Non-contact testing device and method for representing photophysical properties of color conversion material in working state

Abstract

The invention discloses a non-contact testing device and method for representing the photophysical property of a color conversion material in a working state. The non-contact testing device comprises a continuous light source, a pulse light source, a reflecting mirror, a dichroscope, a beam splitting mirror, a photomultiplier, time correlation single photon counting equipment and a fiber optic spectrometer, continuous steady-state light emitted by the continuous light source is emitted to the dichroscope through the reflector, and light reflected by the dichroscope is emitted to the color conversion material; pulsed light emitted by the pulsed light source as a perturbation light source is transmitted to the color conversion material through the dichroscope; the photoluminescence excited by the color conversion material is divided into two parts by the beam splitter, a small part of the photoluminescence emitted by the beam splitter is emitted to the photomultiplier, and an optical signal detected by the photomultiplier is sent to the time-dependent single-photon counting equipment for single-photon event measurement; most of the photoluminescence emitted by the beam splitter enters the fiber optic spectrometer to obtain a steady-state photoluminescence spectrum. The device and the method can be widely applied to the photophysical property test of the color conversion material.

Description

Technical Field

[0001] The invention relates to a non-contact testing device and method for characterizing the photophysical properties of a color conversion material in a working state, and relates to the field of color conversion materials. Background Art

[0002] The research on color conversion materials mainly focuses on improving their quantum efficiency, stability and environmental friendliness for application in display technology and photovoltaic devices. In-depth research on the photophysical properties of color conversion materials is crucial to optimize their performance and improve product quality.

[0003] However, there are some urgent problems to be solved in the current research: (1) Limitations of existing testing methods: Traditional time-resolved photoluminescence spectroscopy (TRPL) technology mainly relies on high-power pulsed light sources (such as picosecond lasers and femtosecond lasers), but the transient power of these light sources is too high, resulting in the generated carrier density being much higher than the level under actual working conditions. This testing method cannot truly reflect the working state of the color conversion material under steady-state lighting conditions, and may therefore lead to deviations in the understanding of its luminescence characteristics. (2) Lag of post-packaging testing: Currently, most tests on the photophysical properties of color conversion materials are performed after packaging, which not only increases manufacturing costs but also lags behind in quality control. If accurate non-contact testing can be performed before packaging, it will help to discover and solve potential problems in advance, significantly improving production efficiency and product quality. Summary of the invention

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, in view of the above problems, the purpose of the present invention is to provide a non-contact testing device and method for characterizing the photophysical properties of the working state of a color conversion material, which can effectively avoid damage to the material or device caused by contact.

[0005] In order to achieve the purpose of the invention, the technical solution provided by the present invention is: In a first aspect, the present invention provides a non-contact testing device for characterizing the photophysical properties of a color conversion material in a working state, the testing device comprising a continuous light source, a pulse light source, a reflector, a dichroic mirror, a beam splitter, a photomultiplier tube, a time-correlated single photon counting device, and a fiber optic spectrometer; The continuous steady-state light emitted by the continuous light source is emitted to the dichroic mirror via the reflector, and the light reflected by the dichroic mirror is emitted to the color conversion material; the pulse light emitted by the pulse light source as a perturbation light source is transmitted to the color conversion material via the dichroic mirror; the photoluminescence excited by the color conversion material is divided into two parts by the beam splitter, a small part of the photoluminescence emitted by the beam splitter is emitted to the photomultiplier tube, and the light signal detected by the photomultiplier tube is sent to the time-correlated single-photon counting device for single-photon event measurement; most of the photoluminescence emitted by the beam splitter enters the fiber spectrometer to obtain a steady-state photoluminescence spectrum.

[0006] In a preferred embodiment, the peak signal intensity of the perturbation light source is controlled within 10% of the signal intensity of the continuous steady-state light, ensuring that the former does not significantly affect the population state of photogenerated carriers.

[0007] In a preferred embodiment, it also includes a first neutral density filter, a second neutral density filter and a third neutral density filter, wherein the first neutral density filter is arranged between the reflector and the dichroic mirror, the second neutral density filter is arranged between the pulse light source and the dichroic mirror, and the third neutral density filter is arranged between the beam splitter and the photomultiplier tube.

