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Broadband near‐infrared (NIR) luminescent materials are of great interest for their potential application in optical communication, remote sensing, imaging, and homeland security. Tellurium (Te) doped glasses were recently recognized as such a promising candidate due to their broadband NIR emission (700–1700 nm). However, the achievement of Te‐doped glasses with high luminescence efficiency and glass stability (GS) remains a daunting challenge. Here, the luminescence behavior and GS of Te‐doped germanate glasses are manipulated by tailoring the glass network topology. Te NIR luminescence is enhanced by tailoring topological cages in germanate glass network structure through varying glass network modifiers. Meanwhile, the GS of potassium germanate glass is significantly enhanced due to increased network connectivity caused by the co‐introduction of alkaline earth oxides. Finally, NIR luminescence intensity of the glass was further enhanced by optimizing the doping concentration of TeO2. The findings here could contribute to designing Te‐activated glasses with improved performance for application in optical amplifiers and tunable fiber lasers. [ABSTRACT FROM AUTHOR]

Bismuth (Bi)‐doped photonic glasses and fibers with broadband near‐infrared (NIR) photoemission have potential applications in tunable lasers and broadband amplifiers. Yet, when it comes to all wavelength amplification of optical communication, it remains challenging to achieve efficient Bi NIR emission in the technically relevant C‐ and L‐ bands (1530‐1625 nm). Here, we propose a scheme by fluorination triggered enhancement of ultra‐broadband Bi NIR emission in nitrided germanate glasses. Besides, compared to previous research, a unique and efficient Bi‐activated ultra‐wideband NIR emission with new emission bands peaked at ~924 and ~1520 nm under excitation of 450 nm are obtained in nitrided germanate glasses after fluorination. Moreover, the fluorination can modulate the local chemical environment by forcing the conversion of aluminum species from AlO4 to AlO5 and AlO6 and consequently increase the flexibility of the glass network structure, which finally induces the conversion of Bi species and then manipulates the relative emission intensity of different Bi NIR centers. Thus, a flat and tunable emission spectrum covering the entire optical communication band is obtained by optimizing the fluoride amount. We believe this work is helpful to design the Bi‐doped tunable fiber lasers and ultra‐broadband amplifiers for all wavelength amplification of optical communication. [ABSTRACT FROM AUTHOR]

Till now, many doped persistent luminescence (PersL) phosphors have been investigated and found various applications in such as bioimaging, photocatalysis and information storage, but introducing PersL emitters into a proper host is mostly complex. In this research, a self‐activated PersL phosphor Ba2Zr2Si3O12 (BZSO) is prepared by solid state reaction. By adding NH4Cl, the self‐activated PersL intensity is evidently enhanced. The trap depths and concentrations are examined by thermoluminescence spectra. Meanwhile, Bi3+ ions are introduced into BZSO and show wide band photoluminescence (PL) from 300 to 600 nm. Moreover, the PL of Bi3+ is tunable under excitation by 265‐350 nm lights. Furthermore, as a proof‐of‐concept design, we designed a patterned quick response (QR) code based on the self‐activated PersL of BZSO, and the information of "South China University of Technology (SCUT)" can be read out by the code scanning technology. Bi3+‐doped BZSO phosphors are suggested to provide potential applications in information storage by its self‐activated PersL, and to excite researchers to study the tunable PL in Bi3+‐doped phosphor. [ABSTRACT FROM AUTHOR]

Thermal quenching of phosphor is an important challenge for its practical application in phosphor‐converted white light‐emitting diodes (pc‐WLEDs) and it usually becomes aggravated with the increase of activator concentration. Conversely, this work finds the thermal quenching of Eu2+ emission at 490 nm in Sr4Al14O25:Eu2+ does not follow this in the temperature range of 300 to 480 K, and the rate of it is even slowed down as the concentration of Eu2+ increases. However, at the same time, the experiment on three heating‐cooling cycles of Sr4Al14O25:Eu2+ reveals that the thermal degradation of Eu2+ emission becomes improved. Once Eu2+ ions are doped into Sr4Al14O25, they will prefer substituting for the 10‐ and 7‐coordinated strontium sites Sr1 and Sr2, respectively. The emission centers Eu1 and Eu2, therefore, appear. The abnormal phenomenon is perhaps partly due to the enhanced energy transfer from the emission center Eu1 at 407 nm to the one Eu2 at 490 nm. It is also found interesting that the introduction of AlN can enhance the emission of Sr4Al14O25:Eu2+ without leading to the deterioration of thermal degradation. In the end, a prototype of pc‐WLED was fabricated with Sr4Al14O25:Eu2+ to demonstrate the application of white lighting. This work is not only beneficial to the understanding of the relationship between concentration and thermal quenching, but also conducive to the design of the heavily doped phosphor for WLEDs with better resistance to thermal quenching. [ABSTRACT FROM AUTHOR]

