Ion track-based nanowire arrays with gradient and programmable diameters towards rational light management

Integrating nanowires with nonuniform diameter and random spatial distribution into an array can afford unconventional and additional means for modulating optical response.However,experimental realization of such a nanowire array is quite challenging.In this work,we propose a new fabrication strategy which takes advantage of ion track technology,via sequential swift heavy ion irradiation and ion track etching.Based on this strategy,we unprecedentedly realize nanowire arrays,using gold as an example,with gradient and programmable diameters in a controlled manner.We further demonstrate that such nanowire arrays can support broadband,tunable,and enhanced plasmonic responses.We believe that our new type of nanowire arrays will find great potential in applications such as light management and optoelectronic devices.

Photocurrent improvement of an ultra-thin silicon solar cell using the localized surface plasmonic effect of clustering nanoparticles

The cluster-shaped plasmonic nanostructures are used to manage the incident light inside an ultra-thin silicon solar cell.Here we simulate spherical,conical,pyramidal,and cylindrical nanoparticles in a form of a cluster at the rear side of a thin silicon cell,using the finite difference time domain(FDTD)method.By calculating the optical absorption and hence the photocurrent,it is shown that the clustering of nanoparticles significantly improves them.The photocurrent enhancement is the result of the plasmonic effects of clustering the nanoparticles.For comparison,first a cell with a single nanoparticle at the rear side is evaluated.Then four smaller nanoparticles are put around it to make a cluster.The photocurrents of 20.478 mA/cm2,23.186 mA/cm2,21.427 mA/cm2,and 21.243 mA/cm2 are obtained for the cells using clustering conical,spherical,pyramidal,cylindrical NPs at the backside,respectively.These values are 13.987 mA/cm2,16.901 mA/cm2,16.507 mA/cm2,17.926 mA/cm2 for the cell with one conical,spherical,pyramidal,cylindrical NPs at the backside,respectively.Therefore,clustering can significantly improve the photocurrents.Finally,the distribution of the electric field and the generation rate for the proposed structures are calculated.

Enhancing light absorption for organic solar cells using front ITO nanograting and back ultrathin Al layer

To address the discrepancy between carrier collection and light absorption of organic solar cells caused by the limited carrier mobility and optical absorption coefficient for the normally employed organic photoactive layers,a light management structure composed of a front indium tin oxide(ITO)nanograting and ultrathin Al layer inserted in between the photoactive layer and the electron transport layer(ETL)is introduced.Owing to the antireflection and light scattering induced by the ITO nanograting and the suppression of light absorption in the ETL by the inserted Al layer,the light absorption of the photoactive layer is significantly enhanced in a spectral range from 400 nm to 650 nm that also covers the main energy region of solar irradiation for the normally employed active materials such as the P3HT:PC_(61)BM blend.The simulation results indicate that comparing with the control device with a planar configuration of ITO/PEDOT:PSS/P3HT:PC_(61)BM(80-nm thick)/ZnO/Al,the short-circuit current density and power conversion efficiency of the optimized light management structure can be improved by 32.86%and 34.46%.Moreover,good omnidirectional light management is observed for the proposed device structure.Owing to the fact that the light management structure possesses the simple structure and excellent performance,the exploration of such a structure can be believed to be significant in fabricating the thin film-based optoelectronic devices.

Broadband light management in hydrogel glass for energy efficient windows

Windows are critically important components in building envelopes that have a signifcant efect on the integral energy budget.For energy saving,here we propose a novel design of hydrogel-glass which consists of a layer of hydrogel and a layer of normal glass.Compared with traditional glass,the hydrogel-glass possesses a higher level of visible light transmission,stronger near-infrared light blocking,and higher mid-infrared thermal emittance.With these properties,hydrogel-glass based windows can enhance indoor illumination and reduce the temperature,reducing energy use for both lighting and cooling.Energy savings ranging from 2.37 to 10.45 MJ/m2 per year can be achieved for typical school buildings located in diferent cities around the world according to our simulations.With broadband light management covering the visible and thermal infrared regions of the spectrum,hydrogel-glass shows great potential for application in energy-saving windows.

Nano-enabled solar driven-interfacial evaporation:Advanced design and opportunities

Solar-driven interfacial evaporation(SDIE)is emerging as a promising pathway to solving the worldwide water shortage and water pollution.Nanomaterials(e.g.,plasmonic metals,inorganic/organic semiconductors,and carbon nanomaterials)and related nanochemistry have attracted increasing attention for the solar-to-vapor process in terms of broadband absorption,electronic structure adjustment,and surface/interface chemistry manipulation.Furthermore,the assembly of nanomaterials can contribute to the mass transfer,heat management,and enthalpy regulation of water during solar evaporation.To date,numerous nano-enabled materials and structures have been developed to improve the solar absorption,heat management(i.e.,heat confinement and heat transfer),and water management(i.e.,activation,evaporation,and replenishment).In this review,we focus on a systematical summary about the composition and structure engineering of nanomaterials in SDIE,including size and morphology effects,nanostructure optimizations,and structure-property relationship decoupling.This review also surveys recent advances in nanochemistry(e.g.,preparation chemistry and structural chemistry)deployed to conceptual design of nanomaterials.Finally,the key challenges and future perspectives of nanomaterials for solar evaporation are overviewed.This review aims at providing guidance for the design and construction of nanomaterials for high-efficiency SDIE on the basis of the aspects of materials science and chemical engineering.