Selectivity of TiOx-Based Electron-Selective Contacts on n-Type Crystalline Silicon and Solar Cell Efficiency Potential

The selectivity parameter S10 of titanium oxide (TiOx)-based selective contacts on n-type silicon is experimentally extracted through measurements of the specific contact resistivity ρc and the recombination current density prefactor J0, both parameters measured on fully Al-metallized samples. The contact resistivity ρc is determined applying the Cox and Strack method and the J0 values are extracted using dynamic infrared lifetime mapping, allowing for contactless lifetime measurements on fully metallized silicon samples in contrast to conventionally applied lifetime measurement techniques. The highest selectivity after annealing of an n-Si/SiOy/TiOx/Al contact is determined to be S10 = 11.6, which corresponds to a maximum achievable efficiency of 24.1% for this type of electron-selective contact. The maximum selectivity is achieved after low-temperature annealing at 500 °C or through a contact-firing step at a set-peak temperature of 820 °C in an industrial conveyor-belt furnace, as used in today's commercial solar cell production. © 2021 The Authors. physica status solidi (RRL) Rapid Research Letters published by Wiley-VCH Gmb

Composition and electronic structure of SiOx/TiOy/Al passivating carrier selective contacts on n-type silicon solar cells

Carrier-selective and passivating SiOx/TiOy heterocontacts are an attractive alternative to conventional contacts due to their high efficiency potentials combined with relatively simple processing schemes. It is widely accepted that post deposition annealing is necessary to obtain high photovoltaic efficiencies, especially for full area aluminum metallized contacts. Despite some previous high-level electron microscopy studies, the picture of atomic-scale processes underlying this improvement seems to be incomplete. In this work, we apply nanoscale electron microscopy techniques to macroscopically well-characterized solar cells with SiOx/TiOy/Al rear contacts on n-type silicon. Macroscopically, annealed solar cells show a tremendous decrease of series resistance and improved interface passivation. Analyzing the microscopic composition and electronic structure of the contacts, we find that partial intermixing of the SiOx and TiOy layers occurs due to annealing, leading to an apparent thickness reduction of the passivating SiOx. However, the electronic structure of the layers remains clearly distinct. Hence, we conclude that the key to obtain highly efficient SiOx/TiOy/Al contacts is to tailor the processing such that the excellent chemical interface passivation of a SiOx layer is achieved for a layer thin enough to allow efficient tunneling through the layer. Furthermore, we discuss the impact of aluminum metallization on the above mentioned processes

Diode Factor in Solar Cells with Metastable Defects and Back Contact Recombination

To achieve a high fill factor, a small diode factor close to 1 is essential. The optical diode factor determined by photoluminescence is the diode factor from the neutral zone of the solar cell and thus a lower bound for the diode factor. Due to metastable defects transitions, the optical diode factor is higher than 1 even at low excitation. Here, the influence of the backside recombination and the doping level on the optical diode factor are studied. First, photoluminescence and solar cell capacitance simulator (SCAPS) simulations are used to determine the back surface recombination velocity of Cu(In, Ga)Se2 with various back contacts and different doping levels. Then, experimental results and simulations show that both back surface recombination and high doping density reduce the optical diode factor. The back surface recombination reduces the optical diode factor with undesirable extra nonradiative recombination. The smaller value achieved by higher doping can increase quasi-Fermi level splitting at the same time. The simulations show that the back surface recombination reduces the optical diode factor due to an illumination-dependent recombination rate. In addition, a higher majority carrier doping reduces the influence of majority carrier gain from metastable defect transitions, thus reducing the optical diode factor

Implementation of Enterprise Resource Planning service: 1C Logistics system in the warehouse processes in construction companies.

The main aim of the research is to show the importance of Enterprise Resource Planning service implementation for warehouse department of the company was described with close connection to theoretical background of warehousing and inventory management. Most of background for the research was taken from actual working process in the company. All results of the process were calculated and analyzed by both analytical and marketing departments of the company. The implementation process of Enterprise Resource Planning service took almost a year and about 3 million rubles of investments. Deep integration process that consisted not only of technical changes, but also of personnel training, space reorganizing and many other things made it possible for the company to highly develop its potential in the future and ability to gain a bigger market share. Results have shown that all investments and integration processes were worth spending time and money. Company has reorganized all aspects of working process of the company and provided ability for future development of the company. In overall enormous amount of work has resulted in a positive way with several critical point during the implementation project. Results of research concluded in the end of the work can help same kind of companies in Russia to make decision for upgrading existing working process and see all positive and negative aspects that might appear

Implementation of full-area-deposited electron-selective TiOx layers into silicon solar cells

We examine two different silicon solar cell designs featuring full-area electron-selective contacts based on ultrathin (2-3 nm) titanium oxide (TiOx) films deposited by atomic layer deposition. The first cell design applies a layer stack to the cell front, which is composed of an ultrathin intrinsic amorphous silicon (i-a-Si:H) layer for interface passivation, the TiOx film and an indium tin oxide (ITO) layer to provide a good lateral conductance for electrons to the metal fingers. Whereas carrier lifetime measurements on test structures promise high implied open-circuit voltages Voc up to 726 mV, the realized solar cells achieve disappointingly low Voc values <400 mV. The J-V parameters of this cell type are negatively affected by a reverse diode occurring due to the contacting of the TiOx by the high-work function ITO layer. In the second cell type, we implement a layer stack to the cell rear, which is composed of an ultrathin silicon oxide (SiOy) layer, the TiOx film and a full-area-deposited aluminum (Al) layer. Initial Voc values of these cells are relatively low (<600 mV), but improve significantly after annealing at 350°C. The best cell featuring a SiOy/TiOx/Al rear contact achieves an open-circuit voltage of 661 mV and an efficiency of 20.3%. No reverse diode is observed, which is attributed to the lower work function of the Al compared to ITO in the first cell design. From internal quantum efficiency measurements, we extract a rear surface recombination velocity Srear of (52±20) cm/s for our best cell, which is well compatible with efficiencies exceeding 23%

