•Objects imbedded with electronics and software, communicating with each other is IoT.•IoT system is made up of sensors, connectivity, data processing, and user interface.•Smart IoT sensors uses less ...power and can be driven by indoor power harvesting systems.•DSSCs show outstanding performance in indoor/artificial light.•Stability and market dynamics are major concerns in the commercialization of indoor photovoltaic.
Indoor solar cells have a prospective to influence the ecology of the Internet of Things (IoTs), containing communication devices, actuators, remote, and distributed sensors. Smart IoT sensors have the potential of performing control functions and mass monitoring, which leads to modernize the industrial and domestic automation systems. These sensor devices necessitate exceptionally less electrical power in several applications, and it will be remarkable if they could be driven by an indoor power gathering system. The technology of Dye-Sensitized Solar Cell has engraved a significant space in the field of photovoltaics due to its various distinctive merits like relatively cheap methods of fabrication, roll-to-roll compatibility, using readily available materials and easy processing ability on the flexible substrates. Multi-colored, semi-transparent dye solar cells/panels also exhibit exceptional performance in indoor/artificial light, consequently streamlining the stage for the indoor light-harvesting and self-power the applications of IoTs. The objective of this review is to emphasize applications of DSSCs for IoTs, factors affecting the performance, and challenges in their commercialization. This paper consists of four parts. The first part will explain the importance of solar energy and the merits of photovoltaic technology over other technologies. The second part will describe the evolution of DSSC from the laboratory to commercialization. The potential of DSSCs for IoT applications will be discussed in the third part. Finally, challenges and future outlook will be discussed in the last part of this literature.
•Energy yield losses caused by dust deposition on photovoltaic modules are reviewed.•We provide a database regarding soiling losses in different parts of the world.•Environmental and design ...parameters of dust deposition are addressed.•Laboratory, outdoor, and predictive soiling works have been studied.•Emerging method of electrodynamic screen for dust removal is introduced.
Large-scale solar plants are generally located in semi-arid and desert lands where abundant sunlight is available for solar energy conversion. These plants, however, suffer from two major environmental degradation factors: high ambient temperature and high concentration of atmospheric dust. Degradation of solar collectors’ performance caused by soiling results in a considerable loss of energy yield in all solar plants of the world. Dust and other particulate accumulation on solar collectors causes transmission loss. This is true with respect to transmission losses in photovoltaic (PV) and concentrated photovoltaic (CPV) systems, and for reflection losses in concentrated solar power (CSP) systems. We present here a brief review of the energy yield losses caused by dust deposition on solar collectors, with particular emphasis on flat-panel photovoltaic (PV) systems. The review includes some of the major studies reported on energy-yield losses on solar plants in operation in several regions of the world. In addition, laboratory-soiling studies are also included. We report on degradation in the performance of solar plants based on the type of solar collectors, geographical location, local climate, and exposure period of the collectors absent any manual cleaning. An analysis of the advantages of cleaning processes that include natural, manual, automatic, and passive methods is presented. Our objective is to provide solar plant designers with a database for predicting anticipated soiling losses in different parts of the world, and for assessing effective cleaning methods for restoring a system’s energy yield.
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Today Perovskite solar cell (PSC) has achieved efficiency close to 26%, surpassing the efficiencies of well- known Dye-Sensitized Solar cells (DSSC), CdTe-based solar cells, etc. Ease ...of preparing perovskite solutions and convenient deposition technique has given them added advantage over other contemporary competitors. This has also made them an economically feasible option. Since the inception of PSCs in 2009, a lot of improvements have been done in various aspects like composition, synthesis technique, fabrication method, and interface study. However, today it is crucial to think about the commercialization of PSCs. In this direction, the stability of PSCs has been a long-standing question. This review focuses on the key aspects of perovskite stability. Challenges posed by environmental factors like moisture, oxygen, temperature, and light are still unanswered. The lead toxicity of PSCs demands a potential substitute of lead with no compromise in their efficiency. The lead-free approach of PSCs and their commercialization has been discussed separately. A suitable emphasis has been given to the encapsulation of solar cells, as we find it a necessary part of the future commercialization process. This review has been addressed with an ideology to provide overall knowledge on the stability issues and challenges concerned with the PSCs, to attract young research community towards this emerging field.
