X-ray detectors play a pivotal role in development and advancement of humankind, from far-reaching impact in medicine to furthering the ability to observe distant objects in outer space. While other electronics show the ability to adapt to flexible and lightweight formats, state-of-the-art X-ray detectors rely on materials requiring bulky and fragile configurations, severely limiting their applications. Lead halide perovskites is one of the most rapidly advancing novel materials with success in the field of semiconductor devices. Here, an ultraflexible, lightweight, and highly conformable passively operated thin film perovskite X-ray detector with a sensitivity as high as 9.3 ± 0.5 µC Gy −1 cm −2 at 0 V and a remarkably low limit of detection of 0.58 ± 0.05 Gy s −1 is presented. Various electron and hole transporting layers accessing their individual impact on the detector performance are evaluated. Moreover, it is shown that this ultrathin form-factor allows for fabrication of devices detecting X-rays equivalently from front and back side.

Surface photovoltage spectroscopy (SPS) allows for obtaining a detailed picture of the electronic structure of semiconductors. In SPS, changes in band bending at the free semiconductor surface are monitored as a function of external illumination. Surface photovoltage spectroscopy can provide detailed, quantitative information on bulk properties (e.g. bandgap and conductivity type, defect states energy, and lifetime) and can be used for complete construction of surface and interface band diagrams, including the measurement of energy levels in quantum structures. Measurements using SPS are contactless and non‐destructive. In addition, they can be performed both in situ and ex situ, at any reasonable temperature, on many semiconducting materials, at any ambient and at any lateral resolution down to the atomic scale. In this review an overview of SPS‐related theory is presented, the SPS experimental set‐up is described and applications for the characterization of a wide variety of materials and structures are presented (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

It is demonstrated that boron-doped nanowires have predominantly long-term stable wurtzite phase while the majority of phosphorus-doped ones present diamond phase. A simplified model based on the different solubility of boron and phosphorus in gold is proposed to explain their diverse effectiveness in retaining the wurtzite phase. The wurtzite nanowires present a direct transition at the Γ point at approximately 1.5 eV while the diamond ones have a predominant emission around 1.1 eV. The aforementioned results are intriguing for innovative solar cell devices.

AlInN/AlN/GaN heterostructures were characterized by atomic force microscopy. V-defects and channels were observed. In phase-contrast mode, these features were found related to inhomogeneities associated with In-segregation (and/or In-diffusion) and Al-rich surface reconstruction. The electrical characterization via conductive atomic force microscopy showed enhanced conductivity regions related to In-rich traces within channels and V-defects.

High-efficiency perovskite-based solar cells comprise sophisticated stacks of materials which, however, often feature different thermal expansion coefficients and are only weakly bonded at their interfaces. This may raise concerns over delamination in such devices, jeopardizing their long-term stability and commercial viability. Here, we investigate the root causes of catastrophic top-contact delamination we observed in state-of-the-art p-i-n perovskite/silicon tandem solar cells. By combining macroscopic and microscopic analyses, we identify the interface between the fullerene electron transport layer and the tin oxide buffer layer at the origin of such delamination. Specifically, we find that the perovskite morphology and its roughness play a significant role in the microscopic adhesion of the top layers, as well as the film processing conditions, particularly the deposition temperature and the sputtering power. Our findings mandate the search for new interfacial linking strategies to enable mechanically strong perovskite-based solar cells, as required for commercialization.