This technology identifies several first-in-class organic polymers exhibiting intramolecular singlet fission at yields approaching 200% that are extremely tunable and amenable to mass-production.
Silicon-based photovoltaics (PV) are used in the vast majority of solar energy devices, but are limited by (a) the wavelength of an incoming photon and (b) the ability to generate only a single electron-hole pair per incoming photon, leading to a theoretical maximum efficiency of ~33%. Singlet fission (SF) occurs when a single high-energy particle is absorbed by a material and divides the energy into two or more excitons, each capable of generating an electron-hole pair. This process, referred to as multiple exciton (ME) generation, has recently attracted much interest for its potential to increase the theoretical maximum efficiency of any optoelectronic system, notably raising the efficiency of solar cells from ~33% to ~44%. Aggregates of conjugated/aromatic molecules have been shown to exhibit SF, but lack tunability, efficiency, and triplet formation rate/stability, which make their applications limited. Alternatively, currently available conjugated polymers that exhibit SF suffer from lack of solubility, limited efficiency, or are difficult to synthesize which make their applications impractical.
This technology addresses these shortcomings by describing several first-in-class polymers that can undergo rapid singlet fission while generating a large population of long lived triplets (microsecond time scale). By linking the acceptor and donor molecules into a co-polymer, design and manufacturing constraints on previously described solid intermolecular SF systems are relieved. These materials have been optimized for adoption in third-generation solar cells by offering high solubility for mass-production combined with high yield of ME that approaches 200% to dramatically improve efficiency. Importantly, by combining various derivations of linkers, polymer subunits, and functionalized acceptor or donor molecules, the materials allow for extensive tuning of electronic, optical, structural, and physical properties, offering a suite of applications beyond solar cells, to include photonic devices, sensors, and integrated circuits.
IR CU17103
Licensing Contact: Greg Maskel
