物理学报Issue(9)：1-16,16.DOI:10.7498/aps.64.094210
单线态分裂的超快光谱学研究∗
Ultrafast sp ectroscopic study for singlet fission
摘要
Abstract
Singlet fission is a spin-allowed process that creates two triplet excitons from one photo-excited singlet exciton in organic semiconductors. This process of carrier multiplication holds the great potential to break the theoretical efficiency limit in single-junction solar cells by making better use of high-energy photons, while capturing lower-energy photons in the usual style. Photovoltaic devices based on singlet fission have achieved external quantum efficiencies in excess of 100%. In this paper, we first introduce the basic concept about singlet fission and review the history of the field briefly. Then, we report some recent advances in the research of singlet fission progress with the combination of our group’s productions. Tetracene and pentacene are chosen as typical polyacene materials for discuss. We describe how scientists make progresses in understanding the underlying physics in singlet fission process. The experimental methods of transient absorption spectra, time-resolved fluorescence spectra and time-resolved two-photon photoemission spectra render numerous results for analysis. Moreover, a survey about the debate on the direct or indirect mechanism with transient optical study is provided. It has been verified that multiexciton state intermediates in singlet fission process and the factors of energy level alignments, intermolecular interaction as well as lattice vibrations play a role in it. Last, we briefly summarize the implications of singlet fission in organic solar devices by introducing several composite architectures for singlet-fission photovoltaics. Designing efficient and cheap solar cells is the ultimate goal for understanding the intrinsic photophysics of singlet fission. To obtain high efficiencies, it is important to adapt proper materials and new organic/inorganic architectures may become a promising direction. Also, finding a way for efficient triplet exciton dissociation should be considered seriously. It is believable that these guidelines can lead to the development of cheap and efficient fission–based devices.关键词
瞬态光谱/分子间作用/三线态激子/有机光伏电池Key words
transient spectrum/intermolecular coupling/triplet exciton/organic photovoltaic引用本文复制引用
张博,张春峰,李希友,王睿,肖敏..单线态分裂的超快光谱学研究∗[J].物理学报,2015,(9):1-16,16.基金项目
Project supported by the National Basic Research Program of China (Grant Nos.2013CB932903,2012CB921801), and the National Natural Science Foundation of China (Grant Nos.91233103,61108001,11227406,11321063) （Grant Nos.2013CB932903,2012CB921801）
