Photon skin based on friction-induced electroluminescence and construction method thereof
By designing composite photonic thin films and stretchable electrodes, and combining them with the triboelectric nanogenerator effect, the problems of insufficient stretchability and triboelectric properties of traditional photonic skin are solved, achieving efficient photoelectric dual response, which can be applied to intelligent sensing and human-computer interaction.
Patent Information
- Application Number
- CN202511025410.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-24
- Publication Date
- 2025-10-31
AI Technical Summary
Traditional photonic skin has low stretchability and insufficient triboelectric properties, which limits its application in the fields of intelligent sensing and human-computer interaction.
By employing composite photonic thin films and stretchable electrodes, and combining ZnS:Cu electroluminescent particles, PVDF piezoelectric materials, and PDMS flexible matrix, high dielectric constant and piezoelectric effect are achieved. Combined with the triboelectric nanogenerator effect, efficient conversion of mechanical energy into light and electrical energy is realized.
It achieves highly sensitive gesture recognition and highly secure handwriting authentication, with a maximum stretching rate of 222.2%. It provides visual gesture monitoring in low-light environments, with a handwriting recognition accuracy of 90.28%, and requires no external power supply.
Smart Images
Figure CN120882229A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of flexible electronics and intelligent sensing technology, and in particular to a photonic skin based on triboluminescence and its construction method. Background Technology
[0002] With the rapid development of modern technology, the requirements for portability and environmental friendliness of electronic products are increasing, leading to an explosive growth in demand for intelligent electronic devices, sensors, and luminescent materials. Advances in Artificial Intelligence (AI) and the Internet of Things (IoT) technologies have placed higher standards on the flexibility, portability, and low power consumption of sensors. Currently, most intelligent sensing devices rely on electrical signal control and lack intuitive human-computer interaction interfaces, necessitating the development of new interactive media with perceptible signal outputs such as visible light and sound. Among these, optical signals, with their high spatial resolution and intuitiveness, have become an ideal choice for display and visual sensing applications. In recent years, luminescent devices based on mechanisms such as photoluminescence, mechanoluminescence, and electroluminescence have achieved commercial applications and are developing towards flexibility, lightweighting, and intelligence. However, traditional electroluminescent devices suffer from complex external circuits, high energy consumption, and safety hazards; mechanoluminescent devices are limited by MPa-level pressure thresholds and irreversible damage. Therefore, developing new self-luminescent technologies with self-powered characteristics and low trigger thresholds has significant scientific value and application potential for promoting the development of emerging fields such as wearable devices and intelligent interactive interfaces.
[0003] Triboelectrification-induced electroluminescence (TIEL), as an innovative self-luminescent mechanism, achieves efficient conversion of mechanical energy into electrical energy and then into light energy by coupling triboelectric charging and electroluminescence effects. TIEL-based luminescent systems require no external power supply or complex circuitry, emitting light under mild mechanical stimulation and exhibiting excellent stability and repeatability. These properties make TIEL a promising candidate for applications in smart sensing, electronic skin, and anti-counterfeiting. However, current TIEL materials still face challenges such as insufficient luminescence intensity and limited application range, necessitating the development of novel material systems with optimized performance. Summary of the Invention
[0004] To address the shortcomings of existing technologies, this invention provides a photonic skin based on triboelectric electroluminescence and its construction method, which solves the problems of low stretchability and low triboelectric properties of traditional photonic skin.
