Method for preparing an integrated photonic-electronic chemical membrane electrode

Abstract

The application discloses a preparation method of an integrated photonic-electronic chemical membrane electrode, and belongs to the technical fields of optical fiber chemistry, micro-nano manufacturing and photoelectrocatalysis. The method takes an optical fiber or an optical fiber preform as a substrate, and first carries out the following treatments: glue removal, annealing and plasma activation treatment, then constructs micro-nano grooves and through holes by using ultraviolet / deep ultraviolet lithography and reactive ion etching; then sequentially deposits a photocatalytic layer, an electrocatalytic layer, an electrically conductive layer and an ion exchange layer on the outer wall of the optical fiber by ALD / CVD / PVD, and realizes patterning and doping by cooperating with multiple rounds of lithography-etching; after 200-450 DEG C protection atmosphere annealing, the membrane electrode array is integrated with a driving circuit and a microfluidic chip by using CMOS compatible wafer level or roll-to-roll packaging technology. The obtained membrane electrode can realize CO2 electro-reduction to prepare methanol, N2 electro-reduction to prepare ammonia and methanol oxidation to generate power under normal temperature and pressure, has the advantages of high uniformity, three-field synergistic effect, remote laser driving, batch manufacturing and low cost, and can be widely applied to the fields of distributed green synthesis, fuel cells and high-throughput catalytic chip.

Description

I. Technical Field

[0001] This invention relates to the interdisciplinary fields of fiber optic chemistry, micro / nano manufacturing, and photoelectrocatalysis, and in particular to a method for fabricating multilayer heterogeneous interface film electrodes on the surface of optical fibers based on integrated circuit (IC) micro / nano processes and chemical / physical thin film deposition processes. This method can be used in green energy conversion and chemical synthesis scenarios such as carbon dioxide reduction, nitrogen fixation, and fuel cells. II. Background Technology

[0002] 1. Current Status of Fiber Optic Chemistry

[0003] Optical fiber chemistry systems utilize the long-distance, low-loss light-guiding properties of optical fibers to directly introduce light energy into the reaction interface, enabling photo-driven chemical reactions. They hold great potential in artificial photosynthesis, environmental monitoring, and distributed energy networks.

[0004] 2. Shortcomings of existing technologies

[0005] Existing fiber optic electrodes mainly employ wet chemical methods (such as sol-gel, dip-coating, and spin-coating), which have the following drawbacks:

[0006] 1. Poor film uniformity and difficulty in precisely controlling thickness limit the exposure of catalytic active sites;

[0007] 2. Insufficient adhesion makes the film layer prone to peeling off during hot and cold cycles, resulting in poor reliability;

[0008] 3. Lack of multi-field coordination, separation of optical, electronic, and proton transport paths, and severe recombination;

[0009] 4. Difficult to scale up, poor wet chemical reproducibility, and incompatible with semiconductor processes.

[0010] In summary, a new method for fabricating fiber optic film electrodes that is compatible with wafer-level processes, has precise and controllable structure, and is easy to mass-produce is needed. III. Summary of the Invention

[0011] 1. Purpose of the invention

[0012] The purpose of this invention is to provide a method for preparing an integrated photonic electronic chemical film electrode with high uniformity, high adhesion, and synergistic photoelectric-electric-proton three-field system, so as to overcome the shortcomings of the prior art.

[0013] 2. Technical Solution

[0014] To achieve the above objectives, the present invention adopts the following technical solution:

[0015] 1. Select optical fibers or optical fiber preforms with optical guiding function as the substrate, and pretreat them by degumming, annealing, and plasma activation.

[0016] 2. Coat with photoresist and use ultraviolet or deep ultraviolet lithography to define micro / nano trenches, vias, or wiring patterns;

[0017] 3. A three-dimensional heterostructure interface is constructed on the outer wall of the optical fiber using reactive ion etching (RIE) or deep silicon etching (DRIE);

[0018] 4. A photocatalytic layer, electrocatalytic layer, conductive layer and ion exchange layer are deposited sequentially using ALD / CVD / PVD, and patterning and doping are achieved through multiple rounds of photolithography / etching;

[0019] 5. Annealing in a protective atmosphere at 200–450℃ improves the crystallinity of the film and the interfacial bonding strength;

[0020] 6. Using CMOS-compatible wafer-level or roll-to-roll packaging technology, the membrane electrode array is integrated with the driving electrode, circuit and microfluidic chip to form a modular device.

[0021] 3. Beneficial effects

[0022] • High uniformity and repeatability: The thickness accuracy of the ALD process can be controlled within ±1nm;

[0023] • Synergistic effect of three fields: The optical field, electric field and proton field are coupled in the same plane, reducing the electron-hole recombination rate by about 60%;

[0024] • Low energy consumption and green manufacturing: operates at normal temperature and pressure, without precious metal catalysts;

[0025] • Strong system-level integration: Compatible with existing IC / MEMS processes, suitable for mass production. IV. Description of the attached drawings

[0026] Figure 1 Schematic diagram of the method flow of this invention;

[0027] Figure 2 Schematic diagram of the cross-section of a multilayer film electrode;

[0028] Figure 3 Schematic diagram of the micro-nano etched cross-section of the outer wall of an optical fiber; V. Detailed Implementation Methods

[0029] The following embodiments are intended to further illustrate the present invention, but do not limit the scope of protection of the present invention in any way.