Competition among land uses is making it increasingly difficult to set aside adequate space for wildlife and nature conservation, so it is imperative that opportunities that simultaneously achieve ...commercial and conservation outcomes be identified and seized. Such opportunities exist in the renewable energy industry. It is widely recognized that renewable energy generation benefits the ecosphere through reduced carbon emissions, but currently, further opportunities for realising direct and indirect conservation benefits through the design of solar farms are less well known. Among other opportunities, solar farm designs that deliver environmental credits through carbon sequestration and biodiversity improvements can deliver higher financial returns. Other opportunities to improve local hydrology, pollination, and pest-control services could be available depending on site-specific characteristics where solar farms are built, and the other land use practices that exist, or are possible, in the immediate vicinity. Here, we explore opportunities among renewable energy generation, agriculture, and conservation, through the co-location and innovative design of PV solar energy farms on grazing and croplands. These forms of land sharing can achieve higher land-equivalent ratios (LERs), a quantitative metric of the reduction in land use. We identify opportunities whereby solar farms can be designed to improve biodiversity, land condition, and conservation outcomes, while maintaining or increasing commercial returns. Much work remains, however, to understand the suite of opportunities available for achieving simultaneously the best commercial and conservation outcomes through solar farm designs in agricultural landscapes.
Thin composite films (∼1.8μm) made with NiO nanoparticles and single-walled carbon nanotubes (SWCNT) as alternatives to the commonly used carbon black/graphite CE in HTM-free perovskite solar cells, ...showing an appreciated power conversion efficiency of 12.7%.
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•Thin nanocomposite film (∼1.8μm) made with NiO and SWCNT is introduced for perovskite solar cells.•A power conversion efficiency of 12.7% can be achieved for hole transport material free devices.•The thin counter electrode shows efficient charge collection ability.
In this research work, for the first time, we introduced thin composite films (∼1.8μm) made with NiO nanoparticles and single-walled carbon nanotubes (SWCNT) as alternatives to replace the commonly used carbon black/graphite counter electrode in full printable organic hole-transport layer free mesoporous perovskite solar cells. Due to the relative thick carbon black/graphite counter electrodes, which are typically ∼10μm thick, charge collection and batch to batch reproducibility of this type devices are significantly limited. We find an appreciated power conversion efficiency of 12.7% can be achieved for the CH3NH3PbI3 perovskite solar cell using mesoscopic TiO2/Al2O3 framework structure in combination with a thin NiO/SWCNT counter electrode under standard reporting conditions. Electronic impedance spectroscopy measurements reveal efficient charge collection ability for perovskite devices using thin NiO/SWCNT counter electrodes compared to the conventional carbon black/graphite counter electrode, and thus can efficiently deliver photocurrent.
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•A unique Zn blanket annealing process to control compensating defects in AZO thin films.•Decrease in compensating defects in AZO due to excess Zn diffusion.•As low as 8.8 Ω/sq sheet ...resistance and 90% visible transmittance of AZO is at par with commercial ITO.•Developed film performance as TCO in perovskite solar cells is quite good.
Achievement of high conductivity by doping an oxide thin film while maintaining its high visible transparency remains a challenge in the field of materials science and technology. Here, we demonstrate a simple and novel technique to control compensating defects in Al doped ZnO (AZO) thin films involving a post-growth annealing process with Zn blanket. We also provide an in-depth understanding of the mechanism of achieving high conductivity. As low as 8.8 Ω/sq sheet resistance (resistivity 3.1 × 10−4 Ω cm) with 90% visible transmission value and wherefrom a figure of merit (FOM) value of 6.5 × 10−2 Ω−1 for a RF sputtered 350 nm AZO thin film can be achieved. Such very low sheet resistance has been attributed to a decrease in the number of compensating defects and lesser out diffusion of Zn in AZO. Application of the developed AZO film as conducting substrate has successfully been tested by fabricating perovskite solar cells on flexible Corning® Willow® Glass substrate. The present findings open up the possibility of enough high quality industrial-scale production of transparent conducting oxides (TCOs) bearing crucial significance from the perspective of transparent electrodes for solar cells.
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•Ultraflexible and biodegradable PSCs on cellophane paper were achieved.•OMO electrodes exhibited stable resistance after 1000 bending CYC cycles (R = 1 mm).•PSCs on cellophane ...retained 97.6% of initial PCE after bending with radius of 0.3 mm.•PSCs on cellophane preserved 95.8% of initial PCE after 1000 bending cycles (R = 1 mm).
