Polythiophene Charge Transporting Composition for Non-Fullerene Organic Photovoltaics
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Solution Overview
Problem
Current organic photovoltaic devices with fullerene acceptor active layers have limitations in achieving high photoelectric conversion efficiency due to energy gaps with hole collecting layers, necessitating the development of charge transporting compositions that can deepen the ionization potential and reduce energy gaps with non-fullerene active layers.
Innovation Solution
A charge transporting composition comprising a polythiophene derivative, specific electron accepting dopants, and solvents is used to form a thin film that functions as a hole collecting layer, enhancing the ionization potential and reducing the energy gap with non-fullerene active layers, thereby increasing the voltage of organic photovoltaic devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If PEDOT/PSS hole collecting layer material is used with FA active layer, then mass production process is simplified, but photoelectric conversion efficiency is limited and approaches theoretical limit
Solution Approach 1:
The patent changes the material parameters of the hole collecting layer by using MoO3 instead of PEDOT/PSS, and adjusts the active layer composition by incorporating non-fullerene acceptors. This parameter change enables both high photoelectric conversion efficiency (18%) and maintains coating-type hole collecting layer advantages for mass production.
Solution Approach 2:
The patent creates a composite active layer system combining non-fullerene acceptors with appropriate donors, and uses composite hole collecting layer materials. This composite approach allows optimization of both efficiency and manufacturability by leveraging the properties of multiple materials working together.
2Productivity
If MoO3 hole collecting layer is used with NFA active layer, then photoelectric conversion efficiency increases to 18%, but manufacturing complexity increases due to vapor deposition requirement
Solution Approach 1:
The patent changes the deposition method parameter from vapor deposition to coating-type application, while maintaining MoO3 as the hole collecting layer material. This allows the system to achieve high efficiency (18%) with NFA active layers while simplifying the manufacturing process for mass production.
3Ease of manufacture
If conventional hole collecting layer material is used, then manufacturing is simple, but energy gap with NFA active layer is large resulting in lower voltage
Solution Approach 1:
The patent changes the ionization potential parameter of the hole collecting layer material to match the deeper HOMO level of NFA active layers. By adjusting the energy level parameters, the patent reduces the energy gap and increases device voltage while maintaining coating-type fabrication simplicity.
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 composition allows for the deepening of the ionization potential of the charge transporting thin film, reducing the energy gap with non-fullerene active layers and achieving higher voltage in organic photovoltaic devices, while being cost-effective and easily synthesizable.
Implementation Method 1
a charge transporting composition for forming a charge transporting thin film in a photovoltaic device having a non-fullerene active layer, which composition includes a charge transporting substance comprised of a polythiophene derivative... an electron accepting dopant substance
Implementation Method 2
Electronic devices, especially organic photovoltaic devices, are devices which use an organic semiconductor to convert light energy into electrical energy
Data Source
AI summary
Provided is a charge-transporting composition for formation of an electrical charge-transporting thin film for use in a photoelectric conversion element, together with a non-fullerene active layer. The charge-transporting composition comprises: a charge-transporting substance composed of a polythiophene derivative containing a repeating unit represented by formula (1); an electron-accepting dopant substance; and a solvent. The electron-accepting dopant substance includes at least one of an arylsulfonic acid represented by formula (2) and a heteropoly acid.(R1 and R2 are, mutually independently, a hydrogen atom, an alkoxy group, —O—[Z—O]p—Re, a sulphonic acid group, etc. p is an integer of 1 or greater, and Re is a hydrogen atom or an alkyl group, etc. that may be substituted with a sulphonic acid group, or the like.)(A is a naphthalene ring, etc.; B is a divalent through tetravalent perfluorobiphenyl group; l is an integer that satisfies 1≤l≥4; and q is an integer of 2-4.)