Organic Semiconductor Layer Thickness Uniformity via Solvent Resistance
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Solution Overview
Problem
Ink-jet processes for forming organic semiconductor layers in organic electroluminescent devices often result in nonuniform film thickness due to inconsistent lyophobic or lyophilic surface properties, leading to nonuniformity in the thickness of formed films and electrical conductivity.
Innovation Solution
A method involving the formation of a liquid composition film on a substrate or existing organic semiconductor layer, where a portion of the film is altered to be insoluble in a solvent and the remaining portion is removed, ensuring a uniform thickness of the organic semiconductor layer, and optionally cross-linking using heat, UV, or plasma irradiation to enhance stability and uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If ink-jet processes are used to form organic semiconductor layers, then large area substrates can be processed easily, but the film thickness becomes nonuniform due to inconsistent surface properties
Solution Approach 1:
The patent applies a preliminary action by forming an altered portion (cross-linked or cured layer) at the interface between the organic semiconductor layer and the substrate or underlying layer before completing the layer formation. This altered portion is created by irradiating with ultraviolet light or applying heat after applying the liquid composition but before the layer is fully formed, preventing dissolution and ensuring uniform thickness throughout the process.
Solution Approach 2:
The patent changes the physical and chemical parameters of the organic semiconductor material by altering its solubility characteristics. Through cross-linking or curing reactions initiated by ultraviolet irradiation or heat treatment, the material transitions from a soluble state to an insoluble altered portion, enabling precise control over film formation and thickness uniformity during the ink-jet process.
2Device complexity
If organic semiconductor layers are formed by conventional methods, then the process is simple, but the electrical conductivity becomes nonuniform due to thickness variations
Solution Approach 1:
The patent introduces a preliminary action step where an altered portion is formed at the interface region before the organic semiconductor layer completion. This is achieved by irradiating with ultraviolet light or applying heat to cross-link or cure the material in the region adjacent to the substrate or underlying layer, ensuring uniform thickness and consequently uniform electrical conductivity across the entire layer.
Solution Approach 2:
The patent modifies the chemical parameters of the organic semiconductor material by inducing cross-linking or curing reactions. This parameter change transforms the material properties in the altered portion, preventing dissolution and ensuring consistent thickness, which directly translates to uniform electrical conductivity while maintaining process simplicity.
3Manufacturing precision
If the organic semiconductor layer thickness is nonuniform, then light emission becomes nonuniform, but increasing process control measures increases manufacturing complexity
Solution Approach 1:
The patent employs a preliminary action approach by forming the altered portion (cross-linked or cured region) at the interface before completing the organic semiconductor layer formation. This is accomplished through ultraviolet irradiation or heat treatment applied after liquid composition application, which prevents dissolution and ensures uniform thickness without requiring complex real-time process control.
Solution Approach 2:
The patent introduces an intermediary altered portion that acts as a mediator between the organic semiconductor layer and the substrate or underlying layer. This altered portion, created through cross-linking or curing, serves as a stable interface that ensures uniform thickness distribution and prevents dissolution, achieving manufacturing precision without increasing overall process complexity.
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 method allows for the production of organic semiconductor devices with uniform thickness and improved conductivity, reducing non-uniformity in light emission and enhancing display accuracy by ensuring consistent thickness across organic layers.
Implementation Method 1
a film of a liquid composition is formed on a target surface, the liquid composition being composed of a material constituting one of the plurality of organic semiconductor layers, the material being dissolved or dispersed in a first solvent
Implementation Method 2
a portion, having a predetermined thickness, of the film adjacent to the target surface is altered so as not to be dissolved in a predetermined solvent containing the first solvent
Implementation Method 3
an unaltered portion of the film is removed with a predetermined solvent, the unaltered portion being not altered in the step of altering the portion
Data Source
AI summary
A method for producing an organic semiconductor device including a plurality of organic semiconductor layers laminated on a substrate includes forming a film of a liquid composition on a target surface, the liquid composition being composed of a material constituting one of the plurality of the organic semiconductor layers, the material being dissolved or dispersed in a first solvent, and the target surface including a substrate surface and a surface of any of the other of the plurality of organic semiconductor layers; altering a portion of the film adjacent to the target surface, the portion having a predetermined thickness, in such a manner that the portion is not dissolved in a predetermined solvent containing the first solvent; and removing an unaltered portion of the film in the step of altering the portion with the predetermined solvent.