Quantum Dot Perovskite Absorption Layer for Two-Step Solar Conversion
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Solution Overview
Problem
Intermediate-band solar cells face limitations in improving photoelectric conversion efficiency due to poor combinations of energy levels between bulk semiconductors and quantum dots, leading to restricted two-step light absorption efficiency.
Innovation Solution
A light absorption layer is created using a perovskite compound with a specific band gap energy and quantum dots dispersed within it, forming an intermediate-band that enhances two-step light absorption efficiency, achieved through a wet process manufacturing method.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a dry process such as molecular beam epitaxy (MBE) method is used to manufacture intermediate-band solar cell, then the photoelectric conversion efficiency can be improved by forming intermediate-band, but the manufacturing cost increases and material selection is limited
Solution Approach 1:
The patent replaces the dry process (molecular beam epitaxy) with a wet process (solution-based method). Specifically, quantum dots are dispersed in a solvent to form a solution, which is then applied to the substrate and processed through liquid-phase deposition and heat treatment, substituting complex vacuum-based mechanical systems with simpler liquid-phase chemical processes
Solution Approach 2:
The patent changes the manufacturing parameters from gas-phase deposition to liquid-phase processing. By dissolving quantum dots in solvents and controlling solution concentration, temperature, and processing time, the patent achieves intermediate-band formation through wet chemistry rather than vacuum deposition, reducing manufacturing complexity and cost
2Adaptability or versatility
If quantum dots are dispersed in amorphous IGZO matrix layer, then the manufacturing flexibility is improved, but the combination of energy levels (band structure) between bulk semiconductor and quantum dot is poor, limiting photoelectric conversion efficiency
Solution Approach 1:
The patent systematically adjusts the band gap energy parameter of the matrix material, selecting perovskite compounds with specific band gap ranges (1.5-3.0 eV) to match quantum dot energy levels. This parameter optimization ensures proper energy level alignment for efficient two-step light absorption while maintaining wet process manufacturing flexibility
Solution Approach 2:
The patent creates a composite light absorption layer combining perovskite matrix material with dispersed quantum dots. This composite structure leverages the advantages of both materials: the perovskite provides suitable band gap and crystalline structure, while quantum dots contribute size-tunable energy levels, achieving both manufacturing flexibility and high photoelectric conversion efficiency
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 approach significantly improves the quantum efficiency of two-step light absorption, potentially surpassing the Shockley-Queisser limit, and reduces production costs while expanding substrate flexibility.
Implementation Method 1
By regularly arranging nano-sized semiconductors (quantum dots) in a bulk (matrix) semiconductor at high density, an 'intermediate-band' due to quantum dot interaction is formed within the band gap of the bulk semiconductor
Implementation Method 2
photoexcitation from the valence band of the bulk semiconductor to the 'intermediate-band' and photoexcitation from the 'intermediate-band' to the conduction band of the bulk semiconductor (two-step light absorption) become possible
Implementation Method 3
A light absorption layer is created using a perovskite compound with a specific band gap energy and quantum dots dispersed within it, forming an intermediate-band that enhances two-step light absorption efficiency
Data Source
Figure 1
AI summary
The present invention relates to a light absorption layer for forming a photoelectric conversion element and an intermediate-band solar cell excellent in quantum efficiency of two-step light absorption, a photoelectric conversion element having the light absorption layer, and an intermediate-band solar cell. The present invention also relates to a method for manufacturing a light absorption layer having an intermediate-band, using a "wet process", which method can be expected to greatly reduce costs and expand to use for flexible substrates. The light absorption layer of the present invention has an intermediate-band, wherein quantum dots are dispersed in a matrix of a bulk semiconductor having a band gap energy of 2.0 eV or more and 3.0 eV or less.