Wide-range lifetime-tunable and responsive ultralong organic phosphorescent multi-host/guest system

Abstract

The rational lifetime-tuning strategy of ultralong organic phosphorescence is extraordinarily important but seldom reported. Herein, a series of multi-host/guest ultralong organic phosphorescence materials with dynamic lifetime-tuning properties were reported. By doping a non-room-temperature phosphorescence emitter into various solid host matrices with continuously reduced triplet energy levels, a wide-range lifetime (from 3.9 ms gradually to 376.9 ms) phosphorescence with unchangeable afterglow colors were realized. Further studies revealed that the host matrices were employed to afford rigid environment and proper energy levels to generate and stabilize the long-live triplet excitons. Meanwhile, these multi-host/guest ultralong organic phosphorescence materials also exhibited excitation-dependent phosphorescence and temperature-controlled afterglow on/off switching properties, according to the virtue of various photophysical and thermal properties of the host matrices. This work provides a guiding strategy to realize lifetime-tuning ultralong organic phosphorescence with lifetime-order encoding characteristic towards widespread applications in time-resolved information displaying, higher-level security protection, and dynamic multi-dimensional anti-counterfeiting.

Toward phosphorescent and delayed fluorescent carbon quantum dots for next-generation electroluminescent displays

“…These mainly include co-crystal assembly, 49 rigid matrix host–guest systems, 83 structurally modified host–guest systems, 84 and dopant-based systems. 54 By dissolving 1,8-naphthalic anhydride in certain organic solid hosts, purely organic phosphorescence with a lifetime of over 600 ms and an overall quantum yield of over 20% were realized, 55 where it was proposed that a cluster exciton spanning the host and guest forms as a transient state before the guest acts as an energy trap for the RTP state. Overall, the key to achieving efficient phosphorescence lies in enhancing k ISC , accelerating phosphorescent decay and minimizing the non-radiative decay rate and quenching rate.…”

“…Accordingly, these two approaches harvest light from both triplet and singlet excitons, allowing the internal quantum efficiency (IQE) of the devices to reach nearly 100%. 45,46 In the last several years, through versatile design principles, such as halogen bonding, 47–49 H-aggregation, 50 and n–π transitions, 51,52 while phosphorescence enhancement strategies based on co-crystallization 49 and rigid matrix host–guest systems, 53–55 pure organic molecules have been progressively endowed with long-lived and strong room-temperature phosphorescence (RTP). Generally, pure organic RTP emitters, including sulfur–nitrogen-containing heteroaromatic derivatives, 56 borate derivatives, 57 polyacid derivatives, 58 etc.…”

Progress on Exploring the Luminescent Properties of Organic Molecular Aggregates by Multiscale Modeling

“…In addition, introducing a supramolecular host molecule into the AIEgen can effectively enhance the emission efficiency in both the monomer and aggregated states due to the non-covalent interactions between the host and guest molecules ( Liang et al, 2014 ; Song et al, 2014 ; Liang et al, 2016 ; Liow et al, 2017 ). And, doping trace amounts of luminophores into host molecules makes efficient room temperature phosphorescence ( Hirata et al, 2013 ; Kabe and Adachi, 2017 ; Han et al, 2019 ; Lei et al, 2019 ; Lei et al, 2021 ; Xie et al, 2021 ). Therefore, the luminescent properties of organic molecular aggregates are sensitive to molecular packing and intermolecular non-covalent interactions and are highly complicated.…”

Theoretical Insight Into the Ultralong Room-Temperature Phosphorescence of Nonplanar Aromatic Hydrocarbon

“…Namely, the ultralong RTP in aromatic hydrocarbon materials is extremely rare, ( Clapp, 1939 ; Bilen et al, 1978 ), because of the forbidden intersystem crossing (ISC) process between singlet and triplet excited states. To overcome this issue, the heavy atoms (eg., Br and I) ( Cai et al, 2018 ; Wang et al, 2021b ) and carbonyl groups ( Zhao et al, 2016 ; Jia et al, 2020 ) were incorporated into organic molecules to promote ISC process for achieving ultralong RTP, in combination with the suppression of the nonradiative quenching through rigid environment, ( Wu et al, 2020 ; Zheng et al, 2020 ; Zhou et al, 2020 ; Chen et al, 2021 ; Xie et al, 2021 ), such as crystal engineering and host-guest system. Very recently, Bechtold et al reported that the nonplanar aromatic hydrocarbon, named as 5,6,11,12,17,18-hexahydrobenzo [2,1-p]chrysene (HD), ( Salla et al, 2019 ), can show an ultralong RTP, which was attributed to the pronounced SOC induced by non-planar configuration.…”