The subwavelength confinement feature of localized surface plasmon resonance(LSPR) allows plasmonic nanostructures to be functionalized as powerful platforms for detecting various molecular analytes as well as weak ...The subwavelength confinement feature of localized surface plasmon resonance(LSPR) allows plasmonic nanostructures to be functionalized as powerful platforms for detecting various molecular analytes as well as weak processes with nanoscale spatial resolution. One of the main goals of this field of research is to lower the absolute limit-of-detection(LOD)of LSPR-based sensors. This involves the improvement of(i) the figure-of-merit associated with structural parameters such as the size, shape and interparticle arrangement and,(ii) the spectral resolution. The latter involves advanced target identification and noise reduction techniques. By highlighting the strategies for improving the LOD, this review introduces the fundamental principles and recent progress of LSPR sensing based on different schemes including 1) refractometric sensing realized by observing target-induced refractive index changes, 2) plasmon rulers based on target-induced relative displacement of coupled plasmonic structures, 3) other relevant LSPR-based sensing schemes including chiral plasmonics,nanoparticle growth, and optomechanics. The ultimate LOD and the future trends of these LSPR-based sensing are also discussed.展开更多
The photocatalytic reduction of CO2 with H2O to fuels and chemicals using solar energy is one of the most attractive but highly difficult routes.Thus far,only a very limited number of photocatalysts has been reported ...The photocatalytic reduction of CO2 with H2O to fuels and chemicals using solar energy is one of the most attractive but highly difficult routes.Thus far,only a very limited number of photocatalysts has been reported to be capable of catalyzing the photocatalytic reduction of CO2 under visible light.The utilization of the localized surface plasmon resonance(LSPR)phenomenon is an attractive strategy for developing visible-light photocatalysts.Herein,we have succeeded in synthesizing plasmonic MoO3?x-TiO2 nanocomposites with tunable LSPR by a simple solvothermal method.The well-structured nanocomposite containing two-dimensional(2D)molybdenum oxide(MoO3?x)nanosheets and one-dimensional(1D)titanium oxide nanotubes(TiO2-NT)showed LSPR absorption band in the visible-light region,and the incorporation of TiO2-NT significantly enhanced the LSPR absorption band.The MoO3?x-TiO2-NT nanocomposite is promising for application in the photocatalytic reduction of CO2 with H2O under visible light irradiation.展开更多
The influences of the anisotropy of the outer spherically anisotropic (SA) layer on the far-field spectra and near- field enhancements of the silver nanoshells are investigated by using a modified Mie scattering the...The influences of the anisotropy of the outer spherically anisotropic (SA) layer on the far-field spectra and near- field enhancements of the silver nanoshells are investigated by using a modified Mie scattering theory. It is found that with the increase of the anisotropic value of the SA layer, the dipole resonance wavelength of the silver nanoshell first increases and then decreases, while the local field factor (LFF) reduces. With the decrease of SA layer thickness, the dipole wavelength of the silver nanoshell shows a distinct blue-shift. When the SA layer becomes very thin, the modulations of the anisotropy of the SA layer on the plasmon resonance energy and the near-field enhancement are weakened. We further find that the smaller anisotropic value of the SA layer is helpful for obtaining the larger near-field enhancement in the Ag nanoshell. The geometric average of the dielectric components of the SA layer has a stronger effect on the plasmon resonance energy of the silver nanoshell than on the near-field enhancement.展开更多
A fast and facile method of fabricating fiber-optic localized surface plasmon resonance sensors baseff on spherical gold nanoparticles was introduced in this study. The gold nanoparticles with an average diameter of 5...A fast and facile method of fabricating fiber-optic localized surface plasmon resonance sensors baseff on spherical gold nanoparticles was introduced in this study. The gold nanoparticles with an average diameter of 55 nm were synthesized via the Turkevich method and were then immobilized onto the surface of an uncladded sensor probe using a polydopamine layer. To obtain a sensor probe with high sensitivity to changes in the refractive index, a set of key optimization parameters, including the sensing length, coating time of the potydopamine layer, and coating time of the gold nanoparticles, were investigated. The sensitivity of the optimized sensor probe was 522.80 nm per refractive index unit, and the probe showed distinctive wavelength shifts when the refractive index was changed from 1.328 6 to 1.398 7. When stored in deionized water at 4 ℃, the sensor probe proved to be stable over a period of two weeks. The sensor also exhibited advantages, such as low cost, fast fabrication, and simple optical setup, which indicated its potential application in remote sensing and real-time detection.展开更多
Photocatalytic nitrogen reduction for the green synthesis of ammonia at ambient conditions has been slowed by the narrow light harvesting range,low activity and high charge recombination of photocatalysts.Plasmonic se...Photocatalytic nitrogen reduction for the green synthesis of ammonia at ambient conditions has been slowed by the narrow light harvesting range,low activity and high charge recombination of photocatalysts.Plasmonic semiconducting nanomaterials are becoming the promising candidates for nitrogen photofixation because of the broad absorption spectrum,rich defects and hot carriers.In the present study,plasmonic SrMoO_(4) is developed by regulating the concentration of oxygen vacancies that are accompanied in the reduction process from Mo^(6+) to Mo^(5+).The stable and tunable localized surface plasmon resonance(LSPR)absorption in visible and near infrared light range makes the wide bandgap SrMoO_(4) utilize the solar energy more efficiently.Energetic electrons from both the intrinsic band excitation and the LSPR excitation enable the reduction of dinitrogen molecules thermodynamically in ultrapure water to ammonia.This work provides a unique clue to design efficient photocatalysts for nitrogen fixation.展开更多
According to the plasmon hybridization theory, the plasmon resonance characteristics of the gold nanocrescent/nanoring(NCNR) structure are systematically investigated by the finite element method. It is found that the...According to the plasmon hybridization theory, the plasmon resonance characteristics of the gold nanocrescent/nanoring(NCNR) structure are systematically investigated by the finite element method. It is found that the extinction spectra of NCNR structure exhibit multiple plasmon resonance peaks, which could be attributed to the result of the plasmon couplings between the multipolar plasmon modes of nanocrescent and the dipolar, quadrupolar, hexapolar, octupolar,decapolar plasmon modes of nanoring. By changing the geometric parameters, the intense and separate multiple plasmon resonance peaks are obtained and can be tuned in a wide wavelength range. It is further found that the plasmon coupling induces giant multipole electric field enhancements around the tips of the nanocrescent. The tunable and intense multiple plasmon resonances of NCNR structure may provide effective applications in multiplex biological sensing.展开更多
