太阳能长余辉庭院灯照明系统在宾馆的应用

太阳能长余辉庭院灯是阳光发电技术与荧光技术的有机结合。其特点 :白天通过太阳电池吸收光能 ,夜间点亮庭院。关掉电源后 ,荧光灯仍能持续发光 。

NiFe layered double-hydroxide nanoparticles for efficiently enhancing performance of BiVO_4 photoanode in photoelectrochemical water splitting

A bismuth vanadate(BiVO4)photoanode with a cocatalyst consisting of NiFe layered double‐hydroxide(NiFe‐LDH)nanoparticles was fabricated for photoelectrochemical(PEC)water splitting.NiFe‐LDH nanoparticles,which can improve light‐absorption capacities and facilitate efficient hole transfer to the surface,were deposited on the surface of the BiVO4 photoanode by a hydrothermal method.All the samples were characterized using X‐ray diffraction,scanning electron microscopy,and diffuse‐reflectance spectroscopy.Linear sweep voltammetry and current‐time plots were used to investigate the PEC activity.The photocurrent response of NiFe‐LDH/BiVO4 at 1.23 V vs the reversible hydrogen electrode was higher than those of Ni(OH)2/BiVO4,Fe(OH)2/BiVO4 and pure BiVO4 electrodes under visible‐light illumination.NiFe‐LDH/BiVO4 also gave a superior PEC hydrogen evolution performance.Furthermore,the stability of the NiFe‐LDH/BiVO4 photoanode was excellent compared with that of the bare BiVO4 photoanode,and offers a novel method for solar‐assisted water splitting.

Preparation and photoelectric properties of Ho^(3+)-doped titanium dioxide nanowire downconversion photoanode

Ho^3＋-doped titanium dioxide（TiO2：Ho^3＋） downconversion（DC） nanowires were synthesized through a simple hydrothermal method followed by a subsequent calcination process after being immersed in Ho（NO3）3 aqueous solution. Moreover, TiO2：Ho^3＋ nanowires（HTNWs） were used as the photoanode in dye-sensitized solar cells（DSSCs） to investigate their photoelectric properties. Scanning electron microscopy（SEM） and X-ray diffraction（XRD） were used to characterize the morphology and structure of the material, respectively. The photofluorescence and ultraviolet-visible absorption spectra of HTNWs reveal a DC from the near and middle ultraviolet light to visible light which matches the strong absorbed region of the N719 dye. Compared with the pure TNW photoanode, HTNWs DC photoanodes show greater photovoltaic efficiency. The photovoltaic conversion efficiency（η） of the DSSCs with HTNWs photoanode doped with 4% Ho2O3（mass fraction） is two times that with pure TNW photoanode. This enhancement could be attributed to HTNWs which could extend the spectral response range of DSSCs to the near and middle ultraviolet region and increase the short-circuit current density（Jsc） of DSSCs, thus leading to the enhancement of photovoltaic conversion efficiency.

Multifarious function layers photoanode based on g-C_3N_4 for photoelectrochemical water splitting

We report on a novel g-C3N4/TiO 2/Co-Pi photoanode combining a TiO2 protection layer, Co-Pi hole capture layer, and g-C3 N4 light-absorption layer layer for photoelectrochemical（PEC） water splitting to generate hydrogen for the first time. This new photoanode with three function layers exhibits enhanced PEC performance with a photocurrent density of 0.346 mA ·cm–2 at 1.1 V（vs. RHE）,which is approximately 3.6 times that of pure g-C3N4 photoanode. The enhanced PEC performance of g-C3N4/TiO 2/Co-Pi photoanode benefits from the following：（1） excellent visible light absorption of g-C3N4;（2） stable protection of TiO2 to improve the durability of g-C3N4 film; and（3） photogenerated holes capture Co-Pi to separate photogenerated electron-hole pairs efficiently. This promising multifarious function layers structure provides a new perspective for PEC water splitting to generate hydrogen.

