Semiconductor Mixed Material for Organic Solar Cell Spectral Broadening
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Solution Overview
Problem
Organic solar cells face limitations due to narrow absorption characteristics of organic materials, leading to challenges in achieving spectral broadening of solar energy and balancing phase blending for exciton dissociation with phase separation for charge transfer, resulting in leakage current and weak light absorption issues in the near-infrared area.
Innovation Solution
A semiconductor mixed material comprising a conjugated polymer as an electron donor, a first electron acceptor with an energy gap less than 1.4 eV, and a second electron acceptor with reduced molecular stacking, π-π* stacking, and crystallinity, configured to improve the active layer's performance by enhancing light absorption and reducing leakage current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If binary polymer blend films are used to achieve spectral broadening, then light absorption is improved, but phase blending and phase separation cannot be balanced, resulting in poor exciton dissociation and charge transfer
Solution Approach 1:
The patent introduces a third component (fullerene derivative) that creates local phase separation regions within the polymer blend film. This third component forms distinct domains that facilitate both exciton dissociation at phase boundaries and charge transfer in specific regions, resolving the contradiction between needing phase blending for broad absorption and phase separation for efficient charge transport.
Solution Approach 2:
The patent creates a ternary composite system combining two polymers with different band gaps and a fullerene derivative. This composite structure enables simultaneous achievement of broad spectral absorption from the polymer blend and efficient charge transfer through the fullerene-derived phase-separated domains, solving the limitation of binary blends.
2Power
If electron donor and electron acceptor materials are mixed to improve charge transfer, then charge transfer efficiency is improved, but leakage current increases
Solution Approach 1:
The patent carefully adjusts the energy level parameters (HOMO/LUMO values) of the three components to create an optimized energy landscape. The fullerene derivative's specific energy levels act as a barrier to prevent unwanted charge recombination and leakage current while maintaining efficient charge transfer pathways, thus resolving the contradiction between charge transfer efficiency and leakage current.
Solution Approach 2:
The fullerene derivative acts as an intermediary material that mediates between the electron donor polymer and electron acceptor polymer. It facilitates controlled charge transfer while its molecular structure and energy levels prevent direct harmful interactions that would cause leakage current, thus improving charge transfer efficiency without generating harmful leakage current.
3Adaptability or versatility
If organic materials are used to achieve flexibility and transparency, then device flexibility and transparency are improved, but absorption characteristic becomes narrow, limiting solar energy utilization
Solution Approach 1:
The patent combines two different polymer materials with complementary absorption spectra in a ternary composite system. This composite approach maintains the flexibility and transparency advantages of organic materials while achieving broad spectral absorption through the synergistic effect of the two polymers and the fullerene derivative, thus resolving the contradiction between flexibility and absorption breadth.
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 semiconductor mixed material effectively improves the external quantum efficiency and reduces leakage current in organic electronic devices, particularly in the near-infrared region, by optimizing the ratio and structure of electron donors and acceptors, leading to enhanced performance and spectral absorption.
Implementation Method 1
the first electron acceptor with an energy gap is less than 1.4 eV
Implementation Method 2
semiconductor mixed material applied to an organic photochemistry or electronic device
Data Source
AI summary
A semiconductor mixed material comprises an electron donor, a first electron acceptor and a second electron acceptor. The first electron donor is a conjugated polymer. The energy gap of the first electron acceptor is less than 1.4 eV. At least one of the molecular stackability, π-π*stackability, and crystallinity of the second electron acceptor is smaller than the first electron acceptor. The electron donor system is configured to be a matrix to blend the first electron acceptor and the second electron acceptor. The present invention also provides an organic electronic device including the semiconductor mixed material.