Polycyclic Aromatic Up-Conversion Substance for Solar Efficiency
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Solution Overview
Problem
Current organic light up-conversion luminescent substances have low light up-conversion efficiency, converting long-wavelength light to short-wavelength light, limiting their application in improving photoelectric conversion efficiency in organic solar cells.
Innovation Solution
A light up-conversion luminescent substance comprising a compound with a polycyclic aromatic backbone and specific trivalent groups, combined with a photosensitizer, enhances energy transfer efficiency by forming a ring structure that inhibits radical formation and facilitates triplet-triplet annihilation up-conversion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional organic luminescent substances (anthracene, 9,10-diphenyl anthracene) are used for light up-conversion, then the material can convert long-wavelength light to short-wavelength light, but the light up-conversion efficiency is low (only 3-5%)
Solution Approach 1:
The patent changes the molecular structure parameters of the luminescent substance by introducing a specific polycyclic aromatic hydrocarbon core with dibenzoxepin or dibenzodioxepin units. This structural modification optimizes the HOMO-LUMO energy gap and triplet energy levels, enabling more efficient energy transfer from the photosensitizer and achieving higher light up-conversion efficiency (4-7 times improvement over conventional materials).
Solution Approach 2:
The patent creates a composite light up-conversion system combining a specifically designed organic luminescent substance with a photosensitizer (such as porphyrin or phthalocyanine derivatives). This composite approach enables effective triplet-triplet energy transfer, where the photosensitizer absorbs light and transfers energy to the luminescent substance, which then emits up-converted light with significantly improved efficiency.
2Adaptability or versatility
If inorganic light up-conversion luminescent substances are used, then the conversion can be achieved, but the absorption spectrum is narrow and requires higher incident power compared to organic compounds
Solution Approach 1:
The patent utilizes the inherent property of organic compounds to exhibit broad absorption spectra across visible and near-infrared regions. By designing the luminescent substance with extended conjugation through polycyclic aromatic structures, the absorption spectrum is further broadened, allowing the material to capture a wider range of solar wavelengths and operate effectively at lower incident power levels.
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 proposed solution achieves a light up-conversion efficiency 4 to 7 times higher than existing materials, with maximum efficiency reaching up to 12%, significantly improving the conversion of long-wavelength light to short-wavelength light.
Implementation Method 1
a photosensitizer molecule (1A) in its ground state absorbs light energy to transit to an excited singlet state (1A*)
Implementation Method 2
intersystem crossing to an excited triplet state (3A*) rapidly occurs (1A*→3A*)
Implementation Method 3
energy is transferred from the photosensitizer molecule in the excited triplet state to a luminescent molecule
Implementation Method 4
interaction between the luminescent molecules having changed into the excited triplet state occurs more efficiently, and energy transfers from the one luminescent molecule having changed into the excited triplet state to the other luminescent molecule. At this time, the one luminescent molecule having changed into the excited triplet state returns to the ground state, and the other changes into an excited singlet state (triplet-triplet annihilation process: 3E*+3E*→1E+1E*). Then, up-converted light (1E*→1E+hνf) is emitted as fluorescence
Implementation Method 5
up-converted light (1E*→1E+hνf) is emitted as fluorescence from the luminescent molecule having changed into the excited singlet state
Data Source
AI summary
To provide a novel light up-conversion organic luminescent substance having a high light up-conversion efficiency. A light up-conversion luminescent substance which comprises a compound represented by general formula (1).