Nigeria's energy review: Focusing on solar energy potential and penetration.

In Nigeria, the rapid population increase and the overreliance on fossil fuel have created significant environmental, health, political, and economic consequences leading to severe socio-economic drawbacks. These factors have developed a wide gap between energy demand and supply due to insufficient local production, necessitating a clean energy supply for all. The photovoltaic device's economic and environmental merits have made it the most suitable clean energy alternative to help developing countries such as Nigeria achieve the SDG-7. However, apart from the device's low efficiency, which is undergoing intensive study globally, other factors affect the penetration of the technology in developing countries, particularly Nigeria. This report systematically reviews the literature on the country's energy crisis and renewable energy potential, leading to an overview of solar energy potential and penetration. The potential of the technology and its penetration in the country were provided. A list highlighting challenges hindering technology penetration was also provided, and a solution for each was recommended.

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

Dextran-templating hydrothermal synthesis of monoclinic WO3 exhibits excellent specific surface area of ∼110 m2/g and a monomodal pore distribution with an average pore diameter of ∼20 nm. Dextran plays a crucial role in generating 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 photoluminescence and X-ray photoelectron spectroscopy studies reveal the existence of oxygen vacancies in substoichiometric WO3, which creates localized defect states in WO3 as synthesized through this templating method. The highly mesoporous WO3 has been further explored as an interfacial cathode buffer layer (CBL) in dye-sensitized solar cells (DSSCs) and perovskite solar cells (PSCs). A significantly enhanced photoconversion efficiency has boosted up the performance of the counter electrode used in traditional DSSC (as platinum) and PSC (as carbon) devices by ∼48 and ∼29%, respectively. The electrochemical impedance and incident photon to current conversion efficiency (IPCE) studies were also analyzed in order to understand the catalytic behavior of the WO3 interfacial CBL for both DSSCs and PSCs, 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 were able to unequivocally establish the importance of buffer layer incorporation, which can further help to integrate the DSSC and PSC devices toward more stable, reliable, and enhanced efficiency-generating devices. In spite of this, using WO3 constitutes an important step toward the efficiency improvement of the devices for futuristic photoelectrochromic or self-powered switchable glazing for low-energy adaptive building integration.

Study of COVID-19 pandemic in London (UK) from urban context.

COVID-19 transmission in London city was discussed in this work from an urban context. The association between COVID-19 cases and climate indicators in London, UK were analysed statistically employing published data from national health services, UK and Time and Date AS based weather data. The climatic indicators included in the study were the daily averages of maximum and minimum temperatures, humidity, and wind speed. Pearson, Kendall, and Spearman rank correlation tests were selected for data analysis. The data was considered up to two different dates to study the climatic effect (10th May in the first study and then updated up to 16th of July in the next study when the rest of the data was available). The results were contradictory in the two studies and it can be concluded that climatic parameters cannot solely determine the changes in the number of cases in the pandemic. Distance from London to four other cities (Birmingham, Leeds, Manchester, and Sheffield) showed that as the distance from the epicentre of the UK (London) increases, the number of COVID-19 cases decrease. What should be the necessary measure to be taken to control the transmission in cities have been discussed.

Facile Surfactant-Free Synthesis of p-Type SnSe Nanoplates with Exceptional Thermoelectric Power Factors.

A surfactant-free solution methodology, simply using water as a solvent, has been developed for the straightforward synthesis of single-phase orthorhombic SnSe nanoplates in gram quantities. Individual nanoplates are composed of {100} surfaces with {011} edge facets. Hot-pressed nanostructured compacts (Eg ≈0.85 eV) exhibit excellent electrical conductivity and thermoelectric power factors (S(2) σ) at 550 K. S(2) σ values are 8-fold higher than equivalent materials prepared using citric acid as a structure-directing agent, and electrical properties are comparable to the best-performing, extrinsically doped p-type polycrystalline tin selenides. The method offers an energy-efficient, rapid route to p-type SnSe nanostructures.

Effect of novel graphitic carbon/NiO hole transporting electrode on the photovoltaic and optical performance of semi-transparent perovskite solar cells.

Perovskite devices can play a critical role as tunable semi-transparent photovoltaics managing the buildings' energy health for energy harvesting, storage and utilization. Here we report ambient semi-transparent PSCs with novel graphitic carbon/NiO-based hole transporting electrodes having variable thicknesses achieving a highest efficiency of ∼14%. On the other hand, the altered thickness produced the highest average visible transparency (AVT) of the devices, nearly 35%, which also influenced other glazing-related parameters. This study envisages the impact of the electrode deposition technique on indispensable parameters like colour rendering index, correlated colour temperature, and solar factor evaluated using theoretical models to illuminate these CPSCs' colour and thermal comfort for BIPV integration. The solar factor value between 0 to 1, CRI value >80 and CCT value >4000 K make it a significant semi-transparent device. This research work suggests a possible approach to fabricating carbon-based PSC for high-performance semi-transparent solar cells.

