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Ein Energiemanagementsystem nach DIN EN ISO 50001 hilft Unternehmen, ihren Energieverbrauch zu erfassen und ihre Energieeffizienz zu verbessern. Da beim Energiemanagement eine große Menge an Daten erhoben und verwaltet werden muss, wird in diesem Beitrag eine Methode vorgestellt, wie relevante Einflussgrößen (Variablen) auf den Energieverbrauch identifiziert und in Leistungskennzahlen berücksichtigt werden können. Die Methode ist konform mit den ISO-Standards 50001 und 50006. Zur Verwaltung der Daten wird ein Prozess-Informationsmodell verwendet, welches weiterhin die Übertragbarkeit der Methode auf verschiedene Produktionssysteme vereinfacht. Die sechs Schritte der Methode werden im Verlauf des Beitrages erläutert und auf einen beispielhaften Anwendungsfall des Zerkleinerungsprozesses von Erz in einer Mine angewendet. So wird gezeigt, wie die Methode zur Verringerung des Energieverbrauchs und der Treibhausgasemissionen beitragen kann.

Mit steigender Energiegewinnung aus erneuerbaren Energien kommt Speichersystemen eine zunehmend wichtige Bedeutung zu. Die notwendigen Planungsfunktionen für den automatisierten, wirtschaftlichen und ökologischen Betrieb von Speichern sind Fokus dieses Beitrags. Zunächst werden diese Funktionen beschrieben, und es werden Anforderungen an sie hergeleitet. In einer Fallstudie wird ein einfaches Beispiel einer Planungsfunktion in Form eines mathematischen Optimierungsmodells verwendet, um Strom möglichst günstig und emissionsarm an der Intraday-Strombörse einzukaufen. Die Kosten und Emissionen des Stromeinkaufes lassen sich durch den Einsatz von Speichern in der betrachteten Fallstudie signifikant reduzieren, wobei sich auch zeigt, dass das Einsparpotenzial für Speicher mit Größen von über vier Betriebsstunden zunehmend abflacht.

A sacrificial film of polystyrene nanoparticles was utilized to introduce nano-cavities in mesoporous metal oxide layers. This enabled the growth of larger perovskite crystals inside the oxide scaffold with significantly suppressed non-radiative recombination and improving device performance. This work exemplifies potential applications of such nanoarchitectonic approaches in perovskite opto-electronic devices., 4 pages

In this work we compare seven different types of natural and synthetic graphite particles and examine how their integration into the cathode of carbon-based perovskite solar cells (C–PSCs) is influencing their opto-electronic properties. By combining x-ray diffraction, Raman spectroscopy and 4-point probe measurements we show that the differences in graphite crystallinity significantly affect the sheet resistance of the carbon-based cathode. The most conductive carbon-based film with an exceptional sheet resistance of 4 Ω/sq. have been produced from scaly graphite with the crystallite dimensions of La = 60.6 nm and Lc = 28.6 nm. Electrochemical Impedance Spectroscopy further revealed that charge transfer resistance at the perovskite/carbon contact differ for each graphite type. Overall, the pyrolytic graphite was found to be the best compromise between high conductivity and low charge transfer resistance leading to least series resistance losses and a fill factor (FF) above 74% (in perovskite solar cells with area of 0.64 cm2). However, an overall efficient hole extraction and lower non-radiative charge recombination in C–PSCs with scaly graphite resulted in the highest average power conversion efficiency and a champion device reaching 14.63%. All the C–PSCs show exceptional moisture stability for 5,000 h under ambient condition, with a PCE decrease of less than 3%.

While perovskite photovoltaic (PV) devices are on the verge of their commercialization, promising methods to recycle or remanufacture fully-encapsulated perovskite solar cells (PSCs) and modules are still missing. Through detailed life-cycle assessment shown in this work, we identify that the majority of the greenhouse gas emissions can be reduced by re-using the glass substrate and parts of the PV cells. Based on these analytical findings, we develop a novel thermally-assisted mechanochemical approach to remove the encapsulants, the electrode and the perovskite absorber, allowing to re-use most of the device constituents for remanufacturing PSCs, which recovered nearly 90% of their initial performance. This remanufacturing strategy allows to save up to 33% of the module’s global warming potential. Finally, we demonstrate that the CO2-footprint of these remanufactured devices can become less than 30g/kWh, which is the value for state-of-the-art c-Si PV modules and can even reach 15g/kWh assuming a similar lifetime

Summary Although it still contributes to less than 2% of the worldwide electricity generation, photovoltaics (PVs) is on the way to becoming a key energy technology for a global future renewable energy infrastructure. We present projections of worldwide CO2 emissions of the future PV industry, finding that these emissions will likely surpass those caused by the global shipping or aviation sector. As an alternative, we propose a fully printed PV reverse manufacturing concept that minimizes the carbon footprint to the ultimate lower limit of the glass substrate fabrication. This so called “in situ” approach is based on a perovskite absorber that is highly durable and encapsulated with glass solder between float glass substrates, reducing the CO2-footprint of conventional PV modules by 1/20th. Yielding a certified stabilized efficiency of 9.3%, this record efficiency for glass-solder-encapsulated perovskite PV paves the way for future solar cells with the lowest carbon footprints.