Localized surface plasmon (LSPR) resonance and sensing properties of a novel nanostructure (sexfoil nanoparticle) are studied using the finite-difference time-domain method. For the sandwich sexfoil nanoparticle, ...Localized surface plasmon (LSPR) resonance and sensing properties of a novel nanostructure (sexfoil nanoparticle) are studied using the finite-difference time-domain method. For the sandwich sexfoil nanoparticle, the calculated extinction spectrum shows that with the thickness of the dielectric layer increasing, long-wavelength peaks blueshift, while short- wavelength peaks redshift. Strong near-field coupling of the upper and lower metal layers leads to electric and magnetic field resonances; as the thickness increases, the electric field resonance gradually increases, while the magnetic field resonance decreases. The obtained refractive index sensitivity and figure of merit are 332 nm/RIU and 3.91 RIU^-1, respectively. In order to obtain better sensing ability, we further research the LSPR character of monolayer Ag sexfoil nanoparticle. After a series of trials to optimize the thickness and shape, the refractive index sensitivity approximates 668 nm/RIU, and the greatest figure of merit value comes to 14.8 RIU^-1.展开更多
A transparent display simultaneously enables visualization of the images displayed on it as well as the view behind it,and therefore can be applied to,for instance,augmented reality(AR),virtual reality(VR),and head up...A transparent display simultaneously enables visualization of the images displayed on it as well as the view behind it,and therefore can be applied to,for instance,augmented reality(AR),virtual reality(VR),and head up display(HUD).Many solutions have been proposed for this purpose.Recently,the idea of frequency-selective scattering of red,green and blue light while transmitting visible light of other colours to achieve transparent projection display has been proposed,by taking advantage of metallic nanoparticle’s localized surface plasmon resonance(LSPR).In this article,a review of the recent progress of frequency-selective scattering of red,green and blue light that are based on metallic nanoparticle’s LSPR is presented.A discussion of method for choosing appropriate metal(s)is first given,followed by the definition of a figure of merit used to quantify the performance of a designed nanoparticle structure.Selective scattering of various nanostructures,including sphere-shaped nanoparticles,ellipsoidal nanoparticles,super-sphere core-shell nanoparticles,metallic nanocubes,and metallic nanoparticles combined with gain materials,are discussed in detail.Each nanostructure has its own advantages and disadvantages,but the combination of the metallic nanoparticle with gain materials is a more promising way since it has the potential to generate ultra-sharp scattering peaks(i.e.,high frequency-selectivity).展开更多
We apply the localized surface plasrnon resonance (LSPR) of gold nanoparticles (GNPs) covalently coupled with cytochrorne c (cyt c) to create a nanobiosensor for detecting hydrogen sulfide (H2S) in the range o...We apply the localized surface plasrnon resonance (LSPR) of gold nanoparticles (GNPs) covalently coupled with cytochrorne c (cyt c) to create a nanobiosensor for detecting hydrogen sulfide (H2S) in the range of 15 lOOppb. Monolayer formation of GNPs on glass surface functionalized with 3-aminopropyltrirnethoxysilane (APTMS) is performed for fabricating a chip-based format of the optical transducer. By chemical introduction of short-chain thiol derivatives on cyt c protein shell via its lysine residues, a very fast self-assembled rnonolayer (SAM) of cyt c is formed on the GNPs. Significant shifts in the LSPR peak (△λLSPR) are observed by reacting H2S with cyt c. Results show a linear relationship between △λLSPR and H2S concentration. Furthermore, shifts in the LSPR peak are reversible and the peak positions return to their pre-exposure values once the H2S is removed. The experirnental results strongly indicate that the protein based LSPR chip can be successfully used as a simple, fast, sensitive and quantitative sensor for H2S detection.展开更多
Localized surface plasmon resonance(LSPR)biosensors,which enable nanoscale confinement and manipulation of light,offer the enhanced sensitivity and electromagnetic energy localization.The integration of LSPR with the ...Localized surface plasmon resonance(LSPR)biosensors,which enable nanoscale confinement and manipulation of light,offer the enhanced sensitivity and electromagnetic energy localization.The integration of LSPR with the fiber-optic technology has led to the development of compact and versatile sensors for miniaturization and remote sensing.This comprehensive review explores various sensor configurations,fiber types,and geometric shapes,highlighting their benefits in terms of sensitivity,integration,and performance improvement.Fabrication techniques such as focused non-chemical bonding strategies and self-assembly of nanoparticles are discussed,providing control over nanostructure morphology and enhancing sensor performance.Bio-applications of fiber-optic LSPR(FOLSPR)sensors are detailed,specifically in biomolecular interactions and analysis of proteins,pathogens and cells,nucleic acids(DNA and RNA),and other small molecules(organic compounds and heavy metal ions).Surface modification and detection schemes are emphasized for their potential for label-free and real-time biosensing.The challenges and prospects of FOLSPR sensors are addressed,including the developments in sensitivity,fabrication techniques,and measurement reliability.Integration with emerging technologies such as nanomaterials is highlighted as a promising direction for future research.Overall,this review provides insights into the advancements and potential applications of FOLSPR sensors,paving the way for sensitive and versatile optical biosensing platforms in various fields.展开更多
