Comparison of ICP-AlOx and ALD-Al2O3 layers for the rear surface passivation of c-Si solar cells

The deposition rate of the standard (i.e. sequential) atomic layer deposition (ALD) process is very low compared to the plasma-enhanced chemical vapour deposition (PECVD) process. Therefore, as a short- and medium-term perspective, PECVD aluminium oxide (AlOx) films might be better suited for the implementation into industrial-type solar cells than ALD-Al 2O3 films. In this paper, we report results achieved with a newly developed PECVD deposition process for AlOx using an inductively coupled plasma (ICP). We compare the results to high-quality ALDAl2O3 films. We examine a stack consisting of a thin AlOx passivation layer and a PECVD silicon nitride (SiNy) capping layer. Surface recombination velocities below 9 cm/s were measured on low-resistivity (1.4 Ωcm) p-type crystalline silicon wafers passivated either by ICP-PECVD-AlOx films or by ALD-Al2O3 films after annealing at 425°C. Both passivation schemes provide an excellent thermal stability during firing at 910°C with SRVs below 12 cm/s for both, Al2O3/SiNy stacks and single Al 2O3 layers. A fixed negative charge of -4×10 12 cm-2 is measured for ICP-AlOx and ALD-Al2O3, whereas the interface state density is higher for the ICP-AlOx layer with values of 11.0×1011 eV-1cm-2 compared to 1.3×1011 eV -1cm-2 for ALD-Al2O3. Implemented into large-area screen-printed PERC solar cells, an independently confirmed efficiency of 20.1% for ICP-AlOx and an efficiency of 19.6% for ALD-Al2O3 are achieved.BMU/0325296Solland Solar Cells BVSolarWorld Innovations GmbHSCHOTT Solar AGRENA GmbHSINGULUS TECHNOLOGIES A

Oxide‐Based Solid‐State Batteries: A Perspective on Composite Cathode Architecture

The garnet-type phase Li$_7$La$_3$Zr$_2$O$_{12}$ (LLZO) attracts significant attention as an oxide solid electrolyte to enable safe and robust solid-state batteries (SSBs) with potentially high energy density. However, while significant progress has been made in demonstrating compatibility with Li metal, integrating LLZO into composite cathodes remains a challenge. The current perspective focuses on the critical issues that need to be addressed to achieve the ultimate goal of an all-solid-state LLZO-based battery that delivers safety, durability, and pack-level performance characteristics that are unobtainable with state-of-the-art Li-ion batteries. This perspective complements existing reviews of solid/solid interfaces with more emphasis on understanding numerous homo- and heteroionic interfaces in a pure oxide-based SSB and the various phenomena that accompany the evolution of the chemical, electrochemical, structural, morphological, and mechanical properties of those interfaces during processing and operation. Finally, the insights gained from a comprehensive literature survey of LLZO–cathode interfaces are used to guide efforts for the development of LLZO-based SSBs

Mechanisms of HsSAS-6 assembly promoting centriole formation in human cells

SAS-6 proteins are thought to impart the ninefold symmetry of centrioles, but the mechanisms by which their assembly occurs within cells remain elusive. In this paper, we provide evidence that the N-terminal, coiled-coil, and C-terminal domains of HsSAS-6 are each required for procentriole formation in human cells. Moreover, the coiled coil is necessary and sufficient to mediate HsSAS-6 centrosomal targeting. High-resolution imaging reveals that GFP-tagged HsSAS-6 variants localize in a torus around the base of the parental centriole before S phase, perhaps indicative of an initial loading platform. Moreover, fluorescence recovery after photobleaching analysis demonstrates that HsSAS-6 is immobilized progressively at centrosomes during cell cycle progression. Using fluorescence correlation spectroscopy and three-dimensional stochastic optical reconstruction microscopy, we uncover that HsSAS-6 is present in the cytoplasm primarily as a homodimer and that its oligomerization into a ninefold symmetrical ring occurs at centrioles. Together, our findings lead us to propose a mechanism whereby HsSAS-6 homodimers are targeted to centrosomes where the local environment and high concentration of HsSAS-6 promote oligomerization, thus initiating procentriole formation

Investigating the Nucleation of Lithium Deposits in Polycrystalline Solid Electrolytes

All-solid-state batteries (ASSB) are candidates for the next-generation of battery electric vehicles. They potentially enable the use of lithium metal as an anode material thereby highly improving the energy density of the battery. For traditional liquid electrolytes this has not been feasible to date due to the formation of dendritic lithium structures during battery charge. It is generally believed that the mechanical properties of the solid electrolyte stop dendrite growth and several studies using LiPON in a thin film configuration as solid electrolyte demonstrate stable cycling even for elevated current densities of up to 10 mA/cm² [1,2]. However, recently short circuits after only a few cycles under moderate current densities were reported for other polycrystalline electrolyte materials, such as LLZO [3]. Moreover, it was found that lithium does not only deposit at the anode, but also nucleates inside the bulk electrolyte [4], facilitating dendrite growth even for stable solid electrolyte –anode interfaces. The cause for these dendrites might be the higher electronic conductivity of LLZO compared to LIPON, however, this has not yet been resolved conclusively. In our contribution we explore different mechanisms for these internal lithium deposits using models and theories on the continuum scale [5,6]. In our studies we focus on the effect of grain boundaries and structural defects within the solid electrolyte. These structural features are obstacles for the flux of lithium ions and electrons and thereby affect the transient potential landscape during the charging and discharging of the ASSB. In combination with insights on the spatial distribution of lithium ions at the grain boundaries our simulations will provide indications for nucleation centers and, additionally, will allow us to analyze the stability of lithium clusters during discharge. The aim of our work is to get an understanding of the influence of material properties, manufacturing processes, and cycling conditions on the nucleation of local lithium deposits and their effect on dendrite growth. This information will give important directions for the development of future ASSBs