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With the rapid consumption of nonrenewable resources and the increasing demand for energy, finding stable and efficient renewable energy has become an effective way to solve energy problems. Efficient storage, conversion, and application of renewable energy have become increasingly essential. Phase change materials (PCMs) are effective carriers for thermal energy storage and conversion, which is one of the most practical media for improving energy efficiency. Improving the storage efficiency of PCMs and achieving multi-source driven storage conversion are effective methods to broaden the application of PCMs. MXene, as a series of excellent two-dimensional materials, owing rich chemical structures and outstanding physical properties, exhibit an extraordinary impact on energy storage and conversion. This study reviews the synthesis methods of MXenes and their composite PCMs (CPCMs), as well as the mechanism and application of multi-source storage conversion. Furthermore, the potential applications of MXene-based CPCMs in fields such as electronics, electromagnetic shielding, seawater desalination, and flame retardancy are studied. [ABSTRACT FROM AUTHOR]

Perovskite solar cells (PSCs) offer a promising avenue for renewable energy due to their ease of preparation, high energy conversion efficiency, and environmental friendliness. However, the traditional trial-and-error approach in preparing high-efficiency PSCs is inefficient. To address this, our study introduces a goal-driven approach that integrates machine learning and data mining techniques to rapidly screen high-efficiency PSCs based on key features. By successfully predicting high-efficiency PSCs and identifying the dominant factors affecting their performance, namely the perovskite bandgap and the total thickness of the electron transport layer (ETL), this research provides valuable insights for optimizing preparation processes and advancing the development of high-efficiency PSCs, thus significantly contributing to the renewable energy sector. • Our study presents a goal-oriented framework designed to predict the potential of high-efficient perovskite solar cells. • We created a correlation graph for the bandgap and PCE of perovskite solar cells. • We have meticulously curated a comprehensive dataset tailored specifically for the field of perovskite solar cells. [ABSTRACT FROM AUTHOR]

Nowadays, converting and storing solar energy is crucial in contemporary society. Thermal energy storages (TESs) can be vital in harnessing solar energy effectively. Phase change materials (PCMs) are favorable candidates for TESs owing to the smoothing outcome and, thus, increasing reliability. However, these materials suffer from limited thermal conductivity, inadequate light absorption, and high leakage during phase transition. In the present study, a facile and scalable graphitized carbon foam/Ni nanoparticles composite with exciting properties such as excellent light adsorption and high thermal conductivity was prepared as a platform to overcome the PCMs challenges. To obtain this composite, the coated commercial melamine foams (CMF) with an ethanolic solution containing the phenolic resin and NiCl 2.6H 2 O were pyrolyzed at 900 °C. The composite foam (CNiF) was utilized as a framework for paraffin (PA), which was soaked in melted PA at 75 °C under the vacuum drying oven for 50 min (CNiF/PA). The prepared black and magnetic composites exhibited high photo-to-thermal energy efficiency of 66, 80, and 92 % under light intensities of 900, 1000, and 1100 W/m2, respectively. In addition, the composite controls voltage fluctuations and prevents voltage drops in thermoelectric generators (TEGs) in solar thermal systems. The output voltages were 0.51, 0.63, and 0.81 V under light intensities of 1500, 1800, and 2100 W/m2, respectively. Moreover, the magnetically moving magnetic carbon foam solar absorber within the molten PA along the solar illumination path dramatically enhances the speed of solar-thermal energy storage. The set-up was subjected to light with an intensity of 1500 W/m2, which revealed a decrease in melting time, with the PA melting in 86 min. The PA melting time decreased by 37 % under solar irradiation. [Display omitted] • Facile and scalable graphitized carbon foam/Ni nanoparticles composite. • A magnetic PCM composite with high photo-to-thermal energy efficiency of 92 %. • High performance solar thermoelectric power generator with output voltage of 0.81 V • Controls voltage fluctuations and prevents voltage drops in thermoelectric generators. [ABSTRACT FROM AUTHOR]

To cope with rapid increase in energy demand and the related sustainability issues, it is of paramount importance to improve existing energy conversion machines. In this paper, a 3D model of roll bond photovoltaic thermal (RB-PVT) unit incorporating a novel channel of hexagon-grid coupled with serpentine arrangement, was considered. In ANSYS Fluent 18, the model was solved both as an evaporator and a condenser to investigate its operation in perspective of performance and environment. The difference in temperature between two areas (refrigerant and ambient) and pressure drop in micro-channels were found the main two causes to change the performance of RB-PVT evaporator/condenser. In this view, the maximum average values of 9.25 and 17.56 % were respectively achieved for COP h and electrical efficiency of RB-PVT evaporator. In addition, the maximum COP refr of 4.64 was obtained from the RB-PVT condenser. Considering the compressor to be powered by non-renewable energy for a period of 15years, 6946USD would be spent in buying power equivalent to 144442.35 kWh. Moreover, 797USD would be spent to sequestrate 26.5tons of CO 2 emissions. RB-PVT evaporator/condenser integrating hexagon-grid coupled with fluid channel of serpentine arrangement not only can improve the performance characteristics but can also be a best alternative to achieve net zero emissions. • RB-PVT evaporator/condenser incorporating novel channel was developed and solved. • Maximum average for COP h , N elec , COP refr were proportionated to 9.25,17.56 %,4.64. • RB-PVT evaporator/condenser would save 797USD to sequestrate 26.5tons of CO 2. [ABSTRACT FROM AUTHOR]

Thermophotovoltaic (TPV) energy conversion systems have gained great interest in recent years as they can directly convert thermal energy into electricity using photovoltaic (PV) cells. The increase of the radiative power and the power conversion efficiency in TPV systems is mainly due to two key factors. The first one deals with the nature of the selective emitter. A new high temperature selective emitter should be designed to have a high emissivity (absorptivity) above the bandgap energy (E g) and a low emissivity below E g of the PV cells. The second key factor is related to the cooling mechanism of the PV cell as the conversion efficiency of the latter degrades with increasing temperature. In this work, we first propose and investigate a new efficient metamaterial thermal emitter, to reach a desired emissivity in the wavelength range 0.8 − 1.72 μ m. Secondly, to minimize the operating temperature of the TPV system, a passive radiative cooling approach is suggested in which an efficient double-layer coating deposited on the substrate of PV cells is elaborated. It has a high emissivity in the atmospheric transparency windows 8 − 13 μ m and low absorptivity in the solar spectrum 0.3 − 8 μ m. We show that the high-temperature metamaterial design can achieve high emissivity, over 0.97 in the wavelength range, 0.8 − 1.72 μ m , while reducing the sub-band loss of the PV cells. At 1400K, we demonstrate that adding the proposed cooling design to the substrate of a GaSb PV cell panel with an area ratio between the passive radiative cooler and the PV cell panel of γ = 20 , can improve the efficiency of the latter by 2 % and drop its operating temperature by 44 K. • A high-temperature thermal emitter is designed and achieves a high emissivity between 0 and 1.72 μm. • A passive radiative cooler is developed with a high emissivity between 8 and 13 μm. • A new thermophotovoltaic system combined with a passive radiative cooling approach is developed. • The surface ratio between the passive radiative cooler and the photovoltaic cells was studied. • The energy conversion efficiency reaches 60% and the operating temperature drops by 44K. [ABSTRACT FROM AUTHOR]

