Optoelectronic Component Crystallization Control
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Solution Overview
Problem
Current organic solar cells with small molecule-based absorber layers are limited in thickness due to issues like torsion in oligomer units and excessive crystallization, leading to short circuits and poor charge transport, which restricts quantum yield and efficiency.
Innovation Solution
An optoelectronic component with a photoactive layer comprising a mixed multiple layer of at least three materials, including a donor and an acceptor, with a third material that affects the crystallization propensity of the donor and acceptor, forming a donor-acceptor system to enhance charge transport and prevent crystallization, thereby improving quantum yield.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the photoactive layer thickness is increased to improve quantum yield, then more excitons can be absorbed, but excessive crystallization occurs leading to short circuits and poor charge transport
Solution Approach 1:
A third material is introduced as an intermediary substance between the donor and acceptor materials. This third material acts as a mediator that suppresses excessive crystallization of the donor and/or acceptor, thereby maintaining good charge transport properties even when the photoactive layer thickness is increased to improve quantum yield.
Solution Approach 2:
The photoactive layer is designed as a composite material system comprising three components: a donor material, an acceptor material, and a third material. This composite structure allows the combination of materials with complementary properties, where the third material specifically addresses the crystallization issue while the donor-acceptor system maintains photoactive function.
2Productivity
If the photoactive layer thickness is increased to improve efficiency, then more light can be absorbed, but torsion in oligomer units occurs leading to poor charge transport
Solution Approach 1:
The third material serves as a structural intermediary that prevents torsion in oligomer units of the donor material. By incorporating this third material, the system maintains molecular packing and charge transport pathways even at increased thickness, allowing efficiency improvement without sacrificing charge transport reliability.
3Use of energy by moving object
If donor and acceptor materials are used to form excitons, then light energy conversion is achieved, but excessive crystallization leads to short circuits
Solution Approach 1:
The third material acts as a protective intermediary that suppresses excessive crystallization of the donor and acceptor materials. This prevention of excessive crystallization eliminates the formation of conductive pathways that would cause short circuits, while allowing the donor-acceptor system to continue functioning for light energy conversion.
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 addition of a third material in the photoactive layer increases the layer thickness, reduces crystallization, and enhances charge transport, leading to improved quantum yield and efficiency by allowing more excitons to be separated into charge carriers, contributing to a higher current generation.
Implementation Method 1
at least one material is a donor and at least one material is an acceptor, wherein the donor and the acceptor form a donor-acceptor system with at least one third material which is set up so as to affect the propensity of the donor and/or acceptor to crystallize
Implementation Method 2
A solar cell converts light energy to electrical energy. The term 'photoactive' in the case of solar cells refers to the conversion of light energy to electrical energy. In contrast to inorganic solar cells, the light does not directly produce free charge carriers in organic solar cells; instead, excitons are formed at first, i.e. electrically neutral excited states (bound electron-hole pairs). Only in a second step are these excitons separated into free charge carriers which then contribute to the flow of electrical current.
Data Source
AI summary
An optoelectronic component includes a photoactive layer which is arranged between an electrode and a counter electrode. In addition to a donor-acceptor system, the photoactive layer includes a third material which influences the crystallization of the donor-acceptor system. The third material selected from a group consisting of crown ethers, triphenyls, sorbitols, quinacridones and bis(4-(tert-butyl)benzoato-O) hydroxyaluminium. Crown ethers are especially preferred.