Visible Light Range Research Articles

Boron nitride quantum dots supported hollow NH2-MIL-125 drive photo-Fenton-PMS system for photocatalytic tetracycline degradation: Contribution of tannic acid etching

NH2-MIL-125(Ti) materials had great potential for photocatalytic applications but had low activity due to exciton effect and narrow absorption range of visible light. The surface oxygen-containing negative functional groups of boron nitride quantum dots (BNQDs) could overcome these defects, but due to the low load capacity, a higher specific surface area of the substrate was usually required. In this paper, a hollow Ti-MOF material was developed by etching technology. The hollow structure formed by tannic acid etching broadened the absorption range of visable light and provided more alternative surfaces for loading BNQDs. The 85.2% of high tetracycline (TC) removal efficiency for the best sample (BNQDs-5@20-Ti-MOF + PMS) was obtained, which was about 56.8 and 1.9 times of the 20-Ti-MOF and BNQDs-5@20-Ti-MOF, respectively. BNQDs-5@20-Ti-MOF + PMS system showed a great TC degradation efficiency in a wide pH range (pH = 5–9). In addition, reaction temperature and the inorganic ions did not show significant inhibition effect for TC removal. Both free radical and non-free radical pathways were involved in the TC degration by BNQDs-5@20-Ti-MOF + PMS system, among which O2•− and 1O2 played the key roles. Interestingly, multiple 1O2 production paths contributed to the high efficiency and stability of BNQDs-5@20-Ti-MOF + PMS system. This study revealed a reasonable combination of Ti-MOF and BNQDs, which provided a new efficient photocatalyst for environmental remediation.

Tunable Spectral Emission from 0D Rb3ZnBr5 Crystals for Single‐Component Multi‐Color LED Applications

AbstractThe development of efficient, stable, and cost‐effective luminescent materials is crucial for advancing lighting and display technologies. In this study, a series of tunable luminescent materials based on the novel 0D all‐inorganic perovskite (AIP) crystal Rb₃ZnBr₅ (RZB) is obtained. The emission of Sn2⁺ doped RZB spans the entire visible light range and extends into the near‐infrared (NIR) region, achieving a photoluminescence quantum yield (PLQY) of 75%. The distinct lifetimes combined with theoretical calculations, indicate that the broadband dual‐peak emissions at 496 and 636 nm originate from the singlet and triplet states of Sn2⁺, respectively, which is rarely observed in Sn2⁺‐doped perovskite crystals. The phosphor RZB:Sn2⁺ demonstrates the high thermal stability, along with excellent moisture and air stability. Co‐doping RZB with Sn2⁺ and Mn2⁺ broadens the excitation spectrum and allows precise control over the excitation wavelength, facilitating dynamic transitions from warm white to yellow and green light. This feature is particularly beneficial for multicolor LEDs and multi‐level anti‐counterfeiting applications.

Band-gap engineering enabled emission switch in solid-solution phosphors LiIn1-xScxGeO4:Bi3+ for spectral-temporal anti-counterfeiting

The interaction between matrix lattice and doped activator has long been pivotal topic in the research of the state-of-the-art functional materials, particularly luminescent materials. With the ceaseless development of advanced anti-counterfeiting, there are imperative need for developing luminescent materials with wide emission tunability, excellent visibility, and adjustable persistent luminescence. Herein, we present a paradigm to obtain great emission tunability in a solid-solution phosphors LiIn1-xScxGeO4:Bi3+ (x = 0–1) via band-gap engineering. With the increase in Sc content, the band-gap enlarges, causing the Bi3+ emissions gradually shift from 580 to 456 nm. As Sc substitution continues, the Bi3+ emissions transfer from the metal-to-metal charge transfer band to the inter s-p transition, resulting in a rapid shift in emission from 456 to 356 nm. This emission shift not only achieves a record total tunability of 224 nm among Bi3+-doped solid-solution phosphors but also an informative band-gap dependent emission mechanism of the Bi3+ activator. Furthermore, the samples gradually exhibited a persistent luminescence through the substitution process, attributed to the increasing traps by the thermoluminescence analysis. Leveraging these unique spectral properties, we designed two types of patterns that can be distinguished from color and time within the visible light range, demonstrating that the obtained phosphors can serve as promising candidate materials for spectral-temporal anti-counterfeiting.

