Tandem Solar Cell Dielectric Recombination Layer for Carrier Tunneling
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Solution Overview
Problem
Existing tandem solar cells have a large deviation in actual photoelectric conversion efficiency from theoretical efficiency, and their structure needs optimization to improve efficiency.
Innovation Solution
A solar cell structure is proposed, including a bottom cell, a recombination layer with a dielectric layer and a transparent conductive layer, and a top cell stacked in a specific direction. The dielectric layer enhances carrier tunneling capability, reduces recombination loss, and provides surface passivation to improve photoelectric conversion efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a tandem solar cell structure is adopted to improve photoelectric conversion efficiency, then the utilization rate of incident light increases, but the actual efficiency deviates significantly from theoretical efficiency due to structural limitations
Solution Approach 1:
The solar cell is divided into multiple semiconductor cell sheets with different energy gaps (e.g., perovskite top cell, silicon bottom cell) stacked in sequence. Each segment absorbs a specific portion of the solar spectrum, with the top cell absorbing high-energy photons and the bottom cell absorbing lower-energy photons that pass through, thereby segmenting the light absorption function to reduce reflection and improve overall photoelectric conversion efficiency
Solution Approach 2:
A recombination layer is introduced as an intermediary component between the top and bottom cells. This recombination layer facilitates carrier recombination and extraction, mediating the interaction between the two semiconductor cell sheets with different energy gaps. The recombination layer includes a dielectric layer and a transparent conductive layer that work together to optimize carrier transport and reduce recombination losses at the interface
2Device complexity
If the recombination layer structure is simplified to reduce manufacturing complexity, then device complexity decreases, but carrier tunneling capability and surface passivation are insufficient leading to increased recombination loss
Solution Approach 1:
The recombination layer is constructed as a composite structure consisting of a dielectric layer and a transparent conductive layer. The dielectric layer (e.g., silicon oxide, silicon nitride, or aluminum oxide) provides high-quality surface passivation and enables carrier tunneling, while the transparent conductive layer (e.g., ITO, IZO, or ZnO) provides electrical conductivity and additional passivation. This composite material approach achieves both low recombination loss and manageable manufacturing complexity by combining materials with complementary properties
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
The proposed structure enhances the photoelectric conversion efficiency of the solar cell by reducing recombination loss, improving surface passivation, and optimizing the structure to align with the requirements for better light absorption and carrier transfer.
Implementation Method 1
the dielectric layer is formed on at least a portion of the first surface... enhancing carrier tunneling capability
Implementation Method 2
provides surface passivation to improve photoelectric conversion efficiency
Implementation Method 3
solar cell... improve the photoelectric conversion efficiency
Data Source
AI summary
Embodiments of the present disclosure relate to a solar cell and a photovoltaic module. The solar cell includes a bottom cell, a recombination layer, and a top cell stacked in a first direction. The bottom cell includes at least one first electrode, a first semiconductor conductive layer, a substrate, and a second semiconductor conductive layer stacked in the first direction. The recombination layer includes a dielectric layer and a first transparent conductive layer stacked in the first direction, the second semiconductor conductive layer has a first surface facing towards the top cell, and the dielectric layer is formed on at least a portion of the first surface. In this way, the photoelectric conversion efficiency of the solar cell can be at least improved.