Shape-Stabilized PEGylated Silica Aerogel-Composite as an Energy Saving Building Material.

Balancing thermal and visual comfort in buildings necessitates effective insulation to counteract heat loss and gain, especially with temperature variances. One promising approach is to combine phase change materials, such as poly(ethylene glycol) (PEG), with high-performance insulators like silica aerogel (Siag). To bolster opto-thermal performance in building envelopes, we introduce a smart insulation composite material through PEG integration, i.e., PEGalyation with Siag. Central to this thermal behavior is the PEG's phase change properties, which foster a shape-stabilized framework with Siag through their porous confinement. Preliminary observations indicate notable capabilities of obstructing near-infrared light while preserving satisfactory visible transparency. An optimized Siag@PEG composite with 5% loading of PEG has the visible range transmission of ∼92%, a decrease of ∼72% in thermal conductivity which is lower than pure glass and PEG, leading to a temperature dependent switchable hydrophobic to hydrophilic wettability characteristics. As a prototype window, the thermal performance evaluation of the synthesized composite, through experimental and computational studies, shows a decrease in indoor temperature of ∼20% with a higher temperature difference of ∼20 °C between outdoor and indoor weather conditions. This lightweight composite can act as sponge media to fill inside the double-paned window and for retrofitting existing glazing to boost the energy efficiency of buildings with facile manufacturing and scalability.

Advancing Thermoelectric Materials: A Comprehensive Review Exploring the Significance of One-Dimensional Nano Structuring.

Amidst the global challenges posed by pollution, escalating energy expenses, and the imminent threat of global warming, the pursuit of sustainable energy solutions has become increasingly imperative. Thermoelectricity, a promising form of green energy, can harness waste heat and directly convert it into electricity. This technology has captivated attention for centuries due to its environmentally friendly characteristics, mechanical stability, versatility in size and substrate, and absence of moving components. Its applications span diverse domains, encompassing heat recovery, cooling, sensing, and operating at low and high temperatures. However, developing thermoelectric materials with high-performance efficiency faces obstacles such as high cost, toxicity, and reliance on rare-earth elements. To address these challenges, this comprehensive review encompasses pivotal aspects of thermoelectricity, including its historical context, fundamental operating principles, cutting-edge materials, and innovative strategies. In particular, the potential of one-dimensional nanostructuring is explored as a promising avenue for advancing thermoelectric technology. The concept of one-dimensional nanostructuring is extensively examined, encompassing various configurations and their impact on the thermoelectric properties of materials. The profound influence of one-dimensional nanostructuring on thermoelectric parameters is also thoroughly discussed. The review also provides a comprehensive overview of large-scale synthesis methods for one-dimensional thermoelectric materials, delving into the measurement of thermoelectric properties specific to such materials. Finally, the review concludes by outlining prospects and identifying potential directions for further advancements in the field.

Effectual visible light photocatalytic reduction of para-nitro phenol using reduced graphene oxide and ZnO composite.

Removing wastewater pollutants using semiconducting-based heterogeneous photocatalysis is an advantageous technique because it provides strong redox power charge carriers under sunlight irradiation. In this study, we synthesized a composite of reduced graphene oxide (rGO) and zinc oxide nanorods (ZnO) called rGO@ZnO. We established the formation of type II heterojunction composites by employing various physicochemical characterization techniques. To evaluate the photocatalytic performance of the synthesized rGO@ZnO composite, we tested it for reducing a common wastewater pollutant, para-nitro phenol (PNP), to para-amino phenol (PAP) under both ultraviolet (UV) and visible light irradiances. The rGOx@ZnO (x = 0.5-7 wt%) samples, comprising various weights of rGO, were investigated as potential photocatalysts for the reduction of PNP to PAP under visible light irradiation. Among the samples, rGO5@ZnO exhibited remarkable photocatalytic activity, achieving a PNP reduction efficiency of approximately 98% within a short duration of four minutes. These results demonstrate an effective strategy and provide fundamental insights into removing high-value-added organic water pollutants.

Certified high-efficiency "large-area" perovskite solar module for Fresnel lens-based concentrated photovoltaics.

