Pengzhong Chen

Purely organic long-persistent luminescence materials capable of efficiently utilizing triplet excitons through multiple radiative pathways remain difficult to realize because triplet generation, stabilization, and recycling must be simultaneously regulated. Herein, a melt-processable host–guest afterglow system is constructed by dispersing a fluorene-containing difluoroboron β-diketonate luminophore, 3-OMe, into a crystalline 4-methoxybenzophenone (MeOBP) matrix. The rigid MeOBP matrix suppresses molecular motions and nonradiative deactivation, thereby enabling long-lived guest-centered emission. The optimized material exhibits a bright yellow afterglow visible for more than 5 seconds under ambient conditions and two delayed-emission bands located at approximately 480-500 and 540-545 nm. Temperature-dependent spectroscopy and decay measurements assign the shorter-wavelength emissions predominantly to thermally activated delayed fluorescence and the longer-wavelength emissions to room-temperature phosphorescence. The apparent intersystem crossing and reverse intersystem crossing rate constants are estimated to be approximately 7.70 – 8.96 × 107 s-1 and 10.24 – 11.93 s⁻¹, respectively. Moreover, the material can be readily processed into powders, patterned films, and aqueous dispersions, demonstrating the potential of controlled triplet-exciton recycling for constructing efficient and processable organic afterglow materials.

As a critical consumable in extreme ultraviolet (EUV) lithography, EUV photoresists directly improve the efficiency and performance of the lithography process through enhancements to their sensitivity and resolution. Herein, two Ti–Zr heterometallic oxo clusters (TiZrs) are designed and synthesized via a straightforward approach. TiZrs are demonstrated superior film formation properties and excellent thermal stability. Among the candidates, TiZr2, which contains a higher concentration of Ti atoms with excellent EUV absorption and easily cleavable butoxy‐metal bonds, exhibits increased sensitivity, and can be used as a single‐component photoresist to achieve high‐resolution patterns with low line‐edge roughness and high etching selectivity for silicon, under both electron beam (EB) and EUV lithography. Furthermore, the photoreaction mechanism of TiZrs is systematically investigated using TiZr2 as a model system. These findings underscore the efficacy of tailoring structural design and modulating cluster materials via heterometal and heteroligand strategies to enhance lithography sensitivity, thereby providing valuable insights for future material design and applications.

Organotin clusters are promising candidates for extreme ultraviolet (EUV) lithography but often suffer from insufficient sensitivity. To address this challenge, we report the first systematic library of halogen‐engineered isostructural dinuclear organotin clusters (Sn2‐4X, X = F, Cl, Br, I), designed to enhance EUV absorption via halogen incorporation. Our strategy features a synergistic tripartite molecular design integrating: (1) radiation‐labile Sn─C bonds for efficient ionization and cleavage; (2) halogenated aromatic ligands to boost absorption cross‐sections and etch resistance; and (3) triethanolamine (TEA) ligands to facilitate intermolecular cross‐linking via hydrogen atom transfer (HAT). This rational engineering significantly amplifies lithographic performance. Notably, Sn2‐4F achieves a record sensitivity of 10 mJ cm ⁻² alongside ultrahigh resolution (10 nm), establishing a new benchmark for metal–organic clusters (MOCs). Mechanistically, we reveal a fundamental dichotomy where inner‐shell ionization of heavy atoms governs EUV sensitivity, whereas “kinetic overkill” dominates electron beam lithography (EBL). Furthermore, a halogen‐dependent dissociative electron attachment (DEA) pathway is elucidated, which reinforces the lithographic network through Sn─X coordination. This work bridges the gap between molecular design, radiation physics, and chemistry, offering a robust roadmap for next‐generation high‐sensitivity EUV photoresists.

