Spectral Overlap Research Articles

Active Control of Energy Transfer in Plasmonic Nanorod-Polyaniline Hybrids.

The hybridization of plasmonic energy and charge donors with polymeric acceptors is a possible means to overcome fast internal relaxation that limits potential photocatalytic applications for plasmonic nanomaterials. Polyaniline (PANI) readily hybridizes onto gold nanorods (AuNRs) and has been used for the sensitive monitoring of local refractive index changes. Here, we use single-particle spectroscopy to quantify a previously unreported plasmon damping mechanism in AuNR-PANI hybrids while actively tuning the PANI chemical structure. By eliminating contributions from heterogeneous line width broadening and refractive index changes, we identify efficient resonance energy transfer (RET) between AuNRs and PANI. We find that RET dominates the optical response in our AuNR-PANI hybrids during the dynamic tuning of the spectral overlap of the AuNR donor and PANI acceptor. Harnessing RET between plasmonic nanomaterials and an affordable and processable polymer such as PANI offers an alternate mechanism toward efficient photocatalysis with plasmonic nanoparticle antennas.

Plasmon Energy Transfer Driven by Electrochemical Tuning of Methylene Blue on Single Gold Nanorods.

Plasmonic photocatalysis has attracted interest for its potential to generate energy-efficient reactions, but ultrafast internal conversion limits efficient plasmon-based chemistry. Resonance energy transfer (RET) to surface adsorbates offers a way to outcompete internal conversion pathways and also eliminate the need for sacrificial counter-reactions. Herein, we demonstrate RET between methylene blue (MB) and gold nanorods (AuNRs) using in situ single-particle spectroelectrochemistry. During electrochemically driven reversible redox reactions between MB and leucomethylene blue (LMB), we show that the homogeneous line width is broadened when spectral overlap between AuNR scattering and absorption of MB is maximized, indicating RET. Additionally, electrochemical oxidative oligomerization of MB allowed additional dipole coupling to generate RET at lower energies. Time-dependent density functional theory-based simulated absorption provided theoretical insight into the optical properties, as MB molecules were electrochemically oligomerized. Our findings show a mechanism for driving efficient plasmon-assisted processes by RET through the change in the chemical states of surface adsorbates.

Ratiometric lysosome-targeting luminescent probe based on a coumarin-ruthenium(II) complex for formaldehyde detection and imaging in living cells and mouse brain tissues.

Ratiometric luminescence probes have attracted widespread attention because of their self-calibration capability. However, some defects, such as small emission shift, severe spectral overlap and poor water solubility, limit their application in the field of biological imaging. In this study, a unique luminescence probe, Ru-COU, has been developed by combining tris(bipyridine)ruthenium(II) complex with coumarin derivative through a formaldehyde-responsive linker. The probe exhibited a large emission shift (Δλ>100nm) and good water solubility, achieving ratiometric emission responses at 505nm and 610nm toward formaldehyde under acidic conditions. Besides, ratiometric luminescence imaging of formaldehyde in living cells and Alzheimer disease mouse's brain slices demonstrates the potential value of Ru-COU for the diagnosis and treatment of formaldehyde related diseases.

Three–step cascaded artificial light–harvesting systems with tunable efficiency based on metallacycles

It is still challenging to develop multi–step cascaded artificial light–harvesting systems (ALHSs) with tunable efficiency. Here, we designed novel cascaded ALHSs with AIE–active metallacycles as the light–harvesting antenna, Eosin Y (ESY) and sulforhodamine 101 (SR101) as conveyors, near–infrared emissive chlorin–e6 (Ce6) as the final acceptor. The close contact and fair spectral overlap between donor and acceptor molecules at each level ensured the efficient sequential three–step energy transfer. The excited energy was sequentially and efficiently funneled to Ce6 along the cascaded line MTPEPt1 → ESY → SR101 → Ce6. Additionally, a unique strategy for regulating the efficiency of ALHS was illustrated by adjusting hydrophilic and hydrophobic interactions.