Copper is relatively low cost and highly abundant compared with the well-studied noble metals such as gold and silver.However,the poor plasmonic and high susceptibility towards oxidation limit the study of its optical...Copper is relatively low cost and highly abundant compared with the well-studied noble metals such as gold and silver.However,the poor plasmonic and high susceptibility towards oxidation limit the study of its optical properties and applications as well.Herein,copper nanoparticles@polycarbonate(Cu@PC)composites were prepared by using a facile one-step solvothermal method.The Cu@PC composites have strong localized surface plasmon resonances(LSPR)due to that the PC shell can induce the particles to form many-particles system with different particle numbers,which not only lead to overlap and hybridize of the LSPR modes,but also shift the LSPR away from the interband transitions,and the PC layer also prevents the oxidation of Cu nanoparticles.The photothermal conversion efficiency of Cu@PC composites reaches 41.1%under 808 nm continuous wave(CW)laser irradiation which is higher than previously reported Cu nanomaterials that have been reported.Meanwhile,the composites also have high photothermal stability.Moreover,interfacial evaporator is prepared by assembling the Cu@PC composites on scouring sponge as light absorption layer which has>92.8%absorption in entire solar spectrum range.Its seawater evaporation rate is 3.177 kg·m^(-2)·h^(-1)with a E_(evaporator)/E_(water)of 5.2.The high evaporation rate interfacial evaporator with low cost,simple,and scalable approach shows great application value in the field of photothermal evaporation.展开更多
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 clust...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.展开更多
Using numerical simulation, we investigate the high-order plasmon resonances in individual nanostructures of an Ag nanorice core surrounded by an Al2O3 shell. The peak positions of localized surface plasmon resonances...Using numerical simulation, we investigate the high-order plasmon resonances in individual nanostructures of an Ag nanorice core surrounded by an Al2O3 shell. The peak positions of localized surface plasmon resonances (LSPRs) are red-shifted exponentially with the increase of the dielectric shell thickness. This is due to the exponential decay of electromagnetic field intensity in the direction perpendicular to the interface. This exponential red-shift depends on the wavelength of the resonance peak instead of the resonance order. In addition, we find that the LSPRs in an Ag nanorice of 60-nm width can be perfectly described by a single linear function. These features make nanorice an ideal platform for sensing applications.展开更多
The ultraviolet(UV)light stability of silicon heterojunction(SHJ)solar cells should be addressed before large-scale production and applications.Introducing downshifting(DS)nanophosphors on top of solar cells that can ...The ultraviolet(UV)light stability of silicon heterojunction(SHJ)solar cells should be addressed before large-scale production and applications.Introducing downshifting(DS)nanophosphors on top of solar cells that can convert UV light to visible light may reduce UV-induced degradation(UVID)without sacrificing the power conversion efficiency(PCE).Herein,a novel composite DS nanomaterial composed of YVO_(4):Eu^(3+),Bi^(3+)nanoparticles(NPs)and AgNPs was synthesized and introduced onto the incident light side of industrial SHJ solar cells to achieve UV shielding.The YVO_(4):Eu^(3+),Bi^(3+)NPs and Ag NPs were synthesized via a sol-gel method and a wet chemical reduction method,respectively.Then,a composite structure of the YVO_(4):Eu^(3+),Bi^(3+)NPs decorated with Ag NPs was synthesized by an ultrasonic method.The emission intensities of the YVO_(4):Eu^(3+),Bi^(3+)nanophosphors were significantly enhanced upon decoration with an appropriate amount of~20 nm Ag NPs due to the localized surface plasmon resonance(LSPR)effect.Upon the introduction of LSPR-enhanced downshifting,the SHJ solar cells exhibited an~0.54%relative decrease in PCE degradation under UV irradiation with a cumulative dose of 45 k W h compared to their counterparts,suggesting excellent potential for application in UV-light stability enhancement of solar cells or modules.展开更多
The localized surface plasmon resonance properties of Al and Alcore/Al2O3shell nanosphere dimers with Al and Al core nanosphere radii of 20 nm and Al2O3 shell of 2 nm in the deep-ultraviolet region have been studied u...The localized surface plasmon resonance properties of Al and Alcore/Al2O3shell nanosphere dimers with Al and Al core nanosphere radii of 20 nm and Al2O3 shell of 2 nm in the deep-ultraviolet region have been studied using the finite difference time domain method. The extinction spectra and the electric field distribution profiles of the two dimers for various gap distances between two individual nanospheres are compared with those of the corresponding monomers to reveal the extent of plasmon coupling. It is found that with the interparticle distance decreasing, a strong plasmon coupling between two Al or Alcore/Al2O3shell nanospheres is observed accompanied by a significant red shift in the extinction spectra at the parallel polarization direction of the incident light related to the dimer axis, while for the case of the perpendicular polarization direction, a weak plasmon coupling arises characterized by a slight blue shift in the extinction spectra. The electric field distribution profiles show that benefiting from the dielectric Al2O3 shell, the gap distance of Alcore/Al2O3shell nanosphere dimers can be tailored to 〈 1 nm scale and results in a very high electric field enhancement. The estimated surface-enhanced Raman scattering enhancement factors suggests that the Alcore/Al2O3shell nanosphere dimers with the gap of 〈 1 nm gave rise to an enhancement as high as 8.1 × 10^7 for interparticle gap = 0.5 nm. Our studies reveal that the Alcore/Al2O3shell nanosphere dimers may be promising substrates for surface-enhanced spectroscopy in the deep-ultraviolet region.展开更多
In this paper, we propose a new form of nanostructures with Al film deposited on a patterned dielectric material for generating structural color, which is induced by local surface plasmonic resonant(LSPR) absorption i...In this paper, we propose a new form of nanostructures with Al film deposited on a patterned dielectric material for generating structural color, which is induced by local surface plasmonic resonant(LSPR) absorption in sub-wavelengthindented hole/ring arrays. Unlike other reported results obtained by using focus ion beam(FIB) to create metallic nanostructures, the nano-sized hole/ring arrays in Al film in this work are replicated by high resolution electron beam lithography(EBL) combined with self-aligned metallization. Clear structural color is observed and systematically studied by numerical simulations as well as optical characterizations. The central color is strongly related to the geometric size, which provides us with good opportunities to dye the colorless Al surface by controlling the hole/ring dimensions(both diameter and radius), and to open up broad applications in display, jewelry decoration, green production of packing papers, security code,and counterfeits prevention.展开更多