Metal‐oxo cluster (MOC) resists are promising candidates for extreme ultraviolet lithography (EUVL), but optimizing the resolution, line‐edge roughness (LER), and sensitivity (RLS) trade‐off remains challenging. Leveraging dissociative electron attachment (DEA) to activate C─F bonds provides a controllable handle to improve this RLS trade‐off, yet remains underexplored. Here, we report a room‐temperature, scalable synthesis of a tunable series of Sn‐oxo clusters and demonstrate hundred‐gram‐scale, single‐batch production. The fluorinated FPAA demonstrates enhanced sensitivity without compromising resolution or LER. Under electron beam lithography (EBL), FPAA achieves a critical dimension (CD) of 9.1 nm and an LER of 2.2 nm, and enables high‐fidelity complex patterning. Additionally, FPAA exhibits robust performance under deep ultraviolet (DUV) lithography and EUVL, achieving a CD of 20.9 nm under EUVL. FPAA also shows exceptional plasma resistance, achieving a high estimated Si:resist etch selectivity of >50:1. Mechanistic analyses indicate that irradiation‐generated low‐energy secondary electrons (LESEs) promote electron‐induced C─F activation, consistent with a DEA‐mediated pathway. Concurrently, organic ligand bridging and Sn─O─Sn network densification occur, forming a crosslinked network that drives the solubility switch. This work elucidates the lithographic mechanisms of Sn‐oxo clusters and provides design principles for MOC resists, supporting progress toward sub‐10‐nm lithographic resolution.

Metal‐oxo cluster (MOC) resists are promising candidates for extreme ultraviolet lithography (EUVL), but optimizing the resolution, line‐edge roughness (LER), and sensitivity (RLS) trade‐off remains challenging. Leveraging dissociative electron attachment (DEA) to activate C─F bonds provides a controllable handle to improve this RLS trade‐off, yet remains underexplored. Here, we report a room‐temperature, scalable synthesis of a tunable series of Sn‐oxo clusters and demonstrate hundred‐gram‐scale, single‐batch production. The fluorinated FPAA demonstrates enhanced sensitivity without compromising resolution or LER. Under electron beam lithography (EBL), FPAA achieves a critical dimension (CD) of 9.1 nm and an LER of 2.2 nm, and enables high‐fidelity complex patterning. Additionally, FPAA exhibits robust performance under deep ultraviolet (DUV) lithography and EUVL, achieving a CD of 20.9 nm under EUVL. FPAA also shows exceptional plasma resistance, achieving a high estimated Si:resist etch selectivity of >50:1. Mechanistic analyses indicate that irradiation‐generated low‐energy secondary electrons (LESEs) promote electron‐induced C─F activation, consistent with a DEA‐mediated pathway. Concurrently, organic ligand bridging and Sn─O─Sn network densification occur, forming a crosslinked network that drives the solubility switch. This work elucidates the lithographic mechanisms of Sn‐oxo clusters and provides design principles for MOC resists, supporting progress toward sub‐10‐nm lithographic resolution.

In response to the increasing demands in advanced lithography for high‐resolution and highly stable photoresists, the development of high‐performance resist materials has become critically important. In this study, a series of poly (tert‐butyl methacrylate‐ co ‐adamantyl methacrylate‐ co ‐[trifluoroethyl methacrylate/1,1,1,3,3,3‐hexafluoroisopropyl isobutyrate methacrylate]) copolymers (PTAF) were rationally designed and synthesized, and their preparation conditions were systematically optimized via a single‐factor experimental design. The molecular weight distribution, thermal properties, hydrophobicity, and electron‐beam lithography (EBL) performance of the resulting polymers were comprehensively investigated. The results show that PTAF exhibits a narrow molecular weight distribution (polydispersity index = 1.2–1.3) and a number‐average molecular weight ( M _n ) of approximately 4271 g mol ⁻¹ . The polymer demonstrates good thermal stability, with an initial decomposition temperature ( T _d ) of 212°C and a glass transition temperature ( T _g ) of 105°C, along with pronounced hydrophobicity. EBL results reveal that PTAF displays intrinsic negative‐tone behavior in the absence of externally added photoacid generators, enabling fabrication of high‐resolution patterns with a minimum linewidth of 16.5 nm. Mechanistic studies indicate that fluorinated monomers undergo ionization upon irradiation, initiating in situ acid generation, which subsequently triggers the deprotection of tert‐butyl ester groups during post‐exposure baking. This process leads to a polarity reversal and a corresponding solubility switch in the resist system. Overall, this work establishes a high‐performance ternary copolymer photoresist platform and elucidates its negative‐tone imaging mechanism, providing valuable insights for the design of polymer‐based resists in advanced lithography, particularly for extreme ultraviolet applications.