An AIE-based ratiometric fluorescent probe for reversible detection of bisulfite and hydrogen peroxide and its application in food samples and biological imaging

Reversible detection of bisulfite (HSO3-) and hydrogen peroxide (H2O2) is highly desirable in biology and food safety owing to their redox pair function in biological systems and their utilization in food industry. In this work, a ratiometric fluorescent probe (TPA-Y) with aggregation-induced emission (AIE) properties based on triphenylamine fluorophore was designed and synthesized for reversibly monitoring of HSO3-/H2O2. Reaction of HSO3- with TPA-Y can result in ratiometric fluorescence changes (I444/I629), and the emission spectrum blue shift reaches 185 nm, which can effectively avoid spectral overlap. Meanwhile, the solution color changed obviously from orange to colorless, enabling naked eye detection of HSO3-. TPA-Y was capable of quantitatively detect HSO3- in sugar and wine samples with the recovery rates ranging from 94.52 to 102.18%. In addition, TPA-Y is suitable to prepare paper strips and anti-counterfeiting ink for HSO3- detection. In addition, the original TPA-Y can be released after the addition product (TPA-Y-HSO3-) is oxidized by H2O2, and the HSO3-/H2O2 redox cycle can repeat for at least six times. The probe TPA-Y can be applied to fluorescence imaging of reversible and dynamic interconversion between HSO3- and H2O2 in living MCF-7 cells.

Heterometallic ZnHoMOF as a Dual-Responsive Luminescence Sensor for Efficient Detection of Hippuric Acid Biomarker and Nitrofuran Antibiotics.

Developing efficient and sensitive MOF-based luminescence sensors for bioactive molecule detection is of great significance and remains a challenge. Benefiting from favorable chemical and thermal stability, as well as excellent luminescence performance, a porous Zn(II)Ho(III) heterometallic-organic framework (ZnHoMOF) was selected here as a bifunctional luminescence sensor for the early diagnosis of a toluene exposure biomarker of hippuric acid (HA) through "turn-on" luminescence enhancing response and the daily monitoring of NFT/NFZ antibiotics through "turn-off" quenching effects in aqueous media with high sensitivity, acceptable selectivity, good anti-interference, exceptional recyclability performance, and low detection limits (LODs) of 0.7 ppm for HA, 0.04 ppm for NFT, and 0.05 ppm for NFZ. Moreover, the developed sensor was employed to quantify HA in diluted urine samples and NFT/NFZ in natural river water with satisfactory results. In addition, the sensing mechanisms of ZnHoMOF as a dual-response chemosensor in efficient detection of HA and NFT/NFZ antibiotics were conducted from the view of photo-induced electron transfer (PET), as well as inner filter effects (IFEs), with the help of time-dependent density functional theory (TD-DFT) and spectral overlap experiments.

Negative Thermal Quenching in Quantum-Cutting Yb3+-Doped CsPb(Cl1-xBrx)3 Perovskite Nanocrystals.

Ytterbium-doped all-inorganic lead-halide perovskites (Yb3+:CsPb(Cl1-xBrx)3) show broadband absorption and exceptionally high near-infrared photoluminescence quantum yields, providing opportunities for solar spectral shaping to improve photovoltaic power conversion efficiencies. Here, we report that Yb3+:CsPb(Cl1-xBrx)3 NCs also show extremely strong negative thermal quenching of the Yb3+ luminescence, with intensities at room temperature >100 times those at 5 K for some compositions. Analysis of this temperature dependence as a function of x shows that it stems from thermally activated quantum cutting related to the temperature dependence of the spectral overlap between the PL of the perovskite (donor) and the simultaneous-pair absorption of two Yb3+ ions (acceptor). In the Yb3+:CsPbBr3 limit, this spectral overlap goes to zero at 5 K, such that only single-Yb3+ sensitization requiring massive phonon emission occurs. At room temperature, Yb3+ PL in this composition is enhanced ∼135-fold by thermally activated quantum cutting, highlighting the extreme efficiency of quantum cutting relative to single-Yb3+ sensitization. These results advance the fundamental mechanistic understanding of quantum cutting in doped perovskites, with potential ramifications for solar and photonics technologies.

Plasmonic Approach to Fluorescence Enhancement of Mesoporous Silica-Coated Gold Nanorods for Highly Sensitive Influenza A Virus Detection Using Lateral Flow Immunosensor.

