Differential scanning calorimetry-fluorescence spectrum synchronous measurement device and measurement method

Abstract

The invention discloses a differential scanning calorimetry-fluorescence spectrum synchronous measurement device and a measurement method. The device comprises a light source unit, an incident light path coupling unit, a fluorescence spectrum unit, a differential scanning calorimetry unit, an upper computer and a signal cooperative control unit. An optical window is matched with a sample pool of the differential scanning calorimeter, so that in-situ coupling of exciting light and fluorescence signals is realized, and heat flow data and spectral data can be synchronously acquired under the same thermal history. The device establishes a direct relation between a thermal signal and a spectrum change by synchronously measuring thermal response and a fluorescence spectrum of a luminescent material. The method overcomes the problems of inconsistent sample states, mismatching of time axes, transient structure information loss and the like caused by traditional fractional measurement, can be used for in-situ structure evolution and thermal behavior correlation research of systems such as high polymer materials, phase change materials and luminescent materials, and reveals physical mechanisms of thermal response and light response of the materials.

Description

Technical Field

[0001] This invention belongs to the field of materials thermal analysis and spectroscopic characterization technology. The invention relates to a differential scanning calorimetry-fluorescence spectroscopy synchronous measurement device and measurement method. Background Technology

[0002] Differential scanning calorimetry (DSC) and fluorescence spectroscopy are indispensable core analytical tools in modern materials science research. DSC, by precisely measuring the heat flow changes of materials during programmed temperature control, can quantitatively characterize various thermodynamic behaviors of materials, such as crystallization, solidification, glass transition, and thermal decomposition, providing crucial data support for understanding the macroscopic thermal properties of materials. However, DSC is a non-specific testing method; its curves not only record complex and variable thermal effects but may also exhibit various "spurious effects" caused by material thermal history and environmental factors. Fluorescence spectroscopy, by detecting the luminescence signal emitted by materials after photoexcitation, sensitively reflects microscopic structural information such as molecular conformation, local microenvironment, orderliness, energy level structure, and energy transfer at the microscopic level, possessing the characteristics of high sensitivity and non-destructive testing. For example, recent studies have found that the luminescence properties of some materials change significantly during structural phase transitions, thus laying the foundation for high-performance fluorescence thermometry applications. However, existing technical systems generally adopt a "separate measurement, independent analysis" model for DSC and fluorescence spectroscopy. This model has the following limitations: 1. Inconsistency between sample and condition: Differences in two independent sample loadings and testing environments, such as temperature history, contact conditions, atmosphere, etc., lead to uncorrectable systematic biases between thermal and optical data; 2. Lack of dynamic process information: It is impossible to capture the structural and thermal effects of transient intermediates during rapid transitions or reactions in real time; 3. Operational redundancy and error introduction: The steps of testing in multiple stages are cumbersome and inefficient, and multiple sample transfers can easily introduce contamination or changes in physical state.

[0003] 4. Ambiguous identification of thermal effect peaks: Traditional differential scanning calorimetry relies solely on heat flow signals and cannot effectively distinguish between the true thermal effect peaks corresponding to the intrinsic thermal behavior of materials, such as crystallization, phase transformation, and melting, and the interference peaks caused by the material's thermal history, such as adsorbed water desorption, residual stress release, and impurity relaxation. This leads to deviations in the interpretation of thermal analysis results. In particular, for materials with complex components or those containing residual thermal history, analyzing only their heat flow signals can easily result in the problem of impure peaks.

[0004] However, the key technologies for achieving high-quality synchronous measurement of thermal analysis and fluorescence spectroscopy mainly focus on two points: First, the sample cell space of differential scanning calorimeter is sealed and thermally sensitive, which is physically contradictory to the open optical detection window required by traditional fluorescence optical paths. It is technically difficult to achieve efficient collection and transmission of weak fluorescence signals in a high-temperature dynamic environment. Second, thermal flow signals and fluorescence signals have fundamental differences in physical properties and dynamic response. Achieving high-precision time synchronization, signal matching and correlation analysis between the two in a rapidly changing temperature field is a key problem that has not yet been effectively solved by existing technologies. Summary of the Invention

[0005] The purpose of this invention is to provide a differential scanning calorimetry-fluorescence spectroscopy synchronous measurement device and method, which constructs an in-situ, synchronous integrated automated measurement platform that can simultaneously measure the thermal transformation process of materials and their microscopic optical structure changes, realize the in-situ coupling of excitation light and fluorescence signals, and enable the synchronous acquisition of heat flow data and spectral data under the same thermal history, thereby achieving real-time in-situ correlation analysis.

[0006] The technical solution to achieve the purpose of this invention is as follows: A differential scanning calorimetry-fluorescence spectroscopy synchronous measurement device, comprising: The light source unit provides controllable excitation light; the excitation light enters the incident light path coupling unit. The incident light path coupling unit is used to adjust the optical path of the excitation light so that it enters the sample cell surface through the optical window, collects the fluorescence signal, separates the excitation light from the fluorescence signal, and transmits the fluorescence signal to the fluorescence spectroscopy unit. The fluorescence spectroscopy unit is used for the purification, spectroscopy, and detection of fluorescence signals; The differential scanning calorimetry unit includes a differential scanning calorimeter, the differential scanning calorimeter being provided with a sealed differential scanning calorimetry sample chamber, the differential scanning calorimetry sample chamber being provided with an optical window, the optical window being used to realize in-situ coupling of the thermal field and the optical path; The control unit is used for control and data acquisition, and generates unified timing control signals to synchronously trigger timing.

