Altering Chain Flexibility of Aliphatic Polyesters for Yellow‐Green Clusteroluminescence in 38 % Quantum Yield

Abstract

Preparation of non-conjugated polymers with longwavelength emission and high quantum yield (QY) is still ahuge challenge.Herein, we report the first example of linear non-conjugated polyester exhibiting yellow-green clusteroluminescence (CL) and ah igh QY of 38 %. We discovered that the polyester P3 with balanced flexibility and rigidity showed the longest CL wavelength and highest QY.S ystematically photophysical characterization unravel the key role of ester cluster in the CL and the cluster formation via the aggregate of ester units was visualized. Moreover,P 3w as demonstrated to be ah ighly selective,q uick-responsive (ca. 1.2 min) and sensitive detector (detection limit is 0.78 mM) for irons owing to the fast disassociation of clusters by irons.T his work not only gains further mechanistic insight into CL but also provides an ew strategy to design high-efficiency and longwavelength CL, meanwhile,enlightens the glorious application prospect of luminescent polyester.

Heteroatom-facilitated blue to near-infrared emission of nonconjugated polyesters

“…S5, ESI†), our previous research has demonstrated that these residual polyether components minimally affect the luminescent properties of the polyester. 23,27 From the GPC spectra (Fig. S19–S22, ESI†), the number-average molecular weight ( M n ) of P1 , P2 , P3 , and P4 catalyzed by TEA/TEB ranged from 1.5 to 17.3 kDa and P1 , P2 , P4 catalyzed by DMCC ranged from 3.9 to 12.9 kDa.…”

“…Recently, the discovery of clusteroluminescence (CL) has captured much attention of researchers. 19,20 CL refers to the nontraditional luminescence from nonconjugated structures, such as cellulose, 21 polypeptide, 22 and polyester, 23,24 at the clustering state. Unlike traditional luminescent materials that rely on through-bond conjugation (TBC), 25 the unconventional luminescence in CL luminogens (CLgens) has been revealed from the intramolecular or intermolecular through-space interaction (TSI).…”

Recent Progress in Nonconventional Luminescent Macromolecules and their Applications

“…Among them, polyester P3 has the longest luminescence wavelength and the highest QY (37.9%, solid state) (Figure 2C). 58 Although TSI theory has greatly advanced the understanding of unconventional luminescence in the past few years, the structure−property relationships of TSI still need to be explored further. Zhang et al found that like the extended TBC in πconjugated photoclusters, hierarchical TSI plays a crucial role in nontraditional chromophores, similar to the multilevel structure of proteins: that is, higher levels of TSI within the molecule may contribute to longer-wavelength emission.…”

“…Therefore, balancing the structural flexibility and rigidity of NCLMs is also a feasible strategy to improve the photophysical properties of NCLMs, such as emission wavelength and efficiency. 57,58 The above strategies have been partly successful in the manipulation of the luminescence properties of NCLMs. However, precisely regulating the photophysical properties of these flexible NCLMs at the molecular level remains a great challenge.…”

“…However, a moderately rigid chain structure can optimize the segmental motion, which is conducive to the formation of more uniform and stable clusters, thereby enhancing the luminescence of the polymer chain. Therefore, balancing the structural flexibility and rigidity of NCLMs is also a feasible strategy to improve the photophysical properties of NCLMs, such as emission wavelength and efficiency. , …”