Laser processing method and device for OPV organic photovoltaic cells

Abstract

The present invention discloses a laser processing method and device for OPV organic photovoltaic cells. A homogenizer device is added to homogenize the laser beam of Gaussian light through an optical diffraction lens to achieve a specified shape. The laser homogenizer refers to a device that can convert a single-mode laser or a multi-mode laser into a uniform light spot of a specific shape. The distribution of the light spot energy has a high degree of uniformity, so that the Gaussian light is converted into a flat-top light of a specified shape. The layer to be etched is scribed and etched, and different homogenizers can be quickly replaced through a detachable connection device to obtain homogenized laser spots of different sizes.

Description

Technical Field

[0001] The invention relates to the field of laser etching, and in particular to a laser processing method and device for OPV organic photovoltaic cells. Background Art

[0002] The device structure of organic solar cells is ITO / HTLs / active layers / ETLs / Ag. The transparent conductive glass with strips of indium tin oxide ITO (cathode) etched on the surface was cleaned with detergent, deionized water, acetone and isopropanol ultrasonic oscillation for 30 minutes, dried with nitrogen flow, and then treated with ultraviolet and ozone plasma for 10 minutes. Preparation of hole transport layer (HTLs): The prepared HTLs solution was spin-coated on the ITO surface at 4500 rpm and annealed at 170 ℃ for 20 min to obtain the HTLs layer, which was then transferred to the glove box. Preparation of active layers: annealing at 100 ℃ for 7 min in the glove box; when the active layer was PM6:BTP-eC9, the solution was 16.5 mg mL-1 of chloroform solution, the donor-acceptor weight ratio was 1:1.2, the additive was 0.25% DIO, the solution spin coating speed was 3000 rpm, and the film was annealed at 90 ℃ for 7 min. Preparation of electron transport layer (ETLs): 1 mg mL-1 of PDINN The methanol solution was spin-coated on the active layer at a rotation speed of 3800 rpm to obtain PDINN ETLs. Preparation of the cathode electrode: A 100 nm thick Ag electrode was deposited by thermal evaporation at a background pressure of 2.0 × 10 -4 Pa.

[0003] Laser etching is currently the most mainstream scribing process, but with the increase of coated superimposed films, the thickness of the film layer required for laser etching is getting thicker and thicker, and the composition is becoming more and more complex. The width of the line groove formed by the traditional laser processing technology is highly restricted, the dead zone area is large, and the line groove formed by etching has a certain taper that is easy to damage the substrate structure. Organic OPV thin-film solar cell modules require three laser scribing and etching in the production process, P1, P2, and P3, to establish a series connection structure between multiple single cells, so that the solar cell obtains a higher open circuit voltage. At present, Gaussian light is often used in laser scribing and etching, but it often fails to achieve the expected effect, thus affecting the photoelectric conversion efficiency and stability of organic OPV thin-film solar cell modules. Especially in P2 and P3 laser scribing and etching, Gaussian light is used, and the light intensity decreases from the center of the spot to the edge of the spot. Obviously, this will lead to a problem, that is, during the laser scribing process, the second transmission layer, the organic active layer, and the first transmission layer in the edge area of ​​the spot absorb part of the laser energy, but it is not enough to remove it. In addition, the organic OPV material itself has poor stability. Obviously, the internal structure of the film surface material that has absorbed the laser energy but not removed is affected, which in turn affects its stability and ultimately affects the photoelectric conversion efficiency of the organic OPV thin-film solar cell module. In addition, due to the characteristics of Gaussian light, on the one hand, the material at the edge of the spot cannot absorb enough heat, making it difficult to etch and fall off the first transmission layer material in the edge area, so that only a narrow groove can be etched in the center area of ​​the spot. On the other hand, in order to obtain lower contact resistance, when the laser power is increased to increase the laser energy at the edge of the spot, thereby expanding the exposed area of ​​the bottom electrode layer, the center area of ​​the spot will damage the bottom electrode layer under the first transmission layer due to excessive energy, thereby affecting the photoelectric conversion efficiency of the organic OPV thin-film solar cell module.