Mechanoluminescence (ML) is a phenomenon upon external mechanical stimuli and it has found diverse applications such as stress sensing, structure health diagnosis, 3‐D signature, energy harvesting etc because of its unique properties of in situ and real‐time response to the stimuli. However, ML of most of the state‐of‐art phosphors primarily appears within the spectral range from ultraviolet to visible, which does not lie in the biological transparent windows, and, therefore, limits its applications in biological field. Here, we report a strong near infrared (NIR) ML from orthorhombic Cmcm perovskite Sr3Sn2O7: Nd3+, which is peaked at ~ 900 nm and located exactly within the first optical transparent window of tissues. The ML apparates after gradual discharge of the traps deeper than 0.73 eV triggered by the external mechanical stimuli and subsequently excitation of Nd3+ to the state of 4F3/2. The rechargable ML presents well repeatable linearity to loaded force at least up to 5000 N, and it can penetrate tissues easily that are thick up to 30 mm such as pigskin and the ceramic disk of hydroxy apatite which is the main constituent of bone. These results demonstrate the potential application for in situ biomechanical sensor. Meanwhile, by recording and processing these ML signals during signing on a pellet sample, for the first time, we provide a novel signature system based on NIR ML. This could raise the security level of existed signature anti‐countering to a higher level. [ABSTRACT FROM AUTHOR]

Light sources as the substitution for sunlight play an important role due to their practical applications in aircraft, medicine, and agriculture. Bi3+ ions show tunable emission from ultraviolet to deep red depending on local crystal field, presenting great potential in mimicking sunlight. However, these emissions are mainly limited to crystals. To stabilize Bi3+ ions inside photonic glasses with desirable emission and excellent physical properties remains challenging. Here, we managed to stabilize Bi3+ with ultrabroad and tunable emission inside glasses at air atmosphere. This emission spans the whole visible range of 350‐780 nm and matches well with the sunlight spectra. For the first time, an external quantum efficiency of 34% was obtained from Bi‐doped photonic glasses without optimizing glass composition. We find that the local oxidation atmosphere from super‐oxide ions and proper crystal field formed by AlO4 are responsible for this unique luminescence, which is revealed by the detailed comparison on the optical and structural properties of calcium aluminate glasses and Ca12Al14O33 crystals with the same composition. Moreover, glasses with distortion structure further results in multiluminescent centers of Bi3+ so as to broaden the emission band. This work provides new insights into the luminescent behaviors of Bi ions in luminescent materials, and should contribute to designing new photonic glasses in future. [ABSTRACT FROM AUTHOR]

The development of efficient red‐emitting persistent phosphor is still an ongoing challenge. In the search of persistent materials in red range, Pr3+ is a good candidate owing to its transitions between 1D2 and 3H4 state at about 612 nm. In this paper, we investigated the red persistent properties of Pr3+‐doped perovskite oxide ABO3, (A: K, Na and B: Nb), which can be elaborated as large single crystal. KNbO3:Pr3+ appears to have weak photoluminescence and no persistent luminescence. However, the cationic substituted compounds K1−xNaxNbO3:Pr3+ (x = 0, 0.4, 0.5, 0.7 0.9, 1) exhibit intense persistent luminescence, which increases steadily with increase in Na content. We correlated persistence behavior with the position of Metal‐to‐Metal Charge Transfer (MMCT) band, which plays crucial role in tuning of the trap depth. The MMCT band position decreases with the addition of Na contents and the thermoluminescence peak shifts toward higher temperature indicating the formation of deeper traps. This is in good agreement with the enhancement of the persistent luminescence suggesting that a proper tailoring of MMCT is needed to design efficient Pr3+‐persistent phosphors with better performance. A detailed analysis on the trap depth, bandgap energy, and persistent luminescence properties is reported tuning the composition in the K1−xNaxNbO3:Pr powder. Tunable traps depths are obtained by Na/K substitution. Electron and hole traps are evidenced by thermal analysis. This gives new insights in the persistent luminescence mechanism in the Pr3+− doped perovskite compounds. [ABSTRACT FROM AUTHOR]

