Colour properties and glazing factors evaluation of multicrystalline based semi-transparent Photovoltaic-vacuum glazing for BIPV application

This is the final version of the article. Available from Elsevier via the DOI in this record.In support of open access research, all underlying article materials (data, models) can be accessed upon request via email to the corresponding author.Low heat loss vacuum glazing offers high heat insulation for indoor space, which reduces the building's heating energy demand. However, the transparent nature of this glazing allows similar daylight to double glazing that creates discomfort glare. Double pane semi-transparent type photovoltaic (PV) glazing introduces control of solar heat gain, daylight and generates clean electricity. The transparent portion between regularly distributed PV cells allows light penetration. Addition of these two technologies can offer low heat loss PV-vacuum glazing that will control heat loss, heat gain, and daylight and generate renewable power. In this work, two different areas of multicrystalline PV cells were employed to form 35% and 42% transparent PV-vacuum glazing. Spectral characterisation, glazing factor and entering light quality through the transparent part of this PV-vacuum glazing were evaluated. Colour rendering and correlated colour temperature of this glazing were compared with an electrically actuated switchable suspended particle device glazing.This work has been conducted as part of the research project ‘Joint UK-India Clean Energy Centre (JUICE)’ which is funded by the RCUK’s Energy Programme (contract no: EP/P003605/1)

Carbon counter electrode mesoscopic ambient processed & characterised perovskite for adaptive BIPV fenestration

This is the final version. Available on open access from Elsevier via the DOI in this recordIn this work, carbon counter electrode perovskite was developed at the laboratory environment and building integrated photovoltaic (BIPV) window application using this material was investigated. At 1 sun (1000 W/m2) continuous incident solar radiation from an indoor simulator, this particular type of perovskite had 8.13% efficiency. Average solar and visible transmittance of this perovskite BIPV window was 30% and 20% respectively. Solar heat gain for different incident angle was evaluated for this perovskite glazing. For the University of Exeter, Penryn (50.16° N, 5.10° W) UK location, solar heat gain coefficient (SHGC) or solar factor (SF) varied from 0.14 to 0.33 at the highest and lowest incident angle respectively. Overall heat transfer coefficient (U-value) of 5.6 W/m2K was realized for this glazing while calculation was performed by window performance analysis programme, WINDOW 6.0. Daylight glare control potential of this glazing was investigated using subjective rating methods and comfortable daylight penetrated through glazing in a typical cloudy condition. Colour properties of this material showed that 20% visible transmittance is threshold limit, and below this value colour or visual comfort using this glazing is not achievable.Engineering and Physical Sciences Research Council (EPSRC

Thermal regulation of building-integrated concentrating photovoltaic system using phase change material

This is the final version. Available from AIP Publishing via the DOI in this record12th International Conference on Concentrator Photovoltaic Systems (CPV-12), 25-27 April 2016, Freiburg, GermanyThermal regulation of building-integrated concentrating photovoltaic (BICPV) systems have a direct influence on the photovoltaic performance. This paper investigates the thermal behavior of a BICPV and phase change material (PCM) system through numerical modeling simulations. Based on an updated mathematical model, theoretical simulation has been conducted for a BICPV-PCM system. The results show a 3% electrical efficiency improvement of the BICPV-PCM system in certain cases.Ministry of Higher Education, Sultanate of Oma

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

Evaluation of thermal performance for a smart switchable adaptive polymer dispersed liquid crystal (PDLC) glazing

This is the final version. Available from Elsevier via the DOI in this record. A new class of smart window technologies are gaining interest as they have the functionality to control dynamic solar radiation, shading, ventilation and energy production. They are capable of improving buildings’ energy performance by adapting to different climate conditions and bring thermal and visual comfort for occupants. Polymer-dispersed liquid crystal (PDLC) is a smart switchable window that changes its optical transmissions from translucent to transparent when an alternating electric current stimulus is introduced. The present paper discusses the results of an indoor investigation for the optical and thermal performance of a PDLC glazing system. The spectral transmittance of the investigated PDLC was evaluated for both the translucent and transparent states using UV–vis–NIR (1050) spectrophotometer. In addition, the thermal investigation was carried out in an indoor condition utilising a test cell equipped with a small scale of PDLC glazing, which was exposed to (1000, 800, 600, 400 W/m2) solar radiation for 180 min. The optical evaluation showed that the investigated PDLC glazing offered low transmission for UV (8%) and NIR (44%) in the translucent state, respectively. The result of SHGC was 0.68 and 0.63 for the transparent and translucent states, respectively, which indicates that the investigated sample could be more effective in reducing heat loads in a cold dominated climate. The U-value for the PDLC glazing was 2.79 W/m2 for the transparent and 2.44 W/m2 translucent.Engineering and Physical Sciences Research Council (EPSRC

HYDROGEL FORMULATION FROM CALOTROPIS GIGANTEA PLANT EXTRACT AGAINST FOOT ULCER CAUSING BACTERIA IN DIABETES

Objective: The objective of present study was to develop hydrogel formulations loaded with Calotropis gigantea leaves extract. Methods: The prepared hydrogel formulations were compliance with their color, odor, homogeneity, pH, and spreadability. Results: As all the formulations were complies with the all parameters and it can be suggest as a Good antibacterial gel. It is evident that, ethanolic extract of Calotropis gigantea showed a maximum inhibitory zone against bacteria associated with foot ulcer. Conclusions: The In vitro studies showed a quantity dependent increase in antibacterial activity against foot ulcer causing bacteria, a contraction which is higher than that produced by the control groups. These contractions were statistically significant (p<0.05), during the study with leave extract against foot ulcer causing bacteria in diabetes

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

Ultrafast changes in lattice symmetry probed by coherent phonons

The electronic and structural properties of a material are strongly determined by its symmetry. Changing the symmetry via a photoinduced phase transition offers new ways to manipulate material properties on ultrafast timescales. However, in order to identify when and how fast these phase transitions occur, methods that can probe the symmetry change in the time domain are required. We show that a time-dependent change in the coherent phonon spectrum can probe a change in symmetry of the lattice potential, thus providing an all-optical probe of structural transitions. We examine the photoinduced structural phase transition in VO2 and show that, above the phase transition threshold, photoexcitation completely changes the lattice potential on an ultrafast timescale. The loss of the equilibrium-phase phonon modes occurs promptly, indicating a non-thermal pathway for the photoinduced phase transition, where a strong perturbation to the lattice potential changes its symmetry before ionic rearrangement has occurred.Comment: 14 pages 4 figure