[0005] The technical solution adopted in this invention is as follows: On the one hand, a photonic skin based on triboelectric electroluminescence includes: a stretchable light-emitting device and a stretchable electrode; The stretchable light-emitting device is specifically a composite photonic thin film, wherein the content of the flexible matrix is 50% of the total mass of the composite photonic thin film, and the mass ratio of electroluminescent particles to piezoelectric material is 6:4; wherein the flexible matrix is a PDMS solution, wherein the ratio of PDMS to curing agent is 10:1, the electroluminescent particles are ZnS:Cu, and the piezoelectric material is PVDF. The stretchable electrode is attached to the composite photonic film; The thickness of the composite photonic thin film is 1 mm; The stretchable electrode is an Ag / TPU composite material; On the other hand, a method for constructing a photonic skin based on triboluminescence, for constructing the aforementioned photonic skin based on triboluminescence, includes the following steps: Step 1: Fabrication of a stretchable light-emitting device; Take PDMS solution, ZnS:Cu electroluminescent powder, and PVDF nanoparticles, wherein the ratio of PDMS to curing agent in the PDMS solution is 10:1, and mix them as follows: the content of PDMS solution is 50% of the total mass, and the ZnS:Cu electroluminescent powder and PVDF nanoparticles are mixed in a ratio of 6:4 and added to the PDMS solution. Stir thoroughly with a glass rod, and after stirring evenly, place it in a vacuum drying oven for 20-30 minutes for vacuum degassing until the bubbles are removed; after degassing, pour the solution into a mold made of tape and place it in a forced-air drying oven to dry and cure at 80℃ for 2-3 hours; a stretchable light-emitting device, namely ZnS:Cu / PVDF / PDMS composite photonic film, is obtained. The self-made mold is a cuboid mold, 60 mm long, 60 mm wide, and 1 mm thick; Step 2: Prepare photon skin; A ZnS:Cu / PVDF / PDMS composite photonic film is fixed, a screen is placed on the film, and a stretchable electrode material is uniformly scraped onto the ZnS:Cu / PVDF / PDMS composite photonic film using a screen printing process, so that the stretchable electrode material Ag / TPU is uniformly attached to the ZnS:Cu / PVDF / PDMS composite photonic film to obtain photonic skin. The beneficial effects of adopting the above technical solution are as follows: This invention provides a photonic skin based on triboluminescence and its construction method. This invention can monitor finger bending angles in real time, accurately recognize various hand gestures, and can be applied to contactless switch control in smart terminals. Furthermore, based on its response to frictional stress and frequency, it can also recognize writing trajectories. The high-brightness, stretchable photoelectric dual-response photonic skin developed in this research and its innovative applications in human-computer interaction and intelligent anti-counterfeiting provide a new material foundation and technical path for the innovative development of self-powered intelligent sensing and flexible display technologies.
[0006] 1. This material exhibits excellent tensile properties, with a maximum elongation of up to 222.2%, which enables it to adapt to various complex working environments and maintain stable performance. 2. The dual role of PVDF: (a) High dielectric constant -> Enhances charge storage and suppresses dissipation; (b) Piezoelectric effect -> Generates additional polarization charge under mechanical stress -> Significantly improves net charge density and triboelectric / luminescent properties; 3. Optical-electric dual-signal self-powered: Through TIEL and TENG coupling, it realizes efficient conversion and synchronous output of mechanical energy into optical and electrical energy without the need for an external power supply.
[0007] 4. Achieve high-sensitivity (linear relationship) gesture recognition (especially in low-light environments) and high-security (90.28% accuracy + dual-modal cross-validation) handwriting authentication. Attached Figure Description
[0008] Figure 1 This is a schematic diagram of the stretchable photonic thin film of the present invention; Figure 2 The TIEL spectrum and CIE color coordinates are shown in the embodiments of the present invention. Figure 3 The following are emission spectra of composite photonic thin films with different mass ratios of ZnS:Cu and PVDF in embodiments of the present invention. Figure 4 The following are emission spectra of composite photonic thin films of different thicknesses according to embodiments of the present invention; Figure 5 This is a test of the TIEL performance stability of the composite photonic thin film in an embodiment of the present invention;
[0009] Figure 6 The photovoltage of the composite photonic thin film in an embodiment of the present invention;
[0010] Figure 7 Electrical signal monitoring of gesture changes in this embodiment of the invention;
[0011] Figure 8This invention provides a handwriting authentication system for the trajectory luminescence images and intensity mappings of the number "2" written by three different volunteers.
