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Journal ArticleDOI

Advanced Organic Optoelectronic Materials: Harnessing Excited-State Intramolecular Proton Transfer (ESIPT) Process

23 Aug 2011-Advanced Materials (Adv Mater)-Vol. 23, Iss: 32, pp 3615-3642
TL;DR: Recent studies on advanced ESIPT molecules and their optoelectronic applications are surveyed, particularly focusing on chemical sensors, fluorescence imaging, proton transfer lasers, and organic light-emitting diodes (OLEDs).
Abstract: Recently, organic fluorescent molecules harnessing the excited-state intramolecular proton transfer (ESIPT) process are drawing great attention due to their unique photophysical properties which facilitate novel optoelectronic applications. After a brief introduction to the ESIPT process and related photo-physical properties, molecular design strategies towards tailored emission are discussed in relation to their theoretical aspects. Subsequently, recent studies on advanced ESIPT molecules and their optoelectronic applications are surveyed, particularly focusing on chemical sensors, fluorescence imaging, proton transfer lasers, and organic light-emitting diodes (OLEDs).
Citations
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Journal ArticleDOI
TL;DR: This paper presents a meta-analysis of the chiral stationary phase transition of Na6(CO3)(SO4)2, a major component of the response of the immune system to Na2CO3.
Abstract: Ju Mei,†,‡,∥ Nelson L. C. Leung,†,‡,∥ Ryan T. K. Kwok,†,‡ Jacky W. Y. Lam,†,‡ and Ben Zhong Tang*,†,‡,§ †HKUST-Shenzhen Research Institute, Hi-Tech Park, Nanshan, Shenzhen 518057, China ‡Department of Chemistry, HKUST Jockey Club Institute for Advanced Study, Institute of Molecular Functional Materials, Division of Biomedical Engineering, State Key Laboratory of Molecular Neuroscience, Division of Life Science, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China Guangdong Innovative Research Team, SCUT-HKUST Joint Research Laboratory, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640, China

5,658 citations

Journal ArticleDOI
TL;DR: The basic photophysics of the excited-state intramolecular proton transfer (ESIPT) chromophores are introduced and the state-of-the-art development of the ESIPT chromophore and their applications in chemosensors, biological imaging and white-light emitting materials are summarized.
Abstract: In this perspective we introduce the basic photophysics of the excited-state intramolecular proton transfer (ESIPT) chromophores, then the state-of-the-art development of the ESIPT chromophores and their applications in chemosensors, biological imaging and white-light emitting materials are summarized. Most of the applications of the ESIPT chromophores are based on the photophysics properties, such as design of fluorescent chemosensors by perturbation of the ESIPT process upon interaction with the analytes, their use as biological fluorescent tags to study DNA–protein interaction by probing the variation of the hydration, or design of white-light emitting materials by employing the large Stokes shift of the ESIPT chromophores (to inhibit the Foster energy transfer of the components). The photophysical mechanism of these applications is discussed. Furthermore, a new research topic concerning the ESIPT chromophores is proposed based on our group's results, that is, to develop organic triplet sensitizers with ESIPT chromophores.

911 citations

Journal ArticleDOI
TL;DR: This review will explore recent advances in the design and application of excited-state intramolecular proton-transfer (ESIPT) based fluorescent probes.
Abstract: In this review we will explore recent advances in the design and application of excited-state intramolecular proton-transfer (ESIPT) based fluorescent probes. Fluorescence based sensors and imaging agents (probes) are important in biology, physiology, pharmacology, and environmental science for the selective detection of biologically and/or environmentally important species. The development of ESIPT-based fluorescence probes is particularly attractive due to their unique properties, which include a large Stokes shift, environmental sensitivity and potential for ratiometric sensing.

