers

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