Monodisperse Six‐Armed Starbursts based on Truxene‐Cored Multibranched Oligofluorenes: Design, Synthesis, and Stabilized Lasing Characteristics. Issue 15 (13th February 2019)

• Record Type: Journal Article
• Authors: Zhang, Hao; Liu, Xu; Lu, Ting‐Ting; Lv, Peng; Lai, Wen‐Yong
• Is Part Of: Chemistry. Volume 25:Issue 15(2019)
• Page Start: 3909
• Page End: 3917
• Publication Date: 2019-02-13
• Subjects: conjugated molecules -- HOMO levels -- organic gain media -- organic light-emitting diodes (OLEDs) -- organic semiconductor lasers (OSLs); Chemistry -- Periodicals; 540
• DOI: 10.1002/chem.201805813
• Languages: English
• ISSNs: 0947-6539

Abstract

Abstract: A series of monodisperse six‐armed conjugated starbursts (Tr1F, Tr2F, andTr3F ) containing a truxene core and multibranched oligofluorene bridges capped with diphenylamine (DPA) units has been designed, synthesized, and investigated as robust gain media for organic semiconductor lasers (OSLs). The influence of electron‐rich DPA end groups on their optoelectronic characteristics has been discussed at length. DPA cappers effectively raise HOMO levels of the starbursts, thus enhancing the hole injection and transport ability. Solution‐processed electroluminescence devices based on the resulting six‐armed starbursts exhibited efficient deep‐blue electroluminescence with clear reduced turn‐on voltages (3.2–3.5 V). Moreover, the resulting six‐armed molecules showed stabilized electroluminescence and amplified spontaneous emission with low thresholds (27.4–63.9 nJ pulse −1 ), high net gain coefficients (80.1–101.3 cm −1 ), and small optical loss (2.6–4.4 cm −1 ). Distributed feedback OSLs made fromTr3F exhibited a low lasing threshold of 0.31 kW cm −2 (at 465 nm). The results suggest that the construction of truxene‐centered six‐armed conjugated starbursts with the incorporation of DPA units can effectively enhance EL properties by precisely regulating the HOMO energy levels, and further optimizing their optical gain properties. Abstract : Bursting of stars : Monodisperse six‐armed starburst conjugated molecules with diphenylamine (DPA) end‐cappers were synthesized, and their optical gain and lasing characteristics were investigated. The incorporation of DPA end groups effectively raised the HOMO levels, thus enhancing the hole injection and transport ability. The resulting starbursts manifested stable optical gain and lasing performance with low thresholds (27.4–63.9 nJ pulse −1 ), high net gain coefficients (80.1–101.3 cm −1 ) and small waveguide loss (2.6–4.4 cm −1 ).