The future of energy generation is well in tune with the critical needs of the global economy, leading to more green innovations and emissions-abatement technologies. Introducing concentrated photovoltaics (CPVs) is one of the most promising technologies owing to its high photo-conversion efficiency. Although most researchers use silicon and cadmium telluride for CPV, we investigate the potential in nascent technologies, such as perovskite solar cell (PSC). This work constitutes a preliminary investigation into a "large-area" PSC module under a Fresnel lens (FL) with a "refractive optical concentrator-silicon-on-glass" base to minimize the PV performance and scalability trade-off concerning the PSCs. The FL-PSC system measured the solar current-voltage characteristics in variable lens-to-cell distances and illuminations. The PSC module temperature was systematically studied using the COMSOL transient heat transfer mechanism. The FL-based technique for "large-area" PSC architectures is a promising technology that further facilitates the potential for commercialization.

Optical analysis of a photovoltaic V-trough system installed in western India.

The low concentrating photovoltaic (PV) system such as a 2× V-trough system can be a promising choice for enhancing the power output from conventional PV panels with the inclusion of thermal management. This system is more attractive when the reflectors are retrofitted to the stationary PV panels installed in a high aspect ratio in the north-south direction and are tracked 12 times a year manually according to preset angles, thus eliminating the need of diurnal expensive tracking. In the present analysis, a V-trough system facing exactly the south direction is considered, where the tilt angle of the PV panels' row is kept constant at 18.34°. The system is installed on the terrace of CSIR-Central Salt and Marine Chemicals Research Institute in Bhavnagar, Gujarat, India (21.47 N, 71.15 E). The dimension of the entire PV system is 9.64 m×0.55 m. The V-troughs made of anodized aluminum reflectors (70% specular reflectivity) had the same dimensions. An in-house developed; experimentally validated Monte Carlo ray-trace model was used to study the effect of the angular variation of the reflectors throughout a year for the present assembly. Results of the ray trace for the optimized angles showed the maximum simulated optical efficiency to be 85.9%. The spatial distribution of solar intensity over the 0.55 m dimension of the PV panel due to the V-trough reflectors was also studied for the optimized days in periods that included solstices and equinoxes. The measured solar intensity profiles with and without the V-trough system were used to calculate the actual optical efficiencies for several sunny days in the year, and results were validated with the simulated efficiencies within an average error limit of 10%.

Synergistic Effect of Paraffin-Incorporated In2O3/ZnO Multifold Smart Glazing Composite for the Self-Cleaning and Energy-Saving Built Environment.

The thermal performance of window glazing requires improvement for a sustainable built environment at an acceptable cost. The current work demonstrates a multifold smart composite consisting of an optimized In2O3/ZnO-polymethyl methacrylate-paraffin composite to reduce heat exchange through the combined self-cleaning and energy-saving envelope of the smart built environment. This work has attempted to develop a smart composite coating that combines photosensitive metal oxide and phase change materials and investigate their thermal comfort performance as a glazed window. It is observed that the In2O3/ZnO (5 wt %) multifold composite film experienced better transmittance and thermal performance compared to its other wt % composite samples. Moreover, the multifold composite-coated glass integrated into a prototype glazed window was further investigated for its thermal performance, where a steady average indoor temperature of ∼30 °C was achieved when the outside temperature reached ∼55 °C, while maintaining good visibility. Interestingly, the transparency reached ∼86% at 60 °C and exhibited a hydrophobic water contact angle (WCA) of ∼138°. In contrast, a similar film exhibits ∼64% transparency at 22 °C, where the WCA becomes moderately hydrophilic (∼68°). Temperature dependency on transparency and wettability properties was examined for up to 60 cycles, resulting in excellent indoor thermal comfort. In addition, a thermal simulation study was executed for the smart multifold glazing composite. Moreover, this study offers dynamic glazing development options for energy saving in the smart built environment.

Evaluation and optimization of the optical performance of low-concentrating dielectric compound parabolic concentrator using ray-tracing methods.

We present a detailed design concept and optical performance evaluation of stationary dielectric asymmetric compound parabolic concentrators (DiACPCs) using ray-tracing methods. Three DiACPC designs, DiACPC-55, DiACPC-66, and DiACPC-77, of acceptance half-angles (0° and 55°), (0° and 66°), and (0° and 77°), respectively, are designed in order to optimize the concentrator for building façade photovoltaic applications in northern latitudes (>55 °N). The dielectric concentrator profiles have been realized via truncation of the complete compound parabolic concentrator profiles to achieve a geometric concentration ratio of 2.82. Ray-tracing simulation results show that all rays entering the designed concentrators within the acceptance half-angle range can be collected without escaping from the parabolic sides and aperture. The maximum optical efficiency of the designed concentrators is found to be 83%, which tends to decrease with the increase in incidence angle. The intensity is found to be distributed at the receiver (solar cell) area in an inhomogeneous pattern for a wide range of incident angles of direct solar irradiance with high-intensity peaks at certain points of the receiver. However, peaks become more intense for the irradiation incident close to the extreme acceptance angles, shifting the peaks to the edge of the receiver. Energy flux distribution at the receiver for diffuse radiation is found to be homogeneous within ±12% with an average intensity of 520 W/m².

