Cuprous Oxide Solar Cell N-Type Layering for Band Alignment
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Solution Overview
Problem
Current solar cells using cuprous oxide (Cu2O) for light-absorbing layers face challenges in achieving high efficiency and low cost while maintaining good crystallinity and transmittance, with existing configurations not effectively optimizing the conduction band minimum connection and carrier concentration across the n-type layers.
Innovation Solution
The solar cell design incorporates a multi-layer n-type structure with specific compositions and thicknesses of Ga-based oxide layers, including a first and second n-type layer, and optionally a third n-type layer, to optimize the conduction band minimum connection and carrier concentration, improving continuity and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a single n-type layer is used in the solar cell, then the device complexity is reduced, but the conversion efficiency and carrier concentration optimization are insufficient
Solution Approach 1:
The n-type layer is divided into multiple sub-layers (first n-type layer, second n-type layer, and optionally third n-type layer) with different compositions and thicknesses. Each sub-layer is optimized for specific functions: the first n-type layer (5-20 nm) provides initial carrier generation, the second n-type layer (20-50 nm) with higher Ga content optimizes conduction band minimum connection, and the third n-type layer (10-30 nm) with ZnO enhances carrier concentration. This segmentation enables precise control of energy structure and carrier distribution, achieving high conversion efficiency while maintaining manageable device complexity through systematic layer design.
2Manufacturing precision
If the n-type layer thickness is increased to improve carrier concentration, then the conversion efficiency improves, but the light transmittance decreases
Solution Approach 1:
Different regions of the n-type layer structure are assigned different compositions and thicknesses to optimize local properties. The first n-type layer (5-20 nm) with specific Ga content is positioned closest to the p-type light-absorbing layer for optimal interface contact. The second n-type layer (20-50 nm) with higher Ga content (0.5-1.5) is placed in the middle to optimize conduction band minimum connection. The third n-type layer (10-30 nm) with ZnO is positioned farthest from the light-absorbing layer to enhance carrier concentration without excessive light absorption. This local quality optimization allows each layer to contribute maximally to carrier concentration while minimizing impact on light transmittance.
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 design enhances the short-circuit current (Jsc), open-circuit voltage (Voc), fill factor (FF), and conversion efficiency of the solar cell by optimizing the energy structure and carrier concentration across the n-type layers, leading to improved performance compared to comparative examples.
Implementation Method 1
A solar cell using a cuprous oxide (Cu2O) for a light-absorbing layer
Data Source
AI summary
A solar cell of an embodiment includes a p-electrode, an n-electrode, a p-type light-absorbing layer located between the p-electrode and the n-electrode and comprising a cuprous oxide, and an n-type layer comprising a first n-type layer, which is located between the p-type light-absorbing layer and the n-electrode and comprising a defined compound aiding in conversion efficiency. The n-type layer further comprises a second n-type layer which is located between the first n-type layer and the n-electrode and mainly contains another compound aiding in conversion efficiency.