Nonlinear optoelectronic processes in organic optoelectronic devices: Triplet-triplet annihilation and singlet fission

Publication date: Available online 15 October 2019Source: Materials Science and Engineering: R: ReportsAuthor(s): Xianfeng Qiao, Dongge MaAbstractOrganic semiconductors with optoelectronic properties have attracted intensive interests in the fields of organic light-emitting diodes, organic photovoltaics and organic photodetectors. In these functional devices, exciton evolution is the key process. Generally, linear process is dominant that one photon is created from each injected electron-hole pair, vice versa. This linear process restricts the internal quantum efficiency to be 100% in optoelectronic devices. Alternatively, nonlinear optoelectronic processes, like triplet-triplet annihilation (TTA) and singlet fission (SF), can theoretically break the limitation stated in linear optoelectronic processes. TTA and SF are two dynamic reversible processes, which link one high-lying energy singlet with two low-lying energy triplet excitons on two neighboring chromophores. These nonlinear processes bring the possibility of novel functions and application scenarios, and hence have attracted more and more attentions recently.This review will systematically and comparatively summarize the basic properties of TTA and SF processes, and their applications in optoelectronic devices in the view of device physics. It starts with a concise introduction of basic knowledge of TTA and SF. Then, the characteristics used to identify these processes are described. Subsequently, implementing them in...
Source: Materials Science and Engineering: R: Reports - Category: Materials Science Source Type: research