НАЦИОНАЛЬНАЯ КУХНЯ КАК СПОСОБ МЕЖКУЛЬТУРНЫХ КОММУНИКАЦИЙ В ЕВРЕЙСКОЙ АВТОНОМНОЙ ОБЛАСТИ

Thisarticle review the features of the national cuisine of the Jewish Autonomous region. In the conditions of intercultural communication knowledge about the ethnic mentality, the lifestyle, the cuisine, in particular, are of great interest among many researchers. Analysis of the national peculiarities of culinary and symbolic components of traditional food allows you to form certain conceptual markers, which are among the conditions of successful realization of intercultural dialogue.Ни что не разделяет людей так, как вкусы,И не объединяет, так как аппетит. В статье обзорно раскрыты особенности национальной кухни Еврейской автономной области. В условиях межкультурных коммуникаций знания об этническом менталитете, образе жизни, национальной кухне, в частности, вызывают немалый интерес среди многих исследователей. Анализ национальных особенностей кулинарии и символических компонентов традиционной пищи позволяет сформировать определенные концептуальные маркеры, являющиеся одними из условий успешной реализации межкультурного диалога

Computational modeling and analysis of moisture distribution in Insulated Gate Bipolar Transistors (IGBTs) : a comprehensive study

Within an inverter system, the utilization of insulated-gate bipolar transistor (IGBT) power electronics plays a pivotal role in the distribution and conversion of direct current sourced from photovoltaic (PV) modules, facilitating the generation of alternating current. It has become imperative to investigate the internal humidity within an IGBT module, so it increasingly becomes a focal point of scientific exploration. This heightened focus stems from the pursuit of performance enhancements, aimed at fortifying the reliability and dependability of power electronics. By dedicating attention to the accurate representation of internal humidity conditions in IGBT modules, a significant stride can be made in optimizing their operational efficiency and fostering heightened system resilience. This study presents a rigorous investigation into the characterization of semiconductor power devices, employing a combination of experimental and simulation methods. Our research demonstrates a meticulously designed experimental setup within a controlled climate chamber, enabling a comprehensive characterization process of the humidity transfer into the device's silicone gel. This setup allows a detailed exploration of the influence of moisture as well as the impact of temperature on the humidity distribution within an IGBT module. To complement our experimental endeavors, we employ the advanced capabilities of Comsol Multiphysics software to conduct our simulations. These simulations enable us to gain a deeper understanding of the humidity distribution within an IGBT module to predict stress induced by moisture. By leveraging the power of simulation, we enhance our comprehension of the complex dynamics involved and pave the way for more robust and reliable power electronic systems. The combination of experimental investigations and sophisticated simulations provides valuable insights into the thermal behavior of semiconductor power devices. This research not only contributes to the broader scientific understanding of IGBT module´s thermal loading, but also holds significant implications for the design and optimization of power electronic systems, improving their overall performance and reliability. The numerically solved models demonstrate a high degree of concurrence with our measurement results, attesting to their accuracy and reliability. Our overarching objective is to propose a comprehensive system that effectively responds to real-time conditions generated by the model. This integrated approach holds immense potential for achieving optimal system performance and facilitating self-optimization, thereby enhancing the overall operational efficiency and effectiveness of the inverter.Bundesministerium für Wirtschaft und KlimaschutzPeerReviewe

Data-driven PV system engineering : comprehensive modelling and simulation of a grid-connected three-phase inverter

In a data-driven modelling approach, the intelligent integration of data between physical and virtual entities of a photovoltaic (PV) system can facilitate innovation, control and optimization of the entire PV power plant. In an inverter, the insulated-gate bipolar transistor (IGBT) power electronics are used to distribute and convert the direct current from the PV module to alternating current. Due to the demand for performance improvements, the need to model these IGBT stacks is constantly increasing [1, 2]. Consequently, to reduce thermal resistance and improve the reliability of power electronics, new data points such as thermal loading and internal humidity are increasingly moving into the scientific focus [3]. In this contribution, we pursue two approaches towards anomaly detection in the operation of a PV plant. A comparison-based approach, analyzing the operation-induced data of an inverter to a physically motivated inverter model, and a failure-motivated approach using numerical modelling methods to reveal the hidden characteristics for latter data analysis. We present a MATLAB/Simulink model of a three-phase grid-connected inverter. We demonstrate the responsiveness of our model by changing the polarity in the active and reactive current control. This model shall serve as an idealized digital twin of the inverter to aid in anomaly detection within measured inverter data. Furthermore, we present initial ideas on a failure-motivated modelling approach to improve our model’s accuracy and enable optimized predictive maintenance algorithms. The use of hidden characteristics, such as IGBT junction temperature and power module interior humidity can serve as markers for failure detection in the operation of a PV system. Therefore, we have analyzed initial power loss calculations of an IGBT, which serve as a basis for thermal loss simulations to predict overheating of the switch components within the inverter. We examine the correlation between modelled and measured temperatures of the IGBT stacks. In addition, we propose a humidity model to prevent humidity-induced failures in power electronics.PeerReviewe