High‐performance photoresists are essential for advancing semiconductor technology into the sub‐3‐nm process node. However, photoresist performance has long been constrained by the trade‐off among resolution (R), line edge roughness (L), and sensitivity (S), with the simultaneous enhancement of sensitivity and resolution remains a challenge. In this study, we propose a strategy to overcome the RLS trade‐off by enhancing the polarity of metal‐oxo clusters. A series of Sn‐Ti clusters with increasing polarity were synthesized by adjusting the bridging ligands and reducing the number of low‐polarity ligands. Experimental results confirm that, as the developer polarity decreases, higher polar Sn‐Ti clusters exhibit a more pronounced enhancement in sensitivity. The highest‐polarity cluster, TS‐3, undergoes a significant polarity switch upon exposure, enabling simultaneous improvement in sensitivity and resolution under lower‐polarity developers, ultimately breaking the conventional RLS trade‐off. TS‐3 delivers superior patterning performance in both electron beam lithography and extreme‐ultraviolet lithography, with a minimum linewidth of 8 nm. This study enhances the understanding of the solubility‐transition mechanism in cluster photoresists and provides a new approach for the development of high‐performance photoresists.

Addressing the fundamental trade‐off between thermal stability and optical transparency in polyimides (PIs) is pivotal for next‐generation flexible electronics. Herein, we report a fluorine‐free strategy to develop high‐performance colorless PIs by strategically engineering isomeric diamine monomers featuring meta‐substitutions and sterically bulky fluorenyl side groups. PI‐1 achieves an exceptional optical transmittance of 92.8% at 450 nm and a low yellowness index of 1.49, while maintaining a high glass transition temperature ( T _g ) of 320°C. Theoretical simulations confirm that the highly distorted spatial conformation and high energy gap (5.05 eV) effectively suppress charge‐transfer complex (CTC) formation. Furthermore, PI‐1 demonstrates outstanding mechanical durability, sustaining 200 000 folding cycles at a 2 mm radius without structural failure. Finally, high‐fidelity RGB pixel arrays were successfully fabricated on flexible PI‐1 substrates using a simulated photolithography with thermally stable anthraquinone dyes, which offer superior homogeneity compared to conventional pigment‐based systems by eliminating particle‐induced light scattering. This work provides a sustainable and high‐performance material paradigm for advanced flexible displays and optoelectronic applications.

The development of multiple-resonance (MR) thermally activated delayed fluorescence (TADF) emitters has attracted considerable attention for the development of next-generation deep-blue organic light-emitting diodes (OLEDs) due to their high exciton utilization efficiency and narrowband emission. Nevertheless, their intrinsically strong intermolecular interactions lead to tight packing in solid films, inducing the formation of exciplexes or exciton aggregates even at low doping concentrations, which severely degrades both luminescence efficiency and color purity. Therefore, developing effective strategies to fabricate quenching-resistant MR-TADF emitters without compromising color purity has become an urgent and important challenge in the field. In this study, we present novel MR-TADF deep-blue emitters, tBuICzCz and PhICzCz, synthesized by a straightforward two-step reaction that connects carbazole groups with a mono-indolo[3,2,1-jk]carbazole (ICz). This design effectively integrates the MR effect of the mono-ICz core with a long-range charge transfer (LRCT) process between the carbazole and ICz units, effectively balancing narrowband emission and suppressed intermolecular quenching. Consequently, tBuICzCz and PhICzCz exhibit narrowband deep-blue emissions at wavelengths of 444 nm and 425 nm, respectively, and demonstrate notable TADF characteristics in the films. The fabricated deep-blue OLEDs based on tBuICzCz and PhICzCz with 15 wt% doping-ratios achieve external quantum efficiency (EQE) values of 24.7% and 15.5%, full width at half-maximum (FWHM) values of 24 nm and 33 nm, and CIEy values of 0.041 and 0.021, respectively, thereby meeting the BT.2020 CIEy standard. Importantly, even at an increased doping ratio of 25 wt%, the devices maintain a high EQEmax (> 13%) with nearly unchanged emission spectrum, demonstrating favorable concentration tunability for practical applications. These results contribute to a deeper understanding of the correlation between molecular structure and optical properties in ICz-based MR-TADF emitters.