Organic Thin Film Transistor NBBF Derivatives Threshold Voltage Stability
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Solution Overview
Problem
Existing organic thin film transistors using compounds with naphthobisbenzofuran structure struggle with achieving high carrier mobility and stable threshold voltage fluctuations, particularly when adapted from materials intended for organic light-emitting devices, leading to reliability issues.
Innovation Solution
Incorporating unsubstituted NBBF or NBBF derivatives with specific substituents in the semiconductor active layer to enhance crystallinity and molecular alignment, facilitating high carrier mobility and reducing threshold voltage fluctuations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If organic EL device materials are adapted for organic thin film transistors, then device complexity is reduced, but carrier mobility and threshold voltage stability deteriorate
Solution Approach 1:
The patent applies parameter changes by modifying the molecular structure of NBBF compounds through specific substituent groups (electron-donating or electron-withdrawing groups) to optimize both carrier mobility and threshold voltage stability. This resolves the contradiction by changing material parameters rather than device structure, achieving high performance with simple device architecture.
Solution Approach 2:
The patent uses composite material strategy by combining NBBF core structure with various functional substituent groups to create optimized semiconductor materials. These composite molecular structures achieve both high carrier mobility and stable threshold voltage, resolving the reliability issue while maintaining device simplicity.
2Speed
If high crystallinity materials are used to achieve high carrier mobility, then carrier mobility is improved, but light emission uniformity deteriorates
Solution Approach 1:
The patent applies local quality principle by designing compounds where the NBBF core provides high crystallinity for carrier transport, while peripheral substituent groups control molecular packing and film morphology. This local differentiation allows high carrier mobility in the transport direction while maintaining uniform light emission properties.
3Shape
If naphthobisbenzofuran structure compounds are used, then molecular alignment is improved, but threshold voltage fluctuations increase
Solution Approach 1:
The patent changes material parameters by introducing specific substituent groups on the NBBF structure that modify electronic properties and molecular interactions. These parameter changes achieve both good molecular alignment and stable threshold voltage by controlling charge transport mechanisms at the molecular level.
Data Source
AI summary
An organic thin film transistor containing a compound represented by the formula (1) in a semiconductor active layer has a high carrier mobility and a small fluctuation of the threshold voltage after repeated driving. R1 to R12 represent a hydrogen atom or a substituent, provided that at least one of R1 to R12 represents a substituent represented by the formula (W), or all of R1 to R12 represent a hydrogen atom. * represents a position bonded to the naphthobisbenzofuran skeleton. L represents a single bond, a divalent linking group, an oligoethyleneoxy group having a repeating number of an ethyleneoxy unit of 2 or more, or an oligosiloxane group having 2 or more silicon atoms.