Lead Iodide Crystal Control for Perovskite Solar Cell Stability
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Solution Overview
Problem
Current methods for preparing perovskite solar cells face challenges in achieving both high power conversion efficiency and thermal stability, as existing perovskite materials like MAPbI3 have poor thermal stability and FAPbI3 is thermodynamically unstable at room temperature, leading to complex production conditions.
Innovation Solution
A method for preparing lead iodide by adding an iodine compound to a lead-containing acid solution, heating it to 60° C or above, and maintaining a constant temperature to control the crystal form, resulting in a lead iodide with a peak intensity of the (003) crystal plane greater than or equal to the (110) crystal plane, which is then used to formulate a ternary perovskite precursor solution and coat it on a substrate to form a perovskite film.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If MAPbI3 is used as perovskite material, then it is easy to produce, but it has poor thermal stability and shorter lifespan
Solution Approach 1:
The patent uses composite perovskite materials combining multiple cations (MA, FA, Cs) and anions (I, Br) to create a material that balances ease of production with improved thermal stability. The composite structure allows leveraging the advantages of different materials while mitigating their individual weaknesses.
Solution Approach 2:
The patent systematically varies compositional parameters (cation ratios, anion ratios) to optimize both production ease and thermal stability. By adjusting the proportions of different cations and anions, the material achieves a balance between manufacturability and stability.
2Stability of the object's composition
If FAPbI3 is used as perovskite material, then it has higher thermal stability and power conversion efficiency, but the photoactive black phase is thermodynamically unstable at room temperature and forms non-photoactive yellow phase
Solution Approach 1:
The patent creates a ternary or quaternary composite perovskite (e.g., FAPbI3 mixed with MAPbI3 and/or CsPbI3) to stabilize the photoactive black phase at room temperature. The mixed cation composition reduces the thermodynamic instability of pure FAPbI3 while maintaining its high efficiency characteristics.
Solution Approach 2:
The patent introduces localized compositional variations within the perovskite structure, where different cation distributions create local environments that stabilize the black phase. This local quality adjustment prevents phase transition to the yellow phase while maintaining overall material stability.
3Ease of manufacture
If lead iodide with conventional crystal form is used, then the production conditions are simpler, but the power conversion efficiency of perovskite solar cells is limited
Solution Approach 1:
The patent changes the crystal structure parameters of lead iodide by controlling the (003) and (110) plane intensities through specific synthesis conditions. This crystal structure modification improves charge transport properties and enhances power conversion efficiency without significantly complicating the production process.
Solution Approach 2:
The patent performs preliminary optimization of lead iodide crystal structure before perovskite film formation. By pre-controlling the crystal planes of lead iodide, the subsequent perovskite layer inherits improved structural properties that enhance overall device 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
This approach enhances the photoelectric properties of the perovskite film, optimizing power conversion efficiency and stabilizing the material, thereby improving the performance of perovskite solar cells.
Implementation Method 1
heating the reaction solution to a temperature of 60° C. or above and standing at a constant temperature
Implementation Method 2
a lead compound is dissolved in a first acid solution
Implementation Method 3
adding an iodine compound to a first acid solution, in which a lead compound is dissolved, to form a reaction solution including a first lead iodide
Data Source
AI summary
Provided is a method for preparing lead iodide, which controls the crystal form of lead iodide through temperature, including: dissolving a lead compound in a first acid solution and adding an iodine compound to form a reaction solution including the first lead iodide; and heating the reaction solution to a temperature of 60° C. or more and standing at a constant temperature, to obtain the second lead iodide, wherein a peak intensity of the (003) crystal plane of the second lead iodide is greater than or equal to a peak intensity of the (110) crystal plane. Provided is also a method for preparing the perovskite film.