[0007] In a preferred embodiment, the light source unit includes an excitation light source, a focusing lens, an aperture stop, and a collimating lens arranged sequentially. The light beam output by the excitation light source is focused into converging light by the focusing lens. The aperture stop controls the light transmission aperture. After being converted into parallel light by the collimating lens, the light enters the incident light path coupling unit.

[0008] In a preferred embodiment, the incident light path coupling unit includes a reflecting lens, a dichroic mirror, a collimating lens, a reflecting mirror, and a filter arranged sequentially. The excitation light has its propagation direction changed by the reflecting lens, and after the beam parallelism is calibrated twice by the collimating lens, it is incident perpendicularly onto the sample cell surface through the optical window. The fluorescence signal generated by the sample after excitation is exported through the optical window and converted into parallel light by the collimating lens and incident on the dichroic mirror. The wavelength selectivity of the dichroic mirror is used to reflect and isolate the excitation light, while allowing the fluorescence signal to pass through. The separated fluorescence signal is guided by the reflecting mirror, filtered by the filter to remove residual excitation light and ambient stray light, and then incident on the fluorescence spectroscopy unit.

[0009] In a preferred embodiment, the light source unit includes an excitation source, an aperture, and a focusing lens arranged sequentially. The incident light path coupling unit includes a Y-axis fiber and a fiber collimator. After the excitation light is emitted from the excitation source, it is controlled by the aperture and converged by the focusing lens before being coupled to the incident end of the first Y-axis fiber. The emitting end of the first Y-axis fiber is connected to the first fiber collimator, which is positioned above the optical window. The first fiber collimator simultaneously realizes the emission of excitation light and the collection of fluorescence signal. The fluorescence signal is transmitted through the second Y-axis fiber and the second fiber collimator to a filter to remove residual excitation light and ambient stray light before being transmitted to the fluorescence spectroscopy unit.

[0010] In a preferred embodiment, the fluorescence spectral unit comprises a slit, a first concave mirror, a grating, a second concave mirror, and a detector arranged sequentially. The fluorescence signal received by the incident light path coupling unit enters the slit, which restricts the width of the incident beam. The first concave mirror converts the diverging light into parallel light incident on the grating. The grating decomposes the composite fluorescence signal into monochromatic light through dispersion, which is then focused by the second concave mirror to form a spectral band. The detector is adapted to detect weak fluorescence signals during the synchronous acquisition process.

[0011] In a preferred embodiment, the detector includes an optical switch, a photomultiplier tube, and an electrical coupling device. The photomultiplier tube is used for high-sensitivity detection of the spectral band formed after focusing by the second concave mirror. The electrical coupling device has a wide spectral response range and can simultaneously capture fluorescence signals across the entire wavelength range, acquiring and storing complete fluorescence spectra in a time sequence. The photomultiplier tube and the electrical coupling device are switched by the optical switch.

[0012] In a preferred embodiment, the optical window is made of sapphire or fused silica material with antireflective coatings on both sides.

[0013] In a preferred embodiment, the control unit is used to control the acquisition mode of the fluorescence spectroscopy unit, control the heating and cooling of the differential scanning calorimetry unit according to a preset temperature control algorithm program, generate a unified timing control signal, synchronously trigger the reading of the heat flow signal, and acquire data from the fluorescence spectroscopy unit, so that the heat flow data and fluorescence data are aligned on the time axis. The data processing program integrates data acquisition and caching units, records heat flow data from the differential scanning calorimetry unit and fluorescence data from the fluorescence spectroscopy unit in real time, establishes the correspondence between the two types of data through a time-series correlation algorithm, and performs real-time data storage, correlation analysis, and visualization.

[0014] The present invention also discloses a measurement method using the above-mentioned differential scanning calorimetry-fluorescence spectroscopy synchronous measurement device, comprising the following steps: S1: Place the sample to be tested in the center of the sample cell of the differential scanning calorimetry unit; start the light source unit, monitor the fluorescence signal intensity in real time through the host computer, fine-tune the three-dimensional spatial position of the optical path until the fluorescence signal intensity reaches the maximum value and the fluctuation amplitude is small, and complete the optical focusing; S2: Parameters are set uniformly through the host computer, including the temperature control program of the differential scanning calorimetry unit, the acquisition parameters of the modulation incident light path coupling unit and the fluorescence spectroscopy unit; the differential scanning calorimetry unit and the fluorescence spectroscopy unit are triggered synchronously and heat flow data and fluorescence data are continuously acquired during the program temperature control process and transmitted to the host computer for storage in real time. S3: The host computer's signal processing program performs correlation analysis on the synchronously acquired thermal flow data and fluorescence data. The time-series correlation algorithm is used to establish the correspondence between the two types of data, and the data is stored, analyzed, and visualized in real time.

[0015] In the preferred technical solution, step S3 further includes: Extract fluorescence characteristic parameters, including characteristic peak intensity, peak position, and intensity ratio, and compare their variation curves with the heat flow curve. Establish the correspondence between the thermal behavior of materials and changes in optical signals, and analyze the microscopic mechanism of thermal transformation of materials; Identify thermal history interference peaks and true thermal effect peaks.

[0016] Compared with the prior art, the significant advantages of this invention are: 1. High-precision in-situ synchronous correlation of thermal-optical signals to trace transient information: This invention utilizes an integrated design of "hardware synchronous triggering + software unified analysis" to obtain a unified time-series signal through a host computer and its control program. The fully automatic synchronous drive of the differential scanning calorimeter's temperature control program and fluorescence spectral data acquisition ensures the consistency of thermal flux and fluorescence data. This design fundamentally solves the problem of thermal-optical data mismatch caused by inconsistencies in sample state and testing environment in traditional fractional measurements. It can capture the thermal effects of dynamic processes such as material phase transitions and reactions, along with their corresponding transient spectral changes, in real time and accurately within identical thermal histories, providing direct and reliable data support for in-depth analysis of the microscopic mechanisms of material thermal transformations.