[0008] In a preferred embodiment, a long-wave pass filter is further included, and the long-wave pass filter is arranged between the color conversion material and the beam splitter.

[0009] In a preferred embodiment, the parameter requirements of the continuous light source are: ① wavelength selection range: 375-600nm, ② power range adjustable: 10 -1 -10 3 mW / cm 2 .

[0010] In a preferred embodiment, the pulse light source adopts a pulse light diode, and the parameter requirements are: ① wavelength range: 375-600 nm; ② pulse width: sub-nanosecond to sub-picosecond.

[0011] In a preferred embodiment, a sample device rack is further provided, and the sample device rack is used to place the color conversion material.

[0012] In a second aspect, the present invention further provides a non-contact testing method for characterizing the photophysical properties of a color conversion material in a working state, comprising: Starting the continuous light source and the pulse light source to simultaneously excite the color conversion material to generate a photoluminescent signal; Acquiring a portion of the photoluminescence signal through the optical fiber spectrometer to obtain a steady-state photoluminescence spectrum, and evaluating the photoluminescence characteristics of the color conversion material based on the steady-state luminescence spectrum; Part of the photoluminescence signal is collected by the photomultiplier tube and transmitted to the time-correlated single photon counting device to obtain the photoluminescence kinetic curves under different steady-state light intensities, and based on the photoluminescence kinetic curves under different steady-state light intensities, an exponential function is used to perform numerical fitting to obtain the lifespan of each component and then perform weighted averaging to obtain the photoluminescence lifetime of the color conversion material under different steady-state light intensities.

[0013] In a preferred embodiment, the photoluminescence characteristics of the color conversion material include the luminescence intensity, central wavelength and spectrum width of the color conversion material.

[0014] The present invention adopts the above technical solution, and has the following characteristics: 1. Real dynamics research under working conditions: By adding pulsed light as perturbation light under continuous light irradiation, the present invention can study the dynamic process of the material under lower carrier density and truly reflect its performance under actual working conditions.

[0015] 2. Fully optical non-contact evaluation: This invention is completely based on optical technology and adopts non-contact operation, which not only improves the accuracy and speed of the test, but also avoids the damage to materials or devices caused by contact.

[0016] 3. Performance evaluation before packaging and application in production lines: Evaluation of optical performance and carrier dynamics before device packaging helps to timely discover and correct potential problems, thereby significantly reducing production costs and improving quality control efficiency. At the same time, due to the non-contact characteristics and high efficiency of the present invention, it is expected to be applied to production lines in the future to achieve real-time monitoring and dynamic adjustment, effectively improving production efficiency and product quality.

[0017] In summary, the present invention can be widely used in the photophysical property testing of color conversion materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present invention. Throughout the accompanying drawings, the same reference numerals are used to represent the same components. In the accompanying drawings: Figure 1 is a schematic diagram of a testing device according to an embodiment of the present invention; Figure 2 It is a graph showing the experimental data results of an embodiment of the present invention; Figure 3This is a time-resolved photoluminescence spectrum diagram of an embodiment of the present invention. DETAILED DESCRIPTION

[0019] It should be understood that the terms used in the text are only for the purpose of describing specific example embodiments, and are not intended to be limiting. Unless the context clearly indicates otherwise, the singular forms "one", "an" and "said" as used in the text may also be meant to include plural forms. The terms "include", "comprise", "contain", and "have" are inclusive, and therefore specify the existence of stated features, steps, operations, elements and / or parts, but do not exclude the existence or addition of one or more other features, steps, operations, elements, parts, and / or combinations thereof. The method steps, processes, and operations described herein are not interpreted as necessarily requiring them to be performed in the specific order described or illustrated, unless the execution order is clearly indicated. It should also be understood that additional or alternative steps may be used.

[0020] Although the terms first, second, third, etc. can be used in the text to describe multiple elements, components, regions, layers and / or sections, these elements, components, regions, layers and / or sections should not be limited by these terms. These terms can only be used to distinguish an element, component, region, layer or section from another region, layer or section. Unless the context clearly indicates, terms such as "first", "second" and other numerical terms do not imply order or sequence when used in the text. Therefore, the first element, component, region, layer or section discussed below can be referred to as the second element, component, region, layer or section without departing from the teaching of the example embodiments.