Novel antimicrobial polyvinyl alcohol film by incorporating β-cyclodextrin/berberine inclusion complex preserving the storage quality of salmon fillets

Antimicrobial packaging film mediated by photodynamic inactivation (PDI) based on biodegradable polymers is promising. The photosensitizer berberine chloride (BBR) was encapsulated into the β-cyclodextrin (CD) to exert its aggregation-induced emission (AIE) property. On this basis, novel PDI-mediated polyvinyl alcohol (PVA) films were fabricated by incorporating the CD/BBR inclusion complex. The PVA/CD/BBR films had high light transmittance (∼70 %) in the visible light range, and possessed good biodegradability with the water absorption of 76 % and water solubility of 31 %. Besides, the films exhibited good mechanical properties with the tensile strength of 62.53 MPa at elongation break of 69.14 %, owing to the formation of hydrogen bonds between the PVA and CD/BBR. The PDI-mediated films were irradiated (14.4 J/cm2) to produce ROS to kill ∼4 log CFU/mL of Listeria monocytogenes and Vibrio parahaemolyticus. In addition, the films potently inactivated native bacteria (0.92 log CFU/g) on salmon fillets after 9 days of storage, and maintained their sensory quality, water holding capacity, and notably, inhibited the chemical changes of salmon fillets to extend the shelf-life for at least 3 days.

Hofmann-type MOF-derived CuNiOx photocathode for effective PEC H2 production

A novel mixed metal oxide of CuNiOx has been successfully obtained via electrosynthesis and thermal conversion of a Hofmann-type MOF Cu(pz)2[Ni(CN)4] (pz = pyrazine). CuNiOx has demonstrated a significant enhancement in light absorption within a visible light range, leading to an impressive increase in photocurrent density and photocatalytic activity during light irradiation compared to CuO. The exceptional photoelectrochemical properties of the photocathodes of CuNiOx have been studied using multiple photoelectrochemical instrumental techniques, which proved the electrodes were stable over the whole water photolysis. The coupling of two metal centers has explained their outstanding performance.

An Innovative Azobenzene-Based Photothermal Fabric with Excellent Heat Release Performance for Wearable Thermal Management Device.

Azobenzene (azo)-based photothermal energy storage systems have garnered great interest for their potential in solar energy conversion and storage but suffer from limitations including rely on solvents and specific wavelengths for charging process, short storage lifetime, low heat release temperature during discharging, strong rigidity and poor wearability. To address these issues, an azo-based fabric composed of tetra-ortho-fluorinated photo-liquefiable azobenzene monomer and polyacrylonitrile fabric template is fabricated using electrospinning. This fabric excels in efficient photo-charging (green light) and discharging (blue light) under visible light range, solvent-free operation, long-term energy storage (706 days), and good capacity of releasing high-temperature heat (80-95 °C) at room temperature and cold environments. In addition, the fabric maintains high flexibility without evident loss of energy-storage performance upon 1500 bending cycles, 18-h washing or 6-h soaking. The generated heat from charged fabric is facilitated by the Z-to-E isomerization energy, phase transition latent heat, and the photothermal effect of 420nm light irradiation. Meanwhile, the temperature of heat release can be personalized for thermal management by adjusting the light intensity. It is applicable for room-temperature thermal therapy and can provide heat to the body in cold environments, that presenting a promising candidate for wearable personal thermal management.

Near‐Full‐Spectrum Emission Realized in a Single Lead Halide Perovskite across the Visible‐Light Region

AbstractThe engineering of tunable photoluminescence (PL) in single materials with a full‐spectrum emission represents a highly coveted objective but poses a formidable challenge. In this context, the realization of near‐full‐spectrum PL emission, spanning the visible light range from 424 to 620 nm, in a single‐component two‐dimensional (2D) hybrid lead halide perovskite, (ETA)2PbBr4 (ETA+=(HO)(CH2)2NH3+), is reported, achieved through high‐pressure treatment. A pressure‐induced phase transition occurs upon compression, transforming the crystal structure from an orthorhombic phase under ambient conditions to a monoclinic structure at high pressure. This phase transition driven by the adaptive and dynamic configuration changes of organic amine cations enables an effective and continuous narrowing of the band gap in this halide crystal. The hydrogen bonding interactions between inorganic layers and organic amine cations (N−H⋅⋅⋅Br and O−H⋅⋅⋅Br hydrogen bonds) efficiently modulate the organic amine cations penetration and the octahedral distortion. Consequently, this phenomenon induces a phase transition and results in red‐shifted PL emissions, leading to the near‐full‐spectrum emission. This work opens a possibility for achieving wide PL emissions with coverage across the visible light spectrum by employing high pressure in single halide perovskites.

