Inkjet Printing System for Organic Thin Film Transistors
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Solution Overview
Problem
Inkjet printing of organic thin film transistors often results in poor crystal growth and inferior transistor characteristics due to limited crystallinity of organic semiconductors, restricting their applicability in wide-area flat panel displays.
Innovation Solution
An inkjet printing system with a separate drying chamber that regulates the vapor pressure of the solvent to enhance the crystallinity of organic semiconductors, using solvents like mesitylen and tetralin, improves crystal growth and transistor performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If organic semiconductors are formed by inkjet printing, then the manufacturing process can be simplified and performed at low temperatures, but the crystal growth is poor resulting in inferior transistor characteristics
Solution Approach 1:
The manufacturing process is segmented into two distinct stages: (1) inkjet printing deposition of organic semiconductor ink on substrate, and (2) separate vapor phase annealing treatment in a controlled atmosphere chamber. This segmentation allows each stage to be optimized independently - the inkjet printing maintains simplicity while the subsequent vapor phase treatment specifically addresses crystal growth quality without complicating the overall manufacturing approach.
Solution Approach 2:
The inkjet printing process is performed first to deposit the organic semiconductor material, and then a preliminary vapor phase annealing treatment is applied in a controlled atmosphere chamber before final device completion. This preliminary action of vapor phase treatment prepares and enhances the crystal structure early in the process, ensuring good transistor characteristics are established before subsequent manufacturing steps.
2Device complexity
If conventional drying methods are used for inkjet printed organic semiconductors, then the process is simple, but the crystallinity remains insufficient leading to poor transistor performance
Solution Approach 1:
A controlled atmosphere chamber filled with vapor phase solvent (such as toluene or chloroform vapor) is introduced as an intermediary environment between the inkjet printing and final device completion. This vapor phase atmosphere acts as a mediator that facilitates enhanced crystal growth of the organic semiconductor without requiring complex mechanical drying equipment, thus maintaining process simplicity while dramatically improving transistor performance through superior crystallinity.
3Manufacturing precision
If vapor pressure of solvent is regulated in drying chamber, then crystallinity of organic semiconductor is improved, but the system complexity increases
Solution Approach 1:
The system controls crystallinity by changing the vapor pressure parameter of the solvent in the drying chamber. By regulating the amount of solvent vapor and temperature to achieve specific vapor pressure conditions, the organic semiconductor crystals grow with enhanced order and size. This parameter-based control approach avoids complex mechanical or electronic control systems, achieving precise crystallinity control through relatively simple vapor pressure regulation.
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 system effectively improves the crystallinity of organic semiconductors, leading to enhanced transistor characteristics and broader applicability in flat panel displays.
Implementation Method 1
drying the ink by regulating the vapor pressure of a solvent deposited on substrate
Implementation Method 2
improves the crystallinity of organic semiconductors
Implementation Method 3
forming an organic semiconductor by depositing a solvent containing ink on a substrate within an inkjet printing chamber
Data Source
AI summary
An inkjet printing system according to an exemplary embodiment of the present invention includes an inkjet printing chamber depositing ink on a substrate, and a drying chamber spaced from inkjet printing chamber by a predetermined interval and drying the ink by regulating a vapor pressure of a solvent of the ink deposited on substrate. The drying chamber is provided separately, and the vapor pressure of the solvent within the drying chamber is regulated, so that the drying speed of the ink is regulated so as to improve the crystallinity of the organic semiconductor.