Solution-processed deep-blue (y∼0.06) fluorophores based on triphenylamine-imidazole (donor-acceptor) for OLEDs: computational and experimental exploration

Abstract

Developing solution-processable deep-blue emitters for organic light-emitting diodes (OLEDs) is still a challenging task. In this context, two new solution-processable deep-blue emitters, N,were successfully designed and synthesized by incorporating phenanthroimidazole (PI)/diphenylimidazole (BI)-triphenylamine (TPA), which is functional at the N1 position of the imidazole, with Ph-mCF 3 . The thermal, photophysical, and electrochemical properties of both fluorophores were systematically explored. These fluorophores showed a deep-blue emission in the solution as well as in the solid state. The highest occupied molecular orbital (HOMO)lowest unoccupied molecular orbital (LUMO) energy level of the fluorophores was calculated using electrochemical studies and compared with the theoretical calculation [the density functional theory (DFT)]. The asymmetrically twisted conformation of 4-PIMCFTPA between PI-TPA efficiently showed a high photoluminescence quantum yield. OLED (undoped and doped) devices were fabricated with the newly synthesized emitters, and 4-PIMCFTPA demonstrated better electroluminescence (EL) performance than the BI-based emitter. Thus, the OLED based on 4-PIMCFTPA (1 wt% in the CBP host) had the best EL performance, with a maximum external quantum efficiency 1.7% and CIE coordinates of (0.17, 0.06).

Highly Efficient Multifunctional Luminogens for Near UV/Deep Blue (CIEy ∼0.02) and Hybrid White OLEDs (CIE ∼0.33, 0.37) with Superior Color Stability

“…In the presence of ammonium acetate (NH 4 OAc) and acetic acid (AcOH), intermediates were synthesized via condensation between diketone, aniline derivatives, and aldehyde derivatives, and Suzuki coupling reactions were used to synthesize final products as shown in Scheme . The synthetic procedure was adopted from our previous reports. , …”

Unipolar 1-phenylimidazo[1,5-a]pyridine: a new class of ultra-bright sky-blue emitters for solution-processed organic light emitting diodes

“…[1][2][3][4][5] To understand the useful application of organic light emitting diodes (OLEDs) in display technology and solid-state lighting, the development of highly efficient emitters is imperative. [6][7][8][9] Since the past few decades, numerous efforts have been dedicated to developing new highly efficient blue emitters. 10,11 However, because of the intrinsic wide band gap of blue emitters, it is difficult to develop blue emitters with performance equal to other primary (red and green) counterparts.…”

Multifunctional 4,5-Diphenyl-1H-imidazole-Based Luminogens as Near UV/Deep Blue Emitters/Hosts for Organic Light-Emitting Diodes and Selective Picric Acid Detection

“…Simple functional organic fluorophores have gained enormous attention due to their easy synthetic procedure and structure-dependent alteration, which impact the desired properties (optoelectronics, chemosensing, organic photovoltaics, etc. ). , Owing to their unique features (lower energy consumption, cost-effectiveness, lightweight, and flexibility), organic light-emitting diodes (OLEDs) are considered as promising alternatives for smart displays and solid-state lightings. , In comparison with fluorescent emitters, metal-based phosphorescent dopants as well as thermally activated delayed fluorescence (TADF) emitters have shown promising EQE (>5%) due to their ability to break through the spin statistics rules (to achieve near unity internal quantum efficiency (IQE)). However, preserving high efficiency at high brightness is an incredible task for several applications. , Also, it is worth noting that achieving widened color gamut, near UV/deep blue emitters with a CIE y coordinate of <0.10 that even match the blue standard with the CIE ( x , y ) coordinates at (0.15, 0.06) of European Broadcasting Union (EBU) is crucial to full-color displays.…”

“…Simple functional organic fluorophores have gained enormous attention due to their easy synthetic procedure and structuredependent alteration, which impact the desired properties (optoelectronics, chemosensing, organic photovoltaics, etc.). 1,2 Owing to their unique features (lower energy consumption, cost-effectiveness, lightweight, and flexibility), organic lightemitting diodes (OLEDs) are considered as promising alternatives for smart displays and solid-state lightings. 3,4 In comparison with fluorescent emitters, metal-based phosphorescent dopants 5 as well as thermally activated delayed fluorescence (TADF) emitters have shown promising EQE (>5%) due to their ability to break through the spin statistics rules (to achieve near unity internal quantum efficiency (IQE)).…”