The W(18)O(49) nanoflowers with a diameter of 500 nm are prepared by a facile hydrothermal method. The Er-Yb:NaYF4 nanoparticles are adsorbed on the petals(the position of the strongest local electric field on W...The W(18)O(49) nanoflowers with a diameter of 500 nm are prepared by a facile hydrothermal method. The Er-Yb:NaYF4 nanoparticles are adsorbed on the petals(the position of the strongest local electric field on W(18)O(49) nanoflowers).With a 976 nm laser diode(LD) as an excitation source, the selectively green upconversion luminescence(UCL) is observed to be enhanced by two orders of magnitude in Er-Yb: NaYF4/W(18)O(49) nanoflowers heterostructures. It suggests that the near infrared(NIR)-excited localized surface plasmon resonance(LSPR) of W(18)O(49) is primarily responsible for the enhanced UCL, which could be partly reabsorbed by the W(18)O(49), thus leading to the selective enhancement of green UCL for the Er-Yb: NaYF4. The fluorescence intensity ratio is investigated as a function of temperature based on the intense green UCL, which indicates that Er-Yb: NaYF4/W(18)O(49) nanoflower heterostructures have good potential for developing into temperature sensors.展开更多
Semiconductors typically exhibit long-wavelength LSPR absorption in the infrared region due to lower carrier density.Tuning the carrier density of semiconductors and blue-shifting their LSPR absorption to the visible ...Semiconductors typically exhibit long-wavelength LSPR absorption in the infrared region due to lower carrier density.Tuning the carrier density of semiconductors and blue-shifting their LSPR absorption to the visible and near-infrared region has always been a great challenge.Herein,we discussed how the controllable carrier of(Ag)x(MoO_(3))y composite influences the LSPR based on SERS test and UVeViseNIR absorption spectra.We were surprised to find that the LSPR absorption wavelength can be easily tuned from 950 to 735 nm by changing the sputtering power of MoO_(3)of the(Ag)x(MoO_(3))_(y)composite.This shows that LSPR can be precisely adjusted by increasing the semiconductor content and even the carrier density.In addition,the carrier density was measured by Hall effect to investigate the SERS intensity change caused by electromagnetic(EM)enhancement,and obtain the relationship between the two.The findings of this work provide an idea for tunable LSPR and the research of EM contributions to SERS.展开更多
The optoelectronic performance of CsPbBr_3 nanocrystal(NC) has been dramatically limited by the severe charge carrier recombination and its narrow light absorption range,which are anticipated to be resolved via coupli...The optoelectronic performance of CsPbBr_3 nanocrystal(NC) has been dramatically limited by the severe charge carrier recombination and its narrow light absorption range,which are anticipated to be resolved via coupling with plasmonic Au nanoparticle(NP).In view of this,CsPbBr_3-Au nanocomposite is fabricated and further employed as a concept model to study the electronic interaction between perovskite NC and Au NP for the first time.It has been found that the excitation-wavelength dependent carrier transfer behavior exists in CsPbBr_3-Au nanocomposite.Upon illumination with visible light(λ>420 nm),photo-generated electrons in CsPbBr_3 can inject into Au with an electron injection rate and efficiency of 2.84×10~9 s^(-1) and 78%,respectively.The boosted charge separation is further translated into a 3.2-fold enhancement in CO_2 photocatalytic reduction activity compared with pristine CsPbBr_3.On the other hand,when solely exciting Au NP with longer wavelength light(λ>580 nm),the localized surface plasmon resonance(LSPR) induced hot electrons in Au NPs can transfer to CsPbBr_3 NC and further participate in photocatalytic reaction towards CO_2 reduction.The present study provides new insights into preparing plasmonic nanostructure to enhance the performance of perovskite based optoelectronic devices.展开更多
Simultaneous generation of H_(2) fuel and value-added chemicals has attracted increasing attention since the photogenerated electrons and holes can be both employed to convert solar light into chemical energy.Herein,f...Simultaneous generation of H_(2) fuel and value-added chemicals has attracted increasing attention since the photogenerated electrons and holes can be both employed to convert solar light into chemical energy.Herein,for realizing UV-visible-NIR light driven dehydrogenation of benzyl alcohol(BA)into benzaldehydes(BAD)and H_(2),a novel localized surface plasmon resonance(LSPR)enhanced S-scheme heterojunction was designed by combining noble-metal-free plasmon MoO_(3-x) as oxidation semiconductor and Zn_(0.1)Cd_(0.9)S as reduction semiconductor.The photoredox system of Zn_(0.1)Cd_(0.9)S/MoO_(3-x) displayed an unconventional reaction model,in which the BA served as both electron donor and acceptor.The S-scheme charge transfer mechanism induced by the formed internal electric field enhanced the redox ability of charge carriers thermodynamically and boosted charge separation kinetically.Moreover,due to the LSPR effect of MoO_(3-x) nanosheets,Zn_(0.1)Cd_(0.9)S/MoO_(3-x) photocatalysts exhibited strong absorption in the region of full solar spectrum.Therefore,the Zn_(0.1)Cd_(0.9)S/MoO_(3-x) composite generated H_(2) and BAD simultaneously via selective oxidation of BA with high production(34.38 and 33.83 mmol×g^(–1) for H_(2) and BAD,respectively)upon full solar illumination.Even under NIR light irradiation,the H_(2) production rate could up to 94.5 mmol×g^(–1)×h^(–1).In addition,the Zn_(0.1)Cd_(0.9)S/MoO_(3-x) composite displayed effective photocatalytic H_(2) evolution rate up to 149.2 mmol×g^(–1)×h^(–1) from water,which was approximate 6 times that of pure Zn_(0.1)Cd_(0.9)S.This work provides a reference for rational design of plasmonic S-scheme heterojunction photocatalysts for coproduction of high-value chemicals and solar fuel production.展开更多
基金Project supported by the National Key Basic Research Program(Grant No.2015CB932400)the National Key Research and Development Program of China(Grant Nos.2017YFA0205800 and 2017YFA0303504)the National Natural Science Foundation of China(Grant Nos.11674255 and 11674256)
文摘The subwavelength confinement feature of localized surface plasmon resonance(LSPR) allows plasmonic nanostructures to be functionalized as powerful platforms for detecting various molecular analytes as well as weak processes with nanoscale spatial resolution. One of the main goals of this field of research is to lower the absolute limit-of-detection(LOD)of LSPR-based sensors. This involves the improvement of(i) the figure-of-merit associated with structural parameters such as the size, shape and interparticle arrangement and,(ii) the spectral resolution. The latter involves advanced target identification and noise reduction techniques. By highlighting the strategies for improving the LOD, this review introduces the fundamental principles and recent progress of LSPR sensing based on different schemes including 1) refractometric sensing realized by observing target-induced refractive index changes, 2) plasmon rulers based on target-induced relative displacement of coupled plasmonic structures, 3) other relevant LSPR-based sensing schemes including chiral plasmonics,nanoparticle growth, and optomechanics. The ultimate LOD and the future trends of these LSPR-based sensing are also discussed.