Progress in designing effective photoelectrodes for solar water splitting

Photoelectrochemical(PEC)water splitting process is regarded as a promising route to generate hydrogen by solar energy and at the heart of PEC is efficient electrode design.Great progress has been achieved in the aspects of material design,cocatalyst study,and electrode fabrication over the past decades.However,some key challenges remain unsolved,including the most demanded conversion efficiency issue.As three critical steps,i.e.light harvesting,charge transfer and surface reaction of the PEC process,occur in a huge range of time scale(from10-12s to100s),how to manage these subsequent steps to facilitate the seamless cooperation between each step to realize efficient PEC process is essentially important.This review focuses on an integral consideration of the three key criteria based on the recent progress on high efficient and stable photoelectrode design in PEC.The basic principles and potential strategies are summarized.Moreover,the challenge and perspective are also discussed.

Influence of anodic oxide film structure on adhesive bonding performance of 5754 aluminum alloy

Three types of anodic films(unsealed,hot water sealed and agent sealed)were prepared to study the effects of anodic film structure on the adhesive bonding performance of AA5754 automotive sheets.The morphology of the anodic films was examined by using scanning electron microscope(SEM)and the composition was examined by glow discharge optical emission spectroscopy(GDOES).The adhesive bonding strength and the durability in corrosive environment were investigated by using single lap-hear test and salt spray test(SST),respectively.The results showed that the unsealed sample could provide high initial bonding strength,but the durability was poor in corrosive environment.The hot water sealed sample could provide high durability,but the bonding strength was low.In contrast,the agent sealed sample displayed porous structure at outer layer and partially plugged nano pores structure at inner layer,providing both excellent bonding strength and durability.

Peculiarities of ZnCdSe Nanolayers by Chemical Deposition

In this work, the results on the investigation of the precularity near the solar spectrum region, of Zn1.xCdxSe nanofilms, nanoscale heterojunction prepared on silikon and alumminium substrates by precipitation from aqueous solutions are presented. The temperature dependence of dark and light conductivity, spectrum and optical quenching of primary and impurity photoconductivity are investigated. The obtained results show that when controlling ionic composition and HT （heat-treatment） conditions, one can purposely control the properties of Zn1-xCdxSe （0 ≤ x ≤ 0.6） films, achieve the appropriate degree of compensation of different recombination levels and traps attributed to intrinsic defects or impurities, which result in high level of photoelectrical parameters near the IR region. Just after deposition the photoconductivity spectrum maximum of Zn1-xCdxSe （0 〈 x 〈 0.6） films is observed at λ1 = 0.545 ＋ 0.495/am versus the film composition.

Metastable-phaseβ-Fe_(2)O_(3) photoanodes for solar water splitting with durability exceeding 100 h

Planar films of pure and Ti^(4+)-dopedβ-Fe_(2)O_(3)were prepared by a spray pyrolysis method.X-ray diffraction patterns and Raman spectra of the metastableβ-Fe_(2)O_(3)film showed that its thermal stability was significantly improved because of covalent bonds in the interfaces between the film and substrate,while only weak Van der Waals bonds existed at the interfaces within the particle-assembledβ-Fe_(2)O_(3)film prepared by electrophoretic deposition.The as-prepared planar films were thus able to withstand higher annealing temperature and stronger laser irradiation power in comparison with theβ-Fe_(2)O_(3)particle-assembly.Ti^(4+)doping was used to increase the concentration of carriers in the metastableβ-Fe_(2)O_(3)film.Compared with pureβ-Fe_(2)O_(3)photoanodes,the highest saturated photocurrent for water splitting over the Ti^(4+)-dopedβ-Fe_(2)O_(3)photoanode was increased by a factor of approximately three.Theβ-Fe_(2)O_(3)photoanode exhibited photochemical stability for water splitting for a duration exceeding 100 h,which indicates its important potential application in solar energy conversion.

Performance Evaluation of New Two Axes Tracking PV-Thermal Concentrator

The overall problem with PV （photovoltaic） systems is the high cost for the photovoltaic modules. This makes it interesting to concentrate irradiation on the PV-module, thereby reducing the PV area necessary for obtaining the same amount of output power. The tracking capability of two-axes tracking unit driving a new concentrating paraboloid for electric and heat production have been evaluated. The reflecting optics consisting of flat mirrors provides uniform illumination on the absorber which is a good indication for optimised electrical production due to series connection of solar cells. The calculated optical efficiency of the system indicates that about 80% of the incident beam radiation is transferred to the absorber. Simulations of generated electrical and thermal energy from the evaluated photovoltaic thermal （PV/T） collector show the potential of obtaining high total energy efficiency.

