Ultraviolet light blocking optically clear adhesives for foldable displays via highly efficient visible-light curing

Abstract

In developing an organic light-emitting diode (OLED) panel for a foldable smartphone (specifically, a color filter on encapsulation) aimed at reducing power consumption, the use of a new optically clear adhesive (OCA) that blocks UV light was crucial. However, the incorporation of a UV-blocking agent within the OCA presented a challenge, as it restricted the traditional UV-curing methods commonly used in the manufacturing process. Although a visible-light curing technique for producing UV-blocking OCA was proposed, its slow curing speed posed a barrier to commercialization. Our study introduces a highly efficient photo-initiating system (PIS) for the rapid production of UV-blocking OCAs utilizing visible light. We have carefully selected the photocatalyst (PC) to minimize electron and energy transfer to UV-blocking agents and have chosen co-initiators that allow for faster electron transfer and more rapid PC regeneration compared to previously established amine-based co-initiators. This advancement enabled a tenfold increase in the production speed of UV-blocking OCAs, while maintaining their essential protective, transparent, and flexible properties. When applied to OLED devices, this OCA demonstrated UV protection, suggesting its potential for broader application in the safeguarding of various smart devices.

Highly efficient dual photoredox/copper catalyzed atom transfer radical polymerization achieved through mechanism-driven photocatalyst design

“…While 4DMDP-IPN ( τ delayed = 4.2 μs), 4tCz-IPN ( τ delayed = 1.2 μs), and 4Cz-IPN ( τ delayed = 1.8 μs) showed relatively short delayed fluorescence (DF) lifetimes, 4DP-IPN ( τ delayed = 121.5 μs) and 4DCDP-IPN ( τ delayed = 196.1 μs) exhibited significantly longer DF lifetimes exceeding 100 μs. This indicates that such PCs possess a notably higher T 1 state concentration under a photostationary state compared to other PCs, suggesting a correspondingly faster rate of ET process, and consequently, a reduction in PC loadings 39 , 68 , 76 , 83 . The reference PCs each exhibit an PL emission lifetime that is significantly shorter than those of the cyanoarene PCs ( τ delayed (Eosin Y) = 0.6–4000 μs) 84 , 85 , τ flur.…”

“…2 ). 4DP-IPN, an organic PC, is known for its efficacy in various light-driven organic reactions 67 – 75 , and polymerizations 38 , 76 – 81 , due to its ability to efficiently generate long-lived T 1 state ( τ delayed = 121.5 μs, Φ ISC = 0.84) and exhibit appropriate redox potentials. To minimize the HOMO of PC, 4,4’-dicyanodiphenylamine (i.e., DCDP) was chosen as a donor moiety.…”

Recent progress in ladder-like polysilsesquioxane: synthesis and applications

“…Today, they are indispensable for offering advanced functionalities, including UV protection, reworkability, ease of debonding, and environmental decomposability. 296–299 Among these, switchable adhesives are a type of adhesive that changes adhesion in response to external stimuli such as temperature, light, magnetic fields, or mechanical forces. 300 Baek's group presented research on applying Diels–Alder chemistry to LPSQ to design a switchable adhesive.…”