Fullerene Derivative N-Type Semiconductor for Organic Solar Cells
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Solution Overview
Problem
There is a need for a fullerene derivative that can achieve high conversion efficiency and enable high voltage output as an n-type semiconductor material for organic thin-film solar cells, while also being soluble in organic solvents to facilitate easy production through coating techniques.
Innovation Solution
A fullerene derivative with a specific chemical structure, including aryl and alkyl substituents, is developed, which forms a compound that acts as an n-type semiconductor material, enhancing solubility and compatibility with organic solvents, thereby enabling high conversion efficiency and high voltage output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fullerene derivatives with 3-membered ring moieties (like PCBM) are used as n-type semiconductor materials, then excellent photoelectric conversion performance is achieved, but the structural diversity and solubility in organic solvents are limited
Solution Approach 1:
The patent changes the ring structure parameter from 3-membered rings (PCBM) to 5-membered rings (pyrrolidine), and further to 6-membered rings (piperidine) with various substituents. This parameter change enables diverse solubility characteristics in organic solvents while maintaining n-type semiconductor functionality for photoelectric conversion
Solution Approach 2:
The patent creates composite fullerene derivatives by combining the C60 or C70 fullerene core with various substituted piperidine rings. These composite structures integrate the electron-accepting capability of fullerene with the solubility and stability benefits of substituted piperidine moieties, achieving both excellent photoelectric conversion performance and enhanced processability
2Reliability
If conventional fullerene derivatives are used, then n-type semiconductor function is achieved, but high conversion efficiency and high voltage output cannot be simultaneously obtained
Solution Approach 1:
The patent introduces specific substituents at defined positions on the piperidine ring (positions 2, 6, and 7) to locally optimize electronic properties. The electron-donating or electron-withdrawing nature of substituents at different positions creates localized electronic effects that tune the HOMO-LUMO energy levels, enabling simultaneous achievement of high conversion efficiency and high voltage output while maintaining n-type semiconductor function
Solution Approach 2:
The patent systematically varies substituent types (electron-donating groups like alkyl and alkoxy, electron-withdrawing groups like carbonyl and cyano) and their positions on the piperidine ring to optimize the electronic parameters of the fullerene derivative. This parameter optimization enables tuning of both conversion efficiency and voltage output to achieve superior simultaneous performance
3Stability of the object's composition
If fullerene derivatives with limited solubility are used, then material stability is maintained, but ease of manufacture through coating techniques is compromised
Solution Approach 1:
The patent modifies the solubility parameter by introducing various substituents (alkyl, alkoxy, aryl groups) on the piperidine ring. These substituent changes enhance solubility in organic solvents like chloroform, chlorobenzene, and toluene, enabling easy manufacture through coating techniques while the stable C60/C70 fullerene core and rigid piperidine structure maintain material stability
Solution Approach 2:
The substituted piperidine ring acts as an intermediary between the hydrophobic fullerene core and the organic solvent environment. The substituents on the piperidine ring provide favorable interactions with organic solvents, mediating solubility and processability without compromising the intrinsic stability of the fullerene-based n-type semiconductor material
Data Source
AI summary
An object of the present invention is to provide a novel fullerene derivative usable in n-type semiconductor materials for organic thin-film solar cells and the like. The object is achieved by a fullerene derivative represented by formula (1) wherein R1 represents aryl optionally substituted with at least one substituent, R2 represents an organic group, R3 represents an organic group, with the proviso that at least one of R2 and R3 is alkyl optionally substituted with at least one substituent or alkyl ether optionally substituted with at least one substituent, R4 represents hydrogen or an organic group, and a ring A represents a fullerene ring.