Optimization of the Sb2S3 Shell Thickness in ZnO Nanowire-Based Extremely Thin Absorber Solar Cells

Extremely thin absorber (ETA) solar cells made of ZnO/TiO2/Sb2S3 core–shell nanowire heterostructures, using P3HT as the hole-transporting material (HTM), are of high interest to surpass solar cell efficiencies of their planar counterpart at lower material cost. However, no dimensional optimization has been addressed in detail, as it raises material and technological critical issues. In this study, the thickness of the Sb2S3 shell grown by chemical spray pyrolysis is tuned from a couple of nanometers to several tens of nanometers, while switching from a partially to a fully crystallized shell. The Sb2S3 shell is highly pure, and the unwanted Sb2O3 phase was not formed. The low end of the thickness is limited by challenges in the crystallization of the Sb2S3 shell, as it is amorphous at nanoscale dimensions, resulting in the low optical absorption of visible photons. In contrast, the high end of the thickness is limited by the increased density of defects in the bulk of the Sb2S3 shell, degrading charge carrier dynamics, and by the incomplete immersion of the P3HT in the structure, resulting in the poor hole collection. The best ETA solar cell with a short-circuit current density of 12.1 mA/cm2, an open-circuit voltage of 502 mV, and a photovoltaic conversion efficiency of 2.83% is obtained for an intermediate thickness of the Sb2S3 shell. These findings highlight that the incorporation of both the absorber shell and HTM in the core–shell heterostructures relies on the spacing between individual nanowires. They further elaborate the intricate nature of the dimensional optimization of an ETA cell, as it requires a fine-balanced holistic approach to correlate all the dimensions of all the components in the heterostructures.

Theoretical research of dimensional optimization and choice of material strength in steel-concrete composite beams

The aim of this study is to find out how the change of individual parameters will affect the flexural strength of steel-concrete composite beams. The project was focused on the choice of strength of materials and the choice of dimension, specifically the height of the concrete slab and the size of the steel profile. The research aim is to reveal which parameters have dominant influence on the flexural strength and thus facilitate the optimization of the design in practice.

Optimization-Based Network Identification for Thermal Transient Measurements

Network identification by deconvolution is a proven method for determining the thermal structure function of a given device. The method allows to derive the thermal capacitances as well as the resistances of a one-dimensional thermal path from the thermal step response of the device. However, the results of this method are significantly affected by noise in the measured data, which is unavoidable to a certain extent. In this paper, a post-processing procedure for network identification from thermal transient measurements is presented. This so-called optimization-based network identification provides a much more accurate and robust result compared to approaches using Fourier or Bayesian deconvolution in combination with Foster-to-Cauer transformation. The thermal structure function obtained from network identification by deconvolution is improved by repeatedly solving the inverse problem in a multi-dimensional optimization process. The result is a non-diverging thermal structure function, which agrees well with the measured thermal impedance. In addition, the associated time constant spectrum can be calculated very accurately. This work shows the potential of inverse optimization approaches for network identification.

The Shortcomings of the Existing Economic Theory and Their Elimination

Th e paper analyzes the state and management of country’s economics. A tuple of event-driven optimal management as a method of artifi cial intelligence has been developed. Th e characteristics of event-driven quality management of associative and structurally complex systems and processes are given. Th e events and probabilities in the management of economics and the state are considered. A measure of invalidation has been introduced for parameters. Th e method of synthesis of the probability of an event based on expert information is presented. Th e necessity of orthogonalization of the logical function and the transition to the probabilistic function have been substantiated. Th e eff ect of repeated initiating events is considered. One-dimensional optimization of the system on a logical model instead of arithmetic multiparameter optimization is presented. Schemes for managing of development and exit of economics from stagnation are given. Th e tools for event-driven quality management of systems and processes are described. Th e analysis of the shortcomings of the existing economic theory and the possibility of their elimination is carried out.