[0012] Among them, (a) is the trajectory luminescence image and its luminescence intensity mapping corresponding to the number "2" written by volunteer 1; (b) is the trajectory luminescence image and its luminescence intensity mapping corresponding to the number "2" written by volunteer 2; and (c) is the trajectory luminescence image and its luminescence intensity mapping corresponding to the number "2" written by volunteer 3. Figure 9 HOG feature extraction for the handwriting authentication system in this embodiment of the invention;
[0013] Where (a) is the handwriting image, and (b) is the shape feature map of the handwriting image; Figure 10 The electrical output signal corresponding to a volunteer writing the four letters "TIEL" on the device in the handwriting authentication system of this embodiment of the invention; Where (a) - write the electrical output signal corresponding to the four letters "T", (b) - write the electrical output signal corresponding to the four letters "I", (c) - write the electrical output signal corresponding to the four letters "E", and (d) - write the electrical output signal corresponding to the four letters "L". Figure 11 The dataset distribution obtained by the handwriting authentication system of this invention using the t-SNE method is shown in the embodiment of the invention.
[0014] Figure 12 This is the confusion matrix of the handwriting authentication system recognition results in an embodiment of the present invention. Detailed Implementation
[0015] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and are not intended to limit the scope of the invention.
[0016] The technical solution adopted in this invention is as follows: On the one hand, a photonic skin based on triboelectric electroluminescence includes: a stretchable light-emitting device and a stretchable electrode; The stretchable light-emitting device is specifically a composite photonic thin film, wherein the content of the flexible matrix is 50% of the total mass of the composite photonic thin film, and the mass ratio of electroluminescent particles to piezoelectric material is 6:4; wherein the flexible matrix is a PDMS solution, wherein the ratio of PDMS to curing agent is 10:1, the electroluminescent particles are ZnS:Cu, and the piezoelectric material is PVDF. The stretchable electrode is attached to the composite photonic film; The thickness of the composite photonic thin film is 1 mm; The stretchable electrode is an Ag / TPU composite material; The PVDF enhances the charge storage capacity of the composite photonic film and suppresses charge dissipation through its high dielectric constant. At the same time, it generates additional polarization charge under mechanical stress through the piezoelectric effect, thereby improving the net charge density, triboelectric properties and tribo-induced electroluminescence (TIEL) performance.
[0017] The maximum stretchability of the photonic skin can reach 222.2%.
[0018] The photonic skin achieves efficient self-powered conversion and synchronous output of mechanical energy into light and electrical energy by coupling the triboelectric induced electroluminescence (TIEL) effect and the triboelectric nanogenerator (TENG) effect.
[0019] Figure 1 A schematic diagram of the stretchable photonic thin film in this embodiment is shown. Its composite thin film structure comprises PDMS as a flexible matrix (50 wt%), ZnS:Cu as electroluminescent particles, and PVDF as a dielectric enhancer, with the three components synergistically optimized. The TIEL emission spectrum of the composite photonic thin film was obtained by spectrometer measurement, and its corresponding International Commission on Illumination (CIE) color coordinates are shown below. Figure 2 As shown, the test results indicate that the material exhibits green emission at 510 nm, with corresponding CIE coordinates of (0.20, 0.47). PVDF enhances charge storage through high dielectric properties and utilizes the piezoelectric effect to generate additional polarization charge, significantly improving the net charge density.
[0020] On the other hand, a method for constructing a photonic skin based on triboluminescence, for constructing the aforementioned photonic skin based on triboluminescence, includes the following steps: Step 1: Fabrication of a stretchable light-emitting device; Take PDMS solution, ZnS:Cu electroluminescent powder, and PVDF nanoparticles, wherein the ratio of PDMS to curing agent in the PDMS solution is 10:1, and mix them as follows: the content of PDMS solution is 50% of the total mass, and the ZnS:Cu electroluminescent powder and PVDF nanoparticles are mixed in a ratio of 6:4 and added to PDMS. Stir thoroughly with a glass rod, and after stirring evenly, place in a vacuum drying oven for 20-30 minutes for vacuum degassing until the bubbles are removed. In this embodiment, the degassing time is 20 minutes. After degassing, pour the solution into a mold made of tape and place it in a forced-air drying oven to dry and cure at 80°C for 2-3 hours. In this embodiment, the drying and curing time is 2 hours. A stretchable light-emitting device, namely ZnS:Cu / PVDF / PDMS composite photonic film, is obtained. The self-made mold is a cuboid mold, 60 mm long, 60 mm wide, and 1 mm thick; Step 2: Prepare photon skin; A ZnS:Cu / PVDF / PDMS composite photonic film is fixed, and a screen is placed on the film. In this embodiment, the screen is a 200-mesh screen. A screen printing process is used to uniformly scrape the stretchable electrode material on the ZnS:Cu / PVDF / PDMS composite photonic film, so that the stretchable electrode material Ag / TPU is uniformly attached to the ZnS:Cu / PVDF / PDMS composite photonic film to obtain photonic skin. Figure 3 The effect of the ZnS:Cu phosphor-to-PVDF ratio on TIEL performance was shown. As the PVDF content increased, the luminescence intensity initially increased and then decreased. Excessive PVDF reduced the ZnS:Cu phosphor particle content and hindered luminescence, while insufficient PVDF weakened the triboelectric effect; both of these factors contributed to a decrease in luminescence intensity. The luminescence intensity reached its maximum when the mass ratio of ZnS:Cu phosphor to PVDF was 6:4.