[0021] For ease of description, spatially relative terms may be used herein to describe the relationship of one element or feature relative to another element or feature as shown in the figures, such as "inside", "outside", "inner side", "outside", "below", "above", etc. Such spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation depicted in the figures.

[0022] Since the existing test methods cannot truly reflect the working state of the color conversion material under steady-state illumination conditions, it may lead to a deviation in the understanding of its luminescence characteristics. The non-contact test device and method for characterizing the photophysical properties of the working state of the color conversion material provided by the present invention include a continuous light source, a pulse light source, a reflector, a dichroic mirror, a beam splitter, a photomultiplier tube, a time-correlated single photon counting device and an optical fiber spectrometer; the continuous steady-state light emitted by the continuous light source is emitted to the dichroic mirror through the reflector, and the light reflected by the dichroic mirror is emitted to the color conversion material; the pulse light emitted by the pulse light source as a perturbation light source is transmitted to the color conversion material through the dichroic mirror; the photoluminescence excited by the color conversion material is divided into two parts by the beam splitter, and a small part of the photoluminescence emitted by the beam splitter is emitted to the photomultiplier tube, and the light signal detected by the photomultiplier tube is sent to the time-correlated single photon counting device for single photon event measurement; most of the photoluminescence emitted by the beam splitter enters the optical fiber spectrometer to obtain a steady-state photoluminescence spectrum.

[0023] The exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided in order to enable a more thorough understanding of the present invention and to fully convey the scope of the present invention to those skilled in the art.

[0024] The present invention provides an all-optical non-contact testing method, which can accurately and quickly evaluate the photophysical properties of a color conversion material in a working state.

[0025] Embodiment 1: Figure 1 As shown, the non-contact testing device for characterizing the photophysical properties of the working state of the color conversion material provided in this embodiment includes a continuous light source 1, a pulse light source 2, a reflector 3, a neutral density filter 4, a dichroic mirror 5, a neutral density filter 6, a long-pass filter 7, a beam splitter 8, a neutral density filter 9, a photomultiplier tube 10, a time-correlated single photon counting device 11 and a fiber optic spectrometer 12.

[0026] The continuous steady-state light emitted by the continuous light source 1 is sequentially transmitted through the reflector 3 and the neutral density filter 4 (Neutral Density Filters, ND filter) to the dichroic mirror 5, and the light reflected by the dichroic mirror 5 is transmitted to the sample to be tested 13, so as to achieve a specific concentration of photogenerated carrier population and generate a steady-state photoluminescence background signal; the pulse light emitted by the pulse light source 2 is used as a perturbation light source to generate a time-resolved photoluminescence perturbation dynamics signal, which is sequentially transmitted through the neutral density filter 6 and the dichroic mirror 5 to the sample to be tested 13; at the same time, the peak intensity of the perturbation light signal is controlled within 10% of the steady-state light signal intensity to ensure that the former does not have a significant impact on the photogenerated carrier population state.

[0027] The photoluminescence excited by the sample 13 to be tested is divided into two parts by the long-wave filter 7 and the beam splitter 8. The small part of the photoluminescence emitted by the beam splitter 8 is attenuated to a suitable light intensity (the number of photons within 5% of the pulse light excitation frequency) by the neutral density filter 9, and then enters the photomultiplier tube 10 and the system for testing dynamics, i.e., the time-correlated single photon counting device 11, for recording and analyzing single photon events. Most of the photoluminescence emitted by the beam splitter 8 enters the fiber spectrometer 12, which is used to test and obtain a steady-state photoluminescence spectrum to evaluate the photoluminescence characteristics of the sample 13 to be tested. Among them, the photoluminescence characteristics of the sample 13 to be tested include luminescence intensity, wavelength, and spectral width, etc., which help to understand the light absorption and luminescence ability of the color conversion material. Luminescence intensity: measure the luminescence intensity of the material under a fixed excitation light intensity. If the luminescence intensity is significantly improved under different light intensities, it means that the material performs well under excitation; Spectral characteristics: obtain the luminescence spectrum, analyze its wavelength, half-peak width and peak intensity, and a narrower spectral width usually means better material quality and fewer defects.

[0028] In a preferred embodiment of the present invention, the parameter requirements of the continuous light source 1 are: ① wavelength selection range: 375-600nm (can excite the sample / device to emit light), ② adjustable power range: 10 -1 -10 3 mW / cm 2 .