[0004] In summary, a laser processing method and device for OPV organic photovoltaic cells are needed to solve the deficiencies in the prior art. Summary of the invention

[0005] In view of the deficiencies in the prior art, the present invention provides a laser processing method and device for OPV organic photovoltaic cells, aiming to solve the above problems.

[0006] To achieve the above object, the present invention provides the following technical solution: a laser processing method for an OPV organic photovoltaic cell, comprising the following steps:

[0007] Step S1: Generate a laser beam by a laser, and collimate the laser beam by using a lens beam expander;

[0008] Step S2: using an optical diffraction lens to shape the laser beam to form a diffraction homogenized beam;

[0009] Step S3: According to the process requirements, a suitable homogenizer is selected to meet the requirements of homogenizing laser light plates of different sizes;

[0010] Step S4: laser etching the P1, P2, and P3 layers of the organic OPV photovoltaic cell;

[0011] The etching of the P1 layer is as follows: etching the bottom electrode layer by a Gaussian beam to form an independent strip-shaped conductive electrode;

[0012] The etching of the P2 layer is as follows: the electron transport layer, the organic active layer and the hole transport layer are etched by combining a Gaussian beam and a diffraction homogenized beam;

[0013] The etching of the P3 layer is as follows: the top electrode layer and the organic OPV light absorbing layer on the bottom electrode layer are etched by converting the Gaussian beam into a diffraction homogenized beam.

[0014] Optionally, the etching of the P1 layer is performed in the following manner:

[0015] Step A1: Positioning and calibration: Place the sample on the laser etching platform, and align the laser spot accurately with the predetermined etching starting point through visual alignment or automatic alignment system;

[0016] Step A2: Test etching, verify the laser parameters by performing etching tests on the sample;

[0017] Step A3: Formal etching, scan the designed path on the product, select the appropriate etching speed according to the material thickness and hardness, and monitor the etching effect in real time;

[0018] Step A4: Cooling and cleaning. After etching is completed, the product is cooled and the residues produced by etching are cleaned.

[0019] Optionally, the etching of the P2 layer is performed in the following manner:

[0020] Step B1: pre-treatment, using a homogenized beam to pre-treat the entire area to be etched;

[0021] Step B2: Fine etching, using Gaussian beam for precise etching, and during the etching process, adjusting the laser power and scanning speed according to the actual material properties and etching effect.

[0022] Optionally, the etching of the P3 layer is performed in the following manner:

[0023] Step C1: Loading a suitable phase pattern by controlling the spatial light modulator;

[0024] Step C2: modulating the light wave according to the phase pattern to convert the Gaussian beam into a homogenized beam;

[0025] Step C3: focusing the homogenized light beam onto the top electrode layer and the organic OPV light absorbing layer to be etched.

[0026] Optionally, in step S1, a lens beam expander is used to collimate the laser beam in the following manner:

[0027] Step S11: the laser beam passes through a negative lens to diverge the laser beam and increase the diameter of the beam;

[0028] Step S12: The diverged laser beam passes through a positive lens to focus the laser beam, collimate the laser beam, and adjust the diameter and divergence angle of the laser beam by adjusting the distance between the negative lens and the positive lens.

[0029] Optionally, in step S2, an optical diffraction lens is used to shape the laser beam in the following manner:

[0030] Step S21: Select a suitable optical diffraction lens according to the required spot shape and energy distribution, and install it in the light path;

[0031] Step S22: adjusting the focal length, position and angle of the optical diffraction lens so that the laser beam forms a homogenized spot of a desired spot shape, and optimizing the parameters of the optical diffraction lens through experiments or simulation software.

[0032] Optionally, the process requirements in step S3 include but are not limited to spot size, spot shape, energy distribution, processing materials and processing accuracy.