Bismuth (Bi)‐doped glasses and fibers are of current interest as promising active media for new fiber lasers and amplifiers due to their 800‐1700 nm near‐infrared (NIR) emission. However, the optically active Bi centers in silica are easily volatilized during high‐temperature fiber drawing, which results in low Bi doping concentration and low gain NIR luminescence. Here, we explored the glass‐forming region in a model glass system of sodium tantalum silicate (Na2O‐Ta2O5‐SiO2) glass and attained suitable glass host for enhancing Bi NIR emission, right followed by detailed analysis on optical and structural characterization. Glass‐forming region roughly lies in where Ta2O5 ≤ 30 mol%, SiO2 ≥ 40 mol%, and Na2O ≤ 40 mol%. Not only is glass‐forming ability improved but also Bi NIR emission is enhanced (~60 times) by the introduction of Ta into glass network. Dissociated Na cations are restricted beside Ta, the high‐field‐strength element, so that the negative impacts of Na cations on glass formation and Bi NIR emission are weakened, which is responsible for the highly enhanced Bi NIR emission. This work helps us understand the glass‐forming of tantalum silicate glass systems and luminescent behaviors of Bi. Hopefully, it could contribute to designing the Bi‐doped laser glasses and high gain fibers with stable luminescent properties in future. [ABSTRACT FROM AUTHOR]

Bismuth (Bi)‐doped laser glasses with broadband emission are of current interest in the fields of sensing, bio‐imaging, and photonics. For practical applications, it must be considered how to improve the emission efficiency, in particular, for borate glasses with wide glass‐forming range, low melting point, and excellent fiberizing ability. Herein, we experimentally demonstrate that addition of GeO2 to aluminoborate glasses can effectively enhance Bi NIR emission by more than 300 times with prolonged decay time (~500 μs) and good homogeneity, which is, to our best knowledge, seldom achieved in Bi‐doped borate multi‐component glasses. The addition of second glass‐former GeO2, as revealed by detailed optical and structural analysis, leads to the facile regulation on local glass structure, forcing the conversion of aluminum species from AlO5 and AlO6 to AlO4 and consequently pushes the conversion of Bi3+ to Bi+ and Bi0 and stabilizes Bi NIR centers, which finally results in highly enhanced Bi NIR emission. We believe these results could contribute to designing Bi‐activated multi‐component laser glass and fibers with efficient NIR photoemission. [ABSTRACT FROM AUTHOR]

Nd3+‐doped phosphate laser glasses have been attracting much attention and widespread investigation due to their high solubility of rare earth (RE) ions, excellent spectroscopic properties, and large damage threshold. However, the narrow NIR emission bandwidth (less than 30 nm) of these Nd3+‐doped phosphate glasses limits their further application toward ultrahigh power field and efficient fiber laser in new region. Here, we demonstrate the broadening and enhancing of Nd3+NIR emission in laser glass of zinc aluminophosphate through tuning the glass structure and covalency of Nd‐O bond without limiting the radiative properties of Nd3+. The maximum bandwidth of 1.05 μm emission is broadened to 50 nm, which is comparable to that of Nd3+‐doped aluminate laser glasses. Simultaneously, the lifetime of 4F3/2 level is elongated nearly by two times. Structural and optical properties of prepared glasses were discussed systematically to reveal the mechanism. Detailed analysis on optical spectra and glass structure indicates that the bandwidth is affected by not only the covalency of Nd‐O but also the compactness of glass structure. Our results could enrich our understanding about the relationship between local glass structure and luminescence behaviors of active centers, and may be helpful in designing new RE‐doped laser glass systems. [ABSTRACT FROM AUTHOR]

A novel Mn4+‐doped strontium lanthanum gallate red phosphor SrLaGaO4:Mn4+ has been successfully prepared via the conventional solid‐state reaction method. Phase purity, photoluminescence excitation/emission spectra, concentration quenching, decay curves, and temperature‐dependent photoluminescence have been investigated systematically. SrLaGaO4:Mn4+ phosphor exhibits broad excitation band from 250 to 600 nm and emits intense red light centered at 716 nm arising from spin‐forbidden transition, 2E → 4A2 of Mn4+. The optimal dopant concentration of Mn4+ is determined to be 0.2 mol%. Dipole‐dipole interaction is supposed to be the mechanism of concentration quenching. The crystal‐field strength Dq, the Racah parameters B and C, and the nephelauxetic ratio β1 of SrLaGaO4:Mn4+ have been calculated according to its luminescent spectra. Our systematic investigation on this new phosphor can provide a reference for the development of red‐emitting phosphor. [ABSTRACT FROM AUTHOR]