文摘The photocatalytic reduction of CO2 with H2O to fuels and chemicals using solar energy is one of the most attractive but highly difficult routes.Thus far,only a very limited number of photocatalysts has been reported to be capable of catalyzing the photocatalytic reduction of CO2 under visible light.The utilization of the localized surface plasmon resonance(LSPR)phenomenon is an attractive strategy for developing visible-light photocatalysts.Herein,we have succeeded in synthesizing plasmonic MoO3?x-TiO2 nanocomposites with tunable LSPR by a simple solvothermal method.The well-structured nanocomposite containing two-dimensional(2D)molybdenum oxide(MoO3?x)nanosheets and one-dimensional(1D)titanium oxide nanotubes(TiO2-NT)showed LSPR absorption band in the visible-light region,and the incorporation of TiO2-NT significantly enhanced the LSPR absorption band.The MoO3?x-TiO2-NT nanocomposite is promising for application in the photocatalytic reduction of CO2 with H2O under visible light irradiation.
基金Project supported by the National Basic Research Program of China(Grant No.2012CB921504)the National Natural Science Foundation of China(Grant Nos.10904052,11174113,and 11104319)+1 种基金the Jiangsu Planned Projects for Postdoctoral Research Funds,China(Grant No.1002075C)the Senior Talent Foundation of Jiangsu University,China(Grant No.09JDG073)
文摘The influences of the anisotropy of the outer spherically anisotropic (SA) layer on the far-field spectra and near- field enhancements of the silver nanoshells are investigated by using a modified Mie scattering theory. It is found that with the increase of the anisotropic value of the SA layer, the dipole resonance wavelength of the silver nanoshell first increases and then decreases, while the local field factor (LFF) reduces. With the decrease of SA layer thickness, the dipole wavelength of the silver nanoshell shows a distinct blue-shift. When the SA layer becomes very thin, the modulations of the anisotropy of the SA layer on the plasmon resonance energy and the near-field enhancement are weakened. We further find that the smaller anisotropic value of the SA layer is helpful for obtaining the larger near-field enhancement in the Ag nanoshell. The geometric average of the dielectric components of the SA layer has a stronger effect on the plasmon resonance energy of the silver nanoshell than on the near-field enhancement.
基金Supported by the Ministry of Science and Technology of China(No.2012YQ090194)the National Natural Science Foundation of China(No.51473115)
文摘A fast and facile method of fabricating fiber-optic localized surface plasmon resonance sensors baseff on spherical gold nanoparticles was introduced in this study. The gold nanoparticles with an average diameter of 55 nm were synthesized via the Turkevich method and were then immobilized onto the surface of an uncladded sensor probe using a polydopamine layer. To obtain a sensor probe with high sensitivity to changes in the refractive index, a set of key optimization parameters, including the sensing length, coating time of the potydopamine layer, and coating time of the gold nanoparticles, were investigated. The sensitivity of the optimized sensor probe was 522.80 nm per refractive index unit, and the probe showed distinctive wavelength shifts when the refractive index was changed from 1.328 6 to 1.398 7. When stored in deionized water at 4 ℃, the sensor probe proved to be stable over a period of two weeks. The sensor also exhibited advantages, such as low cost, fast fabrication, and simple optical setup, which indicated its potential application in remote sensing and real-time detection.
文摘Photocatalytic nitrogen reduction for the green synthesis of ammonia at ambient conditions has been slowed by the narrow light harvesting range,low activity and high charge recombination of photocatalysts.Plasmonic semiconducting nanomaterials are becoming the promising candidates for nitrogen photofixation because of the broad absorption spectrum,rich defects and hot carriers.In the present study,plasmonic SrMoO_(4) is developed by regulating the concentration of oxygen vacancies that are accompanied in the reduction process from Mo^(6+) to Mo^(5+).The stable and tunable localized surface plasmon resonance(LSPR)absorption in visible and near infrared light range makes the wide bandgap SrMoO_(4) utilize the solar energy more efficiently.Energetic electrons from both the intrinsic band excitation and the LSPR excitation enable the reduction of dinitrogen molecules thermodynamically in ultrapure water to ammonia.This work provides a unique clue to design efficient photocatalysts for nitrogen fixation.
基金supported by the National Natural Science Foundation of China(Grant Nos.61275153 and 61320106014)the Natural Science Foundation of Zhejiang Province,China(Grant No.LY12A04002)+1 种基金the Natural Science Foundation of Ningbo City,China(Grant Nos.2010D10018 and 2012A610107)the K.C.Wong Magna Foundation of Ningbo University,China
文摘According to the plasmon hybridization theory, the plasmon resonance characteristics of the gold nanocrescent/nanoring(NCNR) structure are systematically investigated by the finite element method. It is found that the extinction spectra of NCNR structure exhibit multiple plasmon resonance peaks, which could be attributed to the result of the plasmon couplings between the multipolar plasmon modes of nanocrescent and the dipolar, quadrupolar, hexapolar, octupolar,decapolar plasmon modes of nanoring. By changing the geometric parameters, the intense and separate multiple plasmon resonance peaks are obtained and can be tuned in a wide wavelength range. It is further found that the plasmon coupling induces giant multipole electric field enhancements around the tips of the nanocrescent. The tunable and intense multiple plasmon resonances of NCNR structure may provide effective applications in multiplex biological sensing.