Abstract An n-type Si nanowire (SiNW) solar cell based on transition metal oxides V 2 O 5 and TiO 2 has been fabricated. The cell is demonstrated in the ITO/V 2 O 5 /n-SiNWs/TiO 2 /Al heterojunction structure, in which the V 2 O 5 and TiO 2 work as the hole- and the electron-selective layers, respectively. Parameters of cells with different lengths of nanowires have been investigated. Owing to the excellent light trapping effect of nanowire arrays and superior carrier transporting properties of thin V 2 O 5 and TiO 2 layers, an improved power conversion efficiency of 12.7% has been achieved in a cell with 1.45-μm-long nanowires. Due to the large work function difference between V 2 O 5 and n-Si, a build-in potential of 0.75 V was obtained from the capacitance-voltage measurement, which implies the possibility of achieving a large open circuit voltage for these nanowire solar cells. The efficiency loss is mainly caused by the recombination via the defects on the unpassivated surface of SiNWs. By solving this problem, the cell efficiency may be improved further and realize the application in PV industries. Highlights • The first study to apply transition metal oxides to form Si nanowire solar cells. • Obtaining a large build-in potential by the high work function V 2 O 5 layer. • The large J SC obtained by the light trapping of nanowires boosts the efficiency. • The formation process of this solar cell is cost-effective and easily manufactured. [ABSTRACT FROM AUTHOR]

Abstract Organic solar cells (OSCs) based on fullerene acceptors demonstrated significant growth over the past two decades with power conversion efficiencies (PCE) exceeding 13%. However, the advent of non-fullerene (NF) acceptors with superior optoelectronic properties, tunable morphology, and absorption characteristics, have resulted in a scenario where the NF OSCs have demonstrated higher PCE of over 14% in single junction and over 17% in tandem OSCs incorporating NF OSCs which is relatively higher than conventional fullerene-based counterparts. In this review, recent progress and advancements made in the field of NF OSCs is discussed and its photovoltaic device performance ranging across several donor: acceptor (D/A) combinations is elaborated. The advantages of each NF materials in conjunction with the donor molecules is deliberated in the context of D/A blends correlating it to device performance. In addition, the challenges in the development and application of NF OSCs are also discussed, providing an overview for future developments. [ABSTRACT FROM AUTHOR]

Abstract Molten chloride salts are promising advanced high-temperature (400–800 °C) thermal energy storage (TES) and heat transfer fluid (HTF) materials in next generation concentrated solar power (CSP) plants for higher energy conversion efficiencies. However, severe corrosion of structural materials in contact with molten chloride salts is one of the most critical challenges limiting their applications at elevated temperatures. In this work, two corrosion mitigation strategies are investigated to alleviate the hot corrosion of structural materials in molten chloride salts: (1) adding corrosion inhibitor and (2) using a Fe-Cr-Al alloy with a protective alumina layer on the surface after pre-oxidation. Three commercial high temperature Fe-Cr-Ni alloys (SS 310, Incoloy® 800 H and Hastelloy® C-276) were exposed to molten MgCl 2 -NaCl-KCl (60–20–20 mol%) mixed salts with 1 wt% Mg as corrosion inhibitor, for 500 h at 700 °C under inert atmosphere. By addition of the Mg inhibitor, the corrosion rates of the studied alloys were found to be significantly reduced, more precisely by ~ 83% for SS 310, ~ 70% for In 800 H and ~ 94% for Ha C-276 compared with the exposure tests without Mg addition. The corrosion mitigation mechanism of Fe-Cr-Ni based alloys in molten chloride salts by adding Mg is discussed based on corrosion thermodynamics. To assess the second mitigation strategy two pre-oxidized alumina forming Fe-Cr-Al alloys were exposed to the same molten chloride salts without Mg corrosion inhibitor under the same conditions. It is observed that the adherent alumina scales can effectively inhibit the dissolution of Cr and Fe and the bulk penetration of corrosive impurities. Overall, both strategies offer enormous potential for enhancing the expected lifetime of commercial alloys in molten chloride salts. Graphical abstract fx1 Highlights • By Mg-addition, the corrosion rates of alloy SS 310, In 800H and Ha C-276 are significantly reduced. • Adding Mg inhibitor not only mitigates the corrosion, but also promotes the formation of MgO layer on metal surfaces. • Impurity-driven corrosions of Fe-Cr-Ni based alloys in molten chloride salts in absence and presence of Mg are discussed. • Pre-oxidized alumina scales show corrosion resistance and stability after 500h exposure in chloride salts at 700°C. [ABSTRACT FROM AUTHOR]

Abstract Intensive research on lead halide perovskites over the last decade led to highly efficient perovskite thin-film photovoltaics. Further enhancement in power conversion efficiency (PCE) of this technology is expected from improved light management. In this simulation-based study, nanophotonic perovskite absorber layers are designed in order to enhance the short-circuit current density (J SC) of perovskite solar cells. The enhancement in J SC is beneficial in one of two ways. Firstly, optimized nanophotonic perovskite layers lead to an enhancement in J SC by 5–6% assuming a constant perovskite absorber volume, which correlates to a similar improvement in PCE and annual energy yield (EY). Secondly, optimized nanophotonic perovskite layers can alternatively allow a high J SC to be maintained at reduced perovskite absorber volumes. The latter approach results in about one third of the harmful lead content being mitigated in conventional perovskite solar cells, for an initial perovskite layer thickness of ~300 nm. This study evaluates and analyzes in detail the design of nanophotonic perovskite layers that can be fabricated by nanoimprint lithography. Various design parameters of the nanophotonic perovskite layers such as the period (150–750 nm), the geometrical filling fraction (0.2–0.6) and the depth (0–500 nm) of the nanostructures are studied. A broad optimum to enhance J SC is found for a period of 400 nm. Finally, the angular stability of simulated nanophotonic perovskite solar cells is shown and their excellent light harvesting for realistic irradiation conditions is demonstrated by EY modelling. Highlights • Nanophotonic perovskite solar cells enhance the short circuit current density and thereby improve the device efficiency and energy yield by around 5–7% relative by coupling light to guided modes in the absorber layer. • High short-circuit currents can be maintained at reduced perovskite absorber volumes, which allows mitigating around 1/3 of environmental harmful lead. • A broad and experimentally feasible optimum of geometrical parameters is found for nanophotonic perovskite solar cells. [ABSTRACT FROM AUTHOR]

Abstract In this study, the stability of polymer-based photovoltaic fibers was investigated in ambient and inert atmosphere. Photovoltaic (PV) fibers, similarly produced by using both polymer blend of wide and low bandgap polymers (P3HT: PTB7: PCDTBT) and only wide bandgap (P3HT) polymer with [6,6]-phenyl C61 butyric acid methyl ester (PCBM) in active layer were measured in ambient and in inert environment after dark storage, and then, their photovoltaic performances and stabilities were compared. Maximum power conversion efficiency of 2.01% was obtained from photovoltaic fiber with P3HT: PTB7: PCDTBT polymer blend. When stability results were considered, at end of 7th day, photovoltaic fibers having P3HT: PTB7: PCDTBT:PCBM active layer showed better performance than P3HT: PCBM-based PV fibers. Highlights • Photovoltaic fibers with different bandgaps were produced. • The lifetime of the photovoltaic fibers first time in literature was investigated. • The lifetime of the photovoltaic fibers in different environments was investigated. • Photovoltaic fibers with low bandgap polymers blend has better efficiency. [ABSTRACT FROM AUTHOR]

Abstract In the past few decades, polymer solar cells (PSCs) have gained great progress. And fullerene PSCs occupy a dominant position in the early stage of the development of PSCs. Recently, non-fullerene PSCs have gained more attention because of their advantages, such as good absorption in the visible and near infra-red (NIR) region, high tunability of energy levels, better complementary absorption spectra with donors. Thus, numerous efforts have focused on the synthesis and modulation of small molecular acceptor (SMAs). And lots of non-fullerene PSCs have achieved higher power conversion efficiencies than fullerene PSCs. This short review focuses on the progress of non-fullerene small-molecule acceptors for high efficiency PSCs in recent years. And it would provide new ideas for designing high efficiency PSCs. Highlights • This review gives a systematically summary of recent significant advances in non-fullerene small molecular acceptors. • Based on the structure-property relationship, we give an outlook on the bright prospect of ITIC-based SMAs. • Some key factors limiting the improvement of photoelectric performance of non-fullerene SMA-based PSCs were pointed out, which give the clues to improve the photovoltaic properties in the future research. [ABSTRACT FROM AUTHOR]

