Chain Sulfone Electrolyte for Dye-Sensitized Solar Cells
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional electrolyte solutions for dye sensitized solar cells face issues with gas generation, volatility, and durability, particularly at varying temperatures, leading to reduced conversion efficiency and limited usability in wide temperature ranges.
Innovation Solution
A chain sulfone compound-based electrolyte solution is developed, which does not freeze at low temperatures and does not evaporate or generate gas at high temperatures, enhancing durability and maintaining conversion efficiency over a wide temperature range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a nitrile solvent (methoxyacetonitrile or acetonitrile) is used in the electrolyte solution, then high initial conversion efficiency is obtained, but the solvent has high vapor pressure and evaporates from the cell, failing to provide sufficient durability
Solution Approach 1:
The patent changes the chemical composition parameters of the electrolyte solution by replacing nitrile solvents with cyclic carbonate solvents (ethylene carbonate, propylene carbonate) and chain sulfone solvents (dimethyl sulfone, diethyl sulfone, dipropyl sulfone). This parameter change maintains ionic conductivity and conversion efficiency while eliminating the high vapor pressure and evaporation problems of nitrile solvents, thus improving durability.
2Stability of the object's composition
If propylene carbonate and γ-butyrolactone are used as solvents, then the electrolyte solution shows improved stability, but these solvents evaporate or generate gas upon decomposition, resulting in a narrow usable temperature range
Solution Approach 1:
The patent uses a composite electrolyte solution containing both cyclic carbonate solvents and chain sulfone solvents. The chain sulfone solvents (particularly dipropyl sulfone and diethyl sulfone) have low freezing points and high thermal stability, extending the usable temperature range to -40°C to 80°C while maintaining the stability benefits of cyclic carbonates.
3Productivity
If an electrolyte solution with high volatility is used, then the initial conversion efficiency may be high, but the vapor pressure increases under high temperature condition, making it difficult to seal completely the cell for maintaining gas tightness
Solution Approach 1:
The patent changes the volatility parameters by selecting solvents with inherently low vapor pressures. The chain sulfone solvents (dimethyl sulfone, diethyl sulfone, dipropyl sulfone) have very low vapor pressures compared to nitrile solvents, eliminating sealing problems under high temperature conditions while maintaining electrolyte functionality.
4Reliability
If the electrolyte solution is designed to have low evaporation, then durability is improved, but the solution may freeze at low temperatures or decompose at high temperatures, limiting the operating temperature range
Solution Approach 1:
The patent adjusts the freezing and decomposition temperature parameters by selecting chain sulfone solvents with appropriate molecular structures. Dipropyl sulfone and diethyl sulfone have low freezing points (-90°C and -70°C respectively) and high decomposition temperatures (>200°C), enabling operation from -40°C to 80°C without freezing or decomposition.
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 chain sulfone compound-based electrolyte solution provides excellent stability and durability, ensuring high conversion efficiency in both low and high temperature conditions, and prevents gas generation, allowing for prolonged use in dye sensitized solar cells.
Implementation Method 1
does not freeze at low temperatures
Implementation Method 2
does not evaporate at high temperatures
Implementation Method 3
the sensitizing dye absorbs the visible light to become an excited state, thereby injecting electron from the sensitizing dye to the semiconductor electrode
Implementation Method 4
The oxidized form of the sensitizing dye is reduced with the redox pair in the electrolyte solution, and thus regenerated
Data Source
Figure 1
AI summary
It is to provide an electrolyte solution for a dye sensitized solar cell that does not generate a gas, can be used in a wide temperature range, and is excellent in durability. The electrolyte solution contains a chain sulfone compound represented by formula (1) as a solvent. (In the formula, R1 and R2 each independently represent an alkyl group having from 1 to 12 carbon atoms, which may be partially substituted by a halogen, an alkoxy group or an aromatic ring, an alkoxy group, or a phenyl group.)