Ink Composition Solvent System for Organic Solar Cell Efficiency
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Solution Overview
Problem
Conventional ink compositions for organic film solar batteries using P-type and N-type semiconductor materials fail to achieve high short circuit current density, limiting their photoelectric conversion efficiency.
Innovation Solution
An ink composition comprising a P-type semiconductor material, an N-type semiconductor material, and two solvents with a total weight percentage of 70% or more, where the solvents have a boiling point difference and hydrogen bond Hansen solubility parameter difference within specific ranges, enhancing the solubility and film formation properties to achieve high short circuit current density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional ink composition containing a single solvent is used to form an active layer, then the manufacturing process is simple, but high short circuit current density cannot be obtained
Solution Approach 1:
The patent applies composite materials by combining multiple solvents (first solvent and second solvent) in the ink composition. Each solvent has different properties (boiling points, Hansen solubility parameters) that complement each other, creating a composite solvent system that achieves high short circuit current density while maintaining manufacturability.
Solution Approach 2:
The patent changes the parameters of the solvent system by specifying different boiling point ranges (first solvent: 80-150°C, second solvent: 150-250°C) and Hansen solubility parameter differences (ΔδH: 2.0-6.0 MPa^0.5, ΔδP: 3.0-8.0 MPa^0.5). These parameter optimizations enable the ink composition to achieve high photoelectric conversion efficiency without complicating the manufacturing process.
2Manufacturing precision
If solvents with large boiling point difference are used, then film formation properties are improved, but the solvent system becomes more complex
Solution Approach 1:
The patent optimizes the boiling point parameters of the solvents within specific ranges (first solvent: 80-150°C, second solvent: 150-250°C) rather than using extreme differences. This controlled parameter change achieves good film formation properties while avoiding excessive complexity in the solvent system.
Solution Approach 2:
The patent assigns different functional roles to each solvent based on their local properties: the first solvent (lower boiling point) primarily facilitates dissolution and initial film formation, while the second solvent (higher boiling point) enhances film quality and stability. This local quality differentiation improves film formation without requiring complex solvent interactions.
3Stability of the object's composition
If the hydrogen bond Hansen solubility parameter difference between solvents is optimized, then solubility of semiconductor materials is enhanced, but the ink composition becomes more complex
Solution Approach 1:
The patent changes the Hansen solubility parameters of the solvent system by specifying the hydrogen bond parameter difference (ΔδH: 2.0-6.0 MPa^0.5) and polarity parameter difference (ΔδP: 3.0-8.0 MPa^0.5). These parameter optimizations enhance the solubility of both P-type and N-type semiconductor materials while keeping the ink composition relatively simple and manageable.
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 ink composition effectively increases short circuit current density, improving the photoelectric conversion efficiency of organic film solar batteries by optimizing the solvent combination and material ratios.
Implementation Method 1
an ink composition containing an active layer constituent material and a solvent
Implementation Method 2
two solvents having a difference in boiling points
Data Source
AI summary
An ink composition comprising a P-type semiconductor material, an N-type semiconductor material and two or more solvents including a first solvent and a second solvent, wherein the total amount of the first solvent and the second solvent is 70% by weight or more with respect to 100% by weight of all the solvents contained in the ink composition; the boiling point of the first solvent is lower than the boiling point of the second solvent; the boiling point of the first solvent is 120°C or more and 400°C or less; and the hydrogen bond Hansen solubility parameter H1 (MPa0.5) of the first solvent and the hydrogen bond Hansen solubility parameter H2 (MPa0.5) of the second solvent are in the relation of 0.5 ≤ (H2-H1) ≤ 5.0; the first solvent is an aromatic hydrocarbon solvent; the P-type semiconductor material is a polymer compound comprising a repeating unit represented by the following (1-1) and/or the following formula (II-1) to (II-4) or (II-6): wherein, Z represents a divalent group represented by (Z-1) to (Z-7), wherein, X1 and X2 each independently represent an oxygen atom or a sulfur atom, R represents a hydrogen atom, a halogen atom, an alkyl group, an aryl group, an alkoxy group, an aryloxy group, an alkylthio group, an arylthio group, a mono-valent heterocyclic group, a substituted amino group, an acyl group, an imine residue, a substituted amide group, an acid imide group, a substituted carboxyl group, an alkenyl group, an alkynyl group, a cyano group or a nitro group.