Performance optimization of (FA)2BiCuI6 perovskite solar cells using transport layer integration

The double-halide perovskite (FA)₂BiCuI₆ has been identified as a key material for enhancing the light absorption in perovskite solar cells (PSCs). In a device structure composed of FTO/STO/(FA)₂BiCuI₆/Spiro-OMeTAD/Au, notable photovoltaic (PV) performance has been achieved. Sulfur-doped tin oxide (STO) is utilized as the electron transport layer (ETL), (FA)₂BiCuI₆ serves as the absorber, and Spiro-OMeTAD functions as the hole transport layer (HTL), with gold (Au) and fluorine-doped tin oxide (FTO) acting as the contacts. Through optimization using the Solar Cell Capacitance Simulator (SCAPS-1D), the thicknesses of the absorber, HTL, ETL, and FTO were set to 1000 nm, 150 nm, 150 nm, and 100 nm, respectively, with the device operating at 300 K. This setup demonstrated high performance under the AM1.5 G spectrum, yielding an open-circuit voltage (VOC) of 1.02 V, a short-circuit current density (JSC) of 25.6 mA/cm², a fill factor (FF) of 87.76 %, and a power conversion efficiency (PCE) of 22.97 %. The device also exhibited a quantum efficiency (QE) of approximately 99.30 % within the visible light range.

Synthesis of Alpha Ferrous Oxalate Dihydrate from Ferrotitaniferous Mineral Sands via Hot Pressurized Aqueous Oxalic Acid: Kinetics and Characterization

Ferrous oxalate dihydrate is a versatile organic mineral with applications across fields. However, little is known about the feasibility of its synthesis directly from iron-bearing minerals using binary subcritical water (sCW) systems and its associated kinetics. In this study, the sCW+oxalic acid system at either 115 °C or 135 °C was investigated as a reaction medium for ferrous oxalate dihydrate (α-FeC2O4∙2H2O) synthesis, starting from ferrotitaniferous sands. The kinetics of the synthesis reaction were studied, and the physicochemical characterization of the as-synthetized ferrous oxalates was performed. Overall, the sCW synthesis was temperature-dependent, following second-order reaction kinetics according to the proposed precipitation pathway. A high reaction rate constant, significantly high yields (up to 89%), and reduced reaction times (2–8 h) were evident at 135 °C. The as-synthetized product corresponded to the monoclinic α-FeC2O4∙2H2O, showed relatively high specific surface areas (from 31.9 to 33.7 m2∙g−1), and exhibited band gap energies within the visible light range (~2.77 eV). These results suggest that α-FeC2O4∙2H2O can be synthesized using an organic dicarboxylic acid and iron-rich, widely available, low-cost mineral precursors. In addition, the as-prepared α-FeC2O4∙2H2O could be further optimized and tested for catalytic and visible light photocatalytic applications.

Excitonic optical properties in monolayer SnP2S6

Abstract Quantum confinement effect and reduced dielectric screening in two-dimensional (2D) dramatically enhance the electron–hole interactions. In this work, we use many-body perturbation theory and Bethe–Salpeter equation (BSE) to investigate the electronic and excitonic optical properties of monolayer SnP2S6. Our findings reveal that the excitonic effect dominates the optical absorption spectra in the visible light range, and the lowest-energy exciton X 0 in monolayer SnP2S6 is optically bright with the binding energy of 0.87 eV and the radiative lifetime of ∼ 10−11 s, which is highly advantageous to the photo-luminescence. Most importantly, the absence of optically forbidden states below the bright states X 0 would give rise to a high quantum efficiency of 2D SnP2S6. We also find that applied biaxial strain can further shorten the radiative lifetime of the bright states. These results imply that 2D SnP2S6 is a promising candidate for the optoelectronic devices.

