Singlet Fission Organic Window Layer for Inorganic Solar Cell Efficiency
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Solution Overview
Problem
Conventional inorganic semiconductor solar cells face challenges in achieving high efficiency due to limitations in producing large crystals without defects and stability issues in amorphous silicon devices, restricting their ability to exceed the Shockley and Quiesser thermodynamic efficiency limit of 31%.
Innovation Solution
The integration of an inorganic subcell with a singlet fission material-based organic sensitizing window layer in a photosensitive optoelectronic device, where the singlet fission material exhibits high absorptivity and excitation triplet energy matching the band gap energy of the inorganic semiconductor, enhancing energy transfer and efficiency beyond traditional limits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional inorganic semiconductor materials are used in solar cells, then the device structure is simple and manufacturing is easier, but the power conversion efficiency is limited to below 31% due to the Shockley and Quiesser thermodynamic limit
Solution Approach 1:
The patent combines organic singlet fission materials with inorganic semiconductor materials to create a hybrid solar cell structure. The organic layer absorbs high-energy photons and undergoes singlet fission to generate two triplet excitons, which are then transferred to the inorganic semiconductor to generate charge carriers. This composite approach enables the cell to exceed the 31% efficiency limit while maintaining a relatively simple layered structure that can be manufactured using existing techniques.
2Productivity
If large crystal inorganic semiconductors are produced to improve efficiency, then the power conversion efficiency increases, but the manufacturing difficulty and cost increase due to problems in producing large crystals without defects
Solution Approach 1:
The patent divides the light absorption function into two parts: the organic singlet fission material handles high-energy photon absorption and exciton generation, while the inorganic semiconductor handles charge carrier generation and collection. This segmentation allows the use of thinner, defect-free inorganic layers, reducing manufacturing complexity while maintaining high efficiency.
Solution Approach 2:
The patent changes the energy transfer mechanism by introducing singlet fission, which converts one high-energy photon into two triplet excitons. This parameter change in the energy conversion process allows the system to utilize high-energy photons more efficiently without requiring larger or more complex inorganic semiconductor structures.
3Ease of manufacture
If amorphous silicon is used to simplify manufacturing, then the ease of manufacture improves, but stability issues arise that limit long-term device performance
Solution Approach 1:
The patent uses a composite structure where the organic singlet fission layer handles light absorption and the inorganic semiconductor (which can be crystalline or polycrystalline) handles charge transport. This combination allows for improved stability from the inorganic material while maintaining manufacturing advantages through the organic layer's solution-processability and tolerance to defects.
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
This approach significantly increases solar energy generation efficiencies, potentially exceeding the 31% efficiency limit by utilizing singlet fission materials to convert a single high-energy photon into two low-energy excited states, thereby improving power conversion efficiency.
Implementation Method 1
utilizing singlet fission materials to convert a single high-energy photon into two low-energy excited states
Implementation Method 2
enhancing energy transfer and efficiency beyond traditional limits
Data Source
AI summary
The present disclosure relates to a photosensitive optoelectronic device comprising two electrodes, an inorganic subcell positioned between the two electrodes, wherein the inorganic subcell comprises at least one inorganic semiconductor material having a band gap energy (EG), and an organic sensitizing window layer disposed on the inorganic subcell. In one aspect, the organic sensitizing window layer comprises a singlet fission material. In another aspect, the organic sensitizing window layer comprises a singlet fission host and a phosphorescent emitter dopant, where the singlet fission host exhibits an excitation triplet energy (ET-SF) greater than or equal to an excitation triplet energy (ET-PE) exhibited by the phosphorescent emitter dopant.