Rapid diagnostic tests based on the lateral flow immunoassay (LFI) enable early identification of viral infection, owing to simple interpretation, short turnaround time, and timely isolation of patients to minimize viral transmission among communities. However, the LFI system requires improvement in the detection sensitivity to match the accuracy of nucleic acid amplification tests. Fluorescence-based LFIs are more sensitive and specific than absorption-based LFIs, but their performance is significantly affected by fundamental issues related to the quantum yield and photobleaching of fluorophores. Metal-enhanced fluorescence (MEF), which is a plasmonic effect in the vicinity of metallic nanoparticles, can be an effective strategy to improve the detection sensitivity of fluorescence-based LFIs. The key factors for obtaining a strong plasmonic effect include the distance and spectral overlap of the metal and fluorophore in the MEF system. In this study, MEF probes were designed based on core-shell nanostructures employing a gold nanorod core, mesoporous silica shell, and cyanine 5 fluorophore. To optimize the efficiency of MEF probes incorporated on the LFI platform (MEF-LFI), we experimentally and theoretically investigated the distance dependence of plasmonic coupling between cyanine 5 and gold nanorods by adjusting the shell thickness, resulting in significant fluorescence enhancement. The proposed MEF-LFI enabled highly sensitive detection of influenza A virus (IAV) nucleocapsid protein with a detection limit of 0.52 pg mL-1 within 20 min and showed high specificity and accuracy for determining IAV clinical samples. Overall, our findings demonstrate the potential of this method as an effective tool for molecular diagnosis under emergency conditions.

Strong Host-Guest Dependence on the Emissive Properties of MOF-5 and [Zn2(BTTB)(DMF)2•(H2O)3]n.

3D-[Zn4O(1,4-BDC)3•x(solvent)]n (MOF-5; BDC = 1,4-benzodicarboxylate) and 3D-[Zn2(BTTB)(DMF)2•(H2O)3]n (MOF-D; BTTB = 4,4',4″,4‴-benzene-1,2,4,5-tetrayltetrabenzoate) have been investigated by means of steady-state UV-visible and fluorescence and time-resolved emission spectroscopy, as a function of solvent and power of the excitation irradiation. The low-temperature X-ray structures (173 K) were permitted to locate solvent molecules (here H2O) in the lattice. They were found distributed in the middle in the voids with no evidence of specific interactions (H-bond, coulombic, and dipole-dipole) with the framework. The fluorescence decays of the ligands (ππ* excited state), τF, for the host-guest composites MOF-5@solvent and MOF-D@solvent (solvent = air, MeCN, EtCN, MeOH, EtOH, and DMF) were found bi-exponential (short τF1 (ps), and long τF2 (ns)) with one important feature: upon cooling from 298 to 77 K, MOF-5's τF1 decreases and τF2 increases, while the opposite trend is generally observed in MOF-D. The low values for τF1 (ps) in MOF-5 are associated with the augmented probability of solvent-ligand collisions leading to nonradiative deactivation, which upon cooling to 77 K increases further as the scaffolding contracts. The augmentation in τF2 is readily associated with the increased rigidity of the ligands that are not submitted to this effect (at the surface of the MOF and as pendent groups). For the low emitter MOF-D, the reversed situation is noted but not as clearly due to the uncertainties in the data. Upon increasing the excitation flux, the fluorescence intensity increases linearly with the laser power indicating the absence of singlet-singlet annihilation, inferring the absence of efficient exciton migration. This observation is explained by the small absorptivity coefficients, which leads to a small J spectral overlap between absorption and fluorescence according to the Forster and Dexter theories, and consequently, a small rate for energy migration. This conclusion drastically changes the perception of the photocatalytic mechanism of MOF-5 and other MOFs exhibiting similar absorption features (i.e., no antenna effect).

Obviously Enhanced Fluorescent Signal of Core‐Shell Nanostructures through Simultaneous Regulation of Spectral Overlap and Shell Thickness for Imaging and Photothermal Therapy of Ovarian Cancer Cells

AbstractIn this research, by simultaneously regulating the two major factors affecting the plasmonic enhanced fluorescence (PEF), spectral overlap and the distance between the fluororophores and the noble metal nanoparticles, a significantly enhanced fluorescent signal is achieved. Core‐shell nanostructures composed of aspect ratio (AR) adjustable gold nanorods (GNRs) and various thickness of SiO2 are prepared and the decorated fluorophores are realized optimized PEF. A typical stimuli‐responsive conjugated polymer, polydiacetylene (PDA), and a near‐infrared (NIR) dye Cy5.5 are selected as fluorophores and their fluorescent signal are enhanced 7.26 and 4.41 times, respectively. Based on the optimized optical properties, a multifunctional antibody modified Mab‐Cy5.5‐GNRs@SiO2 is successfully demonstrated the targeting, imaging, and photothermal therapy (PTT) effects on SKOV‐3 ovarian cancer cells.

Photocatalysis of Metallic Nanoparticles: Interband vs Intraband Induced Mechanisms.

