Solar Cell Nano-Micro Composite Structure Manufacturing
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Solution Overview
Problem
Current solar cell manufacturing methods are limited in their ability to efficiently form microwires and nanowires with varying sizes and aspect ratios, leading to suboptimal light absorption and conversion efficiency.
Innovation Solution
A method involving electroless etching to form microwires with widths of 1 μm to 3 μm and nanowires with widths of 1 nm to 100 nm on a silicon substrate, using a silver nitrate and hydrofluoric acid solution, followed by hydrogen peroxide and nitric acid treatments, to increase the light path and enhance quantum effects, thereby improving efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional planar structures are used for solar cells, then manufacturing is simpler, but light absorption and conversion efficiency are limited
Solution Approach 1:
The solar cell surface is segmented into microwire regions and nanowire regions through photoresist patterning, allowing different structural features to be formed in different areas. This segmentation enables precise control over light absorption paths while maintaining manufacturing feasibility through standardized electroless etching processes.
Solution Approach 2:
The invention transitions from traditional planar (2D) solar cell surfaces to three-dimensional microwire and nanowire structures. This dimensional change increases the effective light absorption area and creates multiple light reflection paths, thereby improving conversion efficiency without significantly complicating the manufacturing process.
2Manufacturing precision
If multiple separate processes are used to form microwires and nanowires, then each structure can be optimized, but processing time and costs increase
Solution Approach 1:
The invention merges the formation of microwires and nanowires into a single integrated electroless etching process. By using photoresist patterns as masks and controlling etching conditions, both microwire and nanowire structures are formed simultaneously in one processing step, eliminating the need for separate fabrication processes and reducing overall processing time and costs.
Solution Approach 2:
The invention uses parameter changes in the electroless etching process (such as etching solution concentration, temperature, and immersion time) to control the formation of different wire structures. By adjusting these parameters, precise control over micrawire width (1 μm to 3 μm) and nanowire width (1 nm to 100 nm) is achieved within a single process.
3Manufacturing precision
If photoresist is patterned with intersecting lines, then micrawires can be formed with precise geometry, but the process complexity increases
Solution Approach 1:
The photoresist pattern serves a dual function: it defines the micrawire geometry through its intersecting line design and simultaneously acts as a mask that controls nanowire formation in the exposed regions. This self-service approach eliminates the need for additional masking steps, simplifying the overall manufacturing process while maintaining precise geometric control.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method allows for the simultaneous formation of microwires and nanowires, reducing processing time and costs, increasing light absorption, and enhancing solar cell efficiency by up to 13% compared to traditional planar structures.
Implementation Method 1
electroless etching the semiconductor substrate to form a micrawire having a width of 1 μm to 3 μm and a height of 3 μm to 5 μm in a region corresponding to the photoresist
Implementation Method 2
second immersing in which the semiconductor substrate having silver particles attached thereto from the silver nitrate solution is immersed in a mixed solution of a hydrogen peroxide solution and a hydrofluoric acid solution
Implementation Method 3
third immersing in which the semiconductor substrate is immersed in a mixed solution of a nitric acid solution and water to remove the silver particles
Implementation Method 4
a plurality of nanowires having a width of 1 nm to 100 nm and a height of 1 μm to 3 μm which is formed at an outer side of the micrawire to increase a path of light
Data Source
AI summary
One embodiment of the present invention relates to a method for manufacturing solar cells having a nano-micro composite structure on a silicon substrate and solar cells manufactured thereby. The technical problem to be solved is to provide a method for manufacturing solar cells and solar cells manufactured thereby, the method being capable of forming micro wires in various sizes according to the lithographic design of a photoresist and forming nano wires, which have various sizes and aspect ratios, by adjusting the concentration of a wet etching solution and immersion time. To this end, the present invention provides a method for manufacturing solar cells and solar cells manufactured thereby, the method comprising the steps of: preparing a first conductive semiconductor substrate having a first surface and a second surface; patterning a photoresist on the second surface of the first conductive semiconductor substrate such that the plane form of the photoresist becomes a form in which multiple horizontal lines and multiple vertical lines intersect each other; electrolessly etching the semiconductor substrate so as to form a micro wire having a width of 1-3 μm and a height of 3-5 μm in a region corresponding to the photoresist and to form multiple nano wires having a width of 1-100 nm and a height of 1-3 μm in a region not corresponding to the photoresist; doping the micro wire and nano wires with a second conductive impurity by using POCl3; forming a first electrode on the first surface of the semiconductor substrate; and forming a second electrode on the micro wire, wherein the efficiency of the solar cells is 10-13%, the efficiency being the ratio of output to incident light energy per unit area.