Tantalum silicate glasses serve as laser host materials to take advantage of their high refractive index and the ability to tailor their physical properties in the design of high‐performance photonic and photoelectric components. However, successful attainment of feature control in tantalum‐doped materials remains a longstanding problem due to the limited understanding of local structure around the tantalum ions, a problem that lies at the heart of predicting the micro‐ and macroscopic properties of these glasses. Herein, we present a novel approach for predicting the local structural environments in tantalum silicate glass based on a phase diagram approach. The phase relations and glass formation region of Li2O–Ta2O5–SiO2 ternary systems are explored to calculate the structure and additive physical properties of lithium tantalum silicate glasses. These measured and calculated results are in good quantitative agreement, indicating that the phase diagram approach can be applied broadly to Li2O–Ta2O5–SiO2 ternary glass systems. Using the phase diagram approach, the local structure of tantalum can be directly obtained. Each Ta atom is surrounded by six atoms, and its polyhedron, the TaO6 octahedron, bonds through oxygen to Li and Ta. As a network modifier, Ta5+ depolymerizes the silicate glass structure by modulating the local structure of lithium atoms in Li2O–Ta2O5–SiO2 ternary glass system. The compositional dependence of structure in lithium tantalum silicate glasses is quantitatively determined based on the structure of the nearest neighbor congruent compound through the lever rule. These findings offer a precise prediction of tantalum silicate glass properties with quantitative control over local structural environment of the disordered materials. [ABSTRACT FROM AUTHOR]

Abstract: Optical gas sensors present fundamental and industrial importance considering their broad applications. Challenges remain to obtain new photonic materials with broadband emission covering the absorption spectrum of typical combustion gases. Here, broadband near‐infrared (NIR) photoluminescence (PL) spanning the wide absorption spectrum of typical combustion products is realized through instant precipitation of stable cubic perovskite KMgF3:Ni2+ nanocrystals inside an aluminosilicate glass matrix after melt‐quenching. Excited by an 808 nm laser diode, NIR luminescence with a peak centered at ~1624 nm and a bandwidth (FWHM) greater than 315 nm is observed, originating from 3T2g(3F) → 3A2g(3F) electronic transition of octahedral coordinated Ni2+ in KMgF3 GC. Controlled precipitation of these perovskite crystals from a supercooled aluminosilicate melt enables immediate encapsulation and, hence, stabilization in an inorganic glass phase. While the precipitation temperature has only a small effect on crystallite size, it controls the redox state of the melt and the degree of dopant incorporation into the crystalline phase so that PL performance can be optimized. Spontaneous crystallization of perovskite nanocrystals inside glass may offer a new way to stabilize these novel nanocrystals. Moreover, spontaneous crystallization can be attractive in the control of activator partitioning and in the fabrication of composite fiber devices with high transparency and emission gain. In the present case, this offers a potential platform for broadly tunable gain media, for example, for combustion gas sensing. [ABSTRACT FROM AUTHOR]

Abstract: Because of ultra‐broadband near‐infrared (NIR) emission bismuth‐activated glasses and fibers offer a new promising platform for novel photonic devices such as new type of optical amplifiers and broadly tunable fiber lasers. Yet, challenge remains to manipulate the NIR emission behavior of bismuth (Bi) in photonic glasses for efficient Bismuth‐doped fiber and fiber lasers. Here, by engineering phosphorus and aluminum's topology, broadly tunable NIR emission has been realized in Bismuth‐doped phosphate laser glass. Structural and optical analyses on 27Al magic‐angle spinning nuclear magnetic resonance (MAS NMR), 31P MAS NMR, fourier transform infrared (FTIR) and static emission spectra suggest that polymerization of glass network can be improved by proper addition of aluminum into the system, which can be evidenced by partial conversion of Q2 to Q3 species of phosphorus and the shift of P–O–P asymmetric stretching vibration toward lower frequency, and this turns out beneficial to Bi NIR emission. Embedding aluminum tetrahedra into phosphorus glass network can reduce the local crystal field around bismuth and therefore lead to the blueshift of Bi emission. This work presents new insights into the luminescent behavior of Bi ions in phosphate glass and it helps the design and fabrication of Bismuth‐doped glasses and fibers in future. [ABSTRACT FROM AUTHOR]