Photocatalysis induced by localized surface plasmon resonance of metallic nanoparticles has been studied for more than a decade, but photocatalysis originating from direct interband excitations is still under-explored. The spectral overlap and the coupling of these two optical regimes also complicate the determination of hot carriers' energy states and eventually hinder the accurate assignment of their catalytic role in studied reactions. In this Featured Article, after reviewing previous studies, we suggest classifying the photoexcitation via intra- and interband transitions where the physical states of hot carriers are well-defined. Intraband transitions are featured by creating hot electrons above the Fermi level and suitable for reductive catalytic pathways, whereas interband transitions are featured by generating hot d-band holes below the Fermi level and better for oxidative catalytic pathways. Since the contribution of intra- and interband transitions are different in the spectral regions of localized surface plasmon resonance and direct interband excitations, the wavelength dependence of the photocatalytic activities is very helpful in assigning which transitions and carriers contribute to the observed catalysis.

Experimental and Theoretical Studies of Fluorescent "Turn Off" Sensor Functionalized With Carboxylic Acid and Naphthalene Group for Selective Detection of 2,4,6-Trinitrophenol.

A fluorescent sensor, 5-((2-hydroxynaphthalen-1-yl)methyleneamino)benzene-1,3-dicarboxylic acid (coded as SB), containing both π-π interacting sites (such as π-electron-rich moieties) and hydrogen bonding (H-bonding) interacting sites (such as highly acidic protons) has been developed via high yield reflux method. It was characterized by the various analytical techniques such as Fourier transform-infrared spectroscopy (FT-IR), proton nuclear magnetic resonance (1H-NMR), thermogravimetric analysis (TGA), field emission scanning electron microscope (Fe-SEM), elemental mapping, and UV - visible spectroscopy etc. The spectral response of the as-synthesized SB sensor has been investigated for various nitro explosives (NEs). It has been found that the SB sensor selectively and sensitive sense highly toxic 2,4,6-trinitrophenol (TNP) via the "turn-off" quenching response. Its limit of detection for TNP was calculated to be 30 ppb. Spectral overlap, detailed mechanistic studies for their mode of action, and density functional theory (DFT) calculations reveals that photo-induced electron transfer process (PET), fluorescence energy transfers process (FRET), and electrostatic interactions (i.e. H-bonding) are the key factors for the turn-off response of SB towards TNP. Notably, the synthesis of the sensor is cost-effective, energy efficient, and economic.

Dual-channel snapshot imaging spectrometer with wide spectrum and high resolution.

The comprehensive analysis of dynamic targets brings about the demand for capturing spatial and spectral dimensions of visual information instantaneously, which leads to the emergence of snapshot spectral imaging technologies. While current snapshot systems face major challenges in the development of wide working band range as well as high resolution, our novel dual-channel snapshot imaging spectrometer (DSIS), to the best of our knowlledge, demonstrates the capability to achieve both wide spectrum and high resolution in a compact structure. By dint of the interaction between the working band range and field of view (FOV), reasonable limits on FOV are set to avoid spectral overlap. Further, we develop a dual-channel imaging method specifically for DSIS to separate the whole spectral range into two parts, alleviating the spectral overlap on each image surface, improving the tolerance of the system for a wider working band range, and breaking through structural constraints. In addition, an optimal FOV perpendicular to the dispersion direction is determined by the trade-off between FOV and astigmatism. DSIS enables the acquisition of 53×11 spatial elements with up to 250 spectral channels in a wide spectrum from 400 to 795nm. The theoretical study and optimal design of DSIS are further evaluated through the simulation experiments of spectral imaging.

Design of a ternary magnetic composite based on a covalent organic framework and Ag nanoparticles for simultaneous photodegradation of organic pollutants under LED light irradiation: Application of BBD-RSM modeling and resolution of spectral overlap of analytes

