A New Supramolecular Hole Injection/Transport Material on Conducting Polymer for Application in Light‐Emitting Diodes

Abstract

A new DNA-mimetic π-conjugated polymer poly(triphenylamine-carbazole) (PTC-U) has been prepared which exhibits high thermal stability, non-corrosion, excellent hole injection and electron-blocking abilities in the solid state owing to the uracil induced physical cross-linking. In addition, a trilayer device with PTC-U as a hole injection/transport layer is approximately 1.6 times higher than that of the commercial product PEDOT:PSS-based devices.

Photo-Crosslinking of Pendent Uracil Units Provides Supramolecular Hole Injection/Transport Conducting Polymers for Highly Efficient Light-Emitting Diodes

“…Figure S5) display plots of the EQE, LE, and power efficiency (PE), respectively, against the current density. The EQEs of the devices incorporating PTC-U-1hr (2.65%), PTC-U-2hr (2.48%), and PTC-U-4hr (2.45%) were all higher than those of the control device based on PTC-U (2.4%), with that of the device incorporating PTC-U-1hr even being 1.8 times that of the corresponding device based on commercial PEDOT:PSS (1.46%) [27]. The LE and PE of the device incorporating PTC-U-1hr (8.9 cd/A and 5.5 lm/W, respectively) were 1.9 and 1.55 times higher, respectively, than those of the corresponding device based on commercial PEDOT:PSS (4.7 cd/A and 3.57 lm/W, respectively) [27].…”

“…All solvents were purchased from TEDIA (Fairfield, OH, USA) and distilled over CaH2 prior to use. 4-butyl-N,N-bis(4-bromophenyl)aniline, 4-butyl-N,Nbis(4,4,5,5-tetramethyl-1,3,2-dioxaborolane-4-phenyl)aniline (1), 4-bromobutyl-9-(3,6-dibromocarbazole) (2), and PTC-U (3) were synthesized according to the procedures reported previously [27]. A solution of PTC-U (1 wt% in 1,1,2,2-tetrachloroethane) was spin-coated (2000 rpm, 30 s) onto ITO glass.…”

“…Scheme 1 displays our synthesis of PTC-U [27] and the structure of the product from photo-crosslinking of PTC-U through 2π + 2π photo-dimerization under UV light at 254 nm. When we subjected PTC-U to UV radiation, its pendent U bases underwent 2π + 2π photo-dimerization to form cyclobutane rings.…”

“…Furthermore, we developed a new DNA-mimetic π-conjugated poly(triphenylamine-carbazole) presenting pendent uracil (U) moieties (PTC-U) that exhibited high thermal stability and excellent hole injection and good electron-blocking ability in the solid state, due to physical crosslinking of the U units [27]. Furthermore, a trilayer device incorporating PTC-U as the HITL displayed a maximum brightness as high as 48,233 cd/m 2 , an EQE of 2.40%, and an LE of 8.0 cd/A, values that are comparable with those reported (efficiency: 1.70 or 1.08 cd/A; maximum brightness: 7500 cd/m 2 ) for a corresponding device featuring conventional PEDOT:PSS as the HITL [28,29].…”

Low‐Temperature Cross‐Linkable Small Molecules for Fully Solution‐Processed OLEDs

“…[21] Solution-processed multilayer OLEDs using physically cross-linking materialsw eref irst reported by Cheng and co-workers. [22,23] They demonstrated that uracil-functionalized poly(3-thiophene) was able to form ap hysically cross-linked layer,r esultingi n high thermals tability and excellent hole injection/transporting capabilities in the solid state. Cheng et al also synthesized an adenine-based polymer and used it as ah ole-transporting material, thereby providing as table hole-transporting layer to OLED devices.…”