[0029] In a preferred embodiment of the present invention, the pulse light source 2 can be a pulse light diode, and its parameter requirements are: ① wavelength: wavelength range: 375-600 nm (can excite the sample / device to emit light); ② pulse width: sub-nanosecond (10 -10 seconds) to sub-picoseconds (10 -13 Second).

[0030] In a preferred embodiment of the present invention, a neutral density filter is used to attenuate light intensity. After light in the visible light region to the near-infrared light region passes through the neutral density filter, different wavelengths are attenuated at the same rate, so that the optical element maintains approximately equal light energy transmittance in a wide band.

[0031] In a preferred embodiment of the present invention, a sample device rack is further provided, and the sample device rack is used to place the sample 13 to be tested. The sample 13 to be tested is a color conversion material and is designed to be non-contact, which is convenient and quick to replace. During the test, the sample 13 to be tested does not contact electrodes, leads and other accessories, thereby avoiding sample damage and test errors caused by human factors during the assembly of the equipment.

[0032] In a preferred embodiment of the present invention, the time-correlated single photon counting device 11 has a counting function for recording and analyzing single photon events. By generating a timestamp for each photon event, it is able to accurately count the time of arrival of photons and store these data for subsequent analysis.

[0033] Embodiment 2: The non-contact testing method for characterizing the photophysical properties of the working state of the color conversion material provided in this embodiment includes: S1. Sample preparation: placing the sample 13 to be tested on the sample device rack.

[0034] S2, start the continuous light source 1 and the pulse light source 2 to simultaneously excite the sample 13 to be tested, and adjust the light intensity of the continuous light source 1 as needed.

[0035] S3. Data collection, the specific process is as follows: S31, the photoluminescence is focused and collected to the optical fiber spectrometer 12 to obtain a steady-state photoluminescence spectrum.

[0036] S32, after passing through the neutral density filter 9, the photoluminescence signal enters the photomultiplier tube 10 to collect part of the photoluminescence signal, and transmits it to the time-correlated single-photon counting device 11 for processing, so as to record and analyze the single-photon event and obtain the photoluminescence kinetic curve under different steady-state light intensities.

[0037] S4. Data analysis: The specific process is as follows: S41. Based on the steady-state luminescence spectrum, data such as luminescence intensity, central wavelength and spectral width are obtained.

[0038] S42. Based on the photoluminescence kinetic curves under different steady-state light intensities, an exponential function is used for numerical fitting to obtain the lifetime of each component and then perform weighted averaging to obtain the photoluminescence lifetime under different steady-state light intensities.

[0039] In summary, there is a significant connection between the photoluminescence dynamics and the photoluminescence properties. The photoluminescence dynamics can obtain the excited state lifetime, reflecting the luminescence intensity and efficiency of the color conversion material. The decay curve of the luminescence intensity over time can be obtained through testing. A longer luminescence lifetime usually indicates a lower non-radiative recombination. If the luminescence lifetime is significantly shortened with the increase of light intensity, it indicates that the material has defects under high intensity. The performance of the material can be analyzed and judged in this way. Through the kinetic decay curve, the influence of each component on the photoluminescence performance can be obtained, which provides support for understanding the photoluminescence mechanism. In the traditional time-resolved photoluminescence spectroscopy technology, a pulse light source with excessive transient power is used, resulting in the generated carrier density being much higher than the level under actual working conditions, and the photoluminescence dynamics, i.e., the photoluminescence dynamics and its photophysical properties under different steady-state light intensities, cannot be reflected in the actual work. However, the present invention can obtain the photoluminescence dynamics and its photophysical properties of the color conversion material in different working states, i.e., under different steady-state light intensities.

[0040] The experimental data results of the non-contact testing method for characterizing the photophysical properties of the color conversion material in the working state of the present invention are described in detail below through specific embodiments.

[0041] Steady-state luminescence spectrum: Figure 2 The luminescence intensity of the sample (CsPbBr3 quantum dot film) under different continuous light intensities can be displayed. At the same time, the in-situ spectrum during the acquisition of time-resolved photoluminescence spectrum can be taken. Data analysis: the photoluminescence intensity shows different change trends with the increase of light intensity, reflecting the photostability and photoelectric properties of the sample.

