Efficient tuning of the conversion from ISC to high-level RISC via adjusting the triplet energies of charge-transporting layers in rubrene-doped OLEDs. Issue 8 (29th January 2021)

• Record Type: Journal Article
• Authors: Tang, Xiantong; Zhao, Xi; Zhu, Hongqiang; Tu, Linyao; Ma, Caihong; Wang, Ying; Ye, Shengnan; Xiong, Zuhong
• Is Part Of: Journal of materials chemistry. Volume 9:Issue 8(2021)
• Page Start: 2775
• Page End: 2783
• Publication Date: 2021-01-29
• Subjects: Materials -- Periodicals; Chemistry, Analytic -- Periodicals; Optical materials -- Research -- Periodicals; Electronics -- Materials -- Research -- Periodicals; 543.0284
• DOI: 10.1039/d0tc05898j
• Languages: English
• ISSNs: 2050-7526

Abstract

Abstract : Charge-transporting layers with different triplet energies can efficiently tune the conversion from intersystem crossing to high-level reverse intersystem crossing processes in rubrene-doped OLEDs. Abstract : Although the host material has been proved to be a crucial factor affecting the occurrence of the high-level reverse intersystem crossing (HL-RISC, T2, rub → S1, rub ) process in rubrene-doped organic light-emitting diodes (OLEDs), the roles of the charge-transporting layers on this amazing process are still unclear. Very interestingly, herein, we found that the efficient conversion from intersystem crossing (ISC) to HL-RISC is observed by tuning the triplet energies of hole- and electron-transporting layers (HTL and ETL) in rubrene-doped devices. Specifically, when the triplet energies of ETL, rubrene guest, and HTL satisfy the criterion of E (T1, ETL ) < E (T2, rub ) < E (T1, HTL ), the conversion process can be observed under various current and temperature conditions, which can be reasonably explained by the weak energy-loss channel from T2, rub to T1, ETL states and the competition effects of excited states in the ETL and guest. Otherwise, ISC (HL-RISC) will dominate in devices due to the existence (non-existence) of energy-loss channels from T2, rub to T1, HTL states. Furthermore, very importantly, by inserting appropriate HTL or ETL materials with high triplet energies into the control devices with energy-loss channels, we found that the full confinement of E (T2, rub ) indeed facilitates the HL-RISC process. Our work deepens the cognition of the HL-RISC process and provides an effective method to achieve the HL-RISC process in organic optoelectronic devices.