[0033] Optionally, the homogenizer in step S3 includes but is not limited to a flat-top light homogenizer, a linear light homogenizer and a multi-mode homogenizer;

[0034] Flat-top light homogenizer, used to produce a flat-top light spot with uniform energy distribution;

[0035] Linear light homogenizer, used to generate linear light spot, suitable for linear etching or cutting;

[0036] Multimode homogenizer, used to generate light spots of various shapes and energy distributions.

[0037] A laser processing device for an OPV organic photovoltaic cell, using a laser processing method for an OPV organic photovoltaic cell, comprising:

[0038] A laser for generating a laser beam;

[0039] A lens beam expander for collimating the laser beam;

[0040] Optical diffraction lenses are used to shape the laser beam to form a flat top light with highly uniform energy distribution;

[0041] The homogenizer device comprises a homogenizer and a detachable connecting device, which is used for quickly replacing homogenizers of different specifications.

[0042] Beneficial effects of the present invention:

[0043] 1. In the present invention, a homogenizer device is added to homogenize the laser beam through an optical diffraction lens to achieve a specified shape. The laser homogenizer refers to a device that can convert a single-mode laser or a multi-mode laser into a uniform light spot of a specific shape. The distribution of the light spot energy has a high degree of uniformity, so that the Gaussian light is converted into a flat-top light of a specified shape. The layer to be etched is scribed and etched, and different homogenizers can be quickly replaced through a detachable connection device to obtain homogenized laser spots of different sizes.

[0044] 2. The present invention is conducive to the groove etching of each functional layer in P2 and P3 laser scribing without damaging the bottom electrode layer and the substrate glass. At the same time, it can also reduce the damage to the OPV material in the edge area of ​​the spot, reduce the width and taper of the groove to obtain lower contact resistance; the dead zone range is effectively controlled to ensure the processing efficiency, and the laser spot formed by laser beam irradiation can be shaped and homogenized, thereby improving the photoelectric conversion efficiency and stability of organic OPV thin-film solar cells. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 This is a Gaussian light three-dimensional image of the present invention.

[0046] Figure 2 This is a Gaussian light spot diagram of the present invention.

[0047] Figure 3 This is a Gaussian photolithography pattern of the present invention.

[0048] Figure 4 This is an imaging diagram of a Gaussian light actual strategy step meter of the present invention.

[0049] Figure 5 This is a three-dimensional diagram of diffraction flat-top light of the present invention.

[0050] Figure 6 This is a diffraction flat-top light spot pattern of the present invention.

[0051] Figure 7 This is a diffraction flat-top photolithography pattern of the present invention.

[0052] Figure 8 This is an imaging diagram of a diffraction flat-top light actual strategy step meter of the present invention.

[0053] Fig. 9 The present invention is a schematic diagram of the structure of a homogenizer.

[0054] In the figure: 1. Laser; 2. Lens expander; 3. Homogenizer; 31. Negative lens; 32. Positive lens; 4. Optical diffraction lens. DETAILED DESCRIPTION

[0055] In order to more clearly illustrate the embodiments of the invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0056] like Figures 1 to 8 As shown, a laser processing method for an OPV organic photovoltaic cell comprises the following steps:

[0057] Step S1: Generate a laser beam by a laser, and collimate the laser beam by using a lens beam expander;

[0058] Step S2: using an optical diffraction lens to shape the laser beam to form a diffraction homogenized beam;

[0059] Step S3: According to the process requirements, a suitable homogenizer is selected to meet the requirements of homogenizing laser light plates of different sizes;

[0060] Step S4: laser etching the P1, P2, and P3 layers of the organic OPV photovoltaic cell;

[0061] The etching of the P1 layer is as follows: etching the bottom electrode layer by a Gaussian beam to form an independent strip-shaped conductive electrode;

[0062] The etching of the P2 layer is as follows: the electron transport layer, the organic active layer and the hole transport layer are etched by combining a Gaussian beam and a diffraction homogenized beam;

[0063] The etching of the P3 layer is as follows: the top electrode layer and the organic OPV light absorbing layer on the bottom electrode layer are etched by converting the Gaussian beam into a diffraction homogenized beam.