Optimization with Genetic Algorithms of PVT System Global Efficiency

PV （photovoltaic） solar panels generally produce electricity in the 6% to 12% efficiency range, the rest is being dissipated in thermal losses. To recover this amount, hybrid photovoltaic thermal systems （PV/T） have been devised. These are devices that simultaneously convert solar energy into electricity and heat. It is thus interesting to study the PV/T system as part of a closed loop single phase water CDU （coolant distribution unit） in laminar forced convection. In particular, the analysis was conducted on the optimal cooling performance of the thermal part, testing polynomial channel profiles of varying order （from zero to fourth） for channels of a real industrial module heat sink, under the following conditions： ideal flux of 1,000 W/m2 on one side, insulation on the opposite side, periodic conditions on the remaining sides, fully developed thermal and velocity profile in laminar flow of water. Through the use of a genetic algorithm, we have optimized the shape of the channel＇s sidewalls in terms of heat transfer maximization. In terms of Nusselt number, results show that fourth order profiles are the most efficient. When limits to allowable pressure loss and module weight are introduced, these bring generally to a lower efficiency of the system than the unconstrained case.

Integration of the Energy and Building Technologies

The performance of each type of building must meet all the needs and requests of new real estate markets. In fact, in the excellent architectures, the user can manage, with autonomy and flexibility, each system and product, according to the new energy and building technologies too. The main objective is the social and environmental sustainability with the reduction of fossil fuels and the greenhouse gas effect, pushing the use of renewable energies, in a new trend of land regeneration with sustainable buildings and settlement recovery. The energy crisis, mainly generated by the climate change, the air pollution, with consequent extinction of the species, reduction of the land and the work, the degradation and the environmental and seismic risk, focuses on the security and quality of construction systems, integrated use of clean resources. The methodologies aimed at integrating of energy-efficient and innovative building technologies in architecture, from design to management, to produce electric and thermal energy with active and passive properties, for a high-performance habitat. Therefore, the use of solar photovoltaic in the buildings, BIPV （Building Integrated Photovoltaic） with high-performance glass vision, efficient systems, intelligent materials, is integrated in architectures with the use of innovative construction systems, finally, technology of OPV （Organic Photovoltaic）, multi-junction cells, the dye sensitized solar cells in the solid state, etc., and adoption of storage systems.

Activating ZnO nanorod photoanodes in visible light by Cu ion implantation

Utilization of visible light is of crucial importance for exploiting efficient semiconductor catalysts for solar water splitting. In this study, an advanced ion implantation method was utilized to dope Cu ions into ZnO nanorod arrays for photoelectrochemical water splitting in visible light. X-ray diffraction （XRD） and X-ray photo-electron spectroscopy （XPS） results revealed that Cu^＋ together with a small amount of Cu^2＋ were highly dispersed within the ZnO nanorod arrays. The Cu ion doped ZnO nanorod arrays displayed extended optical absorption and enhanced photoelectrochemical performance under visible light illumination （A 〉 420 nm）. A considerable photocurrent density of 18 μA/cm^2 at 0.8 V （vs. a saturated calomel electrode） was achieved, which was about 11 times higher than that of undoped ZnO nanorod arrays. This study proposes that ion implantation could be an effective approach for developing novel visible-light-driven photocatalytic materials for water splitting.

Optical analysis of a hybrid solar concentrating Photovoltaic /Thermal (CPV/T) system with beam splitting technique

A novel hybrid solar concentrating Photovoltaic/Thermal (CPV/T) system with beam splitting technique is presented. In this system, a beam splitter is used to separate the concentrated solar radiation into two parts: one for the PV power generation and the other for thermal utility. The solar concentrator is a flat Fresnel-type concentrator with glass mirror reflectors. It can concentrate solar radiation onto solar cells with high uniformity, which is beneficial to improving the efficiency of solar cells. The thermal receiver is separated to the solar cells, and therefore, the thermal fluid can be heated to a relatively high temperature and does not affect the performance of solar cells. A dimensionless model was developed for the performance analysis of the concentrating system. The effects of the main parameters on the performance of the concentrator were analyzed. The beam splitter with coating materials Nb2O3 /SiO2 was designed by using the needle optimization technique, which can reflect about 71% of the undesired radiation for silicon cell(1.1m < 3m) to the thermal receiver for thermal utility. The performance of this CPV/T system was also theoretically analyzed.

