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Photoinduced halide segregation in mixed halide hybrid perovskites [i.e., APb(I1–xBrx)3] represents an intrinsic instability that impedes their commercialization. Resolving this issue requires deve...

Accurate measurements of semiconductor nanocrystal (NC) emission quantum yields (QYs) are critical to condensed phase optical refrigeration. Of particular relevance to measuring NC QYs is a longstanding debate as to whether an excitation energy-dependent (EED) QY exists. Various reports indicate existence of NC EED QYs, suggesting that the phenomenon is linked to specific ensemble properties. We therefore investigate here the existence of EED QYs in two NC systems (CsPbBr3 and CdSe) that are possible candidates for use in optical refrigeration. The influence of NC size, size-distribution, surface ligand, and as-made emission QYs are investigated. Existence of EED QYs is assessed using two approaches (an absolute approach using an integrating sphere and a relative approach involving excitation spectroscopy). Altogether, our results show no evidence of EED QYs across samples. This suggests that parameters beyond those mentioned above are responsible for observations of NC EED QYs.

Mixing bromine and iodine within lead halide perovskites is a common strategy to tune their optical properties. This comes at the cost of instability, as illumination induces halide segregation and degrades device performances. Hence, understanding the behavior of mixed-halide perovskites is crucial for applications. In 3D perovskites such as MAPb(Br

Semiconductor nanocrystals (NCs) are potential materials for verifiable demonstrations of semiconductor-based laser cooling. The key feature that makes NCs appealing for laser cooling is their near unity emission quantum yields (QYs). An unresolved issue regarding NC QYs, however, centers on the existence of an excitation energy dependent (EED) QY. Here, we study EED QYs on three NC systems, aimed at demonstrating NC-based laser cooling (CsPbBr3, CsPbI3, and CdSe/CdS core/shell NCs). We evaluate the impact of EED QYs using two approaches. The first involves direct QY measurements using an integrating sphere. The second entails photoluminescence excitation spectroscopy where changes to NC QYs with excitation energy can be assessed qualitatively.

The article presents the results of assessing the level of social capital of a university department, the mutual influence of the type of organizational culture and the effectiveness of its work. In the course of the study, the concept of social capital was generalized and refined in the context of the concept of sustainable education, as well as in relation to an educational institution, to the community of a higher educational organization. There were tested the ideas of N.P. Makarkin and O.B. Tomilina about the impact of organizational culture on the efficiency of the university. To ensure the comparison of the different departments data with each other there was proposed a method for bringing to a single scale of assessments and calculating weighted average indicators, which made it possible to derive a single integral assessment of the social capital of a department/unit.

The paper presents a certifiable development process applicable to hardware and software development for information processing in the measurement domain, especially the dynamic weighing technology. Thereby it is based on the developments of prototypes for new and predecessor systems and product stages. Particular attention is paid to the possibility of calibration.

For precise length measuring techniques, highly dynamic positioning stages are used to measure and manipulate objects with a resolution in subnanometer range. The position and the orientation of these systems have to be controlled permanently to compensate external disturbances such as sound waves, thermal expansion of the mechanical components, and ground motion. Because of new applications in the area of microsensing devices the dynamic or path accuracy is in addition to the stationary accuracy a critical feature. To improve the dynamic behavior of these machines, an efficient friction compensation as well as a high perfomance signal- and data processing system is necessary. This work presents a realization of a control system with friction compensation for a nanopositioning and nanomeasuring machine based on FPGA technology. Particular attention was paid to the obtainable sampling rate and its impact on the attainable path accuracy.

Developing machines capable of positioning and measuring in nano-metre dimensions is an overall challenging endeavour, which not at least includes providing a highly dynamic and precise trajectory tracking control system. To effectively employ such a control system an adequately performing implementation on an embedded real-time processing system is essential for process performance and quality. In this article an implementation study of a Kalman filter component is presented, comparing the solutions for general purpose processor and digital signal processor to a range of designs for field-programmble gate arrays. Evaluating the performance of the respective implementations for a PXI platform and thus indicating the feasibility of industrial and standard-compliant application is the emphasis of this contribution.