[0017] 2. Dual-Signal Linkage to Remove Thermal History Interference: This invention overcomes the limitations of traditional differential scanning calorimetry (DSC) analysis, which relies solely on a single heat flux signal. It utilizes the physical correlation between real thermal effects and microstructural changes, triggering characteristic responses in fluorescence signals, to establish a linkage mechanism between heat flux peaks and fluorescence signals. For interference peaks caused by thermal history factors such as adsorbed water desorption, residual stress release, and impurity relaxation, the fluorescence signal remains stable because it is not accompanied by changes in molecular conformation or local energy level structure. However, real thermal effect peaks such as those from crystallization, phase transitions, and melting simultaneously trigger characteristic changes in fluorescence signal intensity and peak position shifts. Combined with temperature cycling verification (interference peaks decay by ≥80% or disappear after secondary temperature increases), accurate identification of both types of peaks is achieved, significantly improving the accuracy and reliability of thermal analysis results.

[0018] 3. In-situ optical probe design: This invention creates a sealed testing environment within the differential scanning calorimetry sample chamber that is compatible with optical transmission. The optical window uses sapphire or fused silica with double-sided antireflective coatings, ensuring efficient transmission of excitation light and fluorescence signals (transmittance ≥95%) while maintaining the airtightness of the sample chamber. The mechanical structure in contact with the furnace body uses a low heat capacity material to minimize disturbance to the instrument's original thermal field. This successfully solves the core contradiction in traditional coupled technologies where optical pathways and sealed thermal environments are incompatible, achieving in-situ fusion of thermal analysis and spectroscopic detection.

[0019] 4. A flexible and efficient detection scheme is provided: The incident optical path coupling unit of this invention supports two configuration modes: optical path conduction and fiber conduction. After optical path shaping, the light source forms a uniform excitation light field to avoid local overheating; fiber conduction uses a Y-type dual-branch fiber optic probe to precisely focus on the sample micro-area (focused spot diameter ≤ 1 mm). Spectral detection achieves millisecond-level switching between the PMT and CCD detectors through an optical path switch. The PMT has high gain and fast response characteristics, suitable for single-wavelength dynamic monitoring; the CCD covers a wide spectral range of 200 nm to 1100 nm, with a spectral resolution ≤ 0.1 nm, meeting the requirements for full-spectrum acquisition. It can be flexibly selected according to material characteristics and research objectives, significantly broadening its application range.

[0020] 5. Integrated Control and Data Processing Enhance Analysis Efficiency: This invention achieves unified control of all modules through a host computer and its control program, supporting integrated setting and real-time adjustment of temperature control parameters, excitation light parameters, and acquisition parameters. The built-in data processing algorithm automatically extracts fluorescence characteristic parameters, generating superimposed curves of heat flow and fluorescence characteristic parameters, enabling correlation analysis and visualization of the data. Compared to the cumbersome operation and data stitching of traditional multi-stage measurements, this invention significantly shortens the testing cycle, reduces human error, and significantly improves analysis efficiency and data reliability. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of a differential scanning calorimetry-fluorescence spectroscopy synchronous measurement device using a spatial optical coupling optical path, according to one embodiment. Figure 2 This is a schematic diagram of a differential scanning calorimetry-fluorescence spectroscopy synchronous measurement device using an optical fiber coupled optical path, as described in another embodiment. Figure 3 This is a schematic diagram showing the synchronous measurement results of differential scanning calorimetry and luminescence spectroscopy data of the 5% Eu³⁺ doped LiYO2 sample in this embodiment; Figure 4 This is a schematic diagram of the first synchronous measurement results of differential scanning calorimetry and luminescence spectroscopy data of the 10%Eu³⁺-doped LiYO2 sample in this embodiment. Figure 5 This is a schematic diagram of the second simultaneous measurement results of differential scanning calorimetry and luminescence spectroscopy data of the 10% Eu³⁺ doped LiYO₂ sample in this embodiment.

[0022] In the diagram: 1-Light source unit; 2-Incident light path coupling unit; 3-Fluorescence spectroscopy unit; 4-Differential scanning calorimetry unit; 5-Control unit; 101-Excitation light source; 102-Focusing lens; 103-Aperture stop; 104-Collimating lens; 201-Reflecting lens; 202-Dial mirror; 203-Collimating lens; 204-Reflecting mirror; 205-Filter; 2061-First Y-axis fiber; 2062-Second Y-axis fiber; 2071-First fiber collimating mirror; 2072-Second fiber collimating mirror; 301-Slit; 302-First concave mirror; 303-Grating; 304-Second concave mirror; 305-Optical path switch; 306-Photomultiplier tube (PMT); 307-CCD (Cellular Coupling Device); 401-Differential scanning calorimeter; 402-Optical window; 403-Cooling unit. Detailed Implementation

[0023] The principle of this invention is as follows: This invention constructs an in-situ, synchronous integrated automated measurement platform, which can simultaneously measure the thermal transformation process of materials and their microscopic spectral structure changes, realize the in-situ coupling of excitation light and fluorescence signals, and enable the synchronous acquisition of heat flow data and spectral data under the same thermal history, thereby realizing real-time in-situ correlation analysis.