Role of Hafnium Doping on Wetting Transition Tuning the Wettability Properties of ZnO and Doped Thin Films: Self-Cleaning Coating for Solar Application.

Herein, we successfully synthesized high-quality Hf-ZnO thin films with various Hf contents (0, 3, 6, 9, 12, and 15 at. %), which showed both superhydrophilic (6% Hf-ZnO) and ultrahydrophobic (15% Hf-ZnO) wetting behavior. Different characterization methods were opted to recognize the structural (XRD, SEM, AFM) and defect properties (XPS) of the pristine and doped materials, to understand the mechanisms underlying the tuning of wetting behavior (contact angle). Hafnium doping plays a noteworthy role in tuning the morphology of the ZnO nanostructures, roughness of the material surface, generation of defects, Lewis acid-base interactions, and wettability properties. We achieved a superhydrophilic surface with 6% Hf-ZnO owing to a smooth surface, less basicity, and maximum concentration of oxygen vacancies, and also an ultrahydrophobic surface with 15% Hf-ZnO because of the rough surface, high basicity, and minimum concentration of oxygen vacancies. The as prepared Hf-ZnO samples showed stable performance (stability, wearability, weatherability, and antifouling) under real-life conditions marking them multifunctional and biosafe material to be effectively used in solar and building's window. A wetting mechanism was established to relate the wetting behavior of the samples to oxygen vacancies (active sites for water dissociation: resulted due to charge mismatch of host cation (Zn2+) by the doped cation (Hf4+)), roughness (smooth surface (Wenzel) with minimum Rrms (0.588) portraying hydrophilic property and rough caltropic surface (Cassie-Baxter) with maximum Rrms (2.522) portraying hydrophobic property), basicity (H2O: Lewis Base; ZnO: Lewis acid; HfO2: Lewis base) and morphology (tube-like structure (0-6% Hf-ZnO) and caltrop-like structure (12-15% Hf-ZnO)).

Reduced graphene oxide (rGO) aerogel: Efficient adsorbent for the elimination of antimony (III) and (V) from wastewater.

3D porous, thin sheet-like rGO aerogel was fabricated to explore its antimony (Sb) removal potential from wastewater. Langmuir isothermal and pseudo-second-order kinetic model best-suited the adsorption process. The maximum adsorption capacities were 168.59 and 206.72 mg/g for Sb (III and V) at pH 6.0 respectively. The thermodynamic parameters designated the process to be thermodynamically spontaneous, endothermic reaction, a result of dissociative chemisorption. The rGO aerogel bestowed good selectively among competing ions and reusability with 95% efficiency. rGO posed excellent practicability with Sb-spiked tap water and fixed-bed column experiments showing 97.6% of Sb (III) (3.6 µg/L) and 96.8% of Sb (V) (4.7 µg/L) removal from tap water and from fixed column bed experiments breakthrough volumes (BV) for the Sb (III) and Sb (V) ions were noted to be 540 BV and 925 BV respectively, until 5 ppb, which are below the requirement of MCL for Sb in drinking water (6 µg/L). XPS and DFT analyses explained adsorption mechanism and depicted a higher affinity of Sb (V) towards rGO surface than Sb (III).

How India is dealing with COVID-19 pandemic.

India, which has the second-largest population in the world is suffering severely from COVID-19 disease. By May 18th, India investigated ∼1 lakh (0.1million) infected cases from COVID-19, and as of 11th July the cases equalled 8 lakhs. Social distancing and lockdown rules were employed in India, which however had an additional impact on the economy, human living, and environment. Where a negative impact was observed for the economy and human life, the environment got a positive one. How India dealt and can potentially deal with these three factors during and post COVID-19 situation has been discussed here.

Hydrophilic and Superhydrophilic Self-Cleaning Coatings by Morphologically Varying ZnO Microstructures for Photovoltaic and Glazing Applications.

