Water/alcohol soluble electron injection material containing azacrown ether groups: synthesis, characterization and application to enhancement of electroluminescence

Abstract

Using an environmentally stable metal as the cathode in a polymer light-emitting diode (PLED) is an essential requirement for its practical application. We present the preparation of a water/alcohol soluble copoly(p-phenylene) (P1) containing pendant azacrown ether and ethylene glycol ether groups as a highly efficient electron injection layer (EIL) for PLEDs, allowing the use of environmentally stable aluminum as the cathode. Multilayer PLEDs [ITO/PEDOT:PSS/PF-Green-B/EIL/Al] using P1 as EIL exhibit significantly enhanced device performance, particularly in the presence of K2CO3 or Cs2CO3. The maximum luminous power efficiency and maximum luminance of the device with Cs2CO3-doped P1 as EIL were enhanced to 9.16 lm W(-1) and 17,050 cd m(-2), respectively, compared with those without EIL (0.16 lm W(-1), 890 cd m(-2)). The turn-on voltage was also significantly reduced from 5.7 V to 3.7 V simultaneously. The performance enhancement has been attributed to improved electron injection which has been confirmed by the rise in open-circuit voltage (Voc) obtained from photovoltaic measurements. The incorporation of such an electron injection layer significantly enhances device performance for PLEDs with an environmentally stable metal as the cathode.

Hydroxyethyl cellulose filled with M2+ chelate complexes with ethylenediaminetetraacetic acid (EDTA) as an effective electron-injection layer for polymer light-emitting diodes

“…The chelation and binding of ions by appropriate chelating agents (chelators) increased the interfacial dipole to facilitate electron injection from the cathode [20,41]. Polar pendant groups in polymers, such as ether, amino, crown or azo-crown ether groups, also demonstrated this characteristic by binding with ions [20,41,44,45]. The application of a stable pseudo-metallic state as an intermediate step for effective electron injection opens an efficient way to enhance polymer light-emitting diodes performance.…”

Nanostructuring with Surfactants: The Self-Assembly of a New Poly(thiophene-phenylene) Conjugated Polymer Bearing Azacrown Ether Pendant Groups

“…20 Multilayer PLEDs were constructed with an electron injection layer (EIL) based on a water/alcohol soluble copoly(p-phenylene) with pendant azacrown ether and ethylene glycol ether groups doped with metal carbonate. 21 The device exhibit improved electron injection which resulted in significant enhancement of its performance. The use of polyfluorene grafted with a crown ether intercalated with K + , as the electron transport layer (ETL) in bulk-heterojunction polymer solar cells, led to an improvement in the power conversion efficiency.…”

“…The use of CP with pendant crown ether groups shows great potential and opens new technological possibilities since they combine the optoelectronic properties of CP and the sensitivity/selectivity of the crown ether moieties. This approach has been successfully demonstrated for a wide range of applications, such as chemical − and biological , sensors, polymer light-emitting diodes, − thermoresponsive materials for supramolecular gels, and bulk-heterojunction polymer solar cells . The dynamic and reversible properties of CPs make them suitable to monitor minor changes in the system and can be easily followed by optical methods, such as photoinduced electron transfer (PET), aggregation induced emission (AIE), and aggregation caused quenching (ACQ). ,− A multifunctional fluorene-based material containing triple azacrown ether, 2,4,7-tri­[4-(monoaza-15-crown-5)­styryl]-9,9-dihexylfluorene, was synthesized and successfully used as a chemosensor toward Fe 3+ , and also to enhance the electroluminescence of polymer light-emitting diodes (PLEDs) using an environmentally stable aluminum cathode .…”

“…The dynamic and reversible properties of CPs make them suitable to monitor minor changes in the system and can be easily followed by optical methods, such as photoinduced electron transfer (PET), aggregation induced emission (AIE), and aggregation caused quenching (ACQ). ,− A multifunctional fluorene-based material containing triple azacrown ether, 2,4,7-tri­[4-(monoaza-15-crown-5)­styryl]-9,9-dihexylfluorene, was synthesized and successfully used as a chemosensor toward Fe 3+ , and also to enhance the electroluminescence of polymer light-emitting diodes (PLEDs) using an environmentally stable aluminum cathode . Multilayer PLEDs were constructed with an electron injection layer (EIL) based on a water/alcohol soluble copoly­( p -phenylene) with pendant azacrown ether and ethylene glycol ether groups doped with metal carbonate . The device exhibit improved electron injection which resulted in significant enhancement of its performance.…”

Hole‐buffer polymer composed of alternating p‐terphenyl and tetraethylene glycol ether moieties: Synthesis and application in polymer light‐emitting diodes

“…We have been developing new electron‐injection materials to modify high work‐function cathode such as aluminum and hole/electron transporting materials to improve carrier balance and device performance . In this study, we attempted a different approach to improve device performance of PLEDs.…”