[0024] Example 1: like Figure 1 As shown, a differential scanning calorimetry-fluorescence spectroscopy synchronous measurement device includes a light source unit 1, an incident light path coupling unit 2, a fluorescence spectroscopy unit 3, a differential scanning calorimetry unit 4, and a control unit 5.

[0025] Light source unit 1 is used to provide controllable excitation light; the excitation light enters the incident light path coupling unit; Incident light path coupling unit 2 is used to adjust the optical path of the excitation light so that it enters the sample cell surface through the optical window, collects the fluorescence signal, separates the excitation light from the fluorescence signal, and transmits the fluorescence signal to the fluorescence spectroscopy unit. Fluorescence spectroscopy unit 3 is used for purification, spectroscopy and detection of fluorescence signals; The differential scanning calorimetry unit 4 includes a differential scanning calorimeter, which is equipped with a sealed differential scanning calorimetry sample chamber. An optical window is provided in the differential scanning calorimetry sample chamber, and the optical window is used to realize in-situ coupling between the thermal field and the optical path. Control unit 5 is used for control and data acquisition, and generates a unified timing control signal to synchronously trigger the timing.

[0026] Specifically, the light source unit 1 includes an excitation light source 101, a focusing lens 102, an aperture 103, and a collimating lens 104 arranged in sequence to provide stable and controllable sample excitation light, with the excitation wavelength covering the ultraviolet-visible range, and the output power can be dynamically adjusted according to sample requirements.

[0027] The incident light path coupling unit 2 includes a reflecting lens 201, a dichroic mirror 202, a collimating lens 203, a reflecting mirror 204, and a filter 205 arranged in sequence. It is used for adjusting the optical path of the excitation light (λex) and efficiently collecting the emitted light, so as to realize the separation and transmission of the excitation light and the fluorescence signal (λem).

[0028] The fluorescence spectroscopy unit 3 includes a slit 301, a first concave mirror 302, a grating 303, a concave mirror 2304, an optical path switch 305, a photomultiplier tube (PMT) 306, and an electrical coupling device (CCD) 307 arranged in sequence, which are used to purify, spectrate, and detect fluorescence signals.

[0029] The differential scanning calorimeter unit 4 includes a differential scanning calorimeter 401, an optical window 402, and a cooling unit 403, which are used to provide a precise and controllable temperature environment for the sample (temperature control accuracy up to 0.1℃), and at the same time, the dedicated optical window 402 realizes the in-situ coupling of the thermal field and the optical path.

[0030] The control unit 5 includes a PC terminal, a temperature control program, and a signal processing program, which are used to realize unified control of various modules of the device, timing synchronization triggering, and acquisition and correlation analysis of heat flow data and fluorescence data.

[0031] Incident optical path coupling unit 2 serves as an optical signal transmission and separation unit, and can realize spatial optical coupling optical path as required. Figure 1 ) and fiber-coupled optical path ( Figure 2 Two optical path configuration methods.

[0032] like Figure 1 As shown, the spatial light coupling optical path of the incident light path coupling unit 2 includes a reflective lens 201, a dichroic mirror 202, a collimating lens 203, a reflector 204, and a filter 205 arranged in sequence to realize the path guidance of the excitation light, the separation and extraction of the sample emitted light (fluorescence signal), and the filtering of stray light, so as to ensure the crosstalk-free transmission of the excitation light and the fluorescence signal.

[0033] The spatial optical coupling optical path adopts an integrated optical path design of "unidirectional transmission of excitation light + directional separation of emission light", and the specific transmission mechanism is as follows: Figure 1 As shown, the transmission process is as follows: The excitation beam output from the light source unit 1 is focused into a converging beam by the focusing lens 102, the aperture 103 precisely controls the light transmission aperture, and the collimating lens 104 converts it into parallel light before entering the incident light path coupling unit 2; after being reflected by the reflecting lens 201 to change the propagation direction, and after the collimating lens 203 calibrates the parallelism of the beam a second time, it is perpendicularly incident on the sample cell surface through the optical window 402, forming a uniform excitation light region and a uniform excitation light field on the sample cell surface, avoiding local overheating that could cause changes in the sample state and generate thermal interference; the fluorescence signal generated after the sample is excited is diffused in the form of a spherical wave, and after being led out through the optical window 402, it is converted into parallel light by the collimating lens 203 and incident on the dichroic mirror 202. The dichroic mirror selectively transmits the excitation light and fluorescence wavelengths, realizing the isolation of excitation light reflection and the separation of fluorescence signal transmission; the separated fluorescence signal is guided by the reflecting mirror 204, and after the filter 205 filters out residual excitation light and ambient stray light, it is precisely incident on the slit 301 of the fluorescence spectral unit 3, ensuring a high signal-to-noise ratio of the detection signal.

[0034] The spatial optical coupling optical path realizes the spatial transmission and separation of optical signals through optical elements such as reflective lens 201 and dichroic mirror 202. It is suitable for uniform excitation and signal acquisition of large-area samples, ensuring the stability and consistency of the test.

[0035] like Figure 2 As shown, the fiber-coupled optical path reduces the complexity of the optical path setup and can be used in more compact instrument units. After the excitation light is emitted from the light source unit 1, it is controlled by the aperture 103, focused by the focusing lens 102, and then coupled to the incident end of the first Y-axis fiber 2061. The emitting end of the first Y-axis fiber 2061 is connected to the first fiber collimating lens 2071 and placed above the optical window 402, so as to simultaneously realize the emission of excitation light and the collection of fluorescence signal. The fluorescence signal is transmitted through the second Y-axis fiber 2062 and the second fiber collimating lens 2072 to the filter 205 to filter out residual excitation light and ambient stray light, and then transmitted to the subsequent fluorescence spectroscopy unit 3. This is suitable for precise detection of micro-area samples and testing in space-constrained scenarios.