[0030] Example 1: Single-mode fiber TiO2 / Ni multilayer electrode

[0031] Manufacturing process steps:

[0032] 1. Substrate treatment: Annealing at 125℃ for 2 hours, followed by O2 plasma cleaning for 5 minutes;

[0033] 2. Photolithography: Spin-coating photoresist, i-line exposure at 300 mJ·cm⁻¹ -2 RIE etching at 500nm;

[0034] 3. Thin film deposition: ALD-TiO2 100 cycle (10nm thick), magnetron sputtering Ni 50nm;

[0035] 4. Ion exchange layer: spin-coated with Nafion and baked at 150℃ for 30 min;

[0036] 5. Annealing: 300℃ in N2 atmosphere for 2 hours.

[0037] Performance testing: at 0.1 mol·L⁻¹ -1 In KHCO3 solution, the initial overpotential is reduced by 210 mV compared to the bare optical fiber, and the Faraday efficiency of CO2 reduction to CH3OH reaches as high as 63%.

[0038] Example 2: Photonic Crystal Fiber g-C3N4 / CoP Composite Film Electrode

[0039] Long-term stability test

[0040] At a current density of 10 mA·cm -2 Under the conditions of continuous operation for 200 hours, there was no significant increase in electrochemical impedance, and no peeling or cracking of the film layer.

[0041] VI. Industrial Applicability

[0042] The integrated photonic electronic chemical film electrode fabricated in this invention is suitable for:

[0043] 1. Distributed CO2 resource recovery: Construct a km-level fiber optic network to locally optically drive CO2 reduction;

[0044] 2. Fuel Cells: Reduce PEMFC costs by approximately 60% and improve resistance to poisoning;

[0045] 3. Chip-level high-throughput catalysis: Combined with Lab-on-Fiber technology, it enables array-based chemical synthesis and detection.

[0046] VII. Conclusion

[0047] This invention achieves an integrated photonic electronic chemical film electrode with coplanar optical, electrical, and proton fields through IC micro-nano fabrication and multilayer atomic-level deposition. Compared with existing technologies, it has significant advantages such as controllable structure, superior performance, and ease of mass production, and can be widely used in the fields of green energy and chemical manufacturing.

Claims

1. A method for fabricating an integrated photonic electronic chemical film electrode, characterized in that, The process employs integrated circuit micro / nano fabrication techniques combined with chemical / physical deposition, specifically including the following steps: (1) Select optical fiber or optical fiber preform with optical guiding function as the substrate, and perform degumming, annealing and plasma surface activation treatment under cleanroom conditions. (2) Coating positive or negative photoresist, and forming micro-nano etched trenches, vias or metal trace patterns on the outer wall of the optical fiber by ultraviolet (i-line, g-line) or deep ultraviolet (DUV) lithography for precise alignment of multilayer films; (3) Reactive ion etching (RIE) or deep silicon etching (DRIE) is used to remove the core / cladding material in the exposed area to obtain a three-dimensional heterogeneous interface; (4) Photocatalytic layer, electrocatalytic layer, conductive layer and ion exchange layer are deposited sequentially using chemical vapor deposition (CVD), physical vapor deposition (PVD) or atomic layer deposition (ALD), and each film layer is patterned and doped by photolithography / etching cycle to realize the synergistic transport channel of light-electricity-proton. (5) Annealing in a protective atmosphere at 200–450℃ improves the crystallinity of the film and the interfacial bonding strength. (6) Using wafer-level or roll-to-roll packaging technology, the obtained film electrode array is integrated with the driving electrode, circuit and microfluidic chip to form a modular device that can be mass-produced.

2. The method according to claim 1, characterized in that, The packaging step employs complementary metal-oxide-semiconductor (CMOS) compatible wafer-level packaging to achieve direct interconnection with existing integrated circuit platforms; the photocatalytic layer includes TiO2, g-C3N4, BiVO4 or their composites; the electrocatalytic layer is Ni, Fe, Co, Cu or their alloys, oxides, phosphides or sulfides; the conductive layer is a doped conductive polymer or metal nanofilm.

3. The method according to claim 1, characterized in that, The ion exchange layer includes Nafion, sulfonated polyether ether ketone (SPEEK), or other proton exchange membrane materials.

4. The method according to claim 1, characterized in that, The substrate is also subjected to plasma cleaning and surface roughening before deposition to enhance film adhesion and interface stability.

5. The method according to claim 1, characterized in that, The optical fiber is a single-mode or multi-mode communication optical fiber, compatible with 1.3μm and 1.55μm band lasers; the optical fiber is a photonic crystal fiber with a periodic microstructure pore array, used to enhance the local field strength and propagation control capability of the light field at the catalytic interface.

6. The method according to claim 1, characterized in that, The photo-electric-proton field works in a coplanar manner on the surface of the membrane electrode, and the reaction direction and rate are controlled by adjusting the laser power and the applied voltage.

7. The method according to claim 1, characterized in that, The membrane electrode module can generate electricity by reducing CO2 to CH3OH, N2 to NH3, or oxidizing CH3OH at room temperature and pressure.

8. The method according to claim 1, characterized in that, The photonic input system is based on a tunable laser and can provide wavelengths of 250–1000 nm, phase modulation, intensity modulation, and pulse control.

9. The method according to claim 1, characterized in that, The membrane electrode structure is integrated with a microelectromechanical system (MEMS) to form a miniaturized, high-throughput, multi-channel chemical reactor or energy conversion device.

10. A computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, causes the processor to perform the steps of the method for preparing an integrated photonic electrochemical film electrode as described in any one of claims 1–9.

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