CAJ | 학술논문

有机分子中的单线态分裂过程能将单个光激发的单线态激子转化成两个三线态激子。借助此载流子倍增效应，太阳能电池可以更有效地利用太阳光谱中的高能光子，进而突破单结太阳能电池效率的理论极限。因此，单线态分裂备受关注。本文回顾学术界对单线态分裂物理图像的认识以及争议，结合课题组近年来的一些结果，重点总结此领域中运用瞬态光谱学方法取得的实验进展，讨论有关多激子中间暗态机理的不同观点，并介绍单线态分裂材料的发展以及器件应用。
유궤분자중적단선태분렬과정능장단개광격발적단선태격자전화성량개삼선태격자。차조차재류자배증효응，태양능전지가이경유효지이용태양광보중적고능광자，진이돌파단결태양능전지효솔적이론겁한。인차，단선태분렬비수관주。본문회고학술계대단선태분렬물리도상적인식이급쟁의，결합과제조근년래적일사결과，중점총결차영역중운용순태광보학방법취득적실험진전，토론유관다격자중간암태궤리적불동관점，병개소단선태분렬재료적발전이급기건응용。
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 e?ciency 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 e?ciencies 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 e?cient and cheap solar cells is the ultimate goal for understanding the intrinsic photophysics of singlet fission. To obtain high e?ciencies, it is important to adapt proper materials and new organic/inorganic architectures may become a promising direction. Also, finding a way for e?cient triplet exciton dissociation should be considered seriously. It is believable that these guidelines can lead to the development of cheap and e?cient fission–based devices.