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Electroplated copper contacts on small-area single-junction perovskite solar cells (PSCs) using an atomic layer deposited (ALD) Al2O3 masking layer on ITO are demonstrated for the first time. The photoconversion efficiency of ≈11% after manufacturing the Cu contacts confirms that PSCs can survive the wet-chemical plating process. From the successful realization of plated contact fingers, the creation of an electrical contact between the Cu electrode and the ITO on the FA0.75Cs0.25Pb(I0.8Br0.2)3 perovskite absorber is inferred. Furthermore, scanning electron microscopy (SEM) with energy-dispersive X-ray (EDX) analysis shows the formation of a compact interface between ITO and plated Cu. An additional plating approach, using self-passivated aluminum as mask, allows to produce well-defined 30 mm wide Cu contacts on the PSC. Such a plating process allows for plating a low-resistive Cu grid simultaneously on both sides of a perovskite silicon heterojunction tandem solar cell with TCO, independent of substrate size.

Monolithic perovskite silicon tandem solar cells can overcome the theoretical efficiency limit of silicon solar cells. This requires an optimum bandgap, high quantum efficiency, and high stability of the perovskite. Herein, a silicon heterojunction bottom cell is combined with a perovskite top cell, with an optimum bandgap of 1.68 amp; 8201;eV in planar p i n tandem configuration. A methylammonium free FA0.75Cs0.25Pb I0.8Br0.2 3 perovskite with high Cs content is investigated for improved stability. A 10 molarity increase to 1.1 amp; 8201;m of the perovskite precursor solution results in amp; 8776;75 amp; 8201;nm thicker absorber layers and 0.7 amp; 8201;mA amp; 8201;cm amp; 8722;2 higher short circuit current density. With the optimized absorber, tandem devices reach a high fill factor of 80 and up to 25.1 certified efficiency. The unencapsulated tandem device shows an efficiency improvement of 2.3 absolute over 5 amp; 8201;months, showing the robustness of the absorber against degradation. Moreover, a photoluminescence quantum yield analysis reveals that with adapted charge transport materials and surface passivation, along with improved antireflection measures, the high bandgap perovskite absorber has the potential for 30 tandem efficiency in the near future

Summary A “resistance breaking” isolate of barley yellow mosaic virus-2 (BaYMV-2) was cloned as a cDNA and characterised. Restriction mapping and comparison with a German and a Japanese isolate of BaYMV (BaYMV-G and BaYMV-J) revealed a high level of restriction site conservation for RNAl and the majority of RNA2. However, in a box of approximately 600 nucleotides located on RNA2, striking differences in the restriction pattern could be identified. The nucleotide sequence of this box, as well as of the 3‘-terminal region of RNA1 including the coat protein coding region, and the deduced amino acid sequences were analysed. Identity at the amino acid level was between 99.3% and 92.3% in comparison with the corresponding sequences of BaYMV-G and BaYMV-J, suggesting that BaYMV-2 is closely related to BaYMV. Consequently, the classification of BaYMV-2 as a “resistance breaking” strain of BaYMV is justified.