[0064] The P1 layer is etched in the following ways:

[0065] Step A1: Positioning and calibration: Place the sample on the laser etching platform, and align the laser spot accurately with the predetermined etching starting point through visual alignment or automatic alignment system;

[0066] Step A2: Test etching, verify the laser parameters by performing etching tests on the sample;

[0067] Step A3: Formal etching, scan the designed path on the product, select the appropriate etching speed according to the material thickness and hardness, and monitor the etching effect in real time;

[0068] Step A4: Cooling and cleaning. After etching is completed, the product is cooled and the residues produced by etching are cleaned.

[0069] The P2 layer is etched in the following ways:

[0070] Step B1: pre-treatment, using a homogenized beam to pre-treat the entire area to be etched;

[0071] Step B2: Fine etching, using Gaussian beam for precise etching, and during the etching process, adjusting the laser power and scanning speed according to the actual material properties and etching effect.

[0072] The P3 layer is etched in the following ways:

[0073] Step C1: Loading a suitable phase pattern by controlling the spatial light modulator;

[0074] Step C2: modulating the light wave according to the phase pattern to convert the Gaussian beam into a homogenized beam;

[0075] Step C3: focusing the homogenized light beam onto the top electrode layer and the organic OPV light absorbing layer to be etched.

[0076] In step S1, a lens beam expander is used to collimate the laser beam in the following manner:

[0077] Step S11: the laser beam passes through a negative lens to diverge the laser beam and increase the diameter of the beam;

[0078] Step S12: The diverged laser beam passes through a positive lens to focus the laser beam, collimate the laser beam, and adjust the diameter and divergence angle of the laser beam by adjusting the distance between the negative lens and the positive lens.

[0079] In step S2, an optical diffraction lens is used to shape the laser beam in the following manner:

[0080] Step S21: Select a suitable optical diffraction lens according to the required spot shape and energy distribution, and install it in the light path;

[0081] Step S22: adjusting the focal length, position and angle of the optical diffraction lens so that the laser beam forms a homogenized spot of a desired spot shape, and optimizing the parameters of the optical diffraction lens through experiments or simulation software.

[0082] The process requirements in step S3 include but are not limited to spot size, spot shape, energy distribution, processing materials and processing accuracy.

[0083] In step S3, the homogenizer includes but is not limited to a flat-top light homogenizer, a linear light homogenizer, and a multi-mode homogenizer;

[0084] Flat-top light homogenizer, used to produce a flat-top light spot with uniform energy distribution;

[0085] Linear light homogenizer, used to generate linear light spot, suitable for linear etching or cutting;

[0086] Multimode homogenizer, used to generate light spots of various shapes and energy distributions.

[0087] The beam is emitted by the laser and uses a Galilean lens expander‌; mainly based on the combination of a negative lens and a positive lens, this design allows the collimation of the beam to be optimized by changing the diameter and divergence angle of the laser beam.

[0088] Using an optical diffraction lens to shape the laser beam to a specified shape, shaping the laser to form a homogenized flat-top beam;

[0089] According to the process requirements, etching is required to be performed on the organic OPV photovoltaic cell film layers P1, P2, and P3, and the substrate cannot be damaged. The laser processing method for organic OPV photovoltaic cells etches the coating layer by converting a Gaussian beam into a homogenized flat-top beam.

[0090] In P1 laser etching, a Gaussian beam etches the bottom electrode layer without damaging the substrate. Before the hole transport layer is coated, laser scribing is performed to form independent strip-shaped conductive electrodes, which also serve as positioning points for subsequent P2 and P3 scribing.