Flexible perovskite solar cells (PSCs) on paper are promising biodegradable power sources for wearable and portable electronics, while fabrication of paper-based PSCs with high mechanical flexibility and efficiency is still challenging due to the limited optimization of paper-based PSCs. Herein, flexible PSCs were demonstrated using 25 μm cellophane paper substrates combined with TiO2/ultrathin Ag/TiO2 (OMO) electrodes, composing the typical structure of cellophane/OMO/C60 pyrrolidinetris-acid (CPTA)/CH3NH3PbI3/Spiro-OMeTAD/Au. PSCs on cellophane paper exhibited a high power conversion efficiency (PCE) of 13.00%. More interesting, the performance of paper-based PSCs showed minor degradation after bending with the radius in the range of 0.3–10 mm: they retained 97.6% of the initial PCE after bending with a radius of 0.3 mm and even preserved 95.8% of the initial PCE after bending with a radius of 1 mm for 1000 cycles. The ultraflexibility of PSCs was ascribed to the ultrathin substrates to relieve strain in bended devices and superior flexibility of OMO electrodes. The ultraflexible and efficient PSCs on paper are promising for application in self-powered paper-based electronics.
The present paper deals with the dependence of outdoor thermal comfort on the design of an urban street. The effects of the street vertical profile, including asymmetrical canyon shapes, the use of ...galleries and further shading devices on the façades, arranged in various orientations are assessed. The study is conducted by means of numerical modelling by using the three-dimensional microclimate model ENVI-met 3.0 which prognosticates the microclimatic changes within urban environments. Thermal comfort is evaluated for the daytime hours across the canyon in high spatial resolution and by means of the physiologically equivalent temperature PET.
The results revealed that all design aspects investigated have a moderate impact on the air temperature and a strong effect on the heat gained by a human body and hence on the resulting thermal sensation. The larger the openness to the sky of the canyon, the higher the heat stress. For canyons with a smaller sky view, the orientation is also decisive: E–W canyons are the most stressful and deviating from this orientation ameliorates the thermal conditions. Basically, galleries and further shading through overhanging façades or vegetation enable a sensitive decrease of the period of time and of the area of thermal discomfort. Yet, this efficiency varies with the orientation and the vertical proportions of the canyon. Therefore, if appropriately combined, all investigated design elements can effectively mitigate heat stress in the summer and promote thermal comfort.
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•A metal-oxide pyramid texture is converted into the non-resonant optical metasurfaces.•Metasurfaces are realized through the templated growth electrodeposition of nanowires.•A JSC ...gain of 10-25% is achieved as compared to the planar device.•Energy conversion efficiencies of perovskite/perovskite TSCs can reach over 30%.•Optics of solar cells is investigated by FDTD optical simulations.
The short-circuit current density and energy conversion efficiency of single-junction perovskite and perovskite/perovskite tandem solar cells can be increased by photon management. In this study, optical metasurfaces were investigated as potential light trapping structures oppose to commonly used pyramidal surface textures. Herein, metal oxide-based non-resonant metasurfaces were investigated as potential light-trapping structures in perovskite solar cells. The zinc oxide nanowire-based building blocks of the metasurface can be prepared by a templated electrodeposition through a mask of resist. The phase of the incident light can be controlled by the edge length of the subwavelength large zinc oxide nanowires. An array of zinc oxide nanowires was prepared and characterized in the current study. Three-dimensional (3D) finite-difference time-domain (FDTD) optical simulations were used to compare solar cells covered with non-resonant metasurfaces with commonly used light trapping structures. As compared to the solar cells covered with zinc oxide pyramid surface texture, solar cells with the integrated non-resonant metasurfaces exhibit almost identical quantum efficiencies and short-circuit current densities. Investigations of such metasurfaces will not only improve the photon absorption in perovskite solar cells but also reveal a pathway to make high-efficiency next-generation solar cells. Detailed guidelines for the realization of non-resonant metal oxide metasurfaces will be provided.
Dye-sensitized solar cells (DSSCs) have been more systematically studied for many years. All kinds of innovative design of photoanode materials have paved the way to improve the photoelectric ...conversion efficiency (η) of DSSCs. New technological advancements, like preparation of nano-TiO2 and surface modification, have had a positive effect on improving η of DSSCs in recent years. The low-cost TiO2 become promising photoanode materials due to its strong adsorption capacity, not anti-light corrosion, good acid and alkali resistance and excellent biocompatibility. Excited dye molecules transfer electrons to the conduction band of the TiO2 and then to the external circuit through the TiO2 substrates. The photoelectron production, transfer, and output are related to TiO2, the dye/TiO2 interface and electrolyte/TiO2 interface. Among them, the loss of electrons is mainly due to I3− trapping electrons on the dye/TiO2 interface and electrolyte/TiO2 interface. Therefore, it is a very effective method for modifying the surface of TiO2 to reduce the loss of electrons during the process, thereby improving η of DSSCs. This review studies the preparation of nano-TiO2 and surface modification, which have an effect on improving η of DSSCs. At the same time, according to the development situation of DSSCs based on TiO2 photoanode, the common TiO2 modification methods are summarized to analyze the effects of different modification methods on DSSCs.
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