Determining the effect of defects in fiber-reinforced materials, such as polymer matrix composites (PMCs), can be studied by creating artificial flaws in these materials, for example by introducing artificial PTFE foil to induce material delaminations. For fiber-reinforced ceramics (CMCs), this approach is more difficult due to the more complicated production routes of CMCs, which involve several processing steps at elevated temperatures. This work deals with the fabrication and introduction of defined defects in carbon fiber reinforced silicon carbide (C/C-SiC) composites in a way, which allows their detection by non-destructive material testing methods during and after each production step of the composite. It was shown that the defects produced using boron nitride (BN) and alumina fiber roving were stable over the entire manufacturing process and could be detected by ultrasound and x-ray tomography techniques. To determine any possible effects, an initial sampling of bending samples with artificial defects was manufactured, tested and compared with defect-free reference materials. These tests showed a lower bending strength and failure strain for the defect samples compared to samples without defects.

Carbon-based electrodes have been widely applied in perovskite solar cells (PSCs) because of their chemical inertness and compatibility with up-scalable techniques, signifying their solid potential for mass-production. The material scarcity and complexity of metal ore extraction further highlights that conventionally used noble metal electrodes cannot represent a sustainable option for back-contact in PSCs, while cells with carbon-based electrodes represent an excellent solution to these problems. However, their power conversion efficiencies (PCEs) still lag behind the traditionally processed cells with metal electrodes, resulting in a considerable efficiency gap. To overcome this issue, we propose the use of low-temperature carbon-based (LTCB) electrodes, which offer several key advantages in comparison to mesoscopic high-temperature treated ones: (1) larger choice of selective layers, (2) applicability to all perovskite crystallization methods, (3) compatibility with flexible substrates and (4) faster deposition process. In this review, we analyze numerous techniques to formulate the LTCB-paste and ways to deposit it on the cell stack which have been developed in order to improve the interfacial contact and electrode conductivity. Besides describing the current state-of-the-art perovskite solar cells with LTCB-electrodes, the most promising strategies to enhance the PCE of such photovoltaic (PV) devices are discussed. Overall, we emphasize that PSCs with a LTCB-electrode combine high device stability, low manufacturing costs and low environmental impact, while having options for pushing the efficiency of carbon-based PSCs closer to the record-breaking cells, all of which are vital in order to fulfill the true potential of perovskite PV.

One of the main issues hindering the commercialization of perovskite photovoltaics (PV) is device stability. A myriad of various strategies to stabilize the perovskite layer against degradation under continuous illumination has been demonstrated in perovskite community, such as perovskite passivation with 2D perovskites, organic hydrophobic layers, ionic liquids, as well as the deployment of robust inorganic charge transport layers. However, for commercially established PV technologies, the most detrimental degradation occurs in fact under reverse bias. A cell in a module can be placed under reverse bias due to significant current mismatch between series-interconnected cells, which typically happens under operational conditions when shading takes place. Such situation causes the non-shaded solar cells to act as a reverse-bias voltage source on the shaded cell, causing it to operate at high negative voltages, dissipating its energy as heat producing a so-called This phenomenon is commonly known as "hot-spot" degradation and is considered to be one of the most severe degradation mechanisms even in crystalline silicon PV. Concomitantly, only few studies on the reverse bias degradation in perovskite PV devices have been published, revealing that this is a severe source of degradation. Thus, reverse bias degradation presents one of the most fundamental challenges for commercializing not only single-junction perovskite PV modules, but also the ones with tandem configurations. In this work, we demonstrate that perovskite PV devices with mesoscopic scaffold and carbon-based electrode have outstanding resilience against reverse bias degradation and are able to withstand negative voltages up to -9V. The presence of chemically inert carbon electrode, utilization of single-halide mixed-dimensional 2D/3D perovskite and robust inorganic charge transport layers helps to avoid commonly-occurring issues in state-of-the-art cells, like localized -melting of metal electrodes, ion diffusion and halide segregation. Looking more in-depth at the nature of reverse bias degradation in PSCs we demonstrate that the issue of iodine loss still prevails even in such stable devices. Low activation energy of I- vacancies causes an accumulation of charges at the interfaces, resulting in significant bend bending at the interfaces between perovskite and charge-transport layer. Under reverse bias the bending increases until the so-called "breakdown voltage" is reached beyond which holes are able to tunnel through to the valence band of perovskite. This hole-tunneling oxidizes incorporated iodine to create iodine vacancies and thermodynamically favorable iodine compounds, which decompose perovskite structure. Thus, iodine loss can cause device degradation, if it is exposed to reverse-bias for long time durations. For reverse bias voltages exceeding -9V, via thermographic imaging we overserved in-operando formation of hotspots and thermal degradation of perovskite into PbI2. To demonstrate that modules with carbon electrodes would be able to withstand hot-spot conditions, we manufactured modules with carbon back electrodes of 10x10cm2 size and 11.1% power conversion efficiency and subjected them to requirements of IEC61215 hot-spot test at an accredited laboratory Fraunhofer ISE PV Modules Testlab, which has never been done before according to our knowledge. Finally, the modules were able to pass the conditions of the IEC tests for c-Si and thin-film technologies confirming that mesoscopic scaffold and carbon electrodes provide effective stabilization strategy for perovskite PV devices against reverse-bias degradation. (Bogachuk et al. 2021) This work for the first time demonstrates that perovskite-based modules with carbon-based modules can withstand severe reverse bias, which is an essential attribute of this emerging technology on its path towards commercialization.

