Self‐Assembling Azaindole Organogel for Organic Light‐Emitting Devices (OLEDs)

Abstract

This study reports on the use of a self-assembling organogel, 5-(4-nonylphenyl)-7-azaindole (1), as a new emitter in small-molecule organic light emitting devices (OLEDs). The theoretical calculations along with the photophysical characterization studies suggest the coexistence of the monomer and dimer species at high concentration of compound 1. The presence of this type of dimer (formed via H-bonding) is responsible for the increased emission. However, the most notable feature is the 3D network of vastly interconnected fibers formed in the organogel that modifies the photophysical properties. Based on this, several OLED architectures are made in order to understand the mechanism involved in the electroluminescence (EL) behavior of 1. Although the position of the EL spectra differs from that of the photoluminescence (PL) spectra, the trends observed in the device properties perfectly match with dimer formation. In this framework a better device performance is associated to a higher efficiency of dimer formation, which optimizes in the OLED prepared from the organogel. Therefore, these results show that the rational combination of a moiety showing a strong PL intensity increased upon aggregation with organogel properties is an efficient strategy to create alternative emitters for OLED devices.

Advances in Alternating Current Electroluminescent Devices

“…Electroluminescent (EL) devices have been the research hotspots for decades because of their enormous market value in lighting sources and displays . In particular, tremendous efforts have been put into developing the cost‐effective fabrication approaches for eco‐friendly illumination units, such as organic light‐emitting diodes (OLEDs) and quantum dots based light‐emitting diodes (QLEDs) . OLEDs and QLEDs give rise to light emission when injected charges recombine radiatively at the active emissive layer driven by constant‐voltage or direct current (DC).…”

Bipolar luminescent azaindole derivative exhibiting aggregation-induced emission for non-doped organic light-emitting diodes

“…26 Remarkably, a similar phenomenon has been observed for similar bipolar molecules using the same doublelayer device architecture. 8,9 Although in that example the main EL mechanism was based on electromers, excimers or exciplexes, 8, 9 in our case the presence of a better acceptor group in 2 decreases the formation of electroplex and electromer in favor of the electron-hole recombination in the HOMO-LUMO orbitals of the molecule.…”

“…excimers, exciplexes, electromers or electroplexes. 8,9 Consequently, an appropriate design of these bipolar systems is a key factor to the successfully of the building block emitters generation.…”

Organic Semiconductor Micro/Nanocrystals for Laser Applications

“…Since the turn of century, organic semiconductor micro/nanocrystals (OSMCs) [ 1 , 2 , 3 , 4 , 5 , 6 , 7 ] have attracted continuous attention as a promising research topic with promising electronic and optoelectronic applications, including organic field-effect transistors (OFETs) [ 8 , 9 , 10 , 11 ], organic photovoltaics (OPVs), organic light-emitting diodes (OLEDs) [ 12 , 13 ], photodetectors (PDs) [ 14 , 15 ], and lasers [ 16 , 17 , 18 , 19 , 20 ]. A huge amount of OSMCs have been developed, with several assets over their inorganic counterparts, such us a plethora of molecular structures with diverse properties, low-cost device fabrication, compatibility with stretchy, flexible, and lightweight moldable substrates, etc.…”