Realization of poly (methyl methacrylate) encapsulated solution-processed carbon-based solar cells: emerging candidate for buildings’ comfort

This is the final version. Available from the publisher via the DOI in this record.The self-assembling characteristics allow carbon nanomaterials to be readily explored, environmentally benign, solution-processed, low-cost, and efficient solar light-harvesting materials. An effort has been made to replace the regular photovoltaic device’s electrodes by different carbon allotropebased electrodes. Sequential fabrication of carbon solar cells (SCs) was performed under ambient conditions, where FTO/ graphene/single-walled carbon nanotubes/graphene quantum dotsfullerene/carbon black paste layers were assembled with poly- (methyl methacrylate) (PMMA) as an encapsulating layer. The PMMA layer provides significant improvement toward the entry of water vapor, hence leading to stability up to 1000 h. The photoconversion efficiency of the PMMA-encapsulated carbon SC has been increased by ∼105% and the stability decreased by only ∼10% after 1000 h of exposure to environmental moisture. Besides, the building integrated photovoltaic window properties achieved using this carbon SC were also investigated by using the color rendering index and the correlated color temperature, which can have an impact on the buildings’ occupants’ comfort. This study leads to an extensive integration to improve carbon-based materials because of their effective and useful but less-explored characteristics suitable for potential photovoltaic applicationsEngineering and Physical Sciences Research Council (EPSRC

Color Comfort Evaluation of Dye-Sensitized Solar Cell (DSSC) Based Building-Integrated Photovoltaic (BIPV) Glazing after 2 Years of Ambient Exposure

This is the final version. Available on open access from the American Chemical Society via the DOI in this recordData availability: in support of open access research, all underlying article materials (data, models) can be accessed upon request via email to the corresponding author.Transmitted external daylight through semitransparent type building integrated photovoltaic (BIPV) windows can alter the visible daylight spectrum and render different colors, which can have an impact on building's occupants' comfort. Color properties are defined by the color rendering index (CRI) and correlated color temperature (CCT). In this work, a less explored color comfort analysis of N719 dye-sensitized TiO2 based dye-sensitized solar cell (DSSCs) BIPV window was characterized and analyzed after 2 years of ambient exposure. Three different DSSCs were fabricated by varying TiO2 thickness. The reduced average visible transmission was observed while enhanced color properties were obtained for all three DSSCs. This study could pave way to future developments in the area of BIPV technology using DSSC in terms of their long-term exploration.Engineering and Physical Sciences Research Council (EPSRC

A review on applications of Cu2ZnSnS4 as alternative counter electrodes in dye-sensitized solar cells

This is the final version. Available from AIP Publishing via the DOI in this record. A contribution of counter electrode (CE) emphasis a great impact towards enhancement of a dye-sensitized solar cell's (DSSC) performance and Pt based CE sets a significant benchmark in this field. Owing to cost effective noble metal, less abundance and industrial large scale application purpose, an effective replacement for Pt is highly demanded. There are several approaches to improve the performance of a CE for enhancing the power conversion efficiency with a less costly and facile device. To address this issue, reasonable efforts execute to find out suitable replacement of Pt is becoming a challenge by keeping the same electrochemical properties of Pt in a cheaper and eco-friendlier manner. With this, cheaper element based quaternary chalcogenide, Cu2ZnSnS4 (CZTS) becomes a prominent alternative to Pt and used as a successful CE in DSSC also. This review presents brief discussion about the basic properties of CZTS including its synthesis strategy, physicochemical properties and morphology execution and ultimate application as an alternative Pt free CE for a low cost based enhanced DSSC device. It is therefore, imperative for engineering of CZTS material and optimization of the fabrication method for the improvement of DSSC performance.Research Council of Norwa

An optimal climate-adaptable hydrogel-filled smart window for the energy-saving built environment

This is the final version. Available on open access from the Royal Society of Chemistry via the DOI in this record It is highly desirable to secure the net-zero targets by employing sustainable building materials that can store and release their energy depending on the weather. Conspicuously, windows can play a pivotal role in controlling the energy used in the building by reducing the use of energy-consuming areas that devour massive energy for air conditioning or heater appliances. Presently, the comfort performance of window materials is reaching its storage and processing limit, causing a significant push to find smart materials that can be used in the next generation of the built environment. An innovative solution for sustainable glazing has established an understanding of pH-temperature-transparency modulation. This work uses hydroxypropyl cellulose and polyacrylic acid-based hydrogel as a rational energy stimulus for double-glazed windows, enriching a comfortable indoor daylight environment without sacrificing aesthetic appeal. Hydrogel maintains thermal comfort across various outdoor temperatures from 4 oC to 60 oC. The developed hydrogel-filled prototype glazing’s indoor thermal comfort performance and durability were analsyzed, where hydrogel intermolecular gap and porosity play a pivotal role across various pHs.Engineering and Physical Sciences Research Council (EPSRC