基金supported by the Sichuan Provincial Department of Education,China(Grant No.16ZA0047)the State Key Laboratory of Metastable Materials Science and Technology,Yanshan University,China(Grant No.201509)+1 种基金the Large Precision Instruments Open Project Foundation of Sichuan Normal University,China(Grant Nos.DJ201557,DJ201558 and DJ201560)the State Key Laboratory of Optical Technologies on Nano Fabrication and Micro Engineering,Institute of Optics and Electronics,Chinese Academy of Sciences
文摘Localized surface plasmon (LSPR) resonance and sensing properties of a novel nanostructure (sexfoil nanoparticle) are studied using the finite-difference time-domain method. For the sandwich sexfoil nanoparticle, the calculated extinction spectrum shows that with the thickness of the dielectric layer increasing, long-wavelength peaks blueshift, while short- wavelength peaks redshift. Strong near-field coupling of the upper and lower metal layers leads to electric and magnetic field resonances; as the thickness increases, the electric field resonance gradually increases, while the magnetic field resonance decreases. The obtained refractive index sensitivity and figure of merit are 332 nm/RIU and 3.91 RIU^-1, respectively. In order to obtain better sensing ability, we further research the LSPR character of monolayer Ag sexfoil nanoparticle. After a series of trials to optimize the thickness and shape, the refractive index sensitivity approximates 668 nm/RIU, and the greatest figure of merit value comes to 14.8 RIU^-1.
文摘A transparent display simultaneously enables visualization of the images displayed on it as well as the view behind it,and therefore can be applied to,for instance,augmented reality(AR),virtual reality(VR),and head up display(HUD).Many solutions have been proposed for this purpose.Recently,the idea of frequency-selective scattering of red,green and blue light while transmitting visible light of other colours to achieve transparent projection display has been proposed,by taking advantage of metallic nanoparticle’s localized surface plasmon resonance(LSPR).In this article,a review of the recent progress of frequency-selective scattering of red,green and blue light that are based on metallic nanoparticle’s LSPR is presented.A discussion of method for choosing appropriate metal(s)is first given,followed by the definition of a figure of merit used to quantify the performance of a designed nanoparticle structure.Selective scattering of various nanostructures,including sphere-shaped nanoparticles,ellipsoidal nanoparticles,super-sphere core-shell nanoparticles,metallic nanocubes,and metallic nanoparticles combined with gain materials,are discussed in detail.Each nanostructure has its own advantages and disadvantages,but the combination of the metallic nanoparticle with gain materials is a more promising way since it has the potential to generate ultra-sharp scattering peaks(i.e.,high frequency-selectivity).
文摘We apply the localized surface plasrnon resonance (LSPR) of gold nanoparticles (GNPs) covalently coupled with cytochrorne c (cyt c) to create a nanobiosensor for detecting hydrogen sulfide (H2S) in the range of 15 lOOppb. Monolayer formation of GNPs on glass surface functionalized with 3-aminopropyltrirnethoxysilane (APTMS) is performed for fabricating a chip-based format of the optical transducer. By chemical introduction of short-chain thiol derivatives on cyt c protein shell via its lysine residues, a very fast self-assembled rnonolayer (SAM) of cyt c is formed on the GNPs. Significant shifts in the LSPR peak (△λLSPR) are observed by reacting H2S with cyt c. Results show a linear relationship between △λLSPR and H2S concentration. Furthermore, shifts in the LSPR peak are reversible and the peak positions return to their pre-exposure values once the H2S is removed. The experirnental results strongly indicate that the protein based LSPR chip can be successfully used as a simple, fast, sensitive and quantitative sensor for H2S detection.
基金supported by the National Natural Science Foundation of China(Grant Nos.62375036,62005034,62171076,and 61727816)Liaoning Cancer Hospital Oncology+Funds(Grant No.2024-ZLKF-34)Fundamental Research Funds for the Central Universities(Grant No.DUT21RC(3)080).
文摘Localized surface plasmon resonance(LSPR)biosensors,which enable nanoscale confinement and manipulation of light,offer the enhanced sensitivity and electromagnetic energy localization.The integration of LSPR with the fiber-optic technology has led to the development of compact and versatile sensors for miniaturization and remote sensing.This comprehensive review explores various sensor configurations,fiber types,and geometric shapes,highlighting their benefits in terms of sensitivity,integration,and performance improvement.Fabrication techniques such as focused non-chemical bonding strategies and self-assembly of nanoparticles are discussed,providing control over nanostructure morphology and enhancing sensor performance.Bio-applications of fiber-optic LSPR(FOLSPR)sensors are detailed,specifically in biomolecular interactions and analysis of proteins,pathogens and cells,nucleic acids(DNA and RNA),and other small molecules(organic compounds and heavy metal ions).Surface modification and detection schemes are emphasized for their potential for label-free and real-time biosensing.The challenges and prospects of FOLSPR sensors are addressed,including the developments in sensitivity,fabrication techniques,and measurement reliability.Integration with emerging technologies such as nanomaterials is highlighted as a promising direction for future research.Overall,this review provides insights into the advancements and potential applications of FOLSPR sensors,paving the way for sensitive and versatile optical biosensing platforms in various fields.
基金supported by the Ministry of Education,Singapore(Nos.R-143-000-A41-114 and MOE2018-T2-1-119)the National Natural Science Foundation of China(No.61874074)+4 种基金the Educational Commission of Guangdong Province(No.2016KZDXM008)the Shenzhen Peacock Plan(No.KQTD2016053112042971)the Fundamental Research Funds for the Central Universities(No.2022SCU12003)Science and Technology Project of Shenzhen(No.GJHZ20180928160407303)the Natural Science Foundation of Sichuan Province(No.2023NSFSC0334).