Because of superbroad luminescence in the range of near infrared ( NIR), Bi-doped glasses and fibers have received more attentions recently for the applications in super broadband optical fiber amplifiers or new wavelength lasers. As the luminescence comes from the transitions between naked 6p orbitals of bismuth, it is very susceptible to slight changes of local field around Bi. Therefore, it is always very challenging to predict NIR emission of bismuth in advance. Here, we found bismuth NIR emission shows predictable tendency in ternary glass system of MgO-Al2O3-SiO2. The emission peak shifts red along the content of magnesium upon the excitation of 484 nm, which follows a single exponential growth equation. In the meantime, the full width at half maximum ( FWHM) is broadened while the lifetime keeps decreasing. Glass structure analysis on basis of FTIR, 27Al NMR, 29Si NMR spectra reveals that these changes correlate to integrity of glass network, the increased disorder of local field around bismuth and the enhanced interaction between bismuth and host, which are perhaps due to the linear increase of nonbridging oxygen, and the enhanced Si-O asymmetric stretching vibrations along with magnesium, respectively. Electron probe microanalysis shows good homogeneity of Si, Al, Mg, Bi, and O distribution within the samples, and yoyo experiments of heating and cooling between 30°C and 300°C reveal the good resistance of such doped glasses to thermal degradation. This makes the glasses promising in applications of fiber devices even under extreme condition such as at higher temperature. The finding in this work should be helpful for the design of Bi-doped laser glasses in future. [ABSTRACT FROM AUTHOR]

Bismuth-doped (Bi) glasses and fibers have raised considerable attention for broadband emission and tunable fiber lasers in the near infrared (NIR) region. However, they suffer from low efficiency and it remains challenging to enhance Bi NIR emission. Here, we propose a facile way to enhance and tune the Bi NIR emission by adjusting optical basicity and modulating the boron and aluminum coordination in borate glasses. We find that BO4 and AlO5 species favor Bi NIR emission, right followed by the analyses of static emission spectra, the Fourier transform infrared (FT-IR), and nuclear magnetic resonance (NMR) spectroscopy. Furthermore, abnormal Bi NIR luminescence phenomenon and boron anomaly were observed, which are attributed to the synthetic effect of B and Al coordination transformation. Besides, we find that BO4 tetrahedron plays a major role in enhancing Bi NIR emission at low Al content, while AlO5 hexahedron group will dominate at high Al concentration. Our investigation may give an insight into the luminescent behaviors of Bi in borate glasses and contribute to improving the performance of Bi-doped fiber and fiber lasers in future. [ABSTRACT FROM AUTHOR]

Bismuth-doped glasses and crystals have been widely investigated due to their intriguing potential applications in superbroadband fiber amplifier and lasers in new NIR spectral range. However, few reports have been devoted so far to bismuth-doped transparent glass-ceramics. Here, this work reports on bismuth-doped silicate glasses and glass-ceramics, which were prepared by melt-quenching and consequent annealing processes, respectively. On the basis of the analyses on crystallization kinetics, nucleation and growth rate of crystalline phase can be modulated and Sr2YbF7 nanophase can, therefore, be precipitated uniformly inside the glass matrix in a controlled way to maintain proper transparence especially in optical telecommunication windows. Once the nanophase comes into being, enhanced bismuth NIR luminescence can be observed by more than 40 times upon excitation of 470 nm. Similar enhancement can appear upon different excitation schemes and the mechanism is discussed accordingly. Such Bi doped transparent glass-ceramics with improved luminescence efficiency might find application in fiber lasers for future optical fiber communication. [ABSTRACT FROM AUTHOR]

We report on intense photoluminescence from materials of the (Rb,K)2Ge4O9:Mn4+ solid solution as a novel class of redemitting oxide phosphors. In these compounds, luminescence originates from a virtually ideal substitution of Mn4+ for Ge4+ on octahedral lattice sites which are well-isolated from each other within the unit cell by intermediate GeO4 species. Complete isostructural substitution of K for Rb is possible across the join. The associated slight shrinkage of the unit cell has only little effect on the apparent Mn4+ interionic distance, but enables tuning of the absorption cross section and of the band structure, hence, of the emission lifetime, of the excitation band shape, and of emission quantum yield. Partial substitution was also found to reduce thermal quenching of the Mn4+-related emission, apparently due to the lower polarizability of the K+ ion. In addition, random substitution of Rb by K enables modulation of the interaction of Mn4+ with its surrounding field at lower symmetry, leading to increasing emission bandwidth, i.e., 595 cm-1 in K1.5Rb0.5Ge4O9:Mn4+ vs 558 or 578 cm-1 in Rb2Ge4O9:Mn4+ or K2Ge4O9:Mn4+ respectively. [ABSTRACT FROM AUTHOR]