First-principle calculations of the electronic structure and optical properties of β-Ga2O3 with various vacancy defects

In this work, the effects of five types of vacancy defects on the electronic, optical and thermodynamic properties of β-Ga2O3 were investigated using first-principle calculations. The findings revealed that oxygen vacancies were more prevalent than gallium vacancies, with tetrahedral gallium vacancies being easier to form than octahedral ones. Vacancy defects induced a shift in the energy bands towards the lower energy end, with gallium vacancies reducing the bandgap from 4.9 eV to 3.1 eV, while the effect of oxygen vacancies on the bandgap was negligible. Oxygen vacancies introduced deep impurity levels near the Fermi level, while gallium vacancies introduced shallow impurity levels, primarily due to contributions from O-2p, Ga-4s, and Ga-4p orbital electrons. The differential charge density diagrams illustrated that gallium vacancies had a more pronounced impact on electronic distribution compared to oxygen vacancies, with VO3 exhibiting the least influence. As the temperature increases, the β-Ga2O3 with VO1 and VO2 exhibit higher thermodynamic stability compared to the intrinsic β-Ga2O3 and the one with VO3, while the intrinsic β-Ga2O3 has a superior heat capacity value compared to the β-Ga2O3 containing the five vacancy defects. The defect energy levels resulting from vacancies enhanced light absorption and conductivity, particularly oxygen vacancies, which improved the absorption capacity of β-Ga2O3 in the visible light range. These findings provide valuable insights for elucidating optical absorption experimental phenomena and photoluminescence.

Plasmon‐Enhanced Fluorescence of NIR‐Emitting CdxHg1‐xTe Quantum Dots by Ag Nanoprisms

AbstractNear‐infrared (NIR)‐emitting colloidal semiconductor nanocrystals (NCs) draw a lot of attention due to various fields of their potential application, such as bio‐imaging, photovoltaics, photodetectors, light‐emitting diodes, and optical amplifiers for telecommunication. Since they typically suffer from the partial loss of their fluorescence in a solid state, strategies to increase their quantum yields are of outstanding importance. One of the means to improve it is their coupling with structures exhibiting localized surface plasmon resonance (LSPR). As demonstrated for the visible range of light, plasmon‐exciton interactions can enhance the photoluminescence (PL) of CdSe and CdTe NCs. In this work, the influence of the electromagnetic field of plasmonic silver NCs on the PL of CdxHg1–xTe NCs in the NIR region with a special emphasis on tuning the distance between these particle species is studied. In a series of samples prepared by a layer‐by‐layer deposition through polyelectrolytes, a 1.4‐fold PL enhancement at a distance of 9–11 nm between the two layers is observed, while at any other separation emission quenching is a dominating effect. These findings corroborate well with theoretical predictions of an emission increase at these specific distances and can be applied to other types of plasmonic and emitting materials.

Optimizing novel perovskite Mg3AsBr3 through uniaxial stress: a comprehensive study of its potential in solar and optoelectronic applications

This study presents a detailed investigation into optimizing the novel perovskite Mg3AsBr3 through uniaxial stress for enhanced performance in solar and optoelectronic applications. Using Density Functional Theory (DFT), we examined its structural, electronic, and optical properties under uniaxial stress from 0.5 to 5.0 GPa. Key findings include the tuning of the material’s bandgap from 1.485 eV (without stress) to an optimized range closer to 1.13581 eV under 5.0 GPa, demonstrating potential for improved solar cell efficiency. Our findings reveal a nuanced response of the material’s absorption coefficients at critical energies of 2.92 eV and 4.0 eV, where a descending trend with increasing pressure was observed, indicating a plateau at 1.5 GPa and an anomalous increase at 2.5 GPa. This behavior underscores the significance of stress between 2.5 GPa to 5.0 GPa in tailoring the optical responses essential for enhancing solar absorption efficiency in the ultraviolet to visible light range (300–800 nm). Notably, the dielectric constant increased gradually with stress, peaking at 6.003 under 0.5 GPa and slightly diminishing at 5.0 GPa, suggesting enhanced polarization and intrinsic response to electric fields under mechanical stress. Our research highlights the potential of stress engineering in optimizing perovskite materials for renewable energy applications, offering a pathway to high-efficiency, low-cost solar cells.