Designing novel photocatalysts is crucial in improving pollutant removal and promoting a cleaner and healthier environment. The main objective of this study was to create a novel magnetic core-shell structure that could be used for photocatalytic applications. To achieve this goal, we used CoFe2O4 magnetic nanoparticles as the core and a covalent organic framework (COF) as the shell, which was designed to have magnetic properties and a suitable surface for further functionalization. To improve its photocatalytic properties, we added silver nanoparticles (Ag NPs) by a facile light-assisted reduction process to create a ternary composite. The presence of Ag NPs is expected to result in a broader absorption range of light and more effective degradation of pollutants through plasmonic sensitization and the transfer of bandgap energy into the visible light spectra. We characterized the prepared composite using various chemical and physical techniques, and then examined its ability to remove two stable organic pollutants, methylene blue (MB) dye and 4-nitrophenol (4-NP), simultaneously. The strong spectral overlap between these pollutants posed a challenge for conventional spectroscopic methods to accurately measure their concentration. To overcome this, a rapid and new method, namely extended ratio subtraction method (EXRSM), was utilized to separate and remove the spectral overlap. We further optimized the reaction conditions using response surface methodology (RSM) modeling techniques. Our findings indicated that the designed composite was capable of degrading organic pollutants under the visible light radiation of an LED lamp.

Selective and sensitive sensing of copper(II) by natural compound C-21 steroid caudatin

Selective and sensitive sensing of varied analytes is playing important role in assessing the concentration of different pollutants in aquatic system. In view of this, in the presented study a biocompatible C-21 steroid caudatin (1) has been isolated from C. otophyllum, characterized using multinuclear NMR spectroscopy and mass spectrometry. The obtained natural product had been used as photoluminescent sensor for selective and sensitive detection of cupric cation with limit of detection of 1.93 ppm and KSV value of 3.45 × 103 M−1. Also, interference experiments revealed that 1 can selectively detect Cu2+ ion in presence of other metal cations. Further, theoretical calculations have been done to assess the reason for selectivity of this steroid against the copper cation. The integrated experimental and theoretical studies reveals that the plausible reason for the selectively and sensitivity of caudatin to detect Cu2+ was accredited to the better interaction between Cu2+ and caudatin as well as competitive absorption light due to UV–Vis spectral overlap operates between Cu2+ and caudatin that are collectively responsible for the quenching in emission of caudatin.

Investigation on optical properties of borate Sr3Y2B4O12: Ce/Tb/Sm and its application in wLEDs

Several series of near-ultraviolet (n-UV) convertible white Ce/Tb/Sm-tridoped borate Sr3Y2B4O12 (SYBO) via Ce → Tb → Sm energy transfer (ET) have been successfully obtained by solid-state reaction under reducing atmosphere. The reason why picks Ce/Tb/Sm ions is based on the facts that these lanthanide ions are all extensively used ions in inorganic phosphors and emitting typically in blue, green and red region, respectively, that could be easily mixed and regulated to obtain warm white light within a single phase matrix. The structure, determined from XRD and analysed based on the Rietveld method, shows Y and Sr have 8-fold and 10-, 9- and 8-fold coordination, respectively, and all dopants are more inclined to enter Y sites as compared with Sr sites due to different degrees of radius ratio and charge among the dopants, Y and Sr. The ET mechanism is detailed studied via photoluminescence and decay lifetimes, where the obvious spectral overlap of the PLE for Tb/Sm and PL of Ce with systematic relatively decrease and increase of PL peaks of Ce, Tb/Sm, respectively, clearly indicate the ET occurs. Further, according to spectral studies on codoped (Ce/Tb, Ce/Sm and Tb/Sm) and tridoped phosphors, the Tb acts actually as the ET bridge to better connect Ce and Sm due to ET directly from Ce to Sm is difficult to achieve. Finally, the near-ideal white light from optimal SYBO:Ce/Tb/Sm with color coordinates of (x = 0.328, y = 0.343) and Ra = 86 was observed under n-UV excitation indicates this kind of phosphors could be potentially applied in solid-state lighting.

Determination of glyphosate and its derivative, aminomethylphosphonic acid, in human urine by gas chromatography coupled to tandem mass spectrometry and isotope pattern deconvolution