[0036] The fluorescence spectroscopy unit 3 adopts a combined design of "spectral dispersive module + dual detectors" to adapt to the signal requirements of different detection scenarios. Its core working principle is as follows: slit 301 limits the width of the incident beam to improve spectral resolution; the first concave mirror 302 converts the diverging light into parallel light incident on the grating 303; the grating 303 decomposes the composite fluorescence signal into monochromatic light through dispersion, which is then focused by the second concave mirror 304 to form a spectral band. The detector of the fluorescence spectroscopy unit 3 is adapted for detecting weak fluorescence signals during synchronous acquisition. Its core configuration is as follows: photomultiplier tube (PMT). 306 features high gain and fast response characteristics, enabling highly sensitive detection of monochromatic fluorescence signals after spectral processing by slit 301, first concave mirror 302, grating 303, and second concave mirror 304. It is suitable for the dynamic monitoring of light signals at fixed wavelengths. The charge-coupled device (CCD) 307 has a wide spectral response range (200nm~1100nm), which can simultaneously capture fluorescence signals across the entire wavelength range, collect and save complete fluorescence spectra in a time series, and has a spectral resolution ≤0.1nm, meeting the analytical needs of emission spectra over a wide wavelength range.

[0037] The two types of detectors achieve millisecond-level rapid switching via optical path switch 305, allowing for flexible selection based on sample fluorescence intensity and testing objectives. When high-sensitivity tracking of a specific wavelength signal is required, the detector switches to photomultiplier tube (PMT) 306, with an adjustable gain range ≥10³~10⁻⁶. 6 It is suitable for rapid dynamic process monitoring; when complete spectral information is required, it can be switched to the electrocoupled device (CCD) 307, whose spectral response range covers 200nm~1100nm, spectral resolution ≤0.1nm, and can store full-band spectral data in time series.

[0038] The specific configuration of the differential scanning calorimeter unit 4 is as follows: The differential scanning calorimeter 401 can realize programmable temperature control, execute the heating program preset by the host computer, and provide a closed and stable measurement environment; the optical window 402 is made of sapphire or fused silica material with double-sided antireflection coating, which provides a low-loss transmission channel for excitation light and fluorescence signals, and can maintain the airtightness of the sample chamber; the cooling unit 403 adopts a fluid circulation cooling method, which can quickly and controllably cool the sample chamber after the heating program is completed or according to the program setting, and supports the complete temperature cycle study including the cooling process, such as dynamic monitoring of phenomena such as thermal hysteresis effect and crystallization kinetics.

[0039] Furthermore, the differential scanning calorimeter of the differential scanning calorimeter unit 4 supports a heating rate of 0.1~100℃ / min and can be set with multiple isothermal stages; the optical window 402 is attached to the calorimeter, has a high temperature resistance range of -50℃~500℃, and a light transmittance of ≥95%, which ensures low-loss transmission of optical signals while maintaining the stability of the sealed environment of the sample chamber.

[0040] The control unit 5 undertakes the core functions of signal coordination control and data processing, including: selecting the acquisition mode of the fluorescence spectroscopy unit 3 and adjusting the temperature of the differential scanning calorimeter 4; controlling the programmed temperature rise and fall of the differential scanning calorimeter 401 according to the preset temperature control algorithm program, while generating a unified timing control signal, synchronously triggering the heat flow signal reading, and acquiring data from the fluorescence spectroscopy unit 3 to ensure that the heat flow data and fluorescence data are accurately aligned on the time axis; the data processing program can integrate the data acquisition and caching unit to record the heat flow data from the differential scanning calorimeter 401 and the fluorescence data from the fluorescence spectroscopy unit 3 in real time, establish the correspondence between the two types of data through the timing correlation algorithm, and support real-time data storage, correlation analysis, and visualization.

[0041] This measuring device can simultaneously measure the thermal transition process of materials and their microscopic optical structure changes, enabling real-time in-situ correlation analysis. It is primarily used to reveal the thermal stability, phase transition mechanism, energy transfer process, and evolution of aggregated structures of fluorescent materials such as OLED materials, perovskites, and inorganic phase-change luminescent materials, providing crucial data for the design and optimization of high-performance functional materials.

[0042] In another embodiment, a measurement method using the above-described differential scanning calorimetry-fluorescence spectroscopy synchronous measurement device includes the following steps: S1: Sample loading and optical path alignment: Place the sample to be tested (powder, film or block sample is acceptable) evenly in the center of the sample cell of the differential scanning calorimeter 401, ensuring that the sample is evenly distributed and does not exceed the effective area of ​​the sample cell; start the excitation light source 101, monitor the fluorescence signal intensity in real time through the host computer, and fine-tune the three-dimensional spatial position of the optical path (align the X and Y axes with the sample center, optimize the distance on the Z axis) until the fluorescence signal intensity reaches the maximum value and the fluctuation amplitude is small, and complete the optical focusing; S2: Synchronous measurement parameter setting and start-up: Parameters are set uniformly through the host computer, including the temperature control program of the differential scanning calorimeter 4 (initial temperature, termination temperature, heating and cooling rate, isothermal stage), and the acquisition parameters of the modulation incident light path coupling unit 2 and the fluorescence spectroscopy unit 3 (acquisition mode, integration time, acquisition frequency); the differential scanning calorimeter 401 and the fluorescence spectroscopy unit 3 are triggered synchronously, and heat flow data and fluorescence data are continuously acquired during the program temperature control process and transmitted to the host computer for storage in real time; S3: Data Correlation Analysis: The host computer's signal processing program performs correlation analysis on synchronously acquired thermal flow data and fluorescence data. The time-series correlation algorithm establishes the correspondence between the two types of data, enabling real-time data storage, correlation analysis, and visualization.