Smart glazing thermal comfort improvement through near-infrared shielding paraffin incorporated SnO2-Al2O3 composite

This is the final version. Available on open access from Elsevier via the DOI in this recordBuilding's energy conservation signifies a lowering in building energy consumption without sacrificing thermal comfort. Window glazing is the most suitable approach to the built environment that can be controlled through its sustainable development for global energy consumption. In this work, for the first time, paraffin incorporated SnO2-Al2O3 composite coating is developed on a 5 cm × 5 cm glass using a screen-printing method, which signifies an intelligent cooling behaviour for a comfortable indoor environment irrespective of their emplacement. The composite energy-saving properties exhibit less transmission of infra-red light while keeping high visible light transmittance behaviour resulting superior heat-shielding performance. The composite coated glass's average indoor temperature profile remains at ∼30 °C when the outside temperature reaches a maximum of 45 °C during outdoor testing. While the same composite film is set inside, the indoor average temperature maintains ∼30 °C, whereas outside temperature reaches a maximum of 80 °C. The distinct temperature profile for composite coated glass indicates high transparency of 80% throughout the experiment. Interestingly paraffin has been incorporated into the composite, offering no leakage, translucent characteristics, and limited water ingress. In comparison, non-coated glass is failed to provide them with a comfortable, stable indoor temperature. We believe this study envisages the recent technological innovations combined with phase change material and transparent infrared absorber together as a composite for window glass for warmer climates, which further leads to significant energy savings compared with plain glass.Engineering and Physical Sciences Research Council (EPSRC

A Short Review on Thermoelectric Glazing for Sustainable Built Environment

This is the final version. Available on open access from MDPI via the DOI in this recordSecuring net-zero targets by employing sustainable materials for the built environment is highly desirable, and this can be achieved by retrofitting existing non-smart windows with thermoelectric (TE) glazing, providing improved thermal performance along with green electricity production. It is reported that TE glazing could produce ~4000 kWh of power per year in a cold climate with a temperature differential of ~22 °C. This feature of TE materials drives their emplacement as an alternative to existing glazing materials and could lead to the identification of optimum solutions for smart window development. However, few attempts have been made to employ TE materials in glazing. Therefore, in this brief review, we discuss, for the first time, the efforts made to employ TE in glazing, identify their drawbacks, and discuss potential solutions. Furthermore, the working principle, suitable materials, and methods for developing TE glazing are discussed. In addition, this article introduces a new research area and provides researchers with detailed instructions on how to build and optimize this system. The maximum efficiency of a thermoelectric material is determined by its thermoelectric figure of merit, which is a well-defined metric to characterize a device operating between the hot-side and cold-side temperatures. TE material’s figure of merit promises new perspectives on the conceivable future energy-positive built environment. The role of TE in tackling the energy crisis is also discussed, since it provides sustainable energy alternatives.Higher Committee of Education Development (HCED), Government of IraqEngineering and Physical Sciences Research Council (EPSRC

Incorporating Solution-Processed Mesoporous WO3 as an Interfacial Cathode Buffer Layer for Photovoltaic Applications

This is the final version. Available on open access from the American Chemical Society via the DOI in this recordDextran templating hydrothermal synthesis of monoclinic WO3 exhibits excellent specific surface area of ~110 m2 /g and a mono-modal pore distribution with the average pore diameter of ~20 nm. Dextran plays a crucial role to generate porosity on WO3. The role of supporting dextran has been investigated and found to be crucial to tune the surface area, porosity and morphology. The photo-luminescence and X-ray photoelectron spectroscopy studies reveal about the existence of oxygen vacancies in sub-stoichiometric, which creates localized defect states of WO3 as synthesized through this templating method. The highly mesoporous WO3 have been further explored as an interfacial cathode buffer layer (CBL) in dye sensitized solar cells (DSSCs) and perovskite solar cells (PSCs). A significantly enhanced photo-conversion efficiency has been boosted up the performance of the counter electrode used in traditional DSSC (as platinum) and PSCs (as carbon) devices by ~48% and ~29%, respectively. The electrochemical impedance and the incident photon to current conversion efficiency (IPCE) studies were also analysed in order to understand the catalytic behaviour of the WO3 interfacial CBL for both DSSC and PSC, respectively. The much higher surface area of WO3 enables rapid electron hopping mechanism, which further benefits for higher electron mobility resulting in higher short circuit current. Through this study, we are able to unequivocally establish the importance of buffer layer incorporation, which can further help to integrate the DSSC and PSC devices towards more stable, reliable and enhanced efficiency generated device. In spite of that, using WO3 constitutes an important step towards the efficiency improvement of the devices for futuristic photo-electrochromic or selfpowered switchable glazing for low energy adaptive building integration.Engineering and Physical Sciences Research Council (EPSRC