文摘Copper is relatively low cost and highly abundant compared with the well-studied noble metals such as gold and silver.However,the poor plasmonic and high susceptibility towards oxidation limit the study of its optical properties and applications as well.Herein,copper nanoparticles@polycarbonate(Cu@PC)composites were prepared by using a facile one-step solvothermal method.The Cu@PC composites have strong localized surface plasmon resonances(LSPR)due to that the PC shell can induce the particles to form many-particles system with different particle numbers,which not only lead to overlap and hybridize of the LSPR modes,but also shift the LSPR away from the interband transitions,and the PC layer also prevents the oxidation of Cu nanoparticles.The photothermal conversion efficiency of Cu@PC composites reaches 41.1%under 808 nm continuous wave(CW)laser irradiation which is higher than previously reported Cu nanomaterials that have been reported.Meanwhile,the composites also have high photothermal stability.Moreover,interfacial evaporator is prepared by assembling the Cu@PC composites on scouring sponge as light absorption layer which has>92.8%absorption in entire solar spectrum range.Its seawater evaporation rate is 3.177 kg·m^(-2)·h^(-1)with a E_(evaporator)/E_(water)of 5.2.The high evaporation rate interfacial evaporator with low cost,simple,and scalable approach shows great application value in the field of photothermal evaporation.
文摘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.
基金Project supported by the National Key Basic Research and Development Program of China (Grant Nos.2009CB930700 and 2012YQ12006005)the National Natural Science Foundation of China (Grant Nos.11134013,11227407,and 11004237)the Knowledge Innovation Project of the Chinese Academy of Sciences (Grant No.KJCX2-EW-W04)
文摘Using numerical simulation, we investigate the high-order plasmon resonances in individual nanostructures of an Ag nanorice core surrounded by an Al2O3 shell. The peak positions of localized surface plasmon resonances (LSPRs) are red-shifted exponentially with the increase of the dielectric shell thickness. This is due to the exponential decay of electromagnetic field intensity in the direction perpendicular to the interface. This exponential red-shift depends on the wavelength of the resonance peak instead of the resonance order. In addition, we find that the LSPRs in an Ag nanorice of 60-nm width can be perfectly described by a single linear function. These features make nanorice an ideal platform for sensing applications.
基金supported by the National Natural Science Foundation of China (Grant Nos.52202276 and 51821002)the China Postdoctoral Science Foundation (Grant No.2022M712300)+1 种基金the Natural Science Foundation of the Jiangsu Higher Education Institutions of China (Grant No.22KJB480010)a project funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD)。
文摘The ultraviolet(UV)light stability of silicon heterojunction(SHJ)solar cells should be addressed before large-scale production and applications.Introducing downshifting(DS)nanophosphors on top of solar cells that can convert UV light to visible light may reduce UV-induced degradation(UVID)without sacrificing the power conversion efficiency(PCE).Herein,a novel composite DS nanomaterial composed of YVO_(4):Eu^(3+),Bi^(3+)nanoparticles(NPs)and AgNPs was synthesized and introduced onto the incident light side of industrial SHJ solar cells to achieve UV shielding.The YVO_(4):Eu^(3+),Bi^(3+)NPs and Ag NPs were synthesized via a sol-gel method and a wet chemical reduction method,respectively.Then,a composite structure of the YVO_(4):Eu^(3+),Bi^(3+)NPs decorated with Ag NPs was synthesized by an ultrasonic method.The emission intensities of the YVO_(4):Eu^(3+),Bi^(3+)nanophosphors were significantly enhanced upon decoration with an appropriate amount of~20 nm Ag NPs due to the localized surface plasmon resonance(LSPR)effect.Upon the introduction of LSPR-enhanced downshifting,the SHJ solar cells exhibited an~0.54%relative decrease in PCE degradation under UV irradiation with a cumulative dose of 45 k W h compared to their counterparts,suggesting excellent potential for application in UV-light stability enhancement of solar cells or modules.
基金supported by the National Natural Science Foundation of China(Grant Nos.11104079 and 61378033)the National Key Scientific Instrument Project of China(Grant No.2012YQ150092)+1 种基金the Research Foundation for the Doctoral Program of Higher Education of China(Grant No.20110076120019)the State Key Laboratory of Luminescent Materials and Devices at South China University of Technology
文摘The localized surface plasmon resonance properties of Al and Alcore/Al2O3shell nanosphere dimers with Al and Al core nanosphere radii of 20 nm and Al2O3 shell of 2 nm in the deep-ultraviolet region have been studied using the finite difference time domain method. The extinction spectra and the electric field distribution profiles of the two dimers for various gap distances between two individual nanospheres are compared with those of the corresponding monomers to reveal the extent of plasmon coupling. It is found that with the interparticle distance decreasing, a strong plasmon coupling between two Al or Alcore/Al2O3shell nanospheres is observed accompanied by a significant red shift in the extinction spectra at the parallel polarization direction of the incident light related to the dimer axis, while for the case of the perpendicular polarization direction, a weak plasmon coupling arises characterized by a slight blue shift in the extinction spectra. The electric field distribution profiles show that benefiting from the dielectric Al2O3 shell, the gap distance of Alcore/Al2O3shell nanosphere dimers can be tailored to 〈 1 nm scale and results in a very high electric field enhancement. The estimated surface-enhanced Raman scattering enhancement factors suggests that the Alcore/Al2O3shell nanosphere dimers with the gap of 〈 1 nm gave rise to an enhancement as high as 8.1 × 10^7 for interparticle gap = 0.5 nm. Our studies reveal that the Alcore/Al2O3shell nanosphere dimers may be promising substrates for surface-enhanced spectroscopy in the deep-ultraviolet region.