Anti-photocorrosive photoanode with RGO/PdS as hole extraction layer

Photoelectrochemical(PEC)hydrogen production is of great interest as an ideal avenue towards clean and renewable energy.However,the instability and low energy conversion efficiency of photoanodes hinder their practical applications.Here we address these issues by introducing a hole extraction layer(HEL)which could rapidly transfer and consume photogenerated holes.The HEL is constructed by reduced graphene oxide(RGO)and other cocatalysts that enable rapid transfer and subsequent consumption of holes,respectively.Specifically,we showcase a high-stability photoanode composed of CdSeTe nanowires(CST NWs)and RGO/PdS nanoparticles(PdS NPs)based HEL.The photoanode achieves excellent photocorrosion resistance,which allows stable hydrogen evolution for>2 h at 0.5 VRHE.

Energy analysis of a hybrid solar concentrating photovoltaic/concentrating solar power(CPV/CSP) system

This study presents a novel solar concentrating photovoltaic/concentrating solar power （CPV/CSP） hybrid system, which mainly contains CPV modules with an evaporative cooling subsystem, a thermal receiver and an organic Rankine cycle （ORC）. The cooling fluid is boiled when cooling the CPV modules, and superheated vapor that is effective for power generation with an ORC is generated after absorbing low-concentration solar radiation in the thermal receiver. A steady-state physical model is developed to carry out energy analysis of the hybrid sys- tem. The results show that when saturated vapor is fed into the thermal receiver, the peripheral low-concentration solar radiation that is discarded in conventional CPV or CPV/ thermal systems is effective to get a high-temperature superheated vapor （e.g., above 120 ℃）. The overall solar- to-electricity efficiency can be increased from 28.4 % for the conventional CPV system to 44 % for the hybrid sys- tem with 500 suns. Even though the overall efficiency decreases from 44.0 % to 36.8 % when the concentration ratio increases from 500 to 2,000 suns, there is still a considerable efficiency improvement compared with the conventional CPV systems. The results indicate that the proposed hybrid system provides a viable solution for solar power generation with high efficiencies.

Coordination engineering of Cu-Zn-Sn-S aqueous precursor for efficient kesterite solar cells

Aqueous precursors provide an alluring approach for low-cost and environmentally friendly production of earth-abundant Cu2ZnSn(S,Se)4(CZTSSe)solar cells.The key is to find an appropriate molecular agent to prepare a stable solution and optimize the coordination structure to facilitate the subsequent crystallization process.Herein,we introduce thioglycolic acid(TGA),which possesses strong coordination(SH)and hydrophilic(COOH)groups,as the agent and use deprotonation to regulate the coordination competition within the aqueous solution.Ultimately,metal cations are adequately coordinated with thiolate anions,and carboxylate anions are released to become hydrated to form an ultrastable aqueous solution.These factors have contributed to achieving CZTSSe solar cells with an efficiency as high as 12.3%(a certified efficiency of 12.0%)and providing an extremely wide time window for precursor storage and usage.This work represents significant progress in the non-toxic solution fabrication of CZTSSe solar cells and holds great potential for the development of CZTSSe and other metal sulfide solar cells.

Promoting charge carrier utilization by integrating layered double hydroxide nanosheet arrays with porous BiVO_4 photoanode for efficient photoelectrochemical water splitting

The increasing exploration of renewable and clean power sources have driven the development of highly active materials for photoelectrochemical （PEC） water splitting. However, it is still a great challenge to enhance the charge utilization. Herein, we report a facile method to fabricate composite photoanode with porous BiVO4 film as the photon absorber and layered double hydroxide （LDH） nanosheet arrays as the oxygen-evolution cocatalysts （OECs）. The as-prepared BiVO4/NiFe-LDH photoanode shows an excellent performance for PEC water splitting benefitting from the synergistic effect of the superior charge separation efficiency facilitated by porous BiVO4 film and the excellent water oxidation activity resulting from LDH nanosheet arrays. A photocurrent density is 4.02 mA cm^-2 at 1.23 V vs. the reversible hydrogen electrode （RHE）. Furthermore, the O2 evolution rate at the surface of BiVO4/NiFe-LDH photoanode is as high as 29.6 μmol h^-1 cm^-2 and the high activity for water oxidation is maintained for over 30 h. Impressively, the performance of the as-fabricated composite photoanode for PEC water splitting can be further enhanced through incorporating a certain amount of Co^2＋ cation into NiFe-LDH as OEC. The photocurrent density is achieved up to 4.45 mA cm^-2 at 1.23 V vs. RHE. This value is the highest yet reported for un-doped BiVO4-based photoanodes so far.

