Activating room temperature phosphorescence by organic materials using synergistic effects. Issue 2 (14th November 2018)

• Record Type: Journal Article
• Authors: Kong, Xianggui; Wang, Xinrui; Cheng, Huimin; Zhao, Yufei; Shi, Wenying
• Is Part Of: Journal of materials chemistry. Volume 7:Issue 2(2019)
• Page Start: 230
• Page End: 236
• Publication Date: 2018-11-14
• Subjects: Materials -- Periodicals; Chemistry, Analytic -- Periodicals; Optical materials -- Research -- Periodicals; Electronics -- Materials -- Research -- Periodicals; 543.0284
• DOI: 10.1039/c8tc04482a
• Languages: English
• ISSNs: 2050-7526

Abstract

Abstract : We present a design principle to activate highly efficient organic room temperature phosphorescent (ORTP) of carbon dots (CDs), with layered double hydroxides (LDHs) as the host matrix, that utilizes three synergistic effects, i.e. structural confinement effect, heavy atom effect, and chemical bonding. Abstract : Designing highly effective organic room temperature phosphorescent (ORTP) materials presents great technical challenges due to their weak spin–orbit coupling and intense non-radiative transitions. Herein, we employ layered double hydroxides (LDHs) as a host matrix, and present a design principle to activate ORTP of carbon dots (CDs) through three synergistic effects. Impressively, the obtained Zn-CDs-LDHs present high phosphorescence quantum yield (PQY) of up to 9.58% and ultralong RTP lifetime of 719.9 ms at ambient conditions, which is higher than those of most reported CD-based materials. Activated ORTP originates from: (1) structural confinement provided by the nanospaces of LDHs reduces the non-radiative decay of triplet excitons and boosts the T1 → S0 radiative relaxation; (2) non-noble metal Zn(ii ) in LDH interlayer disturbs the symmetry of triplet excitons and antisymmetry of singlet excitons by strong spin–orbit coupling and enhances the intersystem crossing (ISC) from the singlet excited state (S n ) to the triplet manifold (T n ); and (3) chemical bonding (coordination, covalent, electrostatic, and hydrogen bonding) between the rigid LDH matrix and the interlayer CDs. Design strategies that account for such synergistic effects will open new avenues for the development of advanced ORTP phosphors with ultralong lifetimes.