Block Copolymer Charge Transport Light Emission
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Solution Overview
Problem
Current random copolymers used in light emitting devices do not meet satisfactory performance levels for practical applications as electron materials.
Innovation Solution
A block copolymer comprising multiple blocks of a specific formula with conjugative divalent groups, where at least two blocks have a number average polymerization degree of 5 or more, and adjacent blocks have different divalent groups, enhancing device performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If random copolymers are used as light emitting materials or charge transporting materials, then the materials can be applied in electron devices, but the device performances are not satisfactory for practical purposes
Solution Approach 1:
The patent applies segmentation by transitioning from random copolymers to block copolymers with distinct functional blocks. The block copolymer comprises a first block with charge transporting capability and a second block with light emitting capability, where each block has specific structural characteristics (Ar1 for charge transport, Ar2 for light emission). This segmentation allows each block to independently optimize its function, resolving the contradiction between achieving satisfactory device performance and practical applicability.
Solution Approach 2:
The patent employs composite materials principle by creating a block copolymer that combines two different aromatic hydrocarbon blocks with distinct functions. The first block contains aromatic hydrocarbon units with charge transporting properties, while the second block contains aromatic hydrocarbon units with light emitting properties. This composite structure enables the material to simultaneously achieve both charge transport and light emission functions with optimized performance for practical electron devices.
2Reliability
If the number average polymerization degree of aromatic hydrocarbon units is increased, then the device performance improves, but the solubility and processability may deteriorate
Solution Approach 1:
The patent applies local quality principle by introducing different substituent patterns in different blocks of the copolymer. The first block has substituent groups optimized for charge transport, while the second block has substituent groups optimized for light emission and solubility. This local differentiation allows the material to achieve high molecular weight (improving device performance) while maintaining solubility through strategically placed substituent groups in specific blocks.
Solution Approach 2:
The patent employs parameter changes by systematically varying the number average polymerization degree (m1 and m2) of each block within specific ranges (5 ≤ m1 ≤ 100 and 5 ≤ m2 ≤ 100). This controlled parameter optimization allows achieving satisfactory device performance while maintaining processability. The patent specifically identifies that m1 and m2 should be at least 5 to ensure adequate performance while remaining within manufacturable ranges.
Data Source
AI summary
A block copolymer comprising two or more of blocks of the following formula (1), wherein at least two of a plurality of m's present in the copolymer represent a number of 5 or more, Ar's in adjacent two blocks in the copolymer are mutually different, and the copolymer has two Ar's when composed of 2 blocks of the formula (1), has two or more Ar's when composed of 3 blocks of the formula (1) and has four or more Ar's when composed of 4 or more blocks of the formula (1):(in the formula (1), Ar represents a conjugative divalent group and represents the same divalent group in an identical block, and m represents a number of 1 or more showing the number average polymerization degree of Ar present in one block).