An analytical method for the simultaneous determination of glyphosate (GLY) and its main derivative, aminomethyl-phosphonic acid (AMPA), in human urine has been developed using gas chromatography coupled to tandem mass spectrometry (MS/MS) operated in multiple reaction monitoring mode (MRM). Sample preparation involved dilution of urine with water and derivatization with a mixture of trifluoroacetic acid anhydride and trifluoroethanol. Derivatization conditions such as reaction time and temperature, derivative stability, injection solvent, MS ionization mode and MS-MS transitions, among others, were studied to obtain the highest method sensitivity. The target compounds were initially quantified by the isotope dilution method using isotopically labelled analogs of GLY and AMPA as internal standards. However, due to spectral overlap between GLY and labelled GLY in the selected quantitative transition, a quantification method based on isotope pattern deconvolution (IPD) has been developed. The instrumental limits of detection were 0.05 ng mL−1 for both compounds, while the method detection limits were 0.39 and 0.25 ng mL−1, for AMPA and GLY, respectively. The mean recoveries from urine and water spiked at different concentrations were 77 and 69% for AMPA and 90 and 102% for GLY, respectively, with mean relative standard deviations of 8–10% (urine samples, n = 12) and 3.6–4% (water samples, n = 6). Once validated, the feasibility of the method was tested by determination of AMPA and GLY in human urine samples from people living close to agricultural areas. The developed method affords the determination of these compounds at trace concentrations in complex matrices such as urine, avoiding elaborate handling and cleanup steps. Isotope pattern deconvolution has proven to be a successful alternative to calibration curve for GLY overriding the method uncertainties associated to spectral overlapping.

DNA Origami Assembled Nanoantennas for Manipulating Single-Molecule Spectral Emission.

The emission spectrum of a dye is given by the energy of all of the possible radiative transitions weighted by their probability. This spectrum can be altered with optical nanoantennas that are able to manipulate the decay rate of nearby emitters by modifying the local density of photonic states. Here, we make use of DNA origami to precisely place an individual dye at different positions around a gold nanorod and show how this affects the emission spectrum of the dye. In particular, we observe a strong suppression or enhancement of the transitions to different vibrational levels of the excitonic ground state, depending on the spectral overlap with the nanorod resonance. This reshaping can be used to experimentally extract the spectral dependence of the radiative decay rate enhancement. Furthermore, for some cases, we argue that the drastic alteration of the fluorescence spectrum could arise from the violation of Kasha's rule.

Synthesis, photophysical, and photochemical properties of functional molecules based on a novel zinc(II) phthalocyanine-1,8-naphthalimide skeleton

Designing multifunctional photosensitizers with high efficiency has been significant in the molecular engineering field. In this work, we designed a novel molecular skeleton with a bi-chromophore, in which four 4-substituted-1,8-naphthalimide fluorophores were introduced as energy pumps to the zinc(II) phthalocyanine photosensitive group. Four peripherally symmetrical 4-NH-substituted-1,8-naphthalimide functionalized zinc(II) phthalocyanine molecules (NAZP1, NAZP2, NAZP3, NAZP4) were synthesized and characterized. The photophysical and photochemical properties of the molecules were investigated. The novel molecules showed dual-channel absorption and emission features of both chromophores. The fluorescence resonance energy transfer (FRET) process from 1,8-naphthalimide to zinc(II) phthalocyanine was verified by the spectral overlap and theoretical calculations. NAZP1 had higher FRET efficiency than the other three molecules. The singlet oxygen quantum yields of NAZP1, NAZP2, NAZP3, and NAZP4 in DMF were 0.84, 0.60, 0.68, and 0.73 respectively, being higher than the unsubstituted ZnPc. The introduction of four 1,8-naphthalimide energy pumps greatly improved the photophysical and photochemical properties of zinc(II) phthalocyanine, being hopeful in developing high-performance photosensitizers.

A membrane biosensor based on colour differences encoded upconversion silica nanoparticles for multiplex nucleic acids detection

Upconversion luminescent nanomaterials provide a powerful tool for multiplex nucleic acids detection simultaneously. However, the conventional encoding methods based on emission spectrum or intensity have limitations due to spectral overlap and cross-relaxation quenching among various activators. Herein, we present a facile method for the preparation of high-capacity upconversion luminescent coding nanoparticles by multiple regulating the synthesis kinetics of lanthanide ions doped CaF2 nanocrystals in mesoporous silica nanotemplets (named C@S). The secondary growth of nanocrystals with different lanthanide ions inside mesopores has a similar performance to that of core/multi-shell-structured upconversion nanoparticles prepared through complicated processes. The textural properties and chemical conformations are maintained after repeated recombination, which is beneficial for reproducible multiplex bioassays. A membrane biosensor is constructed using various probe-modified C@S and a flexible graphene oxide-coated film to detect and identify multiple molecular species in one sample. The colour differences of encoded C@S derived from CIE-L*a*b* colour coordinate system are applied to quantify the divergence of upconversion luminescence for the first time, which allows the upconversion nanoparticles with similar spectra and luminescence colours to be used in the same multiplex detection platform and avoids subjective judgement. This work opens new opportunities for upconversion luminescent materials in the field of automatic high-throughput detection.