title: Magnetic dipolar interaction between correlated triplets created by singlet fission in tetracene crystals.
abstract: Singlet fission can potentially break the Shockley-Queisser efficiency limit in single-junction solar cells by splitting one photoexcited singlet exciton (S1) into two triplets (2T1) in organic semiconductors. A dark multiexciton state has been proposed as the intermediate connecting S1 to 2T1. However, the exact nature of this multiexciton state, especially how the doubly excited triplets interact, remains elusive. Here we report a quantitative study on the magnetic dipolar interaction between singlet-fission-induced correlated triplets in tetracene crystals by monitoring quantum beats relevant to the multiexciton sublevels at room temperature. The resonances of multiexciton sublevels approached by tuning an external magnetic field are observed to be avoided, which agrees well with the theoretical predictions considering a magnetic dipolar interaction of ∼ 0.008 GHz. Our work quantifies the magnetic dipolar interaction in certain organic materials and marks an important step towards understanding the underlying physics of the multiexciton state in singlet fission.
authors.affiliation: National Laboratory of Solid State Microstructures, School of Physics, Nanjing University, Nanjing 210093, China.
authors.forename: Rui
authors.initials: R
authors.lastname: Wang
authors.affiliation: National Laboratory of Solid State Microstructures, School of Physics, Nanjing University, Nanjing 210093, China.|Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China.
authors.forename: Chunfeng
authors.initials: C
authors.lastname: Zhang
authors.affiliation: National Laboratory of Solid State Microstructures, School of Physics, Nanjing University, Nanjing 210093, China.|Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China.
authors.forename: Bo
authors.initials: B
authors.lastname: Zhang
authors.affiliation: National Laboratory of Solid State Microstructures, School of Physics, Nanjing University, Nanjing 210093, China.|Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China.
authors.forename: Yunlong
authors.initials: Y
authors.lastname: Liu
authors.affiliation: National Laboratory of Solid State Microstructures, School of Physics, Nanjing University, Nanjing 210093, China.|Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China.
authors.forename: Xiaoyong
authors.initials: X
authors.lastname: Wang
authors.affiliation: National Laboratory of Solid State Microstructures, School of Physics, Nanjing University, Nanjing 210093, China.|Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China.|Department of Physics, University of Arkansas, Fayetteville, Arkansas 72701, USA.
authors.forename: Min
authors.initials: M
authors.lastname: Xiao