Abstract Herein, 1,6-Diaminohexane Dihydrochloride (1,6-DD) is introduced into perovskite precursors to fabricate the inverted planar perovskite solar cells. By regulating the concentration of 1,6-DD additive, the average power conversion efficiency (PCE) of perovskite solar cells is enhanced by 20%. The champion device achieves a relatively high PCE of 17% and an excellent fill factor of 80.1%. The PCE of the large-area (1 cm2) device also reaches to 13.68%. After exposure to the air for 16 days, the device with 1,6-DD additive still retains above 90% of the initial efficiency, exhibiting good stability. We demonstrate that a small amount of 1,6-DD affects the crystallization dynamic, yielding ideal perovskite film with enhanced crystallinity and enlarged grain size. The two terminal -NH 3 + groups passivates the vacancy defects at the perovskite crystal surface, suppressing charge recombination and facilitating charge transportation effectively. Meanwhile, adjacent crystal surfaces are linked through the hexane alkyl chain of 1,6-DD molecule, which enhances the interaction between perovskite grains and anchors the microstructure of perovskite to some degree. Hydrophobic hexane alkyl chains also increase the moisture resistance of perovskite film. Thus, an easy and effective way is provided for fabricating efficient and stable perovskite solar cells. Graphical abstract The incorporation of 1,6-Diaminohexane Dihydrochloride (1,6-DD) additive leads to ideal perovskite film with enhanced crystallinity and enlarged grain size. The inverted planar perovskite solar cells with 1,6-DD additive show an enhancement of 20% in power conversion efficiency. The champion device delivered a relatively high power conversion efficiency of 17% and an excellent fill factor of 80.1%. The two terminal -NH 3 + groups of 1,6-DD passivates the vacancy defects at the perovskite crystal surface. Meanwhile, adjacent crystal surfaces are linked through the hexane alkyl chain of 1,6-DD, which enhances the interaction between perovskite grains and anchors the microstructure of perovskite to some degree. Hydrophobic hexane alkyl chains also increase the moisture resistance of perovskite film. After exposure to the air for 16 days, the device with 1,6-DD additive still retains above 90% of the initial efficiency, exhibiting brilliant stability. fx1 Highlights • 1,6-Diaminohexane Dihydrochloride (1,6-DD) additive is employed for the first time. • Excellent fill factor of 80.1% and power conversion efficiency of 17% are achieved. • The power conversion efficiency of large-area (1 cm2) device reaches to 13.68%. • 1,6-DD passivates the vacancy defects and fixes the perovskite's microstructure. • The devices with 1,6-DD additive exhibit brilliant air stability. [ABSTRACT FROM AUTHOR]

Perovskite/silicon-heterojunction solar cell is a very promising cell structure for using the solar spectrum efficiently and hence improving the energy conversion efficiency. However, perovskite solar cell based on solution technique requires the planar silicon-heterojunction bottom solar cell, which needs a different fabrication process from the textured substrate. In this paper, we developed the high performance planar silicon-heterojunction solar cell by introducing a novel design for the n-type back field and p-type emitter. The results indicate that a wide bandgap and low refractive index nc-SiO x :H for back field improves the open-circuit voltage, fill factor and short-circuit current density by the increased near-infrared long wavelength response. In addition, a nc-Si:H buffer layer between the a-Si:H passivation layer and p-nc-SiO x :H emitter increases the crystallinity in the emitter and then improves device performance further. Combining the developed nc-SiO x :H back field and p-nc-SiO x :H emitter, we achieved an efficiency of 18.77% (Certified 19.1%) on a smooth c-Si wafer. Realization of perovskite/silicon monolithic tandem solar cells with an over 1.7 V output voltage shows the potential application for solar to fuel generation and it also proves that the above strategies are very effective for improving the performance of bottom cell in the tandem solar cells. [ABSTRACT FROM AUTHOR]

In this work, we propose an alternative and fully experimental procedure based only on external quantum efficiency (EQE) measurements for characterizing the efficiency and transmittance of downshifters placed on photovoltaic (PV) devices. The experimental setup requires two PV devices as references, one of them showing a zero EQE in the downshifting spectral range. Therefore, the results obtained are independent of the quantum efficiency of the device, easing the analysis and comparison between experimental results. Also, this method avoids complex theoretical modeling proposed in other works. Those theoretical models are usually based on approximations and/or that require some input parameters difficult to determine without a wide range of experimental equipment in the lab. [ABSTRACT FROM AUTHOR]

In this study, we have investigated the effect of SiO x thickness (1–3 nm) on the performance of polycrystalline (poly) Si/SiO x /monocrystalline Si ( c -Si) passivated contacts. Our results show that for both n - and p -type contacts, there is an optimum SiO x thickness of 1.4–1.6 nm for obtaining the highest implied open-circuit voltage ( i - V oc ) values of ~739 and ~700 mV, respectively. For contacts with SiO x thicker than 1.6 nm, the i - V oc drops due to reduced field-effect passivation. We attribute this to the fact that a thicker SiO x layer hinders the diffusion of both n - and p -type dopants into the c -Si wafer resulting in a junction that is very close to the c -Si/SiO x interface, which increases carrier recombination most likely due to the presence of defects at this interface. The resistivity measured through the metal/poly-Si/SiO x / c -Si stack is independent of SiO x thickness up to 1.6 nm, and increases exponentially by several orders of magnitude with further increase in SiO x thickness due to inefficient tunneling transport. Finally, the extent of metallization-induced degradation of the poly-Si/SiO x / c -Si contacts is worst for the thinnest SiO x investigated (~1 nm), and interestingly it is not completely mitigated even for a ~3 nm thick SiO x . [ABSTRACT FROM AUTHOR]

In this contribution, a novel flexible phase change textiles based on decanoic acid (DA) and polyamide 11 (PA11) blends with various DA/PA11 mass ratios, in which PA11 acted as the polymer matrix, and DA behaved as phase change ingredient, were developed via electrospinning. Besides, a conductive polypyrrole (PPy) coating was designed via in-situ polymerization. Morphological observations carried out by the SEM images demonstrated porous and highly homogeneous morphology with smooth, long, continuous, and free-bead fibers. Furthermore, forming of a uniform PPy layer on the surface was confirmed through the images. As such, conductive textiles with electrical conductivity up to 28.89 ± 1.50 S/m were prepared. Tensile testing showed that the mechanical properties did not change considerably after PPy coating. Moreover, the phase change performance was investigated using DSC analysis, where the melting and crystallization enthalpies were respectively 112.77 J/g and 110.21 J/g in the textile with the highest DA loading, i.e., 70 wt%. More notably, the phase-change enthalpies did not change considerably after 100 DSC thermal cycles. Finally, significant electro- and photo-heat storage and conversion were observed for the conductive PCM textiles. Thus, this work introduced new flexible smart textiles with significant potential in wearable and protective systems. [Display omitted] • Conductive nanofiber textiles were designed for electro-thermal energy management. • The nanofibers consisted of plant-based fatty acid and polyamide 11. • Surface polymerization of conductive PPy was performed on the nanofibers. • The nanofibers demonstrated photo-/electro-thermal energy conversion and storage. • Developed flexible smart textiles have potential in wearable and protective systems. [ABSTRACT FROM AUTHOR]