[0043] In a preferred embodiment, step S3 further includes: Extract fluorescence characteristic parameters, including characteristic peak intensity, peak position, and intensity ratio, and compare their variation curves with the heat flow curve. Establish the correspondence between the thermal behavior of materials and changes in optical signals, and analyze the microscopic mechanism of thermal transformation of materials; Identify thermal history interference peaks and true thermal effect peaks.

[0044] The measurement method is applicable to the correlation analysis of thermal behavior and microstructure of polymer materials, phase change materials, luminescent materials, polymer blends, drug crystal forms, optoelectronic functional materials, and composite materials. Specific characterizable thermal processes include glass transition, crystallization / melting, phase transition, curing and crosslinking, phase separation, and thermal decomposition. By synchronously acquiring changes in fluorescence signals, the method reveals the corresponding molecular conformational evolution, changes in the orderliness of local energy level structures, energy transfer patterns, and changes in the local microenvironment during the above thermal processes, providing comprehensive data support for material performance optimization, mechanism research, and product development.

[0045] Specifically, the following will take LiYO2 material as an example for detailed explanation.

[0046] LiYO2 is a typical material exhibiting a structural phase transition. Its phase transition temperature changes from a low-temperature monoclinic β phase to a high-temperature tetragonal α phase, depending on the type and concentration of dopant ions and the preparation process. With changes in the crystal structure, variations in crystal symmetry and lattice field significantly affect the luminescence properties of the doped rare-earth ions. This characteristic makes it an important fluorescent matrix for highly sensitive thermometric materials. In the thermal analysis characterization of LiYO2, differential scanning calorimetry (DSC) curves show endothermic / exothermic peaks caused by the phase transition, while temperature-dependent fluorescence provides experimental results showing significant changes in the emission spectrum with thermally induced phase transitions, offering experimental evidence for the changes in the emission spectrum caused by structural phase transitions. However, the thermal analysis results of LiYO2 may also produce some interfering peaks due to the material's thermal history and environmental factors. These interfering signals often correspond to irreversible processes such as impurity relaxation and water molecule adsorption / desorption in the material. Although the thermal signals of irreversible phase transitions can be effectively suppressed through multiple heating and cooling cycles, these interfering signals can still affect the thermal signals related to structural phase transitions, thus affecting the efficient and accurate analysis of the material. By using a differential scanning calorimetry-fluorescence spectroscopy synchronous measurement device, the evolution relationship between thermal and spectral signals can be better synchronized, and interfering thermal signals unrelated to changes in the emission spectrum can be effectively eliminated, thus facilitating the accurate analysis of material properties.

[0047] See Figure 1 This embodiment, based on the aforementioned differential scanning calorimetry-fluorescence spectroscopy synchronous measurement device, takes LiYO2:Eu³⁺ ​​fluorescent powder materials with two doping concentrations of 5% and 10% as examples to illustrate the specific implementation process of the present invention in detail. The steps are as follows: (a) Sample loading and optical path alignment See Figure 1 Weigh approximately 10 mg of LiYO2:Eu³⁺ ​​powder sample (one sample each with 5% and 10% doping concentration) and evenly spread it in the center of the open aluminum sample cell of the differential scanning calorimeter 401, ensuring uniform sample distribution and that it does not exceed the effective area of ​​the sample cell. Turn on the light source 101; in this embodiment, a 254 nm ultraviolet light source is selected as the excitation source, as this wavelength can efficiently excite Eu³⁺ ions to produce characteristic fluorescence. Calibrate the incident optical path coupling unit 2 and check the optical window 402 to ensure it is free of stains and scratches, and that the sample chamber is well sealed. Observe the changes in fluorescence signal intensity through the real-time signal monitoring function of the host computer software, and fine-tune the collimating lens 402 until the fluorescence signal intensity reaches its maximum value with minimal fluctuation, thus completing optical focusing and unit signal-to-noise ratio optimization.

[0048] (ii) Synchronous measurement See Figure 1 The following experimental parameters were set using the unified operation interface of the host computer: Differential scanning calorimeter 401 parameters: The temperature control program is set to increase the temperature from 40°C to 120°C at a rate of 10°C / min, and hold the temperature for 1 minute after reaching the highest temperature; Fluorescence spectroscopy unit 3: Adjust the optical path switch 305 to select the CCD307 for full spectrum acquisition mode, set the spectral acquisition range to 550nm~650nm, the integration time to 100ms, and the acquisition cycle to 6s / time, to ensure that fluorescence signal changes can be densely captured during the heating process. Cooling unit 403 parameters: Set to standby mode, start after the test is completed, and cool the sample chamber temperature to room temperature at a rate of 15°C / min.

[0049] After all parameters are configured, the differential scanning calorimeter 401's heating program and the CCD 307's data acquisition process are triggered synchronously. Throughout the entire heating process, data is uploaded in real time in a fully automatic manner. The host computer dynamically displays the data change trend in chart form and stores it by timestamp to ensure data integrity and traceability.