[0042] Time-resolved photoluminescence spectroscopy: Figure 3 As shown, the decay curve of photoluminescence after pulse excitation is shown. Data analysis: Time-resolved spectroscopy reveals the recombination process and kinetic behavior of carriers under different light intensities.

[0043] Each embodiment in this specification is described in a progressive manner, and the same and similar parts between the embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. In the description of this specification, the description of reference terms "a preferred embodiment", "further", "specifically", "in the present embodiment", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the embodiment of this specification. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples without contradiction.

[0044] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A non-contact testing device for characterizing the photophysical properties of a color conversion material in working state, characterized in that: The test device includes a continuous light source, a pulsed light source, a reflector, a dichroic mirror, a beam splitter, a photomultiplier tube, a time-correlated single photon counting device and a fiber optic spectrometer; The continuous steady-state light emitted by the continuous light source is transmitted to the dichroic mirror via the reflector, and the light reflected by the dichroic mirror is transmitted to the color conversion material; the pulse light emitted by the pulse light source as a perturbation light source is transmitted to the color conversion material via the dichroic mirror; The photoluminescence excited by the color conversion material is divided into two parts by the beam splitter. A small part of the photoluminescence emitted by the beam splitter is emitted to the photomultiplier tube, and the light signal detected by the photomultiplier tube is sent to the time-correlated single photon counting device to measure the single photon event; most of the photoluminescence emitted by the beam splitter enters the fiber spectrometer to obtain a steady-state photoluminescence spectrum.

2. The non-contact testing device for characterizing the photophysical properties of the working state of the color conversion material according to claim 1, characterized in that: The signal peak intensity of the perturbation light source is controlled within 10% of the signal intensity of the continuous steady-state light, ensuring that the former does not significantly affect the population state of photogenerated carriers.

3. The non-contact testing device for characterizing the photophysical properties of the working state of the color conversion material according to claim 1, characterized in that: It also includes a first neutral density filter, a second neutral density filter and a third neutral density filter, wherein the first neutral density filter is arranged between the reflector and the dichroic mirror, the second neutral density filter is arranged between the pulse light source and the dichroic mirror, and the third neutral density filter is arranged between the beam splitter and the photomultiplier tube.

4. The non-contact testing device for characterizing the photophysical properties of the working state of the color conversion material according to claim 1, characterized in that: It also includes a long-wave pass filter, which is arranged between the color conversion material and the beam splitter.

5. The non-contact testing device for characterizing the photophysical properties of the working state of the color conversion material according to claim 1, characterized in that: The parameter requirements of the continuous light source are: ① wavelength selection range: 375-600 nm, ② power range adjustable: 10 -1 -10 3 mW / cm 2 .

6. The non-contact testing device for characterizing the photophysical properties of the working state of the color conversion material according to claim 1, characterized in that: The pulse light source adopts a pulse light diode, and the parameter requirements are: ① wavelength range: 375-600 nm; ② pulse width: sub-nanosecond to sub-picosecond.

7. The non-contact testing device for characterizing the photophysical properties of the working state of the color conversion material according to claim 1, characterized in that: A sample device rack is also provided, and the sample device rack is used to place the color conversion material.

8. A non-contact testing method based on the non-contact testing device for characterizing the photophysical properties of the working state of a color conversion material according to any one of claims 1 to 7, characterized in that: include: Starting the continuous light source and the pulse light source to simultaneously excite the color conversion material to generate a photoluminescent signal; Acquiring a portion of the photoluminescence signal through the optical fiber spectrometer to obtain a steady-state photoluminescence spectrum, and evaluating the photoluminescence characteristics of the color conversion material based on the steady-state luminescence spectrum; Part of the photoluminescence signal is collected by the photomultiplier tube and transmitted to the time-correlated single photon counting device to obtain the photoluminescence kinetic curves under different steady-state light intensities, and based on the photoluminescence kinetic curves under different steady-state light intensities, an exponential function is used to perform numerical fitting to obtain the lifespan of each component and then perform weighted averaging to obtain the photoluminescence lifetime of the color conversion material under different steady-state light intensities.

9. The non-contact testing method according to claim 8, characterized in that: The photoluminescence properties of the color conversion material include the luminescence intensity, central wavelength and spectrum width of the color conversion material.

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