Renewable energy from a natural resource is currently significant awareness and is being discussed by researchers worldwide to solve the energy crises. This work paves the way for developing efficient solar-to-thermal energy storage conversion based on the "Soft-rigid" structural formation mechanism of carbon aerogel. Here, low-cost wasted pomelo peels derived three-dimensional (3D) porous networked carbon aerogels (PCAs) as a support matrix for paraffin wax (PW) as organic phase change materials (PCM). Moreover, composite phase change materials (CPCMs) show ultralow density, excellent thermal stability, enhanced thermal and electrical conductivities, outstanding shape stability, and leakage-proof ability. The impregnation loading ratio of PW-based CPCM3 reached 95.6%, ascribed to the unique "Soft-rigid" network structure of PCAs. More importantly, the change in the "Soft-rigid" structure endows PCA750 with a high compressive strength of 466 kPa at 60% compression rates. The obtained CPCM2 displayed a significant latent thermal storage capacity of 159.9 J/g and exhibited superior thermal reliability after 25 frequent heating/cooling cycles. The effective carbonization temperature of CPCM2 caused a significant increase in light absorbance; thus, high solar-to-thermal energy conversion efficiency (85.1%). This study provides new ways to convert waste low–value biomass materials into high-value renewable energy (solar-thermal-electricity) with long-term reusability via a simple and green technology. These are tremendous economic benefits in the thermal energy storage sectors. [Display omitted] • Biomass-derived 3D carbon aerogels (PCAs) to form-stable PCMs composite is proposed. • The "Soft-rigid" structure endows PCAs with a high compressive strength of 466 kPa. • A paraffin wax (PW) loading rate of 95.64% into PCAs is reached. • A possible mechanism of "soft-rigid" structural formation is provided. • High efficiency for solar-to-thermal energy conversion (85.1%) is achieved. [ABSTRACT FROM AUTHOR]

Salinity-gradient osmotic energy conversion is one of the key energy-effective strategies to alleviate global power scarcity and is highly dependent on the saline solution temperature. In this study, a solar thermal boosted salinity-gradient osmotic energy conversion with phase change thermal storage is proposed. Phase change materials (PCMs) are integrated into a solar-driven salinity-gradient osmotic energy conversion system to overcome intermittent solar illumination during the entire diurnal cycle. A graphene oxide membrane (GOM)-based experiment is conducted to study the time-dependent solution temperature, current, and power density with three thermal management materials: Cu/PCM composite, pure PCM, and a reference case without PCM in one diurnal cycle, as well as their periodic stability. The solution temperature can be effectively improved by the solar thermal effect. The utilized PCMs, which absorb solar heat during the daytime and release latent heat at nighttime, can effectively maintain the solution temperature to suppress the power decline at night, thereby improving the power generation capacity of the osmotic system during the entire cycle. The combined interaction mechanism of temperature and solution evaporation on the solution concentration, ion diffusivity, ion conductance, ion selectivity, and power density is revealed. The contributions of ion diffusivity, ion conductance, ion selectivity and solution concentration on the power density are obtained. In an illumination cycle, the power density undergoes three processes of growth stage (0 < t < 5 h), high power output stage (5 < t < 13h), and decline stage (13 < t < 23 h). In addition, the present design also demonstrates a consistent solution temperature and short-current stability during successive cycles. • Sustainable photothermal boosted osmotic system with phase change thermal storage. • Temperature and solution evaporation interaction on energy conversion are obtained. • Integrated PCMs can effectively maintain solution temperature at light vanished. • Osmotic device owns consistent thermal and electric stability during successive cycles. [ABSTRACT FROM AUTHOR]

Zinc phosphide (Zn 3 P 2) has been lauded as a promising solar absorber material due to its functional properties and the abundance of zinc and phosphorous. In the last 4 decades, there has not been any significant improvement in the efficiencies of Zn 3 P 2 -based solar cells. This is vastly due to the limited understanding of how to tune its optoelectronic properties. Recently, significant progress has been made in the growth and characterization of the material, which has shed light on its potential. In this study, we report an energy conversion efficiency as high as 4.4% for a solar cell based on a polycrystalline Zn 3 P 2 /InP heterojunction. This device presents an open circuit voltage of 528.8 mV, 7.5% higher than the Zn 3 P 2 homojunction record. We investigate the dominant recombination mechanisms within the film using different techniques to identify the key factors underpinning our device efficiency. In particular, we pinpoint that reduced carrier collection at the front of Zn 3 P 2 is responsible for the reduced collection of high-energy photons. This allows us to suggest the design rules for next-generation Zn 3 P 2 -based heterojunction solar cells, which should allow us to go beyond the current conversion values. • First demonstration of a Zn 3 P 2 /InP solar cell, based on the heterojunction for charge separation. • AcHievement of an efficiency of 4,4%. • Explanation of the carrier generation and collection mechanisms and outline of the improvement factors. [ABSTRACT FROM AUTHOR]

Passivating contacts based on metal oxides have proven to enable high energy conversion efficiencies for crystalline silicon ( c -Si) solar cells at low processing complexity. In this work, the potential of atomic-layer deposited (ALD) Nb 2 O 5 as novel electron-selective passivating contact is explored in terms of recombination parameter J 0 and contact resistivity ρ c . It is shown that after forming gas annealing, ALD Nb 2 O 5 can provide adequate surface passivation with J 0 values down to 25–30 fA/cm 2 . On HF-treated c -Si surfaces a minimum film thickness of ~ 3 nm is required to achieve this high level of passivation, whereas on surfaces with a wet-chemical SiO 2 interlayer the high passivation level is persistent down to film thicknesses of only 1 nm. Ohmic n -type contacts have been achieved using Al as contacting metal, where annealing the samples after Al contacting proved crucial for obtaining good contact properties. Low contact resistivity values of 70 and 124 mΩ cm 2 for 1 and 2 nm Nb 2 O 5 films, respectively, have been achieved on c -Si substrates that received an HF treatment prior to Nb 2 O 5 deposition. Transmission electron microscopy imaging shows that on such surfaces the annealing treatment leads to the formation of a (1.7   ±   0.2) nm interfacial oxide in between the c -Si substrate and the Nb 2 O 5 film. The presented results demonstrate the potential of ALD Nb 2 O 5 as electron-selective passivating contact and directions for future research are outlined. [ABSTRACT FROM AUTHOR]

PbS nanocrystals are an important narrow-gap material for solar cells and photodetectors. Nevertheless, their application may be limited because device performance can be affected by atmospheric conditions. Indeed, the presence of oxygen and/or water can degrade the active layers, possibly leading to device failure. Strategies to address this issue are therefore actively explored. Here we report a solution-processed PbS quantum dot solar cell, consisting of a PbS-silane functionalized reduced graphene oxide (PbS-rGO) layer on top of the PbS absorber film, which enhances device stability, especially when the solar cells are exposed to moisture. Power conversion efficiency (PCE) measurements demonstrate a slower degradation under continuous illumination for solar cells with PbS-rGO. When storing the samples under saturated water vapor, differences are even more remarkable: with PbS-rGO the solar cells essentially maintain their initial PCE, while the PCE of the PbS reference devices is reduced by 50% after 5 days. Scanning electron microscopy, energy dispersive X-ray and X-ray photoelectron spectroscopy reveal the damage to the PbS films and the formation of PbSO x crystals in the PbS reference devices. Such crystals are not observed in the PbS-rGO devices, further supporting the importance of the PbS-rGO barrier layer. [ABSTRACT FROM AUTHOR]