[0050] (III) Data Correlation Analysis After the experiment, the heating units of the excitation source 101 and the differential scanning calorimeter 401 were turned off, and the cooling unit 403 was started until the sample chamber temperature was reduced to room temperature. The synchronously acquired heat flow data and fluorescence spectral data were correlated using host computer data analysis software. The software can correlate the heat flow curve with the characteristic fluorescence peak of Eu³⁺ (in this embodiment, the characteristic peak at 590 nm, corresponding to Eu³⁺). 5 D0→ 7 The intensity variation curves of the F1 transition are shown in the same coordinate system. The analytical results for 5% doped LiYO2:Eu³⁺ ​​are as follows... Figure 3 The DSC heat flow curve shows a distinct endothermic peak at approximately 80°C, indicating a phase transition process at this temperature. Correspondingly, the characteristic peak in the fluorescence spectrum also shows deflection, representing the change in the lattice field environment experienced by the luminescent element Eu³⁺ due to the phase transition. This demonstrates that differential scanning spectroscopy can clearly capture both the macroscopic thermal response and the microstructural evolution of materials in a single testing environment.

[0051] Thermal history interference differentiation verification test was performed on LiYO2:Eu³⁺ ​​samples with a 10% doping concentration: The samples were exposed to an environment with 60% humidity for 24 hours to allow them to adsorb trace amounts of moisture, thus introducing thermal history interference sources; the test parameters were set as follows: the initial heating program was 40℃→125℃ (heating rate 20℃ / min), and after reaching the highest temperature, it was held for 1 min; after the holding period, it was cooled to 40℃ at a rate of 15℃ / min by the cooling unit 403, and then the initial heating program was repeated for a second heating under the same parameters; the fluorescence signal acquisition adopted the full spectrum mode, with a spectral acquisition range of 550nm~650nm, an integration time of 100ms, and an acquisition cycle of 6s / time to ensure accurate capture of the fluorescence signal response corresponding to temperature changes.

[0052] Test results show: the heat flow curve of the initial temperature rise ( Figure 4 Two endothermic peaks appeared near 80℃ and 115℃, respectively; the corresponding fluorescence spectra showed only a 590nm shift in the Eu³⁺ characteristic fluorescence peak at 115℃, indicating that this peak was the true thermal effect peak caused by the intrinsic phase transition of the sample; while the fluorescence signal corresponding to the heat flow peak at 80℃ showed no significant change, and was determined to be an interference peak caused by thermal history such as water desorption. The heat flow curve for the second heating (…) Figure 5 In the test, the interference peak at 80℃ completely disappeared, and the true thermal effect peak at 115℃ reappeared stably. Moreover, the change pattern of the fluorescence signal was consistent with that of the first heating, which further verified the correspondence between the endothermic peak at 115℃ and the phase change of the sample. This fully demonstrates that the measurement method can effectively remove thermal history interference and accurately identify the true thermal effect peak of the material.

[0053] (iv) Results Explanation The experimental results fully verify the core technological advantages and application reliability of the device of the present invention: First, this device achieves in-situ, synchronous, and precise correlation between the macroscopic thermal behavior of materials and their microscopic fluorescence signals. The DSC endothermic peak of the LiYO2:Eu³⁺ ​​sample at its characteristic temperature (approximately 80℃ for the 5% doped sample and approximately 115℃ for the 10% doped sample) corresponds to the Eu³⁺ characteristic fluorescence peak (at 590nm, corresponding to...). 5 D0→ 7 The simultaneous occurrence of abrupt changes in fluorescence intensity or peak shifts during the F1 transition directly confirms that the changes in fluorescence signal essentially reflect the alteration of the lattice field environment of Eu³⁺ ions during the phase transition. The strict synchronization of the signals demonstrates that this device can capture microstructural evolution information during thermally induced phase transitions in real time, providing direct and reliable data support for in-depth analysis of the thermo-optical correlation mechanism of materials.

[0054] Secondly, this device successfully separated thermal history interference peaks from true thermal effect peaks through dual correlation verification of heat flow and fluorescence signals. For samples with 10% doping and thermal history interference, the additional endothermic peak appearing in the first heating curve, such as at 80℃, did not trigger characteristic changes in the fluorescence signal and was identified as an interference peak caused by thermal history. However, in the second heating curve, this type of interference peak completely disappeared, and only the thermal effect peak corresponding to the true phase transition stably reappeared. This result effectively solves the technical problem that traditional differential scanning calorimetry heat flow signals cannot distinguish between the two types of peaks, providing a solution for the accurate analysis of the thermal behavior of complex components and materials containing residual thermal history.

[0055] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A differential scanning calorimetry-fluorescence spectroscopy synchronous measurement device, characterized in that, include: A light source unit is used to provide controllable excitation light; The excitation light enters the incident light path coupling unit; The incident light path coupling unit is used to adjust the optical path of the excitation light so that it enters the sample cell surface through the optical window, collects the fluorescence signal, separates the excitation light from the fluorescence signal, and transmits the fluorescence signal to the fluorescence spectroscopy unit. The fluorescence spectroscopy unit is used for the purification, spectroscopy, and detection of fluorescence signals; The differential scanning calorimetry unit includes a differential scanning calorimeter, the differential scanning calorimeter being provided with a sealed differential scanning calorimetry sample chamber, the differential scanning calorimetry sample chamber being provided with an optical window, the optical window being used to realize in-situ coupling of the thermal field and the optical path; The control unit is used for control and data acquisition, and generates unified timing control signals to synchronously trigger timing.

2. The differential scanning calorimetry-fluorescence spectroscopy synchronous measurement device according to claim 1, characterized in that, The light source unit includes an excitation light source, a focusing lens, an aperture, and a collimating lens arranged in sequence. The light beam output by the excitation light source is focused into converging light by the focusing lens. The aperture controls the light transmission aperture. After being converted into parallel light by the collimating lens, the light enters the incident light path coupling unit.

