Hydrazine-Free Selenium Ink for CIGS Solar Cell Deposition
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Solution Overview
Problem
Conventional methods for depositing selenium in the manufacture of CIGS materials, such as vacuum-based processes, are costly and have low throughput, and existing solution-based methods using hydrazine or hydrazinium precursors pose safety risks due to their toxicity and explosion hazards.
Innovation Solution
A selenium ink comprising a reaction product of ≥1 wt% selenium with a traceless reducing agent and a liquid carrier, forming a stable dispersion that is hydrazine-free and hydrazinium-free, allowing for the deposition of selenium on a substrate as a mixture of Se0 and Se1-, facilitating the formation of CIGS materials without the need for hazardous chemicals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If vacuum-based deposition processes (vacuum-evaporation, sputtering, chemical vapor deposition) are used to deposit selenium, then deposition quality is maintained, but manufacturing cost increases and throughput decreases
Solution Approach 1:
The patent replaces vacuum-based mechanical deposition processes with a solution-based chemical deposition method. Selenium is delivered dissolved in a liquid carrier solution, eliminating the need for vacuum equipment and enabling low-cost, high-throughput deposition suitable for large-scale manufacturing.
Solution Approach 2:
The invention uses a liquid carrier solution to transport and deposit selenium. The solution can be applied using various liquid delivery methods (spin-coating, spray, dip-coating), enabling hydraulic-based deposition that is inherently more scalable and cost-effective than vacuum-based gas-phase methods.
2Ease of manufacture
If hydrazine or hydrazinium precursors are used in solution-based selenium deposition, then selenium can be deposited, but safety risks increase due to toxicity and explosion hazards
Solution Approach 1:
The patent extracts and removes the hazardous hydrazine and hydrazinium components from the deposition system. The invention achieves selenium deposition using alternative, non-hazardous liquid carriers and precursors, eliminating the safety risks associated with explosive and toxic substances while maintaining solution-based deposition benefits.
Solution Approach 2:
The invention converts the potentially harmful hydrazine-based system into a safe alternative by using benign liquid carriers. The original harmful approach is transformed into a beneficial safe process that maintains all the advantages of solution-based deposition without the associated safety hazards.
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 selenium ink enables a stable, cost-effective, and safe deposition process for CIGS materials, improving manufacturing efficiency and safety by eliminating the use of toxic hydrazine and hydrazinium, thereby supporting large-scale production of high-efficiency solar cells.
Implementation Method 1
a reaction product of: ≥ 1 wt % selenium; a traceless reducing agent; and a liquid carrier
Implementation Method 2
the selenium ink is a stable dispersion
Data Source
AI summary
A selenium ink comprising selenium stably dispersed in a liquid medium is provided, wherein the selenium ink is hydrazine free and hydrazinium free. Also provided are methods of preparing the selenium ink and of using the selenium ink to deposit selenium on a substrate for use in the manufacture of a variety of chalcogenide containing semiconductor materials, such as, thin film transistors (TFTs), light emitting diodes (LEDs); and photo responsive devices (e.g., electrophotography (e.g., laser printers and copiers), rectifiers, photographic exposure meters and photo voltaic cells) and chalcogenide containing phase change memory materials.