Blue excitable red phosphor is the key component to improve the quality of lighting and display which is based on InGaN blue chips. Because of the potential in the area, Mn4+ red phosphors have recently got rising interests. However, most of them were found by trial and error. It remains very challenging to predict which kind of compound can stabilize Mn4+ and which wavelengths Mn4+ ions if they could survive in it will exhibit the excitation and emission at. Here, we first propose to use crystal field calculation on basis of exchange charge model to predict the energy levels of Mn4+ ion in germanate K2Ge4O9 since Mn4+ and Ge4+ are almost identical in size and charge, and the local field around Mn4+ will experience less distortion after substitution for Ge4+. The calculation shows the red emission peaking at 663 nm and the blue absorption of 4A2g (4F) → 4T2g (4F) in 450~470 nm, which matches better to blue chips than commercial phosphor 3.5MgO·0·5MgF2·GeO2:Mn4+. This inspires the synthesis of Mn-doped K2Ge4O9, the optical properties of which confirm the existence of Mn4+ and consist with the prediction. Comparison between theoretical and experimental results implies that no obvious preference of Mn4+ substitution over two different types of octahedral germanium sites, Ge1 and Ge2. Consequent systematic explorations have been made on the effects of flux content, preparation temperature, Mn content, and holding time to find the ways to enhance the Mn4+ luminescence for promotion of practical application. The results reveal the optimal sample can be made under much mild optimal condition (850°C for 4 h in air) with a quantum yield of >30% upon blue excitation of 460~470 nm. As temperature rises from 8 to 573 K, zero photon line (ZPL) emission redshifts along with gradual appearance of anti-Stokes side phonon bands due to the enhanced interaction of Mn4+ with host. This work demonstrates it possible to find Mn4+ red phosphors by guide of crystal field calculation. [ABSTRACT FROM AUTHOR]

For phosphor-converted warm white light-emitting diodes ( WLEDs), it is essential to find highly efficient red oxide phosphors, which are better chemically stable and benign to environment and can be prepared in a much milder condition. Here, we report a red phosphor LiNaGe4O9:Mn4+ with a quantum yield up to 78% after systematic optimization in synthesis temperature, dopant concentration of Mn4+, and sintering time. Best performance of the phosphor can be reached when it is synthesized in a mild reaction condition, that is, at 850°C for 3 h in air. The integrated emission intensity is more than four times stronger than commercial red phosphor 3.5MgO·0.5MgF2·GeO2:Mn4+ ( MFG:Mn4+) under a blue light excitation at 470 nm. Crystal structural analysis reveals that the high efficiency Mn4+ exhibits in the compound is mainly due to the well separation of GeO6 groups from each other by GeO4 tetrahedra in the neighborhood and the ideal substitution of octahedral Ge4+ site by Mn4+ in view of both size and charge matches. The high performance of the phosphor encourages us to apply the blue absorbing red phosphor to WLED, which is based on combination of a blue LED chip and YAG:Ce3+, and the warm perception WLED is therefore achieved with a color temperature of 3353 K. [ABSTRACT FROM AUTHOR]

Structural design is of great importance to the performance of photocatalysts in environmental remediation. Therefore, micro/nanofibrous morphology and nanoporous local structures have been found to be beneficial to improve the photocatalytic activity. In this investigation, we report the design and fabrication of flexible and thermal stable nanoporous SiO2- TiO2 composite fibers as efficient photocatalysts. Combining electrospinning and modified Stöber techniques, core-shell and mesoporous SiO2 fibers with high flexibility were fabricated and employed as the scaffold for supporting TiO2 nanoparticles. A nanoporous shell of TiO2 nanoparticles was then muffled over the SiO2 fibers to form core@dual-shell SiO2- TiO2 composite fibers with hierarchically porous structure, which were conveniently patterned into a nonwoven, recyclable film. This nonwoven film exhibits better photocatalytic activity for Rhodamine B degradation under UV irradiation compared with some other TiO2-based materials reported in recent years. [ABSTRACT FROM AUTHOR]