Co-sensitization effect of N719 dye with Cu doped CdS colloidal nanoparticles for dye sensitized solar cells

This is the final version. Available on open access from Elsevier via the DOI in this recordData availability: Data will be made available on request.Dye-sensitized solar cell’s (DSSC) performances are enhanced by engineering the materials at the interface of various device components owing to easy and inexpensive fabrication steps. Ru (II) polypyridyl-based synthetic dyes are the most widely used photosensitizers for DSSCs due to their superior molar extinction coefficient and facile interaction with metal oxide electrodes. However, these dyes are mostly expensive, and as a result, natural dyes and metal-free organic dyes have become an alternative way for sensitization to reduce the significant drawbacks of synthetic dyes. In this study, minimizing the usage of the N719 dye can be performed through an alternative method for better light-harvesting through supreme optical interfacial interaction with colloidal Cu-doped CdS as a co-sensitizer in a facile approach. This co-sensitization signifies the colloidal CdS (donor), which can corroborate the energy transfer mechanism with the N719 dye (acceptor). The introduction of Cu causes extreme tuning of broad absorption to near-infrared for CdS, enhancing the solar light harvesting entrapment followed by extensive optical interaction with N719 dye. This accelerates the activity of the sensitizers for light absorption enhancement and expects a better performance of DSSC compared to traditional sensitization. A massive improvement in photocurrent density (∼42 %) was observed without sacrificing other photovoltaic parameters, as observed for TiO2-based photoanodes. The sensitizer’s interfacial optical energy transfer process, unless excited electron recombination, may indirectly be used as an excitation source of the acceptor and minimizes the recombination energy loss.Engineering and Physical Sciences Research Council (EPSRC)British Counci

Comparison between deep learning and tree‐based machine learning approaches for landslide susceptibility mapping

The efficiency of deep learning and tree‐based machine learning approaches has gained immense popularity in various fields. One deep learning model viz. convolution neural network (CNN), artificial neural network (ANN) and four tree‐based machine learning models, namely, alternative decision tree (ADTree), classification and regression tree (CART), functional tree and logistic model tree (LMT), were used for landslide susceptibility mapping in the East Sikkim Himalaya region of India, and the results were compared. Landslide areas were delimited and mapped as landslide inventory (LIM) after gathering information from historical records and periodic field investigations. In LIM, 91 landslides were plotted and classified into training (64 landslides) and testing (27 landslides) subsets randomly to train and validate the models. A total of 21 landslide conditioning factors (LCFs) were considered as model inputs, and the results of each model were categorised under five susceptibility classes. The receiver operating characteristics curve and 21 statistical measures were used to evaluate and prioritise the models. The CNN deep learning model achieved the priority rank 1 with area under the curve of 0.918 and 0.933 by using the training and testing data, quantifying 23.02% and 14.40% area as very high and highly susceptible followed by ANN, ADtree, CART, FTree and LMT models. This research might be useful in landslide studies, especially in locations with comparable geophysical and climatological characteristics, to aid in decision making for land use planning

Evidence-based robust optimization of pulsed laser orbital debris removal under epistemic uncertainty

An evidence-based robust optimization method for pulsed laser orbital debris removal (LODR) is presented. Epistemic type uncertainties due to limited knowledge are considered. The objective of the design optimization is set to minimize the debris lifetime while at the same time maximizing the corresponding belief value. The Dempster–Shafer theory of evidence (DST), which merges interval-based and probabilistic uncertainty modeling, is used to model and compute the uncertainty impacts. A Kriging based surrogate is used to reduce the cost due to the expensive numerical life prediction model. Effectiveness of the proposed method is illustrated by a set of benchmark problems. Based on the method, a numerical simulation of the removal of Iridium 33 with pulsed lasers is presented, and the most robust solutions with minimum lifetime under uncertainty are identified using the proposed method