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- ItemRecent developments of stamped planar micro-supercapacitors: Materials, fabrication and perspectives(Amsterdam : Elsevier, 2021) Li, Fei; Li, Yang; Qu, Jiang; Wang, Jinhui; Bandari, Vineeth Kumar; Zhu, Feng; Schmidt, Oliver G.The rapid development of wearable and portable electronics has dramatically increased the application for miniaturized energy storage components. Stamping micro-supercapacitors (MSCs) with planar interdigital configurations are considered as a promising candidate to meet the requirements. In this review, recent progress of the different stamping materials and various stamping technologies are first discussed. The merits of each material, manufacturing process of each stamping method and the properties of stamping MSCs are scrutinized, respectively. Further insights on technical difficulties and scientific challenges are finally demonstrated, including the limited thickness of printed electrodes, poor overlay accuracy and printing resolution.
- ItemExperimental observation of Berry phases in optical Möbius-strip microcavities(London [u.a.] : Nature Publ. Group, 2022) Wang, Jiawei; Valligatla, Sreeramulu; Yin, Yin; Schwarz, Lukas; Medina-Sánchez, Mariana; Baunack, Stefan; Lee, Ching Hua; Thomale, Ronny; Li, Shilong; Fomin, Vladimir M.; Ma, Libo; Schmidt, Oliver G.The Möbius strip, a fascinating loop structure with one-sided topology, provides a rich playground for manipulating the non-trivial topological behaviour of spinning particles, such as electrons, polaritons and photons, in both real and parameter spaces. For photons resonating in a Möbius-strip cavity, the occurrence of an extra phase—known as the Berry phase—with purely topological origin is expected due to its non-trivial evolution in parameter space. However, despite numerous theoretical investigations, characterizing the optical Berry phase in a Möbius-strip cavity has remained elusive. Here we report the experimental observation of the Berry phase generated in optical Möbius-strip microcavities. In contrast to theoretical predictions in optical, electronic and magnetic Möbius-topology systems where only Berry phase π occurs, we demonstrate that a variable Berry phase smaller than π can be acquired by generating elliptical polarization of resonating light. Möbius-strip microcavities as integrable and Berry-phase-programmable optical systems are of great interest in topological physics and emerging classical or quantum photonic applications.
- ItemAdvanced architecture designs towards high-performance 3D microbatteries(Amsterdam : Elsevier, 2021) Li, Yang; Qu, Jiang; Li, Fei; Qu, Zhe; Tang, Hongmei; Liu, Lixiang; Zhu, Minshen; Schmidt, Oliver G.Rechargeable microbatteries are important power supplies for microelectronic devices. Two essential targets for rechargeable microbatteries are high output energy and minimal footprint areas. In addition to the development of new high-performance electrode materials, the device configurations of microbatteries also play an important role in enhancing the output energy and miniaturizing the footprint area. To make a clear vision on the design principle of rechargeable microbatteries, we firstly summarize the typical configurations of microbatteries. The advantages of different configurations are thoroughly discussed from the aspects of fabrication technologies and material engineering. Towards the high energy output at a minimal footprint area, a revolutionary design for microbatteries is of great importance. In this perspective, we review the progress of fabricating microbatteries based on the rolled-up nanotechnology, a derivative origami technology. Finally, we discussed the challenges and perspectives in the device design and materials optimization.
- ItemEditorial for a special issue “Nano energy materials and devices for miniaturized electronics and smart systems”(Amsterdam : Elsevier, 2021) Zhu, Feng; Schmidt, Oliver G.[No abstract available]
- ItemSingle “Swiss-roll” microelectrode elucidates the critical role of iron substitution in conversion-type oxides(Washington, DC [u.a.] : Assoc., 2022) Liu, Lixiang; Huang, Shaozhuan; Shi, Wujun; Sun, Xiaolei; Pang, Jinbo; Lu, Qiongqiong; Yang, Ye; Xi, Lixia; Deng, Liang; Oswald, Steffen; Yin, Yin; Liu, Lifeng; Ma, Libo; Schmidt, Oliver G.; Shi, Yumeng; Zhang, LinAdvancing the lithium-ion battery technology requires the understanding of electrochemical processes in electrode materials with high resolution, accuracy, and sensitivity. However, most techniques today are limited by their inability to separate the complex signals from slurry-coated composite electrodes. Here, we use a three-dimensional “Swiss-roll” microtubular electrode that is incorporated into a micrometer-sized lithium battery. This on-chip platform combines various in situ characterization techniques and precisely probes the intrinsic electrochemical properties of each active material due to the removal of unnecessary binders and additives. As an example, it helps elucidate the critical role of Fe substitution in a conversion-type NiO electrode by monitoring the evolution of Fe2O3 and solid electrolyte interphase layer. The markedly enhanced electrode performances are therefore explained. Our approach exposes a hitherto unexplored route to tracking the phase, morphology, and electrochemical evolution of electrodes in real time, allowing us to reveal information that is not accessible with bulk-level characterization techniques.
- ItemMicromotor-mediated sperm constrictions for improved swimming performance(Berlin ; Heidelberg : Springer, 2021) Striggow, Friedrich; Nadporozhskaia, Lidiia; Friedrich, Benjamin M.; Schmidt, Oliver G.; Medina-Sánchez, MarianaSperm-driven micromotors, consisting of a single sperm cell captured in a microcap, utilize the strong propulsion generated by the flagellar beat of motile spermatozoa for locomotion. It enables the movement of such micromotors in biological media, while being steered remotely by means of an external magnetic field. The substantial decrease in swimming speed, caused by the additional hydrodynamic load of the microcap, limits the applicability of sperm-based micromotors. Therefore, to improve the performance of such micromotors, we first investigate the effects of additional cargo on the flagellar beat of spermatozoa. We designed two different kinds of microcaps, which each result in different load responses of the flagellar beat. As an additional design feature, we constrain rotational degrees of freedom of the cell’s motion by modifying the inner cavity of the cap. Particularly, cell rolling is substantially reduced by tightly locking the sperm head inside the microcap. Likewise, cell yawing is decreased by aligning the micromotors under an external static magnetic field. The observed differences in swimming speed of different micromotors are not so much a direct consequence of hydrodynamic effects, but rather stem from changes in flagellar bending waves, hence are an indirect effect. Our work serves as proof-of-principle that the optimal design of microcaps is key for the development of efficient sperm-driven micromotors.