[0021] Figure 4 The effect of composite photonic film thickness on TIEL performance is shown. It can be seen that when the thickness of the composite photonic film increases to 1 mm, its TIEL performance reaches its maximum. Subsequently, the light emission intensity gradually decreases due to the obstruction of light emission by the excessively thick material.
[0022] Figure 5 The stability test of the TIEL performance of the composite photonic thin film is shown. Using PTFE as the friction material, after 3000 friction cycles (sampling interval 500 ms) under the conditions of 2 Hz frequency and 60 kPa stress, the TIEL performance output of the ZnS:Cu / PVDF / PDMS composite photonic thin film remained stable and no significant attenuation was observed.
[0023] Figure 6 The photovoltage of the composite photonic thin film was shown, with TIEL emission exhibiting 1.56 mW / cm². -2 High brightness (0.1 cdm) -2 ) A stretchable single-electrode TENG fabricated based on composite photonic thin films possesses excellent TIEL and triboelectric output performance, enabling its use as a self-driven photoelectric dual-response photonic skin. This photonic skin can monitor finger bending angles in real time, accurately recognize various hand gestures, and can be applied to contactless switch control in smart terminals. Furthermore, based on its response to frictional stress and frequency, a user recognition system based on writing trajectory has been implemented. Its dual-channel cross-verification mechanism significantly improves the system's security, as detailed below: Example 1: The photonic skin of the present invention can be applied to gesture recognition. Specifically, the photonic skin is attached to the finger joints, and the dynamic changes of light signals or electrical signal intensity generated by the photonic skin during finger bending are monitored in real time to identify the finger bending angle and various gestures. The dynamic changes of light signals include a decrease in the area of the light-emitting region and an increase in the light-emitting intensity. The electrical signal intensity maintains a linear relationship with the finger bending angle.
[0024] The dynamic changes in the luminous image during the bending of the index finger in gesture recognition, when this flexible photonic skin is attached to the finger joint, enable real-time monitoring of various hand gestures. As the bending angle of the index finger increases, the light signal captured by the image detector exhibits a characteristic change of decreasing luminous area and increasing intensity. This unique optical response characteristic makes gesture visualization monitoring possible in dark environments. Figure 7 The study demonstrated the monitoring of electrical signals related to gesture changes. The intensity of the electrical signal output by the photonic skin maintained a good linear relationship with the finger bending angle, exhibiting excellent pressure sensitivity and significantly improving the sensitivity of gesture recognition. This research-developed photonic skin system with both photoelectric and electrical responses provides an innovative technological solution for barrier-free human-computer interaction and intelligent control applications in dark environments.
[0025] Figure 8 (a), (b), and (c) show the luminescence images and intensity mapping results of three volunteers writing the number "2", clearly demonstrating the differences in luminescence intensity distribution caused by individual writing habits.
[0026] Example 2: The photonic skin of this invention can also be applied to existing handwriting authentication user recognition systems. Specifically, the user writes on the surface of the photonic skin, and the system simultaneously captures the luminous image of the writing trajectory and the triboelectric signal generated during the writing process. Features of the luminous image are extracted using the Histogram of Oriented Gradients (HOG) algorithm, and combined with the pen stroke sequence, pressure, and speed features reflected by the triboelectric signal, the user's identity is identified through a dual-channel cross-validation mechanism. The recognition accuracy of the photonic skin of this invention can reach 90.28%.