In this work, we report systematic studies on improving the optical and electrical properties of four-terminal perovskite/c-Si tandem solar cells. Light harvesting power of the device is significantly enhanced due to the complementary absorption spectra of the perovskite and c-Si absorber materials. To obtain high power conversion efficiency (PCE) for the device, careful engineering of optoelectronic properties of the devices are accomplished through: 1. Oxygen annealing treatment for reducing defect density of perovskite materials; 2. Optical engineering of the transparent electrode (MoO 3 /Au/MoO 3 ) to obtain high transmission at long wavelengths for the tandem solar cell applications; and 3. Enhancement of light harvesting power achieved by using the novel biomimicking elastomeric petals as the light trapping layer. The individual perovskite solar cell (PSC) with MoO 3 /Au/MoO 3 electrode with or without light trapping layer yields an average PCE of 16.6% and 16.0% respectively. By combining c-Si bottom cell with perovskite top cell mechanically, an overall PCE of 22.4% is achieved for the averaged value, which is a promising result for future development of perovskite based tandem solar cells. [ABSTRACT FROM AUTHOR]

The interaction between light and wavelength-sized photonic nanostructure is highly promising for light management applied to thin-film photovoltaics (PVs). In this work, we put forward a practical wave-optical dielectric hemispheroidal nanostructure strategy under cost-effective anodic oxidation approach and substrate transfer method. By adjusting the oxidation voltage, periodic hemispheroidal nanostructure with diametral scale over 650 nm was obtained. Due to their wavelength-scale dimension, enhanced diffraction behavior and guided resonance were identified through finite-difference-time-domain (FDTD) simulation resulting in significant forward-scattering capabilities. The coherent optical performance was investigated experimentally and theoretically. To leverage the benefits of hemispheroidal nanostructure, amorphous silicon absorb layer and solar cell were fabricated. Compared with the planer structure, the developed hemispheroidal nanostructure could significantly improve the absorption of a-Si:H layer via light management with a 10.97% enhancement in the overall external quantum efficiency. Effective improvements in Voc and FF performances were also obtained in comparison to an etched AZO structure with high surface roughness. As the first demonstration, it was found that the hemispheroidal nanostructure by coating on the surface of a-Si:H thin film solar cells led to 7.79% and 7.38% enhancements respectively in overall energy conversion efficiency in comparison to the planar and the etched AZO structure. [ABSTRACT FROM AUTHOR]

This work demonstrates the influence of annealing temperature on the phase morphology of the polymer-non-fullerene blend and its relationship with the dielectric constants of the blend layer. It is also the first study to report the annealing induced changes in dielectric environment of the active layer blend employing non-fullerene acceptor. Polymer solar cells (PSCs) annealed at 80 °C were found to possess optimal blend morphology favourable for efficient charge separation owing to reduced coulomb capture radius and relatively high dielectric constant, resulting in high power conversion efficiency (PCE) of ~11.4%. The high performing devices fabricated at optimized temperature also exhibited superior charge transport characteristics including high recombination resistance (R rec ) which is 31% higher than the non-annealed devices. The effect of intermolecular aggregation induced by the annealing temperature and its relationship with the disorder states in the blend layer, influencing the electron transport properties is also investigated in detail. Furthermore, a month long degradation study investigating the operational stability of the as-developed non-fullerene based PSCs was also performed and analysed. [ABSTRACT FROM AUTHOR]

The hole-transporting materials (HTMs) play an important role in energy conversion process of perovskite solar cells (PSCs). Here, two spiro-OMeTAD derivatives, 2,4-spiro-OMeTAD and 3,4-spiro-OMeTAD with asymmetric methoxy substituents, have been designed, synthesized and fully characterized. Optimization of the positions of the two methoxy substituents in each of the quadrants was proved to be able to adjust the electronic and optical properties of the HTMs, as investigated by cyclic voltammetry and UV/vis spectroscopy. In particular, PSC devices based on 2,4-spiro-OMeTAD exhibited highly improved photovoltaic performance showing an overall conversion efficiency of 17.2% with excellent stability, which is higher than that of the device derived from spiro-OMeTAD (15.0%) under the same conditions. Besides, 3,4-spiro-OMeTAD based PSCs only achieved a power conversion efficiency of 9.1%, demonstrating a huge influence of HTM structure on the cell performance. [ABSTRACT FROM AUTHOR]

We have developed heterojunction interdigitated back contact solar cell with conversion efficiency of 26.6% (designated area: 180 cm 2 ) independently confirmed by Fraunhofer Institute for Solar Energysystem Callab. Compared to our previous record efficiency (26.3%), the 0.3% absolute improvement can be regarded as ~10% reduction of remaining losses to the theoretical limit (~ 29%). We discuss the analyzed cell properties together with our recent progress to predict how far we can go in reducing the remaining losses in silicon photovoltaic. [ABSTRACT FROM AUTHOR]

A single junction gallium arsenide (GaAs) solar cell on silicon (Si) substrate with energy conversion efficiency of 11.88% under the AM1.5 G spectrum at 1 sun intensity without an anti-reflection coating (ARC) has been developed. This development was enabled by utilizing an intermediate, thin arsenic-doped germanium (As-doped Ge) buffer layer. The thin epitaxial Ge layer (< 2 µm) grown on the Si substrate created a virtual Ge-on-Si (Ge/Si) substrate for subsequent growth of the GaAs solar cell, providing low threading dislocation density (TDD) of < 5 × 10 6 cm −2 . The energy conversion efficiency could be further improved to 16% upon optimizing the ARC and metal coverage. Hence, a manufacturable III-V photovoltaic on a large-area Si substrate has become possible. [ABSTRACT FROM AUTHOR]

The time-dependent dynamics of the charge and discharge of photo-supercapacitors (PSC), devices which combine a supercapacitor with a solar cell, are investigated using a semi-analytical model. For a given PSC, it is found that the maximum Energy Conversion and Storage Efficiency (ECSE) is a direct function of the Power Conversion Efficiency (PCE) and Fill Factor (FF) of the solar cell. The capacitance, series and shunt resistances of the supercapacitor affect the time constants of the PSC and the value of the maximum ECSE. To experimentally measure the maximum value of ECSE with at most 2 charge-discharge cycles, a simple experimental procedure is proposed, which consists in comparing the power flowing through the supercapacitor and the energy already stored in it. The theoretical results are validated with experiments on a PSC made from an organic solar cell and a commercial supercapacitor. [ABSTRACT FROM AUTHOR]

Multicrystalline (mc) n -type silicon has proven to be a suitable substrate for the fabrication of highly efficient mc-Si solar cells. In this paper, we elaborate the impact of base material parameters on the efficiency potential of n -type mc-Si solar cells featuring a boron-diffused front side emitter and a full-area passivating rear contact (TOPCon). The electrical material quality can be significantly improved by replacing the standard crystallization process with a seed-assisted growth for crystallization of high-performance (HP) mc silicon. Using high-purity quartz crucibles or larger crucibles in combination with an optimization of the grain boundary area fraction with an adapted seed structure leads to further improvements of the material quality in terms of charge carrier lifetimes. However, not only the charge carrier lifetime, but also the base resistivity is of crucial importance for the efficiency potential depending on the cell concept. Based on experimental data and simulations, we assess the optimal range for the base resistivity and the wafer thickness for n -type mc-Si TOPCon solar cells. With the optimal material parameters, an “efficiency limiting bulk recombination analysis” (ELBA) reveals an efficiency potential in the range of 22.5% for n -type mc-Si TOPCon solar cells. Finally, we fabricated TOPCon solar cells based on optimized n -type HP mc-Si substrate and demonstrate a certified efficiency of 21.9%, which is the highest efficiency reported for multicrystalline silicon solar cells so far. [ABSTRACT FROM AUTHOR]

