Perovskite-Silicon Tandem Cell Texture Rounding for Uniform Deposition
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Solution Overview
Problem
The formation of a perovskite absorption layer on a textured silicon substrate is challenging due to the fine pitch and geometric inclination of the texture, leading to non-uniform thickness and degraded optical characteristics in perovskite/crystalline silicon tandem solar cells.
Innovation Solution
A rounding process is applied to the texture of the substrate, increasing the radii of curvature of valley portions and reducing the inclination angle, followed by isotropic etching to form a uniform perovskite absorption layer and inter-layer, using methods like wet etching with a hydrofluoric acid and nitric acid mixture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a textured structure with fine pitch is formed on the silicon substrate to reduce reflectance, then light absorption efficiency is improved, but the uniformity of perovskite absorption layer formation deteriorates
Solution Approach 1:
An isotropic etching process is performed as a preliminary step before perovskite deposition to modify the texture geometry. This preliminary action rounds the peaks and valleys of the texture, creating a more uniform surface topology that enables subsequent uniform perovskite layer formation while preserving the light-trapping benefits of the original texture
Solution Approach 2:
The geometric parameters of the texture are changed through isotropic etching, specifically modifying the radius of curvature of peaks and valleys and reducing the inclination angle of inclined surfaces. These parameter changes transform the original sharp, high-angle texture into a rounded, low-angle texture that is more compatible with uniform perovskite deposition
2Stability of the object's composition
If the texture has a large inclination angle of about 55 degrees, then the geometric stability of the {111} plane is maintained, but the formation of perovskite absorption layer at inclined portions is impeded
Solution Approach 1:
The inclination angle parameter of the texture is reduced from approximately 55 degrees to a smaller angle through isotropic etching. This parameter change maintains the crystalline stability of the silicon substrate while creating gentler slopes that allow uniform perovskite material deposition across all surface regions
3Ease of manufacture
If a solution with high fluidity is used to form the perovskite absorption layer, then the deposition process is simplified, but the solution cannot fill valley portions due to viscous nature
Solution Approach 1:
The isotropic etching process is performed in advance to pre-shape the valley portions with increased radius of curvature. This preliminary modification of the substrate geometry enables subsequent solution-based perovskite deposition to uniformly fill all valley regions without being hindered by solution viscosity, maintaining both process simplicity and deposition quality
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 approach enhances the uniformity and efficiency of the tandem solar cell by stabilizing the perovskite absorption layer deposition, improving light absorption and reducing reflectance, thereby increasing the overall cell performance.
Implementation Method 1
using methods like wet etching with a hydrofluoric acid and nitric acid mixture
Implementation Method 2
wet etching with a hydrofluoric acid and nitric acid mixture
Implementation Method 3
a perovskite absorption layer formed on the substrate
Data Source
Figure 1~2
Figure 3~4
Figure 5(a)~6
AI summary
The present invention relates to: a monolithic tandem solar cell in which a perovskite solar cell is stacked on and joined with a silicon solar cell; and a manufacturing method. According to the present invention, provided are: a tandem solar cell comprising, a substrate on which a texture having both a valley shape and a peak shape is formed, and a perovskite absorbing layer formed on the substrate, wherein the valley part and the peak part of the texture have a round shape; and a manufacturing method therefor, thereby uniformly improving efficiency of the tandem solar cell all over a panel and preventing shorting in a junction layer so as to prevent shorts.