Transient Magnetophotoinduced Absorption Studies of Photoexcitations in π-Conjugated Donor-Acceptor Copolymers
Transient Magnetophotoinduced Absorption Studies of Photoexcitations in π-Conjugated Donor-Acceptor Copolymers
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DOI：
10.1103/physrevlett.119.017401
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发表时间：
2017-07-06
影响因子：
8.6
通讯作者：
Vardeny, Z. Valy
中科院分区：
文献类型：
--
作者：
Huynh, Uyen N. V.;Basel, Tek P.;Vardeny, Z. Valy
我们已经利用了大量的瞬态和稳态的光学和磁光光谱在一个广泛的光谱范围（0.25-2.5 eV）阐明的主要和长寿命的光激发在低带隙π共轭的供体-受体（DA）共聚物用于高效的光伏太阳能电池。我们发现，单重态激子（SE）和链内三重态-三重态（TT）对在DA-共聚物链中光生。从这些物种的皮秒瞬态磁场响应，我们得出结论，SE和TT自旋态耦合。TT分解成两个链内孪生三重态激子保持自旋相干性，因此它们的自旋纠缠持续到微秒时域。
We have utilized a plethora of transient and steady state optical and magneto-optical spectroscopies in a broad spectral range (0.25-2.5 eV) for elucidating the primary and long-lived photoexcitations in a low band-gap pi-conjugated donor-acceptor (DA) copolymer used for efficient photovoltaic solar cells. We show that both singlet excitons (SE) and intrachain triplet-triplet (TT) pairs are photogenerated in the DA-copolymer chains. From the picosecond transient magnetic field response of these species we conclude that the SE and TT spin states are coupled. The TT decomposition into two intrachain geminate triplet excitons maintains spin coherence and thus their spin entanglement lasts into the microsecond time domain.