The use of ionizing radiation such as extreme ultraviolet (EUV) radiation is expected in next-generation lithography. Poly(4-hydroxystyrene) (PHS), which has been used in KrF excimer laser (248 nm) lithography as a backbone polymer, is a promising material for chemically amplified EUV and electron beam resists. In this study, the dynamics of the radical cation of poly(styrene-ran-4-hydroxystyrene) [P(S-HS)] was investigated. It was found that the hole transfer reaction in the matrix plays an important role in the sensitization of the resist. The hole transfer range is estimated to be 2:5 units (1:0 nm).

The elucidation of the reaction mechanism after the irradiation of ionizing radiation onto resist polymers is an important issue for extreme-ultraviolet and electron beam chemically amplified resist. The dynamics of radical cations of polymers is essential for elucidating the mechanism of acid formation (deprotonation) in resists. The transient absorption of poly(4-methoxystyrene) (PMOS) was observed in 1,2-dichloroethane and p-dioxane solutions by pulse radiolysis. In the near-infrared region, a characteristic charge resonance band, which represents the π–π interaction between the two benzene rings of the intramolecular PMOS dimer radical cation [(Ph–OCH3)2 +·], was observed. In the presence of halogenated hydrocarbon molecules acting as electron scavengers, the yield of (Ph–OCH3)2 +· was enhanced by the formation of an ion/charge transfer complex. Density functional theory (DFT) calculations were also performed to investigate the electronic state of (Ph–OCH3)2 +·.

Although sufficient tolerance against attack by superoxide radicals (O 2 À ) has been mainly recognized as an important property for Li-O 2 battery (LOB) electrolytes, recent evidence has revealed that other critical factors also govern the cyclability, prompting a reconsideration of the basic design guidelines of LOB electrolytes. Here, we found that LOBs equipped with a N,N-dimethylacetamide (DMA)based electrolyte exhibited better cyclability compared with other standard LOB electrolytes. This superior cyclability is attributable to the capabilities of quenching 1 O 2 and forming highly decomposable Li 2 O 2 . The 1 O 2 quenching capability is equivalent to that of a tetraglyme-based electrolyte containing a several millimolar concentration of a typical chemical quencher. Based on these overlooked factors, the DMA-based electrolyte led to superior cyclability despite its lower O 2 À tolerance. Thus, the present work provides a novel design guideline for the development of LOB electrolytes.

Although sufficient tolerance against attack by superoxide radicals (O 2 À ) has been mainly recognized as an important property for Li-O 2 battery (LOB) electrolytes, recent evidence has revealed that other critical factors also govern the cyclability, prompting a reconsideration of the basic design guidelines of LOB electrolytes. Here, we found that LOBs equipped with a N,N-dimethylacetamide (DMA)based electrolyte exhibited better cyclability compared with other standard LOB electrolytes. This superior cyclability is attributable to the capabilities of quenching 1 O 2 and forming highly decomposable Li 2 O 2 . The 1 O 2 quenching capability is equivalent to that of a tetraglyme-based electrolyte containing a several millimolar concentration of a typical chemical quencher. Based on these overlooked factors, the DMA-based electrolyte led to superior cyclability despite its lower O 2 À tolerance. Thus, the present work provides a novel design guideline for the development of LOB electrolytes.