Inkjet Printing Ink for OLED Crosslinking to Prevent Layer Damage
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Solution Overview
Problem
The existing inkjet printing methods for OLEDs face challenges in printing the electron transport layer due to mutual solubility issues with the organic light emitting layer, leading to damage and inefficiencies in the manufacturing process.
Innovation Solution
An inkjet printing ink formulation comprising a crosslinking organic host material, an organic doped luminescent material, a surface tension modifier, a viscosity modifier, and a solvent, which includes specific components like u-CzTP, Ir(mppy)3, and a mixed solvent of o-xylene and cyclohexylbenzene, is used to create a stable organic light emitting layer that can withstand the printing of the electron transport layer without damage, achieved through a drying and baking process at 120° C.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional inkjet printing method is used to print electron transport layer on organic light emitting layer, then the manufacturing process can be simplified, but the organic light emitting layer is damaged due to mutual solubility between layers
Solution Approach 1:
The patent applies preliminary action by introducing a crosslinking treatment step before printing the electron transport layer. The organic light emitting layer is pre-treated with crosslinking agents (such as silane crosslinking agents) to form a crosslinked network structure that provides chemical resistance. This preliminary crosslinking action prevents the solvent in the electron transport layer ink from dissolving the underlying organic light emitting layer, thereby resolving the mutual solubility issue while maintaining the simplified inkjet printing manufacturing process
Solution Approach 2:
The patent changes the chemical parameter of the organic light emitting layer by inducing crosslinking reactions. The crosslinking process transforms the linear or branched polymer chains into a three-dimensional crosslinked network, fundamentally altering the solubility parameters of the layer. This parameter change enables the layer to withstand subsequent solvent exposure during electron transport layer printing without damage
2Reliability
If crosslinking treatment is applied to organic light emitting layer, then the layer becomes resistant to solvent damage, but the manufacturing process complexity increases
Solution Approach 1:
The patent merges the crosslinking treatment step with the existing inkjet printing manufacturing process by applying crosslinking agents through the same inkjet printing system or by integrating the crosslinking step into the existing process flow. This merging approach allows the crosslinking treatment to be performed inline without requiring separate equipment or complex additional processing steps, thereby maintaining manufacturing simplicity while achieving the desired layer stability
Solution Approach 2:
The patent uses crosslinking agents as intermediary substances that facilitate the crosslinking reaction. These agents (such as silane compounds) act as mediators between the organic light emitting layer and the solvent environment, forming a protective crosslinked network that prevents direct interaction between the solvent and the layer. This intermediary approach achieves protection without requiring fundamental changes to the manufacturing process
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 effective printing of the organic electron transport layer without damaging the organic light emitting layer, thereby reducing manufacturing costs and improving the efficiency of the inkjet printing process for OLEDs.
Implementation Method 1
a crosslinking type organic host material having a crosslinking temperature in the range of 80 to 120° C.
Implementation Method 2
performing drying process, and performing baking process at 120° C. to form an organic light emitting layer
Data Source
AI summary
The present disclosure relates to an inkjet printing ink and application thereof. In one aspect, the inkjet printing ink includes a crosslinking type organic host material, an organic doped luminescent material, a surface tension modifier, a viscosity modifier, and a solvent. On the other aspect, the present disclosure provides printing the inkjet printing ink on a substrate of a display panel to be prepared, performing drying process, and performing baking process at 120° C. to form an organic light emitting layer. Therefore, avoiding the problem of mutual dissolution of the organic light emitting layer and the electron transport layer when the electron transport layer is printed on the organic light emitting layer, avoiding damage to the organic light emitting layer, realize an inkjet printing process of the organic electron transport layer, thereby reducing the cost of manufacturing.