Vacuum-compatible photon-counting hybrid pixel detector for wide-angle x-ray scattering, x-ray diffraction, and x-ray reflectometry in the tender x-ray range

Abstract

A vacuum-compatible photon-counting hybrid pixel detector has been installed in the ultra-high vacuum (UHV) reflectometer of the four-crystal monochromator (FCM) beamline of the Physikalisch-Technische Bundesanstalt (PTB) at the electron storage ring BESSY II in Berlin, Germany. The setup is based on the PILATUS3 100K module. The detector can be used in the entire photon energy range accessible at the beamline from 1.75 keV to 10 keV. Complementing the already installed vacuum-compatible PILATUS 1M detector used for small-angle scattering (SAXS) and grazing incidence SAXS (GISAXS), it is possible to access larger scattering angles. The water-cooled module is located on the goniometer arm and can be positioned from −90 • to 90 • with respect to the incoming beam at a distance of about 200 mm from the sample. To perform absolute scattering experiments the linearity, homogeneity and the angular dependence of the quantum efficiency, including their relative uncertainties, have been investigated. In addition, first results of the performance in wide-angle X-ray scattering (WAXS), X-ray diffraction (XRD) and X-ray reflectometry (XRR) are presented.

Monolithic perovskite/silicon tandem solar cell with >29% efficiency by enhanced hole extraction

“…To also exclude differences in perovskite composition and crystal orientation due to possible growth differences, we probed the effect of the HTL on these properties by grazing-incidence wide-angle x-ray scattering (GIWAXS) at the four crystal monochromator beamline of the Physikalisch-Technische Bundesanstalt (48). Azimuthally integrated diffraction patterns collected on a movable PILATUS detector module (49) showed comparable composition in each case (Figure S13), with marginally increased PbI 2 scattering intensity on PTAA as we observed in our previous work (7). Comparing azimuthal intensity profiles for perovskite scattering features (Figure S14), we found negligible difference in crystallographic orientation between the samples.…”

“…Grazing incidence angles from 1.5° to 6.5° were used to probe different depths in the film and at high angles the broadening due to the beam footprint on the sample is reduced. Scattering was detected with a vacuum-compatible version of the PILATUS3 X 100K hybrid photon-counting detector (DECTRIS) (49). This detector was rotated around the sample center in 4.5° steps through 16 positions at a sample-to-detector distance of 206 mm with 30 s acquisition at each detector angle.…”

Photoprotection in metal halide perovskites by ionic defect formation

“…PL microscopy can provide detailed information on the photophysical changes induced on the perovskite electronic structure by light, but it requires intense irradiation due to the comparatively low sensitivity provided by such experiments. To demonstrate that similar processes also occur at moderate and device-relevant photon fluxes, we conducted in situ synchrotron wide-angle X-ray scattering (WAXS) measurements in transmission geometry under high vacuum using a fourcrystal monochromator beamline 43,44 (Note S5) to monitor light-induced structural changes in the material with high sensitivity. For light excitation, an LED source (450 nm/2.76 eV, 50 mW/cm 2 ) was used.…”

“…43 The in situ measurement used 8 keV photon energy (l = 1.5498 A ˚) in a transmission geometry under high vacuum (10 À7 mbar). The photon flux from the synchrotron beam, as measured with a photodiode, was 1.8 3 10 8 photons s À1 or 2.42 3 10 9 photons s À1 mm À2 ($0.31 mW/cm 2 ) over the oval-shaped beam spot with a height of 80 mm and a width of 300 mm, and the total beam exposure for the experiment was 5,600 s. Scattered X-rays were detected with a vacuum-compatible version of the PILATUS3 X 100K hybrid photon-counting detector (DECTRIS), 44 Article combined to create the full diffraction pattern, using LaB6 as a calibrant. Data were analyzed and corrected using PyFAI.…”

Challenges of grazing emission X-ray fluorescence (GEXRF) for the characterization of advanced nanostructured surfaces

“…A nanostructured TiO 2 polarizer sample fabricated by state-of-the-art self-aligned double patterning is investigated using both techniques. The use of modern in-vacuum single photon counting area detectors 21,22 combined with a brilliant photon source and the option to vary the incoming photon energy allows us to selectively excite and analyse specific areas inside the nanostructures. The sensitivity variability of the GEXRF method offers new possibilities for dimensional and analytical X-ray nanometrology.…”