Hole-Collecting Layer Composition for Photosensor Elements
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Solution Overview
Problem
Existing photosensor elements face challenges in achieving high photoelectric conversion efficiency while minimizing dark current, particularly due to the limitations of aqueous dispersions of PEDOT/PSS, which lead to device deterioration, clogging, and reduced heat resistance, and increased dark current from external electrical fields.
Innovation Solution
A composition for forming a hole-collecting layer using a relatively low-molecular-weight charge-transporting substance and an organic solvent, specifically aniline or thiophene derivatives, with an electron-accepting dopant such as arylsulfonic acid compounds, and an organosilane compound, to create a uniform and heat-resistant film.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If aqueous dispersions of PEDOT/PSS are used as coating materials for forming hole-collecting layers, then the coating process becomes simpler and more suitable for mass production, but the complete removal of moisture is difficult, moisture reabsorption occurs, and device deterioration is accelerated
Solution Approach 1:
The patent changes the solvent parameter from water-based (aqueous dispersion) to organic solvent, and adjusts the molecular weight parameter of the charge-transporting substance to 200-2000 range. This parameter change enables complete solvent removal and prevents moisture reabsorption while maintaining coating processability
Solution Approach 2:
The patent creates a composite material system combining low-molecular-weight charge-transporting substances (molecular weight 200-2000) with organic solvents. This composite approach achieves both easy coating application and complete moisture removal, resolving the contradiction between manufacturing ease and device reliability
2Productivity
If aqueous dispersions of PEDOT/PSS are used for hole-collecting layers, then mass production becomes more feasible, but solids agglomeration occurs, defects arise in applied films, and coating equipment clogs or corrodes
Solution Approach 1:
The patent changes the molecular weight parameter to 200-2000 and switches to organic solvent system, which prevents solids agglomeration and enables formation of uniform defect-free films suitable for mass production with high manufacturing precision
Solution Approach 2:
The patent achieves uniform local quality throughout the film by using low-molecular-weight charge-transporting substances that dissolve uniformly in organic solvents, preventing localized agglomeration and defects while maintaining high productivity
3Ease of manufacture
If aqueous dispersions of PEDOT/PSS are used to form hole-collecting layers, then the coating process is simplified, but the applied films exhibit insufficient heat resistance
Solution Approach 1:
The patent changes the solvent from water to organic solvent with higher boiling point and adjusts molecular weight to 200-2000, which provides both easy coating process and superior heat resistance in the final film
4Measurement precision
If an external electrical field is applied to maximize light-receiving properties, then light-receiving sensitivity and response speed improve, but injection of holes and electrons from electrodes increases, resulting in increased dark current
Solution Approach 1:
The patent creates local quality differentiation at the electrode-hole-collecting layer interface by using low-molecular-weight charge-transporting substances that form uniform interfaces, reducing charge injection while maintaining high light-receiving sensitivity under external electrical field
Solution Approach 2:
The composite material system of low-molecular-weight charge-transporting substances and organic solvents creates optimal interface properties that simultaneously enable high light-receiving sensitivity and suppress dark current under external electrical field conditions
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 solution results in a photosensor element with high photoelectric conversion efficiency and low dark current, facilitating mass production and improved device yield, while maintaining high heat resistance and uniform film formability.
Implementation Method 1
a photosensor element in which a thin film created from a composition that includes a relatively low-molecular-weight charge-transporting substance and an organic solvent is used as a hole-collecting layer
Implementation Method 2
Photoelectron multipliers which utilize the photoelectric effect and photodiodes which utilize pn junctions have hitherto been used as photosensors
Data Source
AI summary
A photosensor element that is capable of achieving a good balance between high photoelectric conversion efficiency and low dark current is able to be obtained by using a composition for forming a hole collecting layer of a photosensor element, which contains an organic solvent and a charge-transporting material that is composed of an aniline derivative having a molecular weight of 200-2,000 and represented by formula (HI) and containing one or more quinonediimine structure of the following formula within the molecule