Low temperature (Zn,Sn)O deposition for reducing interface open-circuit voltage deficit to achieve highly efficient Se-free Cu(In,Ga)S solar cells.

Cu(In,Ga)S holds the potential to become a prime candidate for use as the top cell in tandem solar cells owing to its tunable bandgap from 1.55 eV (CuInS) to 2.50 eV (CuGaS) and favorable electronic properties.

Origin of Interface Limitation in Zn(O,S)/CuInS-Based Solar Cells.

Copper indium disulfide (CuInS) grown under Cu-rich conditions exhibits high optical quality but suffers predominantly from charge carrier interface recombination, resulting in poor solar cell performance. An unfavorable "cliff"-like conduction band alignment at the buffer/CuInS interface could be a possible cause of enhanced interface recombination in the device. In this work, we exploit direct and inverse photoelectron spectroscopy together with electrical characterization to investigate the cause of interface recombination in chemical bath-deposited Zn(O,S)/co-evaporated CuInS-based devices.

Waste- and Cd-Free Inkjet-Printed Zn(O,S) Buffer for Cu(In,Ga)(S,Se) Thin-Film Solar Cells.

Thin film semiconductors grown using chemical bath methods produce large amounts of waste solvent and chemicals that then require costly waste processing. We replace the toxic chemical bath deposited CdS buffer layer from our Cu(In,Ga)(S,Se) (CIGS)-based solar cells with a benign inkjet-printed and annealed Zn(O,S) layer using 230 000 times less solvent and 64 000 times less chemicals. The wetting and final thickness of the Zn(O,S) layer on the CIGS is controlled by a UV ozone treatment and the drop spacing, whereas the annealing temperature and atmosphere determine the final chemical composition and band gap.

Chemical instability at chalcogenide surfaces impacts chalcopyrite devices well beyond the surface.

The electrical and optoelectronic properties of materials are determined by the chemical potentials of their constituents. The relative density of point defects is thus controlled, allowing to craft microstructure, trap densities and doping levels. Here, we show that the chemical potentials of chalcogenide materials near the edge of their existence region are not only determined during growth but also at room temperature by post-processing.

Potential of the SPY intraoperative perfusion assessment system to reduce ischemic complications in immediate postmastectomy breast reconstruction.

Background: The quality and viability of mastectomy flaps remain a central challenge in reconstructive surgery, particularly for immediate breast reconstruction. Insufficient perfusion in tissue flaps is a leading cause of early complications following reconstructive procedures, and clinical judgment alone is not completely reliable for the assessment of flap viability. Accurate and reliable intraoperative methods for assessment of tissue perfusion are needed to help surgeons identify tissue at risk for ischemia and necrosis, thereby allowing for maneuvers to improve tissue flap viability.