Carbon-electrode-based perovskite solar cells (C-PSCs) are promising candidates for commercialization due to their high stability. However, the absence of a hole selective layer (HSL) often limits their performance, yielding low fill factors (FFs). Herein, a certified FF of 78.8% obtained through HSL-free C-PSCs is focused. This is found to approach the highest values reported for metal-electrode-based PSCs employing highly selective HSLs. The loss mechanisms affecting the FF in fully printed HSL-free C-PSCs are thus investigated. Methods commonly used to analyze and quantify the impact of recombination and transport losses on the FF of established photovoltage devices are assessed, and their applicability in C-PSCs is examined. In the improved devices, non-radiative recombination contributes to only 3%abs loss with respect to the FF in the radiative limit, which is attributed to an optimal diode ideality factor approaching 1.0. Moreover, contributions of shunt resistive losses are determined to be negligible. Interfacial series resistance losses at the perovskite/carbon interface are identified as the main loss channel, highlighting the importance of the quality of the contact between the perovskite and the back-contact electrode.

Most childhood cancers occur sporadically and cannot be explained by an inherited mutation or an unhealthy lifestyle. However, risk factors might trigger the oncogenic transformation of cells. Among other regulatory signals, hypermethylation of

The photocurrent density-voltage (J(V)) curve is the fundamental characteristic to assess opto-electronic devices, in particular solar cells. However, it only yields information on the performance integrated over the entire active device area. Here, a method to determine a spatially resolved photocurrent image by voltage-dependent photoluminescence microscopy is derived from basic principles. The opportunities and limitations of the approach are studied by the investigation of III-V and perovskite solar cells. This approach allows the real-time assessment of the microscopically resolved local J(V) curve, the steady-state Jsc, as well as transient effects. In addition, the measurement contains information on local charge extraction and interfacial recombination. This facilitates the identification of regions of non-ideal charge extraction in the solar cells and enables to link these to the processing conditions. The proposed technique highlights that, combined with potentiostatic measurements, luminescence microscopy turns out to be a powerful tool for the assessment of performance losses and the improvement of solar cells.

Herein, a simple way of tuning the optical and structural properties of porphyrin‐based hydrogen‐bonded organic frameworks (HOFs) is reported. By inserting transition metal ions into the porphyrin cores of GTUB‐5 (p‐H8‐TPPA (5,10,15,20‐Tetrakis[p‐phenylphosphonic acid] HOF), the authors show that it is possible to generate HOFs with different band gaps, photoluminescence (PL) life times, and textural properties. The band gaps of the resulting HOFs (viz., Cu‐, Ni‐, Pd‐, and Zn‐GTUB‐5) are measured by diffuse reflectance and PL spectroscopy, as well as calculated via DFT, and the PL lifetimes are measured. Across the series, the band gaps vary over a narrow range from 1.37 to 1.62 eV, while the PL lifetimes vary over a wide range from 2.3 to 83 ns. These differences ultimately arise from metal‐induced structural changes, viz., changes in the metal‐to‐nitrogen distances, number of hydrogen bonds, and pore volumes. DFT reveals that the band gaps of Cu‐, Zn‐, and Pd‐ GTUB‐5 are governed by highest occupied/lowest unoccupied crystal orbitals (HOCO/LUCO) composed of π‐ orbitals on the porphyrin linkers, while that of Ni‐GTUB‐5 is governed by a HOCO and LUCO composed of Ni dorbitals. Overall, our findings show that metal‐insertion can be used to optimize HOFs for optoelectronics and small‐molecule capture applications.