Two Are Better Than One: A Design Principle for Ultralong‐Persistent Luminescence of Pure Organics

Abstract

drawbacks. In addition to the higher material costs of these rare-earth metals, many inorganic LPLs require harsh synthetic procedures, [11] further increasing research costs. Organic LPL (OLPL) materials, [12][13][14][15][16] offer the promise of a multitude of benefits: easier synthesis, easier modification for targeted functionality, and easier processing. However, the development of OLPL materials has encountered many obstacles. To access long lived states in organic compounds, there have been many designs to exploit the excited triplet state. Though access to and from the triplet state is a forbidden process and once thought to be too inefficient for effective use at room temperature, [17] recent advances have vastly increased intersystem crossing efficiency by enhancing spin-orbit coupling (SOC) with the use of heteroatoms, [18,19] the carbonyl functional group, [20][21][22] heavy atom effects, [23][24][25][26][27] and multimer-enhanced intersystem crossing. [28][29][30][31][32] Equally important is protecting the long-lived triplet after its generation, due to the fact that they are particularly sensitive to molecular vibrational quenching and atmospheric oxygen. In this regard, recent works have accomplished this through the use of crystals, [33,34] metal-organic frameworks, [35] H-aggregation, [36] and others. [30,32,37] Although there have been many achievements in generating organic room-temperature Because of their innate ability to store and then release energy, longpersistent luminescence (LPL) materials have garnered strong research interest in a wide range of multidisciplinary fields, such as biomedical sciences, theranostics, and photonic devices. Although many inorganic LPL systems with afterglow durations of up to hours and days have been reported, organic systems have had difficulties reaching similar timescales. In this work, a design principle based on the successes of inorganic systems to produce an organic LPL (OLPL) system through the use of a strong organic electron trap is proposed. The resulting system generates detectable afterglow for up to 7 h, significantly longer than any other reported OLPL system. The design strategy demonstrates an easy methodology to develop organic long-persistent phosphors, opening the door to new OLPL materials.Long-persistent luminescent [1,2] (LPL) materials have demonstrated great potential and performance in multiple areas, such as life sciences, [3] the biomedical field, [2,4] and photo voltaics, [5] as they offer fascinating possibilities for their ability to store and slowly release excited state energy. For example in biomedical applications, LPL materials can be used postexcitation, overcoming any issue of autofluorescence. [6][7][8] Currently, the most successful LPL materials make use of transition and rare-earth metal ions. [9,10] Although the metals grant exceptionally long afterglows that range from minutes to hours, with some systems lasting days and weeks, [11] they are not without their inherentThe ORCID identification number(s) for the aut...

Metal Halide Regulated Photophysical Tuning of Zero‐Dimensional Organic Metal Halide Hybrids: From Efficient Phosphorescence to Ultralong Afterglow

“…As shown in Figure 2 d,e and the Supporting Information, Figure S3, TPPCl displays two groups of emission peaks with one at 343 nm as fluorescence [7f, 8] and another at 491 nm as room temperature phosphorescence. The average decay lifetime was determined to be 214.7 ms for the emission peaked at 491 nm, similar to those in previous reports, [8,10] confirming its room temperature phosphorescence nature. The PLQE was measured to be 5.7 %.…”

“…This change of photophysical properties is not surprising, as the heavy atom (Br) with strong spin-orbit coupling effect could greatly promote the intersystem crossing from single to triplet states. [10] The processes of photophysical tuning of TPP 2 MX n are proposed as shown in Figure 4 ) would therefore dominate the emissions with decay lifetimes ranging from microseconds to milliseconds. These phenomena have been observed in most of luminescent 0D organic metal halide hybrids reported to date.…”

Aggregate Science: From Structures to Properties

“…The performance is heavily dependent on the synergistic effect between two components, which is a demonstration of the new horizons that can be reached be extending our efforts beyond isolated molecules toward collective aggregates. [251][252][253][254]…”

Organic luminescent materials: The concentration on aggregates from aggregation‐induced emission

“…Besides crystal engineering, the development of host–guest doping system was also an efficient way to realize ultralong RTP emission. [ 47–51 ] In 2017, Kabe and Adachi successfully realized a long persistent luminescence more than 1 h in a host–guest doping system, which could be even comparable to the most outstanding inorganic phosphors (Figure 7A). [ 47 ] In their system, the host material of PPT acted as electron donor and guest of TMB as electron acceptor.…”