The main hindrances which preclude the commercial application of hybrid organic-inorganic halide perovskite solar cells is their thermodynamic instability and fast environmental degradation. Fully inorganic halide perovskites are still far from the MAPbI 3 record power conversion efficiency, but they are significantly more stable. In this work, a significant current increase in the absorbing CsPbBr 3 halide perovskite layer is measured by conductive Scanning Probe Microscopy (c-SPM) after thermal ageing without visible structural degradation. Enhanced local photocurrent along grain boundaries and triple junctions is observed by c-SPM. These effects are accompanied by the appearance of downward band bending along grain boundaries as measured by Kelvin Probe Force Microscopy. It is suggested that the resulting built in electric field effectively acts to facilitate splitting of photogenerated electron-hole pairs at grain boundaries by attracting electrons and repelling holes. The fact of current increase, even though significantly smaller in amplitude, is further confirmed by macroscopic measurements on a complete cell, which may arise from improvement of the ITO/PEDOT:PSS/CsPbBr 3 interfaces upon thermal ageing. These measurements provide advanced understanding of how nanoscale localized structure and function evolve in time and upon thermal ageing. These findings proved further impetus for increasing inorganic halide perovskites power conversion efficiency up to levels sufficient for practical applications. [ABSTRACT FROM AUTHOR]

We report on a high-performance intermediate band solar cell (IBSC) based on Cr-doped ZnTe (ZnTe:Cr) fabricated using a pulsed laser deposition (PLD) method. Chromium (Cr) was uniformly distributed in the ZnTe:Cr thin film with an atomic concentration of about 3.5%, and the ZnTe:Cr thin film showed p-type electrical conductivity. The ZnTe:Cr thin film had higher absorption coefficients than those of undoped ZnTe films in the photon energy range below band gap of ZnTe (2.2 eV). The enhanced absorption coefficients of the ZnTe:Cr thin film were attributed to the photoionization energy between Cr 2+ and Cr + (Cr 2+ ⇌ Cr + ), which acted as the IB to absorb photons below the bandgap of ZnTe (2.2 eV). Illumination with an AM 1.5G solar spectrum on the ZnTe:Cr IBSC generated a large short circuit current of 21.18 mA/cm 2 , an open circuit voltage of 0.48 V, and a fill factor of 0.58, yielding a power conversion efficiency (PCE) of 5.9%, the highest reported PCE in an IBSC based on impurity-doped ZnTe. [ABSTRACT FROM AUTHOR]

Calcium oxide (CaO) is a very promising candidate energy storage material for concentrated solar power plants because of high energy storage density, high temperatures of energy release, and readily available precursors. However, CaO itself not only sinters severely at typical operating temperatures but also has low light absorption capacity. To overcome these challenges, modifying CaO with nanoparticle of magnesium (Mg) and manganese (Mn) oxides was proposed in this work. The Mg and Mn co-modified sample (Ca:Mn:Mg = 9:1:1) demonstrates exceptional thermal stability at 800 °C, the density of energy storage deceases by about 1.1 and 0.7% after 10 and 25 cycles, respectively. Microstructure analysis reveals that MgO and Ca 2 MnO 4 nanoparticles assemble into a net or chain that distributed in the CaO or CaCO 3 particles, which effectively suppresses sintering and provides stable channels for CO 2 to diffuse in CaO or CaCO 3 layer. After 60 cycles, the density of energy storage declines by 7.46%. Additionally, introducing manganese both makes O atoms have more electrons and creates more oxygen vacancies that favor CO 2 activation. The synergistic effect between Mn and Mg achieves high stability, fast calcination reaction and high conversion rate of the energy storage material. The presence of Mn also greatly improves the solar absorption capacity of CaO material, and the co-modified sample exhibits much higher solar absorptance after long-term testing. The proposed CaMnMg911 material could be applied in a concentrated solar power plant for solar energy storage. [Display omitted] • Mg and Mn modified CaO material was synthesized by a wet chemical method. • Cyclability of the material was enhanced by net or chain structure. • Synergistic effect between Mn and Mg achieves high performance. • The solar absorption capacity of modified CaO increases with cycles. [ABSTRACT FROM AUTHOR]

This work initially prepared the ultra-light flexible graphene aerogel (LGA) with the function of electro/photo-thermal conversion by introducing the natural latex into the graphene aerogel. The functional LGA was then used as supporting matrix to fabricate novel form-stable phase change materials (PCMs). The microstructure, thermal performance and multi-energy driven properties of the form-stable PCMs are investigated and results present that both the LGA and form-stable PCMs are flexible. DSC tests indicate that the encapsulation efficiency of LGA to PCM is calculated about 90 wt%. The form-stable PCMs show a superior thermal reliability after 200 thermal cycling. Based on the excellent electro/photo-thermal conversion of LGA, the form-stable PCMs also reveal outstanding photo-sensitive flexibility under a simulated light source, which can convert 73.5% of electric energy into heat energy at low driving voltage of 8 V. Moreover, the form-stable PCMs enable to transform the photo energy into thermal energy, with the maximum conversion effectivity of 91.8%. The form-stable PCMs effectively also extend the output voltage time of the thermoelectric generator coupled with the novel thermal energy storage. Therefore, the form-stable PCMs with multi-energy conversion functions will have extensive application prospects in the energy storage system and thermal management fields. [Display omitted] • The composite PCM has good thermal/photo-sensitive flexibility. • The maximum melting enthalpy of composite PCM is measured as 210.5 J/g. • The enthalpy of composite PCM only reduced by 2.56% after 200 thermal cycles. • The composite PCM can convert 73.5% of electric energy into heat energy at 8 V. • The maximum photo-thermal conversion efficiency of the composite PCM is 91.8%. [ABSTRACT FROM AUTHOR]

In this work, we developed a type of shape-stabilized phase change materials (SSPCMs) based on carbonized melamine foam/graphene aerogel (CMGA) as a supporting material and polyethylene glycol (PEG) as a phase change material. PEG@CMGA SSPCMs were prepared by fabricating a series of CMGA double skeleton with different carbonization temperatures using freeze-drying and high-temperature carbonization, followed by vacuum impregnation of PEG into the CMGA double skeleton. The morphological structure, thermal storage property, shape stability, thermal conductivity, and solar/electric conversion behavior of the fabricated SSPCMs are investigated. The results showed that PEG@CMGA SSPCMs exhibited excellent shape stability, high latent thermal storage capacity of 181.2 J/g, thermal cycling stability, enhanced thermal conductivity with 387% higher than that of pure PEG, solar-to-thermal energy conversion capability with high efficiency of 91.7% and electric-to-thermal energy conversion capability with high efficiency of 87.3%. The results of this work provide a strategy for the design and development of high performance, multiple energy conversion forms of SSPCMs for promising applications in solar energy utilization, energy-efficient buildings, and heat preservation. [Display omitted] • CMGA double skeleton with excellent mechanical property is constructed by in situ self-assembly and carbonization. • The composite phase change materials possess excellent energy storage properties and high thermal conductivity. • PEG@CMGA 1600 SSPCMs achieve efficient solar-to-thermal conversion efficiency of 91.7%. • PEG@CMGA 1600 SSPCMs exhibit electric-to-thermal energy conversion capability with high efficiency of 87.3%. [ABSTRACT FROM AUTHOR]

Increasing photovoltaic conversion efficiency by overcoming the fundamental loss mechanisms due to hot carrier thermalisation remains one of the challenges in solar energy research. A large proportion of dynamic energy is lost due to thermalisation where hot carriers lose their energy to lattice vibrations within picoseconds. Extending hot carrier lifetimes will potentially improve the efficiency of photovoltaic devices. In this study, the bulk hafnium nitride film is proposed as a potential hot carrier absorber from its phononic properties. Hafnium nitride thin films were deposited by sputtering on quartz substrates. The films are polycrystalline as determined from X-ray diffraction and from X-ray photoelectron spectroscopy the chemical composition of the films are estimated to be HfN 0.9 . The absorption coefficient of the film exhibits strong amplitude below 500 nm and free electron absorption at longer wavelengths. Transient absorption spectroscopy was used to investigate carrier dynamics in the visible and near-infrared spectral regions. For the first time we present evidence of up to nanosecond long lifetimes of photo-excited carriers observed in hafnium nitride. We propose that the long lived excited states are due to restricted phonon decay pathways in hafnium nitride. The long lived excited states in the bulk hafnium nitride film provide a simple route to devices designed to utilise hot carriers efficiently. [ABSTRACT FROM AUTHOR]

