In this era of fast-moving technology, new paradigm of Internet of Everything (IoE)—the intelligent connection between people, processes, data, and things—will be accompanied by dramatic changes in modern life that...
With an excellent power conversion efficiency of 25.7%, closer to the Shockley–Queisser limit, perovskite solar cells (PSCs) have become a strong candidate for a next-generation energy harvester. However, the lack of stability and reliability in PSCs remained challenging for commercialization. Strategies, such as interfacial and structural engineering, have a more critical influence on enhanced performance. MXenes, two-dimensional materials, have emerged as promising materials in solar cell applications due to their metallic electrical conductivity, high carrier mobility, excellent optical transparency, wide tunable work function, and superior mechanical properties. Owing to different choices of transition elements and surface-terminating functional groups, MXenes possess the feature of tuning the work function, which is an essential metric for band energy alignment between the absorber layer and the charge transport layers for charge carrier extraction and collection in PSCs. Furthermore, adopting MXenes to their respective components helps reduce the interfacial recombination resistance and provides smooth charge transfer paths, leading to enhanced conductivity and operational stability of PSCs. This review paper aims to provide an overview of the applications of MXenes as components, classified according to their roles as additives (into the perovskite absorber layer, charge transport layers, and electrodes) and themselves alone or as interfacial layers, and their significant importance in PSCs in terms of device performance and stability. Lastly, we discuss the present research status and future directions toward its use in PSCs.
Polymer-based materials
with positive temperature coefficients
(PTC) are regarded as potential candidates for electrical heating
elements in a wide range of applications, such as wearable electronics,
soft robots, and smart skin. They offer many advantages over ceramic
or metal oxide-based composites, including low resistance at room
temperature, excellent flexibility and processability, and low cost.
However, the electrical resistance instability and poor reproducibility
have limited their use in practical applications. In this work, we
prepared carbon blacks-reinforced high-density polyethylene nanocomposites
(CBs–HDPE) loaded with polar additives (polyols or ionomers),
which were subsequently subjected to electron beam (EB) irradiation
to explore their PTC behaviors. We found that the EB-treated nanocomposites
exhibited PTC behaviors, while the untreated samples showed negative
temperature coefficients. Further, EB–ionomer-CBs–HDPE
showed the highest PTC intensity of 3.01 Ω·cm, which was
∼35% higher than that of EB-CBs–HDPE. These results
suggested that the EB irradiation enabled a specific volume expansion
behavior via enhanced crosslinking among CBs, polar additives, and
HDPE, inhibiting the formation of conductive networks in the nanocomposites.
Thus, it can be concluded that polar additives and further EB irradiation
played an important role in enhancing the PTC performances. We believe
the findings provide crucial insight for designing carbon–polymer
nanocomposites with PTC behaviors in various self-regulating heating
devices.
-The purpose of this study is to assess the risk of depending on the presence or absence of safety device of domestic heating and drying furnaces, by derivation and analysis of accident frequency of safety devices through FTA (Fault Tree Analysis). Installation standards are lacking in Korean for the safety device of LPG heating and drying furnace, which have a risk of explosion due to structure to trap the leaked gas. Four different safety devices were selected on the basis of NFPA and national standards for combustors of other equipment. Effects of frequency reduction in accidents were analyzed before and after installing the safety devices respectively. As a result, a minimal leakage safety device was presented for preventing damages from gas leak of domestic LPG heating and drying furnace.
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