Improving UV stability of perovskite solar cells without sacrificing efficiency through light trapping regulated spectral modification

The stability of perovskite solar cells is an important issue to be addressed for future applications.Perovskite solar cells are vulnerable to exposure to UV light due to promoted chemical reactions.However, preventing UV light from entering solar cells lowers the power conversion efficiency by reducing the photocurrent. The challenge is to improve UV stability without sacrificing efficiency. Here, we demonstrate the reduction of UV light-related negative effects from the perspective of spectral modification. By simultaneously introducing UV–visible downshifting and light trapping, perovskite solar cells can achieve a comparable efficiency of over 21% to that of an unmodified device. The optimized device obtains increased UV stability due to UV–visible downshifting. Different from other strategies, spectral modification externally alters the composition of incident light and improves UV stability without changing the internal device architecture, which is broadly applicable to perovskite solar cells with different structures. The present work may also find applications in other types of solar cells to boost the stability of devices exposed to UV light.

Photoluminescence and defect evolution of nano-ZnO thin films at low temperature annealing

Nano-ZnO thin films composed of nanoparticles with sizes of 10-16 nm on silicon substrates at low temperature were prepared by sol-gel method.By placing the nano-ZnO thin films at room temperature or annealing at 100°C in air for 10 h intermittently,within a total 70 h annealing time,the evolution of PL spectra of the nano-ZnO thin films were studied in detail.As the annealing time increases,the PL peaks shift from violet to blue and green bands.The PL peaks at violet and blue bands decrease with the annealing time,but the PL peaks at green band are opposite.The PL spectra are related to the defects in the nano-ZnO thin films.The PL peaks positioned at 430 nm are mainly related to defects of zinc interstatials(Zni),oxygen vacancies and(Vo);the ones at 420 nm to oxygen interstitials(Oi),Zinc vacancies(Vzn),Zni ;and the ones at 468 nm to Vzn,Zni,and charged oxygen interstatials(Vo+).The green luminescence is related to Oi,Vo and Zni.The evolutions of PL spectra and the defects are also related to the concentrations of Zn in the thin films,the thicknesses of the films and the annealing time.For the films with 0.5 M and 1.0 M Zn concentrations,after 20 h and 30 h annealing in air at 100°C,respectively,either placing them in air at room temperature or continuing anneal in air at 100°C,the PL spectra are stable.Under the low temperature annealing,Zni decreases with the annealing time,and Oi increases.Sufficient Oi favors to keep the nano-ZnO thin films stable.This result is important to nano-ZnO thin films as electron transport layers in inverted or tandem organic solar cells.

Nanobowl optical concentrator for efficient light trapping and high-performance organic photovoltaics

Geometrical light trapping is a simple and prom- ising strategy to largely improve the optical absorption and efficiency of solar cell. Nonetheless, implementation of geo- metrical light trapping in organic photovoltaic is challenging due to the fact that uniform organic active layer can rarely be achieved on textured substrate. In this work, squarely ordered nanobowl array （SONA） is reported for the first time and [6,6]- phenyl-C6rbutyric acid methyl ester （PCBM）：poly（3-hexyl- thiophene） （P3HT）-based organic photovoltaic （OPV） device on SONA demonstrated over 28 % enhancement in power conversion efficiency over the planar counterpart. Interestingly, finite-difference time-domain （FDTD） optical simulation revealed that the superior light trapping by SONA originated from optical concentrator effect by nanobowl. Furthermore, aiming at low-cost, solution processible, and resource sus- tainable flexible solar cells, we employed Ag nanowires for the top transparent conducting electrode. This work not only revealed the in-depth understanding of light trapping by nanobowl optical concentrator, but also demonstrated the fea- sibility of implementing geometrical light trapping in OPV.