Lead bromide-based halide perovskites are of interest for wide-band-gap (>1.75 eV) absorbers for low-cost solar spectrum splitting to boost solar-to-electrical energy conversion efficiency/area by adding them to c-Si or Cu(In,Ga)Se 2 PV cells and for photoelectrochemical solar fuel synthesis. Deep in-gap electronic states in PV absorbers serve as recombination centers and are detrimental for the cell's photovoltaic performance, especially for the open-circuit voltage (V oc ). We find four different deep defect states in polycrystalline layers of mixed-cation lead tribromide from highsensitivity modulated surface photovoltage (SPV) spectroscopy. Measurements were performed with different contact configurations, on complete solar cells and on samples before and after aging or stressing at 85 °C under illumination. Three of the four states, with energies of ∼0.63, 0.73, and 1.35 eV below the conduction band edge, are assigned to intrinsic defects, whereas defect states in the middle of the band gap could be associated with (uncontrolled) impurities.

The measurement of surface photovoltage (SPV) transients over 12 orders of magnitude in time was recently demonstrated [Rev. Sci. Instrum. 88, 053904 (2017)]. In dedicated experiments, however, a high-impedance buffer shall be placed outside the measurement chamber, which has consequences for SPV measurements at very short times. By varying the LCR circuit of a measurement configuration, applying a multi-parameter fit and simulating the corresponding SPV transients, we show, on the examples of highly doped silicon and a CdS thin film, that the source function of SPV transients can be reconstructed with a resolution time better than 1 ns.

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The rare-earth (R) magnetism and grain-size dependencies of magnetic field distributions in RBa2Cu3O7−δ (RBCO) vortex states have been studied. A maximum-entropy technique has been applied to transverse field muon-spin-relaxation data of several polycrystalline cuprate superconductors. The main vortex signals for R=Er, Gd, and Ho reveal signs of two peaks in the field distribution below the applied field (Bext=1 kOe) as predicted for d-wave superconductivity. For the RBCO (R=Er, Gd, Ho, Eu, Y) vortex states, we have confirmed low-field tails in the field distributions well below Bext. The low-field tail may be caused by magnetic frustration in the vortex state or possible CuO-chain superconductivity below 25 K. Any interpretation of these (magnetic) vortex anomalies should comprise unconventional non-Bardeen–Cooper–Schrieffer-like fundamental properties of the cuprate vortex states.