3D scanning coherent x-ray microscopy at PtyNAMi

X-ray ptychography in 3D is ideal for quantitative structural analysis with highest spatial resolution. The Ptychographic Nano-Analytical Microscope (PtyNAMi) installed at beamline P06 at PETRA III (DESY, Hamburg) is optimized for high-resolution scanning hard X-ray microscopy. The current data evaluation pipeline for ptychographic tomography at PtyNAMi is outlined and the performance of the microscope demonstrated at the example of an inverse opal Ni sample

Monolithic perovskite/silicon tandems with >28% efficiency: role of silicon-surface texture on perovskite properties

Textured silicon wafers used in silicon solar cell manufacturing offer superior light trapping, which is a critical enabler for high-performance photovoltaics. A similar optical benefit can be obtained in monolithic perovskite/silicon tandem solar cells, enhancing the current output of the silicon bottom cell. Yet, such complex silicon surfaces may affect the structural and optoelectronic properties of the overlying perovskite films. Here, through extensive characterization based on optical and microstructural spectroscopy, it is found that the main effect of such substrate morphology lies in an altering of the photoluminescence response of the perovskite, which is associated with thickness variations of the perovskite, rather than lattice strain or compositional changes. With this understanding, the design of high-performance perovskite/silicon tandems is rationalized, yielding certified power conversion efficiencies of >28%