Notably, however, there is a huge field called “molecular photochemistry” that is especially keen on spin-relaxed molecular triplet states. Photochemists have invested a lot of effort in the synthesis of special particles called sensitizers that can produce triplets upon photoexcitation.
White-light-driven triplet-fusion photon upconversion and singlet oxygen generation by utilizing nanocrystals to flip the spins to generate molecular triplets. Credit: Chem
” We understood that the brief spin lifetimes just recently determined in colloidal nanocrystals should rather find instant applications in molecular photochemistry,” stated Prof. WU.
The scientists showed spin-enabled photochemistry using CsPbBr3 nanocrystals surface-anchored with rhodamine B molecules. Utilizing advanced femtosecond laser spectroscopy, they discovered that excitation of either the nanocrystal or the particle induced efficient charge separation, and the rapid spin-flip of the carrier inside the nanocrystal enabled the high-yield formation of molecular triplets through charge recombination. In contrast, the conventional system of heavy-atom effect was eliminated for this system.
Using the double triplet-formation paths and the complementary spectral coverage of CsPbBr3 and rhodamine B, they accomplished effective white-light-driven molecular triplet photochemistry, consisting of triplet-fusion photon upconversion and singlet oxygen generation.
” This study opens a new opportunity for photochemical applications of solution-processed semiconductor products,” stated Prof. WU. “It might motivate using the spin properties of these affordable products in more fields.”
Reference: 24 March 2022, Chem.
The above work was supported by the National Natural Science Foundation of China, the Ministry of Science and Technology of China, and CAS.
Recent developments in solution-grown semiconductor materials, such as lead halide perovskites and colloidal nanocrystals, begin to consist of chemists into this game. The researchers showed spin-enabled photochemistry using CsPbBr3 nanocrystals surface-anchored with rhodamine B molecules. Utilizing advanced femtosecond laser spectroscopy, they discovered that excitation of either the nanocrystal or the particle induced efficient charge separation, and the fast spin-flip of the provider inside the nanocrystal allowed the high-yield formation of molecular triplets through charge recombination.
White light triplet-fusion photon upconversion utilizing nanocrystal-molecule hybrids. Credit: Chem
A research study group led by Prof. WU Kaifeng from the Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences (CAS) revealed the mechanism for molecular spin-triplets formation from quick spin-flip in colloidal nanocrystals and demonstrated its photochemical applications.
The study was published in Chem today (March 24, 2022).
Generally, semiconductor spin homes are a territory of physics. Recent advancements in solution-grown semiconductor materials, such as lead halide perovskites and colloidal nanocrystals, begin to consist of chemists into this game. However the spin relaxation lifetimes of these products are still too brief (usually a couple of picoseconds at room temperature level) for spintronic and quantum info innovation applications.