Preventive conservation of paper-based relics with visible light high-transmittance ultraviolet blocking film based on carbon dots

Paper-based relics is an important carrier for recording and preserving information, however, it faces irreversible UV-induced damage, including photocleavage, oxidation, acidification and discoloration, which seriously affects its value and lifespan. Carbon dots (CDs) possess excellent UV absorption and good chemical stability, making them suitable for UV protection. Herein, we propose a high-security and efficient method utilizing CDs films (CDFs) for preventive protection of paper against UV damage. The CDFs with high tunable UV absorbance and minimal absorbance in the visible light range, effectively shield paper from UV radiation while preserving its visual appeal. Moreover, the UV transmittance of the film can be fine-tuned to the content of CDs and can be easily removed from the paper without residue. Artificial accelerated UV aging experiments demonstrate the deceleration of acidification, oxidation, and photocleavage in the protected bamboo paper and Xuan paper. This research paces a new direction for the protection of paper and paper-based relics and artworks with emerging carbon materials, offering customizable protection effects tailored to specific preservation and exhibition requirements. This research pioneers a novel approach to preventive protection of paper and paper-based relics using emerging carbon dots materials, offering tailored protection for diverse preservation needs.

Design and modification thienonaphthalimides based non-fullerene acceptors for organic solar cells with high photovoltaic performance in visible light absorption range

Herein, we theoretically designed and characterized eight new thienonaphthalimides-based non-fullerene acceptor (NFA) materials (MT1–MT8) derived from 1ad molecule for organic solar cells (OSCs) devices. In this study, density functional theory (DFT) and time-dependent density functional theory were used to perform theoretical characters of all molecules. All computational analysis were successfully done at mPW1PW91/6-31g(d,p) DFT level. Compared with R (3.25 eV), MT4 showed better planarity and narrower band gap of 2.470 eV. A relatively lower excitation energy (2.039 eV) and binding energy (0.431 eV) were also found in MT4. Meanwhile, molecular electrostatic potential, transition density matrix and hole-electron analyses proved that MT4 had better photovoltaic and photophysical properties than R. We also designed J52-Cl:MT4 blend compound to study the charge transfer behavior at the interface which shown successful shift of electrons from donor to acceptor. Therefore, our newly designed molecules have the potential of being good NFAs for efficient OSC devices.

A multiscale dilated attention network for hyperspectral image classification

Hyperspectral imaging is an image obtained by combining spectral detection technology and imaging technology, which can collect electromagnetic spectra in the wavelength range of visible light to near-infrared. It is an important research content in the field of ground observation in hyperspectral remote sensing. However, hyperspectral image face significant challenges in classification task due to their high spectral dimensions, lack of labeled samples, and strong correlation between bands. In order to fully extract features from both spectral and spatial dimensions and improve classification accuracy in the case of limited training samples, a multiscale dilated attention network is proposed for hyperspectral image classification. First, a three-dimensional convolutional layer is used to extract the shallow features of the image. Then, a multiscale dilated attention module is proposed by combining dilated convolution and channel attention. Using ordinary convolution and dilated convolution to form different receptive fields. Channel attention is used to remodel the obtained multiscale features, enhancing the inter-channel correlation. After that, a multiscale spatial-spectral attention module is constructed using multiple asymmetric convolutions to obtain spatial and spectral attention features at different positions, further enhancing important feature suppression over non-important features. Finally, using softmax to classify the obtained features. Using Indian Pines, Pavia University, KSC and University of Houston as experimental datasets, the overall classification accuracy of this paper’s method achieved 98.97%, 99.14%, 99.45%, and 98.56% respectively, using only 5%, 1%, 10%, and 10% of training samples per class. Compared with seven advanced classification methods, the experimental results show that the proposed method can achieve the highest classification accuracy with limited training samples.

Study on the modulation of luminescence peak position and luminescence mechanism of black phosphorus

The application of black phosphorus in optoelectronic devices is hindered because of its inherent band gap characteristics. In the paper, black phosphorus was prepared by high-energy ball milling, and its related structure and properties were characterized. At the same time, the luminescence mechanism of black phosphorus was explored, and the effect of ultrasonic time on the structure and optical properties of black phosphorus was studied. The luminescence peak of black phosphorus can be modulated to the visible light range after adding polyethylene glycol, and the luminescence of black phosphorus is closely related to the P (020) and P (021). It was found that the luminescence intensity of alcoholized black phosphorus decreases with the increase of ultrasonic time. When the ultrasonic time is 15min, the luminescence intensity of alcoholized black phosphorus decreases greatly, this is because that the content of P (020) in black phosphorus decreases with the increase of ultrasonic time, resulting in the decrease of luminescence intensity.

