Black Ultra-Thin Crystalline Silicon Wafers Reach the 4n2 Absorption Limit–Application to IBC Solar Cells

Cutting costs by progressively decreasing substrate thickness is a common theme in the crystalline silicon photovoltaic  industry for the last decades, since drastically thinner wafers would significantly reduce the substrate-related costs. In addition to the technological challenges concerning wafering and handling of razor-thin flexible wafers, a major bottleneck is to maintain high absorption in those thin wafers. For the latter, advanced light-trapping techniques become of paramount importance. Here we demonstrate that by applying state-of-the-art black-Si nanotexture produced by DRIE on thin uncommitted wafers, the maximum theoretical absorption (Yablonovitch's 4n² absorption limit), that is, ideal light trapping, is reached with wafer thicknesses as low as 40, 20, and 10 µm when paired with a back reflector. Due to the achieved promising optical properties the results are implemented into an actual thin interdigitated back contacted solar cell. The proof-of-concept cell, encapsulated in glass, achieved a 16.4% efficiency with an J_SC = 35 mA cm⁻², representing a 43% improvement in output power with respect to the reference polished cell. These results demonstrate the vast potential of black silicon nanotexture in future extremely-thin silicon photovoltaics.     

Movement Simulation of a Five-Link Crawling Robot with Controlled Friction Forces

This paper considers the motion of a five-link crawling robot equipped with special friction elements for the periodic clamping of the links along a rough horizontal surface. A classification of the modes of motion depending on the presence of obstacles on the surface and ways of crossing them is presented. One of the crawling modes along the surface without obstacles or with obstacles when the end links are detached from the surface and the adjacent ones rotate by a given angle in the motion plane is analyzed. The influence of the control parameters on the average robot speed is established.     

Renal structural-functional relationships in early diabetes mellitus

To define the earliest renal morphological changes in patients with type I diabetes, we studied renal function and morphometric analysis of renal biopsies in 59 patients with diabetes for 5-12 years and normal blood pressure, normal creatinine clearance (CCr), and negative dipstick urinary protein. Arteriolar hyalinization and intimal fibrous thickening were noted in 43%. Glomerular basement membrane thickness and fractional mesangial volume were increased in 51% and 56%, respectively. The pre-pubertal and post-pubertal years of diabetes were associated with similar degrees of renal structural changes, but during the pre-pubertal years normal urinary albumin excretion (UAE) was seen. Principal factor analysis of morphometric structural parameters yielded four clusters of variables: "glomerular size" correlated with patient age, CCr, and UAE; "peripheral capillary decrease" correlated with glycosylated hemoglobin, diastolic blood pressure, glomerular filtration rate, and UAE; "mesangial increase" correlated with UAE; and "interstitial scarring" correlated with diastolic blood pressure. This study provides unique documentation of renal structural abnormalities which precede clinically evident renal functional abnormalities and documents that these early structural abnormalities are present in the pre-pubertal years of diabetes as well as postpuberty, and are associated with each other in constellations that correspond to postulated mechanisms in diabetic nephropathy.     

Local uncontrollability for affine control systems with jumps†

This paper investigates affine control systems with jumps for which the ideal I_f(g₁, …, g_m) generated by the drift vector field f in the Lie algebra L(f, g₁, …, g_m) can be imbedded as a kernel of a linear first-order partial differential equation. It will lead us to uncontrollable affine control systems with jumps for which the corresponding reachable sets are included in explicitly described differentiable manifolds.     

High-Speed Multisensor Method of Measurement,Control and 3D Analysis of Complex Object Shapes in Production Environment

In this research, methods and algorithms of calibration of optical schemes and elements of a triangulation laser system were analyzed. Recommendations for precision enhancement of an optical system are further used in improving parameters of a laser and reverse engineering they are also implemented in engineering of a high-speed linear laser 3D scanner.     

Photoelectric Parameters of Photodetectors Based on Thin Microcrystalline Films of CH3NH3PbI3 Perovskite

Technical Physics Letters - Photoelectric characteristics of photodetectors of the type of a photoresistor based on microcrystalline films of the organometallic perovskite CH3NH3PbI3 with gold and...