[0027] Figure 9 Images (a) and (b) show the HOG features of the handwriting authentication system. Three volunteers each wrote the number "2" 96 times, and the 288 samples were divided into training and test sets at 75% and 25% respectively. The HOG algorithm was used to extract features: the image was segmented into 24×24 pixel cells, the 0°-180° gradient was calculated and divided into 9 groups for statistical analysis, forming a 9-dimensional feature vector; then, using 2×2 cell blocks as blocks, the complete HOG features were generated by sliding the blocks with a 24-pixel stride.
[0028] Figure 10Images (a), (b), (c), and (d) show the electrical output signals corresponding to the volunteers writing the letters "TIEL" on the device. By capturing the triboelectric signals generated during the writing process, behavioral characteristics such as pen stroke order, pressure, and speed can be accurately reflected. Changes in pen stroke order generate characteristic peaks, fluctuations in pen pressure affect the peak intensity, and changes in pen speed regulate the signal periodicity. Therefore, the triboelectric effect can be used to assist this recognition system, thereby further improving the system's recognition accuracy.
[0029] Figure 11 The distribution of the dataset obtained by the handwriting authentication system using the t-SNE method is shown, verifying the system's ability to recognize individual handwriting features; Figure 12 The confusion matrix of the handwriting authentication system is shown, indicating an accuracy rate of 90.28%, demonstrating the application potential of the TIEL effect in the field of identity verification.
[0030] The above description is merely a preferred embodiment of this disclosure and an explanation of the technical principles employed. Those skilled in the art should understand that the scope of the invention involved in the embodiments of this disclosure is not limited to technical solutions formed by specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the above-described inventive concept. For example, technical solutions formed by substituting the above-described features with (but not limited to) technical features with similar functions disclosed in the embodiments of this disclosure.
Claims
1. A photonic skin based on triboelectric induced electroluminescence, characterized in that, include: Stretchable light-emitting devices and stretchable electrodes; The stretchable light-emitting device is specifically a composite photonic thin film, wherein the content of the flexible matrix is 50% of the total mass of the composite photonic thin film, and the mass ratio of electroluminescent particles to piezoelectric material is 6:4; wherein the flexible matrix is a PDMS solution, wherein the ratio of PDMS to curing agent is 10:1, the electroluminescent particles are ZnS:Cu, and the piezoelectric material is PVDF.
2. The photonic skin based on triboluminescence according to claim 1, characterized in that, The stretchable electrode is attached to the composite photonic film; The thickness of the composite photonic film is 1 mm.
3. The photonic skin based on triboluminescence according to claim 1, characterized in that, The stretchable electrode is an Ag / TPU composite material.
4. A method for constructing a photonic skin based on triboelectric induction (TIA), used to construct the photonic skin based on TIA as described in claim 1, characterized in that, Includes the following steps: Step 1: Fabrication of a stretchable light-emitting device; Take PDMS solution, ZnS:Cu electroluminescent powder, and PVDF nanoparticles, wherein the ratio of PDMS to curing agent in the PDMS solution is 10:1, and mix them as follows: the content of PDMS solution is 50% of the total mass, and the ZnS:Cu electroluminescent powder and PVDF nanoparticles are mixed in a ratio of 6:4 and added to the PDMS solution. Stir thoroughly with a glass rod, and after stirring evenly, place it in a vacuum drying oven for 20-30 minutes for vacuum degassing until the bubbles are removed; after degassing, pour the solution into a mold made of tape and place it in a forced-air drying oven to dry and cure at 80℃ for 2-3 hours; a stretchable light-emitting device, namely ZnS:Cu / PVDF / PDMS composite photonic film, is obtained. Step 2: Prepare photon skin; A ZnS:Cu / PVDF / PDMS composite photonic film is fixed, a screen is placed on the film, and a stretchable electrode material is uniformly scraped onto the ZnS:Cu / PVDF / PDMS composite photonic film using a screen printing process, so that the stretchable electrode material Ag / TPU is uniformly attached to the ZnS:Cu / PVDF / PDMS composite photonic film, thus obtaining photonic skin.
5. The method for constructing a photonic skin based on triboluminescence according to claim 4, characterized in that, The self-made mold is a cuboid mold, 60 mm long, 60 mm wide, and 1 mm thick.