Transparent, superhydrophilic materials are indispensable for their self-cleaning function, which has become an increasingly popular research topic, particularly in photovoltaic (PV) applications. Here, we report hydrophilic and superhydrophilic ZnO by varying the morphology for use as a self-cleaning coating for PV applications. Three different ZnO microstructures, such as ZnO nanorods (R-ZnO), ZnO microflowers (F-ZnO), and ZnO microspheres (M-ZnO), were developed by hydrothermal methods. The surface morphology by using X-ray diffraction (XRD), wettability behavior by using water contact angle (WCA) measurements, structural and optical properties by using photoluminescence (PL), Raman, and UV-vis spectrophotometry, and defect estimation by using X-ray photoelectron spectroscopy (XPS) of the ZnO nanostructured films were systematically investigated. XRD confirmed the formation of the hexagonal wurtzite structure of ZnO. The average crystallite sizes of prepared R-ZnO, F-ZnO, and M-ZnO were found to be 28.95, 11.19, and 41.5 nm, respectively. The band gap values of ZnO nanostructures were calculated from the UV-vis absorption spectrum and found to be 3.6, 3.3, and 3.1 eV for R-ZnO, F-ZnO, and M-ZnO, respectively. The WCAs for R-ZnO and F-ZnO were 20.2 and 11.19°, respectively, while M-ZnO behaved like a superhydrophilic material having a WCA of 2.8°.

Emplacement of screen-printed graphene oxide coating for building thermal comfort discernment.

This study demonstrates the development of flexible graphene oxide coatings (GOCs) by the screen-printed technique and further its implementation as a thermal absorber for buildings' thermal comfort purpose. The basic concept consists the integration of the GOC as a flat absorber on the top of a low iron glass or aluminium-based substrate (5 × 5 cm2) connecting through a phase change material channel in contact with direct sun exposure. The function of GOC as an outdoor cover of the prototype chamber is to maintain the high indoor temperature while the outdoor temperature is low. Using the GOC, it has been observed that the indoor temperature (at the substrate) of the prototype chamber always remains higher as compared to the outdoor temperature (at the GOC) as measured under 1 SUN 1.5 AM condition. The temperature difference between outdoor and indoor exterior surface significantly increases during the light exposure time, whereas the difference drastically approaches to zero during the cooling period. The variation of different crucial environmental factors such as high temperature, moisture, flexibility and water resistivity has been investigated on the developed GOCs to understand the stability of the coating further.

Modelling photovoltaic soiling losses through optical characterization.

The accumulation of soiling on photovoltaic (PV) modules affects PV systems worldwide. Soiling consists of mineral dust, soot particles, aerosols, pollen, fungi and/or other contaminants that deposit on the surface of PV modules. Soiling absorbs, scatters, and reflects a fraction of the incoming sunlight, reducing the intensity that reaches the active part of the solar cell. Here, we report on the comparison of naturally accumulated soiling on coupons of PV glass soiled at seven locations worldwide. The spectral hemispherical transmittance was measured. It was found that natural soiling disproportionately impacts the blue and ultraviolet (UV) portions of the spectrum compared to the visible and infrared (IR). Also, the general shape of the transmittance spectra was similar at all the studied sites and could adequately be described by a modified form of the Ångström turbidity equation. In addition, the distribution of particles sizes was found to follow the IEST-STD-CC 1246E cleanliness standard. The fractional coverage of the glass surface by particles could be determined directly or indirectly and, as expected, has a linear correlation with the transmittance. It thus becomes feasible to estimate the optical consequences of the soiling of PV modules from the particle size distribution and the cleanliness value.

White butterflies as solar photovoltaic concentrators.

Man's harvesting of photovoltaic energy requires the deployment of extensive arrays of solar panels. To improve both the gathering of thermal and photovoltaic energy from the sun we have examined the concept of biomimicry in white butterflies of the family Pieridae. We tested the hypothesis that the V-shaped posture of basking white butterflies mimics the V-trough concentrator which is designed to increase solar input to photovoltaic cells. These solar concentrators improve harvesting efficiency but are both heavy and bulky, severely limiting their deployment. Here, we show that the attachment of butterfly wings to a solar cell increases its output power by 42.3%, proving that the wings are indeed highly reflective. Importantly, and relative to current concentrators, the wings improve the power to weight ratio of the overall structure 17-fold, vastly expanding their potential application. Moreover, a single mono-layer of scale cells removed from the butterflies' wings maintained this high reflectivity showing that a single layer of scale cell-like structures can also form a useful coating. As predicted, the wings increased the temperature of the butterflies' thorax dramatically, showing that the V-shaped basking posture of white butterflies has indeed evolved to increase the temperature of their flight muscles prior to take-off.