Solar Cell Doped-Layer Gradients to Reduce Parasitic Absorption
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Solution Overview
Problem
The photoelectric conversion efficiency of conventional solar cells is poor due to inadequate control of doping element concentration in the doped conductive layer, leading to insufficient potential barriers, parasitic absorption, and reduced carrier collection efficiency.
Innovation Solution
The doping element concentration of the first doped conductive layer is lower than that of the second doped conductive layer, with a concentration gradient between alternating first and second portions, enhancing carrier transport and reducing parasitic absorption, thereby improving the photoelectric conversion performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the doping element concentration in the doped conductive layer is increased to form a sufficiently high potential barrier, then carrier recombination is suppressed and field passivation is enhanced, but parasitic absorption increases and photoelectric conversion efficiency deteriorates
Solution Approach 1:
The patent applies local quality by creating alternating first and second portions in the doped conductive layer with different doping element concentrations. The first portions have a first doping concentration optimized for field passivation, while the second portions have a second doping concentration optimized for reducing parasitic absorption. This spatial variation in doping concentration allows different regions to perform different functions, resolving the contradiction between achieving sufficient potential barrier and minimizing parasitic absorption.
2Reliability
If the doping element concentration is uniformly high throughout the doped conductive layer, then a sufficiently high potential barrier is formed for selective carrier transport, but carrier collection efficiency decreases due to excessive parasitic absorption
Solution Approach 1:
The patent implements local quality by dividing the doped conductive layer into alternating first and second portions with different doping concentrations. The first portions maintain high doping concentration to ensure selective carrier transport and field passivation, while the second portions have reduced doping concentration to minimize parasitic absorption and improve carrier collection efficiency. This localized differentiation resolves the contradiction between maintaining potential barrier and improving carrier collection.
Solution Approach 2:
The patent applies segmentation by dividing the doped conductive layer into multiple alternating first and second portions along the thickness direction. This segmentation allows the layer to simultaneously exhibit regions with high doping concentration (for potential barrier formation) and regions with low doping concentration (for reduced parasitic absorption), thereby resolving the contradiction between selective carrier transport and carrier collection efficiency.
3Loss of energy
If the doping element concentration in the doped conductive layer is reduced to decrease parasitic absorption, then photoelectric conversion efficiency improves, but the potential barrier becomes insufficient and carrier recombination increases
Solution Approach 1:
The patent resolves this contradiction by applying local quality through alternating first and second portions with different doping concentrations. The first portions maintain sufficient doping concentration to form the potential barrier and prevent carrier recombination, while the second portions have reduced doping concentration to minimize parasitic absorption. This spatial differentiation allows both requirements to be satisfied simultaneously in different regions.
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 configuration enhances carrier collection and utilization, increasing short circuit current and open circuit voltage, and improves the overall photoelectric conversion efficiency of the solar cell.
Implementation Method 1
the tunneling layer has desirable chemical passivation effect
Implementation Method 2
the doped conductive layer has desirable field passivation effect
Implementation Method 3
make it easier for majority carriers in the substrate to tunnel through the tunneling layer
Implementation Method 4
form a sufficiently high potential barrier between the doped conductive layer and the substrate
Implementation Method 5
forming a concentration gradient to enhance carrier transport and reduce parasitic absorption
Data Source
Figure 1~2
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Figure 5~6
AI summary
The embodiments of the present application relate to the technical field of solar cells, in particular to a solar cell, a method for preparing a solar cell, and a photovoltaic module. The solar cell includes a substrate having a first surface, a tunneling layer disposed on the first surface, and a first doped conductive layer disposed on a surface of the tunneling layer away from the substrate. The solar cell further includes a second doped conductive layer disposed on a surface of the first doped conductive layer away from the substrate, where the second doped conductive layer includes: multiple first portions and multiple second portions arranged alternately in a direction perpendicular to a predetermined direction and perpendicular to a thickness direction of the second doped conductive layer, each of the multiple first portions and the multiple second portions extends along the predetermined direction, a doping element concentration of the first doped conductive layer is lower than a doping element concentration of each of the multiple first portions, and the doping element concentration of each of the multiple first portions is lower than a doping element concentration of each of the multiple second portions. The predetermined direction is any direction parallel to the first surface. The solar cell further includes multiple first electrodes. Each of the multiple first electrodes extends along the predetermined direction, the multiple first electrodes are in an one-to-one correspondence to the multiple second portions, and each of the multiple first electrodes is in electrical contact with a corresponding second portion in the multiple second portions. The embodiments of the present application are beneficial for improving the photoelectric conversion efficiency of the solar cell.