A spin-coating-free fabrication sequence has been developed for the fabrication of highly efficient organic-inorganic halide perovskite solar cells (PSCs). A novel blow-drying method is demonstrated to be successful in depositing high quality mesoporous TiO 2 (mp-TiO 2 ), methylammonium lead halide (CH 3 NH 3 PbI 3 ) perovskite and spiro-MeOTAD layers. When combined with compact TiO 2 (c-TiO 2 ) deposited by spray pyrolysis which is also a spin-coating-free process, a stabilized power conversion efficiency exceeding 17% can be achieved for the glass/FTO/c-TiO 2 /mp-TiO 2 / CH 3 NH 3 PbI 3 /spiro-MeOTAD/Au device. This is the highest efficiency for PSCs fabricated without the use of spin-coating to our knowledge. This method provides a pathway towards a scalable process for fabricating high-performance, large area and reproducible PSCs. [ABSTRACT FROM AUTHOR]

Organic-inorganic perovskite cell has shown a great deal of interest in past few years due to its ability to achieve high power conversion efficiency (PCE). Use of charge transport layers such as n-type TiO 2 and p-type doped spiroOMeTAD in a n-i-p device architecture has shown enhanced perovskite solar cell device performance. Use of doped spiroOMeTAD as hole transport layer in the n-i-p device structure has been effective but possess disadvantages such as complex processing, use of corrosive additives, processing in ambient air for efficient hole doping. Here we report the study of solution processed benzodithiophene based polymer PBDTT-FTTE as an alternative hole transport layer to doped small molecule spiroOMeTAD. PBDT-FTTE doped with 3% DIO (diiodooctane) achieved PCE of 11.6% which was comparable to matching PCE of 11.6% obtained from using spiroOMeTAD as hole transport layer. We showed that unlike spiroOMeTAD, polymer PBDTT-FTTE is processed inside N 2 filled glove box and is easier to process as compared to spiroOMeTAD which requires processing in ambient humid air and is doped with additives mixed in corrosive solvent, causing degradation to perovskite layer underneath. [ABSTRACT FROM AUTHOR]

Recently, organic solar cells have demonstrated high power conversion efficiencies, but extrinsic device stability remains to be a challenge. Often, delamination of the cathode upon water ingress leads to a massive active area loss and to a strong decrease in efficiency. We present highly efficient organic solar cells with an oligothiophene-based donor and two different cathodes. Devices are aged at four different climates under continuous illumination. Al and MoO 3 /Cr/Al cathodes are compared. Additional interlayers are introduced for enhanced cathode adhesion. Aging in different climates reveals a strong dependency of the degradation speed on absolute humidity for standard Al cathodes. However, using additional interlayers, degradation seems to be almost decoupled from the applied climate and device degradation is slowed immensely. Parallel WVTR measurements of the AlO x barrier allow for the assessment of absolute water quantities until devices are degraded to half of their initial efficiency: 24 g m 2 are found for standard Al cathodes, while devices with additional interlayers reach 58 g m 2 . This difference is related to a completely different aging behavior, which trades strong short-circuit current density losses for moderate fill-factor losses. [ABSTRACT FROM AUTHOR]

Dye-sensitized solar cells (DSSCs) with photoanodes composed of chirality selected single-wall carbon nanotubes (SWNTs) have been fabricated and tested for first time. Single chirality SWCNTs separation (93% purity) have been achieved by modifying standard size exclusion gel chromatography. Chirality selection has allowed for “tuning” of the energy barrier at the TiO 2 /SWNT/FTO interface, electronic conductivity enhancement, and reduced SWCNTs-ruthenium dye competition for light absorption resulting in a 81% energy conversion efficiency improvement compared to mixed chirality cells. Unfortunately, energy conversion efficiency has been limited by cells’ low shunt resistance. Additionally, SWCNTs electron transfer properties have been exploited to prepare mixed and chirality specific CNTs based DSSCs’ counter electrodes. [ABSTRACT FROM AUTHOR]

Cubic perovskite BaSnO 3 (BSO) nanostructure has rationally been addressed as a promising charge carrier transporting material in dye sensitized solar cells (DSCs) next to TiO 2 . In the present work, the Fe impurity ions have initially been introduced into BSO crystallographic system with the help of solution chemistry for systematically altering the position of atoms in their lattice point towards developing insight properties. The changing of physical properties (structural, morphological, optical and magnetic) of BSO semiconductor by Fe doping is significantly confirmed by using fundamental characteristic tools. After authentically identifying the desirable physico-chemical properties of BSO by a gradient Fe dopant, we sensitively engineer the pristine, 0.01%, 0.03% and 0.05% Fe doped BSO/TiCl 4 treatment/TiO 2 scattering layer novel photoelectrodes for fabricating DSCs. As scientifically expected that the power conversion efficiency (PCE) of Fe doped BSO/TiCl 4 treatment/TiO 2 scattering layer photoanodes is increased as compared to that of pristine BSO/TiCl 4 treatment/TiO 2 scattering layer photoanode. We have achieved one of the highest PCE in 0.03% Fe doped BSO/TiCl 4 treatment/TiO 2 scattering layer photoelectrode based DSCs, the obtained maximum value is 7.78%. The stability of the novel BSO photoelectrodes is then measured by using transient photocurrent and photovoltage measurements. [ABSTRACT FROM AUTHOR]

Single-junction Ge solar cells have been epitaxially grown on GaAs (001) substrates by a low pressure metalorganic chemical vapor deposition using isobutylgermane. Various growth conditions have been studied to reduce the high doping level of over 1×10 19 cm −3 of the p-type Ge epitaxial layer, which is detrimental to the minority carrier collection efficiency. By increasing the growth rate and employing a discontinuous doping technique, the p-type doping level of the epitaxial Ge layer has been lowered to 2×10 18 cm −3 , and the hole mobility increased from 44 to 162 cm 2 /V s. A high power conversion efficiency of 6.72% can be achieved under AM1.5 G illumination by the epitaxial Ge solar cell with the lowered doping level in the p-type Ge base region. The spectral response of the epitaxial Ge solar cell with a 5 µm thick base layer is good enough to use for InGaP/GaAs/Ge triple-junction solar cells. [ABSTRACT FROM AUTHOR]

We achieved an inverted pyramid structure, meeting the tradeoff between the light reflection minimization and carrier recombination by adjusting the one-step Cu-assisted texturization of silicon wafer, and silicon solar cells based on this structure were fabricated, which gained a high conversion efficiency of 18.87% without using any complex techniques. These data were compared with the performance of conventional upright pyramid silicon solar cells as manufactured using identical raw wafers, the Cu-etched inverted pyramid silicon cells collected 0.59 mA/cm 2 more short-circuit current density and 0.47% more efficiency. Importantly, our data demonstrate the better performance and manufacturability of inverted pyramid structured silicon solar cell and as such may open new perspectives for high efficiency solar cell applications. [ABSTRACT FROM AUTHOR]