基金partially supported by the National Natural Science Foundation of China(Grant No.61205148)
文摘In this paper, we propose a new form of nanostructures with Al film deposited on a patterned dielectric material for generating structural color, which is induced by local surface plasmonic resonant(LSPR) absorption in sub-wavelengthindented hole/ring arrays. Unlike other reported results obtained by using focus ion beam(FIB) to create metallic nanostructures, the nano-sized hole/ring arrays in Al film in this work are replicated by high resolution electron beam lithography(EBL) combined with self-aligned metallization. Clear structural color is observed and systematically studied by numerical simulations as well as optical characterizations. The central color is strongly related to the geometric size, which provides us with good opportunities to dye the colorless Al surface by controlling the hole/ring dimensions(both diameter and radius), and to open up broad applications in display, jewelry decoration, green production of packing papers, security code,and counterfeits prevention.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11474046 and 61775024)the Program for Liaoning Innovation Team in University,China(Grant No.LT2016011)+1 种基金the Science and Technique Foundation of Dalian,China(Grant Nos.2017RD12 and 2015J12JH201)the Fundamental Research Funds for the Central Universities,China(Grant No.DC201502080203)
文摘The W(18)O(49) nanoflowers with a diameter of 500 nm are prepared by a facile hydrothermal method. The Er-Yb:NaYF4 nanoparticles are adsorbed on the petals(the position of the strongest local electric field on W(18)O(49) nanoflowers).With a 976 nm laser diode(LD) as an excitation source, the selectively green upconversion luminescence(UCL) is observed to be enhanced by two orders of magnitude in Er-Yb: NaYF4/W(18)O(49) nanoflowers heterostructures. It suggests that the near infrared(NIR)-excited localized surface plasmon resonance(LSPR) of W(18)O(49) is primarily responsible for the enhanced UCL, which could be partly reabsorbed by the W(18)O(49), thus leading to the selective enhancement of green UCL for the Er-Yb: NaYF4. The fluorescence intensity ratio is investigated as a function of temperature based on the intense green UCL, which indicates that Er-Yb: NaYF4/W(18)O(49) nanoflower heterostructures have good potential for developing into temperature sensors.
基金supported by the National Natural Science Foundation(Grant Nos.22011540378 and 21773080)of P.R.ChinaThe Development Program of the Science and Technology of Jilin Province(20190701003GH,20190201215jc and 20200404193yy).
文摘Semiconductors typically exhibit long-wavelength LSPR absorption in the infrared region due to lower carrier density.Tuning the carrier density of semiconductors and blue-shifting their LSPR absorption to the visible and near-infrared region has always been a great challenge.Herein,we discussed how the controllable carrier of(Ag)x(MoO_(3))y composite influences the LSPR based on SERS test and UVeViseNIR absorption spectra.We were surprised to find that the LSPR absorption wavelength can be easily tuned from 950 to 735 nm by changing the sputtering power of MoO_(3)of the(Ag)x(MoO_(3))_(y)composite.This shows that LSPR can be precisely adjusted by increasing the semiconductor content and even the carrier density.In addition,the carrier density was measured by Hall effect to investigate the SERS intensity change caused by electromagnetic(EM)enhancement,and obtain the relationship between the two.The findings of this work provide an idea for tunable LSPR and the research of EM contributions to SERS.
基金financial supports from the National Natural Science Foundation of China (21875288, 21802172)the GDUPS (2016)the NSF of Guangdong Province (2018A030313009)。
文摘The optoelectronic performance of CsPbBr_3 nanocrystal(NC) has been dramatically limited by the severe charge carrier recombination and its narrow light absorption range,which are anticipated to be resolved via coupling with plasmonic Au nanoparticle(NP).In view of this,CsPbBr_3-Au nanocomposite is fabricated and further employed as a concept model to study the electronic interaction between perovskite NC and Au NP for the first time.It has been found that the excitation-wavelength dependent carrier transfer behavior exists in CsPbBr_3-Au nanocomposite.Upon illumination with visible light(λ>420 nm),photo-generated electrons in CsPbBr_3 can inject into Au with an electron injection rate and efficiency of 2.84×10~9 s^(-1) and 78%,respectively.The boosted charge separation is further translated into a 3.2-fold enhancement in CO_2 photocatalytic reduction activity compared with pristine CsPbBr_3.On the other hand,when solely exciting Au NP with longer wavelength light(λ>580 nm),the localized surface plasmon resonance(LSPR) induced hot electrons in Au NPs can transfer to CsPbBr_3 NC and further participate in photocatalytic reaction towards CO_2 reduction.The present study provides new insights into preparing plasmonic nanostructure to enhance the performance of perovskite based optoelectronic devices.
文摘Simultaneous generation of H_(2) fuel and value-added chemicals has attracted increasing attention since the photogenerated electrons and holes can be both employed to convert solar light into chemical energy.Herein,for realizing UV-visible-NIR light driven dehydrogenation of benzyl alcohol(BA)into benzaldehydes(BAD)and H_(2),a novel localized surface plasmon resonance(LSPR)enhanced S-scheme heterojunction was designed by combining noble-metal-free plasmon MoO_(3-x) as oxidation semiconductor and Zn_(0.1)Cd_(0.9)S as reduction semiconductor.The photoredox system of Zn_(0.1)Cd_(0.9)S/MoO_(3-x) displayed an unconventional reaction model,in which the BA served as both electron donor and acceptor.The S-scheme charge transfer mechanism induced by the formed internal electric field enhanced the redox ability of charge carriers thermodynamically and boosted charge separation kinetically.Moreover,due to the LSPR effect of MoO_(3-x) nanosheets,Zn_(0.1)Cd_(0.9)S/MoO_(3-x) photocatalysts exhibited strong absorption in the region of full solar spectrum.Therefore,the Zn_(0.1)Cd_(0.9)S/MoO_(3-x) composite generated H_(2) and BAD simultaneously via selective oxidation of BA with high production(34.38 and 33.83 mmol×g^(–1) for H_(2) and BAD,respectively)upon full solar illumination.Even under NIR light irradiation,the H_(2) production rate could up to 94.5 mmol×g^(–1)×h^(–1).In addition,the Zn_(0.1)Cd_(0.9)S/MoO_(3-x) composite displayed effective photocatalytic H_(2) evolution rate up to 149.2 mmol×g^(–1)×h^(–1) from water,which was approximate 6 times that of pure Zn_(0.1)Cd_(0.9)S.This work provides a reference for rational design of plasmonic S-scheme heterojunction photocatalysts for coproduction of high-value chemicals and solar fuel production.