Analysis of mechanisms responsible for the formation of dark spots in organic light emitting diodes (OLEDs): A review

Thermoconformational Behavior of Cellulose Nanofiber Films as a Device Substrate and Their Superior Flexibility and Durability to Glass

“…Flexible devices made from organic materials are showing great promise for various applications, including in the manufacture of portable and foldable devices with enhanced functionality. − They show outstanding performance in electronic medical devices, optoelectronics, and field-effect transistors, leading to a trending nanoempowerment of a huge field of flexible and transportable product applications. − However, this projected advancement has been significantly impeded over the past decades by poor thermal expansion coefficients coupled with a low optical clarity of polymer-based organic substrates such as polyesters and polyamides. , Moreover, thermal stability over a prolonged service period is another key parameter that deterred further progress. Different chemical dopants, additives, and stabilizers were incorporated to improve the properties of these polymer substrates; however, no improvement in synergistic light transmittance and thermal characteristics have been observed.…”

“…4−12 However, this projected advancement has been significantly impeded over the past decades by poor thermal expansion coefficients coupled with a low optical clarity of polymer-based organic substrates such as polyesters and polyamides. 13,14 Moreover, thermal stability over a prolonged service period is another key parameter that deterred further progress. Different chemical dopants, additives, and stabilizers were incorporated to improve the properties of these polymer substrates; however, no improvement in synergistic light transmittance and thermal characteristics have been observed.…”

New Thiophene Imines Acting as Hole Transporting Materials in Photovoltaic Devices

“…Despite appreciable development of optoelectronics in recent years, many problems related to semiconductor processing and the efficiency of the devices are still unresolved. Therefore, new stable, processable organic compounds that are able to meet the continually increasing demands are being sought. − Among the various π-conjugated compounds, azomethines have attracted broad research interest as components in optoelectronic devices. − Imines are synthesized under mild reaction conditions, where only water is formed as a byproduct (the reaction is not harmful to the environment), and do not require a complicated purification process and metal catalysts. − , The possibility of modification of the azomethine structure through the appropriate selection of amines and carbonyl compounds allows for the preparation of new compounds with the desired properties. Considering the chemical structure of the investigated imines for organic electronics, special attention is paid to heterocyclic azomethines with a thiophene unit. − Compounds with a thiophene structure exhibit many desirable properties in optoelectronics, such as low oxidation potentials, low band-gap energy, good electrical conductivity, and chemical and thermal stability. ,− ,, Apart from the various fields of imine applications, they are also investigated as materials for photovoltaic (PV) cells. − Nowadays, they are examined in bulk heterojunctions (BHJs), − dye-sensitized solar cells (DSSCs), and perovskite solar cells (PSCs).…”

“…Instrumental techniques including1 H NMR,13 C NMR, FTIR, and elemental analysis were performed to confirm the chemical structure and purity of the prepared imines. In the1 H NMR spectra, the signal of the proton of the −HCN− bond was observed in the range of 7.92 (Az-2)−8.32 (Az-5) ppm. The lack of the characteristic signal of the proton of the aldehyde group (−COH) confirmed the condensation reaction.…”

CaF2/ZnS Multilayered Films on Top-Emission Organic Light-Emitting Diode for Improving Color Purity and Moderation of Dark-Spot Formation

“…Consequently, a non-light-emitting area called a dark spot is formed without stringent encapsulation. 9 Therefore, it is necessary to develop high-performance thin-film encapsulation technology to realize an OLED display that can be driven in the atmosphere for a long time. Currently, the most commonly used method is to fabricate an OLED and then rigorously encapsulate it with a cover glass using an ultraviolet (UV)-epoxy resin.…”