Highly stable, low voltage, flexible photodetector in UV-visible region from self-assembled organic small molecule

The fabrication of a high-performance, low voltage operated flexible organic photodetector (OPD) based on solution self-assembled crystalline thin film of a small molecule, viz, 6,13 bis(tri-isopropylsilylethynyl) pentacene (Tips pentacene) is reported. The OPD demonstrated excellent photodetection ability under range of visible light as well as under UV light, with low illumination intensity. Under 590 nm illumination (5.6 µW/cm2), the device showcased photo to dark current ratio (Iphoto/Idark), ca. 25, photoresponsivity (P) of 89 mA/W, detectivity of 1.81×1010 jones at 1 V bias and response times of 0.04/0.2 sec. Photocurrent modulation of the OPD has been realized by varying the channel width, incident wavelength, applied bias and the illumination intensity. The OPD exhibited excellent photodetection ability under different tensile bending, with roughly 55 % decline in Iphoto/Idark value and 30 % decline in R value under bending radius of 7.5 mm. The OPD could withstand thousands of repeated bending/folding cycles, and regain its initial photoresponse characteristics, if put at rest for 2 hours. The excellent device performances with its precise tuning via various input stimuli suggests that present OPD have great potential for future low cost, low energy and wearable optoelectronics.

A novel hydrogen-bonded organic framework/g-C3N4 heterojunction for improved sulfadiazine photodegradation via effective electron transfer

As one of the most widely used antibiotics, sulfamethoxazole (SDZ) poses significant health risks to the ecological environment by causing harm to aquatic organisms and accelerating evolution of antibiotic resistant bacteria. Metalloporphyrin hydrogen-bonded organic framework (PFC-72) demonstrates promising prospect in the field of photocatalysis owing to its high specific surface area, wide light harvesting range, stable physical and chemical properties, and semiconductor properties. Herein, we constructed an efficient photocatalyst PFC-72/g-C3N4 by one-step solvent thermal method for photocatalytic degradation of SDZ. When doping content of PFC-72 is 10 %, photocatalytic degradation efficiency of SDZ can reach 96.82 % after 120 min of visible light irradiation, and PFC-72/g-C3N4 exhibits excellent structural stability. The photocatalytic efficiency of SDZ is improved by increasing specific surface area, enhancing absorption range of visible light, and inhibiting recombination of photogenerated electron-hole pairs. In addition, photodegradation pathways of SDZ in PFC-72/g-C3N4 was determined by UPLC-MS/MS analysis. Finally, dominant reactive species (·O2−, hVB+, and ·OH) in the system were detected through free radical masking experiments, and photocatalytic mechanism was clarified. This work investigates a novel and efficient porphyrin-HOF based photocatalyst, which has great potential for degradation of SDZ.

Ferroelectric, flexoelectric and photothermal coupling in PVDF-based composites for flexible photoelectric sensors.

A ferroelectric polyvinylidene fluoride (PVDF) film with excellent flexibility possesses great potential for photodetection and wearable devices. However, the relatively weak photo-absorption and the consequent small photocurrent limit its photofunctional properties. Herein, we embedded a strongly visible-light active material system, 0.5Ba(Zr0.08Ti0.8Mn0.12)O3-0.5(Ba0.7Ca0.3)TiO3 (BZTM-BCT) loaded with Ag and Au nanoparticles, into a PVDF film, which demonstrates a significantly higher photovoltaic response in the whole visible light range with a β-phase content of over 90%. In a state of "bending + poling", the PVDF/BZTM-BCT:Au film presents an optimal response for photoelectric properties by exhibiting a photocurrent that is 57 times higher than that of a pure PVDF film when illuminated with 405 nm LED light at 100 mW cm-2. Photoexcitation and thermal excitation jointly contribute to the generation of free carriers, while the flexoelectric and ferroelectric coupling electric field provides a greater driving force for carrier separation and transport. More interestingly, composite film-based photoelectric sensors can simultaneously respond to light and the movement and deformation of contacted things, indicating its potential in versatile applications. Overall, this work puts forward a new route for designing new flexible multifunctional photoelectric devices.