[0091] In P2 laser etching, laser scribing is performed after the electron transport layer is coated and before the top electrode is deposited, and the electron transport layer, the organic active layer, and the hole transport layer are etched. It is required to perform scribing on the organic active light-absorbing layer on the bottom electrode layer so that the bottom electrode layer is exposed and not damaged. The laser processing method for organic OPV photovoltaic cells etches the organic OPV light-absorbing layer through Gaussian beams and homogenized beams. The uniform energy distribution of the Gaussian beam and the diffraction homogenized beam conversion is conducive to scratching the perovskite light-absorbing layer and ensuring the efficiency of the scribing process. The beam shape and energy homogenization are conducive to fine processing of the edges of the wire grooves, so that the edges of the wire grooves are smoother and the risk of short circuits is reduced. Compared with the use of Gaussian beam processing alone, it is conducive to reducing the processing width of the wire grooves and the damage of the conical energy to the bottom pad electrode.

[0092] In P3 laser etching, it is necessary to scribe the top electrode layer and the organic OPV light absorbing layer on the bottom electrode layer (the organic OPV light absorbing layer includes: electron transport layer, organic active layer, hole transport layer). The processing layer includes exposing the bottom electrode layer without damaging the bottom electrode layer, and the superimposed thickness of the top electrode layer and the organic OPV light absorbing layer is relatively large. In order to reduce the width and taper of the line groove and ensure the processing efficiency, the laser processing method for organic OPV photovoltaic cells uses Gaussian beam and diffraction homogenized beam conversion to process and etch the top electrode layer and part of the organic OVP light absorbing layer. Compared with single Gaussian beam processing, it is beneficial to reduce the width of the line groove, thereby reducing the dead zone area and improving the photoelectric conversion efficiency of the organic OPV photovoltaic cell.

[0093] After passing through the homogenizer, Gaussian light is converted into a flat-top light of a specific shape of the homogenizer. Different shapes of lenses can be used according to the required characteristics of a single lens to make it a square lens, so the flat-top light is square. The principle is mainly to use the wave nature of light and change the transmission phase of the light wave by designing the microstructure on the surface of the lens, so as to phase modulate the incident light and disperse the light to different diffraction orders. This lens utilizes the diffraction phenomenon of light and a specific structural design so that the laser can be dispersed into a specific beam distribution when passing through the lens. The design of laser diffraction lenses involves the wave theory of light and optical design. Specifically, the diffraction optical element modulates the phase of the incident light and uses the wave nature of light to cause the light wave to change phase when passing through the lens, thereby producing a specific optical effect. This design method includes precise control of the microstructure on the surface of the lens to ensure that the transmission phase of the light wave meets expectations.

[0094] like Fig. 9 As shown, a laser processing device for an OPV organic photovoltaic cell adopts a laser processing method for an OPV organic photovoltaic cell, comprising:

[0095] A laser 1, for generating a laser beam;

[0096] A lens beam expander 2, used for collimating the laser beam;

[0097] An optical diffraction lens 4 is used to shape the laser beam to form a flat top light with highly uniform energy distribution;

[0098] The homogenizer device comprises a homogenizer 3 and a detachable connecting device, and is used for quickly replacing homogenizers of different specifications.

[0099] The present invention adds a homogenizer device to homogenize the laser beam through an optical diffraction lens to achieve a specified shape. The laser homogenizer refers to a device that can convert a single-mode laser or a multi-mode laser into a uniform light spot of a specific shape. The distribution of the light spot energy has a high degree of uniformity, so that the Gaussian light is converted into a flat-top light of a specified shape. The layer to be etched is scribed and etched, and different homogenizers can be quickly replaced through a detachable connection device to obtain homogenized laser spots of different sizes.

[0100] It is beneficial to the groove etching of each functional layer in P2 and P3 laser scribing without damaging the bottom electrode layer and the substrate glass. At the same time, it can also reduce the damage to the OPV material in the edge area of ​​the spot, reduce the width and taper of the groove to obtain lower contact resistance; the dead zone range can be effectively controlled to ensure the processing efficiency, and the laser spot formed by laser beam irradiation can be shaped and homogenized, thereby improving the photoelectric conversion efficiency and stability of organic OPV thin-film solar cells.

