CIGS Nanoparticle Ink with Inorganic Salts for Scalable PV Deposition
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Solution Overview
Problem
Conventional methods for producing copper indium gallium diselenide/disulphide (CIGS)-based thin film photovoltaic devices are costly and difficult to scale due to the use of expensive vapor phase techniques, and they face challenges in achieving large grain sizes and uniform film deposition.
Innovation Solution
A solution-based deposition method using ternary, quaternary, or quinary chalcogenide nanoparticles and inorganic salts in an ink formulation, which can be printed on a substrate, allowing for annealing to form a crystalline CIGS layer, thereby tuning stoichiometry, promoting grain growth, and improving coating properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional vapor phase techniques (MO-CVD, RF sputtering, flash evaporation) are used to deposit CIGS films, then high quality films are achieved, but production cost increases and scalability to large-area deposition becomes difficult
Solution Approach 1:
The patent replaces mechanical vapor deposition techniques (MO-CVD, RF sputtering, flash evaporation) with a solution-based printing approach. CIGS precursor ink containing nanoparticles and inorganic salts is deposited through printing methods, eliminating the need for complex vacuum equipment and high-energy vapor phase processes. This substitution enables large-area deposition and reduces production costs while maintaining film quality.
Solution Approach 2:
The patent changes the physical and chemical parameters of the deposition process by using a solution-based ink formulation instead of vapor phase materials. The ink contains nanoparticles suspended in a solvent with dissolved inorganic salts, allowing deposition at lower temperatures and pressures. This parameter change enables scalability to large-area substrates and reduces equipment complexity.
2Manufacturing precision
If selenisation process is used to convert CuInS2 to CuInSe2, then high quality dense absorber layers are formed, but volume expansion occurs and process complexity increases
Solution Approach 1:
The patent incorporates inorganic salts (such as NaCl, KCl, CsCl) and dopants directly into the CIGS precursor ink formulation before deposition. This preliminary incorporation eliminates the need for subsequent selenisation treatment to achieve desired stoichiometry and doping levels. The absorber layer forms with correct composition directly during the deposition and annealing process, reducing process complexity while maintaining high density.
3Manufacturing precision
If inorganic salts are added to tune stoichiometry and promote grain growth, then coating properties improve, but ink formulation complexity increases
Solution Approach 1:
The patent merges multiple functions into the ink formulation by combining CIGS precursor nanoparticles, inorganic salts for stoichiometry control, and dopants for grain growth promotion into a single solution-based ink. This unified formulation simplifies the deposition process while achieving precise control over film composition, stoichiometry, and microstructure through careful selection of ink components and their concentrations.
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 enables the production of high-efficiency CIGS films with larger grain sizes and improved coating uniformity, reducing production costs and enabling scalable deposition, thus enhancing the power conversion efficiency of solar cells.
Implementation Method 1
The ink can be deposited on a substrate by conventional coating techniques and then annealed to form a crystalline layer
Implementation Method 2
The ink can be deposited on a substrate by conventional coating techniques
Data Source
AI summary
Compositions for solution-based deposition of CIGS films are described. The compositions include ternary, quaternary or quinary chalcogenide nanoparticles (i.e., CIGS nanoparticles) and one or more inorganic salts dissolved or dispersed in a solvent to form an ink. The ink can be deposited on a substrate by conventional coating techniques and then annealed to form a crystalline layer. Further processing can be employed to fabricate a PV device. The inorganic salts are included to (i) tune the stoichiometry of the CIGS precursor ink to a desirable ratio, thus tuning the semiconductor band gap, to (ii) dope the CIGS layer with additives, such as Sb and/or Na, to promote grain growth, and/or to (iii) modify and improve the coating properties of the CIGS precursor ink.