3. The differential scanning calorimetry-fluorescence spectroscopy synchronous measurement device according to claim 1, characterized in that, The incident light path coupling unit includes a reflecting lens, a dichroic mirror, a collimating lens, a reflecting mirror, and a filter arranged in sequence. The excitation light has its propagation direction changed by the reflecting lens, and after the beam parallelism is calibrated twice by the collimating lens, it is incident perpendicularly on the sample cell surface through the optical window. The fluorescence signal generated by the sample after excitation is exported through the optical window and converted into parallel light by the collimating lens and incident on the dichroic mirror. The wavelength selectivity of the dichroic mirror is used to reflect and isolate the excitation light, while allowing the fluorescence signal to pass through. The separated fluorescence signal is guided by the reflecting mirror and filtered by the filter to remove residual excitation light and ambient stray light before being incident on the fluorescence spectroscopy unit.

4. The differential scanning calorimetry-fluorescence spectroscopy synchronous measurement device according to claim 1, characterized in that, The light source unit includes an excitation source, an aperture, and a focusing lens arranged sequentially. The incident light path coupling unit includes a Y-axis fiber and a fiber collimator. After the excitation light is emitted from the excitation source, it is controlled by the aperture and focused by the focusing lens before being coupled to the incident end of the first Y-axis fiber. The emitting end of the first Y-axis fiber is connected to the first fiber collimator, which is positioned above the optical window. The first fiber collimator simultaneously realizes the emission of excitation light and the collection of fluorescence signal. The fluorescence signal is transmitted through the second Y-axis fiber and the second fiber collimator to a filter to filter out residual excitation light and ambient stray light before being transmitted to the fluorescence spectroscopy unit.

5. The differential scanning calorimetry-fluorescence spectroscopy synchronous measurement device according to claim 1, characterized in that, The fluorescence spectral unit includes a slit, a first concave mirror, a grating, a second concave mirror, and a detector arranged sequentially. The fluorescence signal received by the incident light path coupling unit enters the slit, which restricts the width of the incident beam. The first concave mirror converts the diverging light into parallel light incident on the grating. The grating decomposes the composite fluorescence signal into monochromatic light through dispersion, and then the light is focused by the second concave mirror to form a spectral band. The detector is adapted to detect weak fluorescence signals during the synchronous acquisition process.

6. The differential scanning calorimetry-fluorescence spectroscopy synchronous measurement device according to claim 5, characterized in that, The detector includes an optical switch, a photomultiplier tube, and an electrical coupling device. The photomultiplier tube is used to perform high-sensitivity detection of the spectral band formed after focusing by the second concave mirror. The electrical coupling device has a wide spectral response range and can simultaneously capture fluorescence signals across the entire wavelength range, and collect and save complete fluorescence spectra in a time sequence. The photomultiplier tube and the electrical coupling device are switched by the optical switch.

7. The differential scanning calorimetry-fluorescence spectroscopy synchronous measurement device according to claim 1, characterized in that, The optical window is made of sapphire or fused silica material with antireflective coatings on both sides.

8. The differential scanning calorimetry-fluorescence spectroscopy synchronous measurement device according to claim 1, characterized in that, The control unit is used to control the acquisition mode of the fluorescence spectroscopy unit, control the temperature rise and fall of the differential scanning calorimetry unit according to the preset temperature control algorithm program, generate a unified timing control signal, synchronously trigger the heat flow signal reading, and perform data acquisition of the fluorescence spectroscopy unit, so that the heat flow data and fluorescence data are aligned on the time axis. The data processing program integrates data acquisition and caching units, records heat flow data from the differential scanning calorimetry unit and fluorescence data from the fluorescence spectroscopy unit in real time, establishes the correspondence between the two types of data through a time-series correlation algorithm, and performs real-time data storage, correlation analysis, and visualization.

9. A measurement method using the differential scanning calorimetry-fluorescence spectroscopy synchronous measurement device according to any one of claims 1-8, characterized in that, Includes the following steps: S1: Place the sample to be tested in the center of the sample cell of the differential scanning calorimetry unit; start the light source unit, monitor the fluorescence signal intensity in real time through the host computer, fine-tune the three-dimensional spatial position of the optical path until the fluorescence signal intensity reaches the maximum value and the fluctuation amplitude is small, and complete the optical focusing; S2: Parameters are set uniformly through the host computer, including the temperature control program of the differential scanning calorimetry unit, the acquisition parameters of the modulation incident light path coupling unit and the fluorescence spectroscopy unit; the differential scanning calorimetry unit and the fluorescence spectroscopy unit are triggered synchronously and heat flow data and fluorescence data are continuously acquired during the program temperature control process and transmitted to the host computer for storage in real time. S3: The host computer's signal processing program performs correlation analysis on the synchronously acquired thermal flow data and fluorescence data. The time-series correlation algorithm is used to establish the correspondence between the two types of data, and the data is stored, analyzed, and visualized in real time.

10. The differential scanning calorimetry-fluorescence spectroscopy synchronous measurement method according to claim 9, characterized in that, Step S3 also includes: Extract fluorescence characteristic parameters, including characteristic peak intensity, peak position, and intensity ratio, and compare their variation curves with the heat flow curve. Establish the correspondence between the thermal behavior of materials and changes in optical signals, and analyze the microscopic mechanism of thermal transformation of materials; Identify thermal history interference peaks and true thermal effect peaks.

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