[0101] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modification, equivalent substitution or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A laser processing method for an OPV organic photovoltaic cell, characterized in that: The following steps are involved: Step S1: Generate a laser beam by a laser, and collimate the laser beam by using a lens beam expander; Step S2: using an optical diffraction lens to shape the laser beam to form a diffraction homogenized beam; Step S3: According to the process requirements, a suitable homogenizer is selected to meet the requirements of homogenizing laser light plates of different sizes; Step S4: laser etching the P1, P2, and P3 layers of the organic OPV photovoltaic cell; The etching of the P1 layer is as follows: etching the bottom electrode layer by a Gaussian beam to form an independent strip-shaped conductive electrode; The etching of the P2 layer is as follows: the electron transport layer, the organic active layer and the hole transport layer are etched by combining a Gaussian beam and a diffraction homogenized beam; By: Step B1: pre-treatment, using a homogenized beam to pre-treat the entire area to be etched; Step B2: fine etching, using Gaussian beam for precise etching, and during the etching process, adjusting the laser power and scanning speed according to the actual material properties and etching effect; The etching of the P3 layer is as follows: the top electrode layer and the organic OPV light absorbing layer on the bottom electrode layer are etched by converting the Gaussian beam into the diffraction homogenized beam; By: Step C1: Loading a suitable phase pattern by controlling the spatial light modulator; Step C2: modulating the light wave according to the phase pattern to convert the Gaussian beam into a homogenized beam; Step C3: focusing the homogenized light beam onto the top electrode layer and the organic OPV light absorbing layer to be etched.

2. The laser processing method for OPV organic photovoltaic cells according to claim 1, characterized in that: The etching of the P1 layer is carried out in the following manner: Step A1: Positioning and calibration: Place the sample on the laser etching platform, and align the laser spot accurately with the predetermined etching starting point through visual alignment or automatic alignment system; Step A2: Test etching, verify the laser parameters by performing etching tests on the sample; Step A3: Formal etching, scan the designed path on the product, select the appropriate etching speed according to the material thickness and hardness, and monitor the etching effect in real time; Step A4: Cooling and cleaning. After etching is completed, the product is cooled and the residues produced by etching are cleaned.

3. The laser processing method for OPV organic photovoltaic cells according to claim 1, characterized in that: In step S1, a lens beam expander is used to collimate the laser beam in the following manner: Step S11: the laser beam passes through a negative lens to diverge the laser beam and increase the diameter of the beam; Step S12: The diverged laser beam passes through a positive lens to focus the laser beam, collimate the laser beam, and adjust the diameter and divergence angle of the laser beam by adjusting the distance between the negative lens and the positive lens.

4. The laser processing method for OPV organic photovoltaic cells according to claim 1, characterized in that: In step S2, an optical diffraction lens is used to shape the laser beam in the following manner: Step S21: Select a suitable optical diffraction lens according to the required spot shape and energy distribution, and install it in the light path; Step S22: adjusting the focal length, position and angle of the optical diffraction lens so that the laser beam forms a homogenized spot of a desired spot shape, and optimizing the parameters of the optical diffraction lens through experiments or simulation software.

5. The laser processing method for OPV organic photovoltaic cells according to claim 1, characterized in that: The process requirements in step S3 include spot size, spot shape, energy distribution, processing materials and processing accuracy.

6. The laser processing method for OPV organic photovoltaic cells according to claim 1, characterized in that: The homogenizer in step S3 includes a flat-top light homogenizer, a linear light homogenizer or a multi-mode homogenizer; Flat-top light homogenizer, used to produce a flat-top light spot with uniform energy distribution; Linear light homogenizer, used to generate linear light spot, suitable for linear etching or cutting; Multimode homogenizer, used to generate light spots of various shapes and energy distributions.

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