Cu(In, Ga)Se 2 (CIGS) based thin film solar cells have been extensively studied and today, power conversion efficiencies higher than 20% have been demonstrated on both rigid and flexible substrates. However, very little is known about the mechanical resistance of flexible CIGS solar cells under flexion. Here we report an original study on the mechanical properties of CIGS solar cells fabricated on 100 µm-thick ultra-thin glass substrates. The Young's modulus and hardness of Mo and CIGS thin films are measured by nanoindentation, a technique well adapted to the characterization of thin film materials. Young's modulus values of 289 GPa and 70 GPa are obtained for the Mo and the CIGS layers respectively, as well as a CIGS hardness of 3.4 GPa. These values, combined with an analytical model, allow calculating the strain induced in thin film during the flexion of solar cells fabricated on ultra-thin glass substrate as well as on polyimide substrate. Thereby, we show that using a substrate with a low thickness and a low Young's modulus enables to lower the thin films strain during the flexion of cells. [ABSTRACT FROM AUTHOR]

Plasmonics are applied to concentrate light at the nanoscale and are integrated into photothermal technologies to improve solar energy absorption. Here, we report a one-step synthetic route of super broadband Ag@TiO 2 core–shell nanoparticles under well-defined conditions using silver nitrate (AgNO 3 ) and titanium butoxide (TBT) in N , N -dimethylformamide as raw materials and hexadecyl trimethyl ammonium chloride (CTAC) as both an inducer and a protective agent. Transmission electron microscopy revealed that the prepared nanoparticles have well-defined core–shell structures. The intermediates and final product were further characterized by UV–vis absorption, which showed that the synthesized Ag@TiO 2 core–shell nanoparticles exhibit super broadband absorbance in the visible light range, and the surface plasmon resonance (SPR) peak can be systematically tuned between 414 and 499 nm. In addition, X-ray diffraction and energy-dispersive spectroscopy confirmed the compositions of the nanoparticles. The nanoparticles prepared under well-defined conditions, i.e., a TBT:AgNO 3 molar ratio of 3:1, CTAC concentration of 0.6 mM, temperature of 80 °C, and reaction time of 70 min, show an SPR peak at 474 nm, which is close to the maximum solar irradiation intensity and has great potential for promoting solar energy conversion. [ABSTRACT FROM AUTHOR]

Broad-band solar thermal conversion materials are highly desired for solar energy harvesting. The purpose of this work is to demonstrate a simple and straightforward strategy to engineer broad-band solar thermal conversion nanofluids. Stable two-component nanofluids containing copper (II) oxide (CuO) and antimony doped tin oxide (ATO) nanoparticles were prepared after surface modification of the CuO nanoparticles. As a reference, the CuO nanofluids have strong absorption in the visible region but not the near-infrared region. On the contrary, the ATO nanofluids have strong absorption in the near-infrared region, but the absorption in the visible region is comparatively weak. The combination of CuO and ATO nanoparticles endows the two-component nanofluids with broad-band absorption across the visible and near-infrared region. The two-component nanofluids of 0.1 vol% show an absorption spectrum match well with the solar spectrum and give a solar weighted absorption fraction of 99.6% compared to 89.5% and 89.8% for the CuO and ATO nanofluids, respectively. The solar thermal utilization efficiency of the two-component nanofluids was determined to be 92.5% compared to 81.3% and 80.7% for the CuO and ATO nanofluids, respectively. The enhanced solar thermal conversion properties of the two-component nanofluids are attributed to the complementary optical absorption of the CuO and ATO nanoparticles. This work provides a promising strategy to engineer nanofluids for solar energy harvesting. [ABSTRACT FROM AUTHOR]

Solution-processed small molecule-fullerene bulk heterojunction (SM BHJ) solar cells now have power conversion efficiency (PCE) greater than 10%. However, degradation of SM BHJ solar cells has not been well studied. This work reports the first stability study of six high performance molecules including the record SM BHJ solar cells under device operating conditions. Solar cells with a range of donor molecular weight from 1200 to 2300 Da giving 6–10% PCE are monitored in nitrogen gas under 1 sun illumination with maximum power point tracking as well as at 25 °C and 70 °C in the dark. Both heat and light contribute to initial exponential decay or burn-in with total reduction in efficiency from 31% to 66%. Larger molecules are found to be resistant to heat induced burn-in, while more crystalline active layers are more resistant to light induced burn-in. After burn-in, the linear degradation is observed to be governed by thermal processes. Stabilized TS80 lifetimes of the SM BHJ solar cells range from 3450 h to 5600 h. Molecular design towards higher stability should aim at increasing thermal stability while maintaining crystallinity for photostability. [ABSTRACT FROM AUTHOR]

To improve the energy utilization efficiency of solar energy, Ti 4 O 7 /PEG/SiO 2 form-stable phase change material (PCM) with characters of light-heat conversion and thermal conductivity enhancement was developed by in-situ doping titanium black (Ti 4 O 7 ) through acid and alkali catalytic sol-gel method. The structure and properties of PCM were investigated by SEM, FT-IR, XRD, DSC, TG, coefficient of thermal conductivity and thermal conversion testing, etc. The results showed that the Ti 4 O 7 /PEG/SiO 2 could effectively absorb UV–visible light of solar radiation, simultaneously, the light energy was translated into thermal energy which was storied by PCM. Furthermore, the composite PCM exhibited good thermal stability below 360 °C, excellent shape-stabilized effect and high thermal conductivity. The Ti 4 O 7 /PEG/SiO 2 as novel thermal storage material can usefully enhance the utilization efficiency of solar energy. [ABSTRACT FROM AUTHOR]

The inefficient charge separation is one of the major impediments to improve the overall power conversion efficiency of the organic photovoltaics. Herein we demonstrate a new inorganic hole transporting materials for organic photovoltaics. Cu 2 CdSnS 4 hole transport layer was deposited by solution based approach in low temperature by simple method. The thickness dependence of Cu 2 CdSnS 4 hole transport layer on photovoltaic performance of organic solar cells was studied in details. The hole extraction activity of Cu 2 CdSnS 4 thin films were compared with the reference PEDOT:PSS hole transport layer in the fabrication of P3HT:PCBM solar cells. [ABSTRACT FROM AUTHOR]

This article reviews the state of the art and historical development of thermophotovoltaic (TPV) energy conversion along with that of the main competing technologies, i.e. Stirling, Brayton, thermoelectrics, and thermionics, in the field of space power generation. Main advantages of TPV are the high efficiency, the absence of moving parts, and the fact that it directly generates DC power. The main drawbacks are the unproven reliability and the low rejection temperature, which makes necessary the use of relatively large radiators. This limits the usefulness of TPV to small/medium power applications (100 W e -class) that includes radioisotope (RTPV) and small solar thermal (STPV) generators. In this article, next generation TPV concepts are also revisited in order to explore their potential in future space power applications. Among them, multiband TPV cells are found to be the most promising in the short term because of their higher conversion efficiencies at lower emitter temperatures; thus significantly reducing the amount of rejected heat and the required radiator mass. [ABSTRACT FROM AUTHOR]

Two different process approaches for growing high-performance multi-crystalline silicon (HPM-Si) material for photovoltaic applications are presented. Assisted nucleation was achieved by seeding on fine polycrystalline silicon chunks and on a rough silica crucible bottom, respectively. For each of the two methods industrially sized ingots of 650 kg were directionally solidified. Wafers of these ingots and those from conventionally solidified multi-crystalline (mc) silicon ingots were used to produce solar cells on industrial line. Solar cell parameters were analyzed and compared. Both assisted nucleation methods are suitable for industrial growing of HPM-Si ingots. The grain size is more homogeneously distributed resulting in improved material quality. Less dislocation clustering results in higher average conversion efficiency of solar cells compared to those made of conventionally solidified mc-Si material. Moreover, it is also experimentally proven that assisted nucleation procedure is effective for both Siemens polysilicon feedstock and cheaper solar grade silicon. Further improvements of nucleation procedures, which can be used to achieve higher conversion solar cell efficiency and lower product cost, are proposed. [ABSTRACT FROM AUTHOR]