844 citations

Journal ArticleDOI
TL;DR: This review highlights recently developed solid state ESIPT emitters with focus on molecular design strategies and their photophysical properties, reported in the last five years.
Abstract: Solid state emitters based on excited state intramolecular proton transfer (ESIPT) have been attracting considerable interest since the past few years in the field of optoelectronic devices because of their desirable unique photophysical properties. The photophysical properties of the solid state ESIPT fluorophores determine their possible applicability in functional materials. Less fluorescence quantum efficiencies and short fluorescence lifetime in the solid state are the shortcomings of the existing ESIPT solid state emitters. Designing of ESIPT chromophores with high fluorescence quantum efficiencies and a long fluorescence lifetime in the solid state is a challenging issue because of the unclear mechanism of the solid state emitters in the excited state. Reported design strategies, detailed photophysical properties, and their applications will help in assisting researchers to overcome existing challenges in designing novel solid state ESIPT fluorophores for promising applications. This review highlights recently developed solid state ESIPT emitters with focus on molecular design strategies and their photophysical properties, reported in the last five years.

739 citations

Journal ArticleDOI
TL;DR: This tutorial review summarizes the recent progress in the development of specific AIEgen-based light-up bioprobes and hopes to provide guidelines for the design of more advanced AIE sensing and imaging platforms with high selectivity, great sensitivity and wide adaptability to a broad range of biomedical applications.
Abstract: Driven by the high demand for sensitive and specific tools for optical sensing and imaging, bioprobes with various working mechanisms and advanced functionalities are flourishing at an incredible speed. Conventional fluorescent probes suffer from the notorious effect of aggregation-caused quenching that imposes limitation on their labelling efficiency or concentration to achieve desired sensitivity. The recently emerged fluorogens with an aggregation-induced emission (AIE) feature offer a timely remedy to tackle the challenge. Utilizing the unique properties of AIE fluorogens (AIEgens), specific light-up probes have been constructed through functionalization with recognition elements, showing advantages such as low background interference, a high signal to noise ratio and superior photostability with activatable therapeutic effects. In this tutorial review, we summarize the recent progress in the development of specific AIEgen-based light-up bioprobes. Through illustration of their operation mechanisms and application examples, we hope to provide guidelines for the design of more advanced AIE sensing and imaging platforms with high selectivity, great sensitivity and wide adaptability to a broad range of biomedical applications.

641 citations

References
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Journal ArticleDOI
10 Sep 1998-Nature
TL;DR: In this article, a host material doped with the phosphorescent dye PtOEP (PtOEP II) was used to achieve high energy transfer from both singlet and triplet states.
Abstract: The efficiency of electroluminescent organic light-emitting devices1,2 can be improved by the introduction3 of a fluorescent dye. Energy transfer from the host to the dye occurs via excitons, but only the singlet spin states induce fluorescent emission; these represent a small fraction (about 25%) of the total excited-state population (the remainder are triplet states). Phosphorescent dyes, however, offer a means of achieving improved light-emission efficiencies, as emission may result from both singlet and triplet states. Here we report high-efficiency (≳90%) energy transfer from both singlet and triplet states, in a host material doped with the phosphorescent dye 2,3,7,8,12,13,17,18-octaethyl-21H,23H-porphine platinum(II) (PtOEP). Our doped electroluminescent devices generate saturated red emission with peak external and internal quantum efficiencies of 4% and 23%, respectively. The luminescent efficiencies attainable with phosphorescent dyes may lead to new applications for organic materials. Moreover, our work establishes the utility of PtOEP as a probe of triplet behaviour and energy transfer in organic solid-state systems.

7,023 citations

Journal ArticleDOI
TL;DR: The restriction of intramolecular rotation is identified as a main cause for the AIE effect and a series of new fluorescent and phosphorescent AIE systems with emission colours covering the entire visible spectral region and luminescence quantum yields up to unity are developed.

3,324 citations

Journal ArticleDOI
13 Apr 2006-Nature
TL;DR: This device challenges incandescent sources by exhibiting total external quantum and power efficiencies that peak at 18.7 ± 0.6 lm W-1, respectively, and two distinct modes of energy transfer within this device serve to channel nearly all of the triplet energy to the phosphorescent dopants, retaining the singlet energy exclusively on the blue fluorescent dopant.
Abstract: Lighting accounts for approximately 22 per cent of the electricity consumed in buildings in the United States, with 40 per cent of that amount consumed by inefficient (approximately 15 lm W(-1)) incandescent lamps. This has generated increased interest in the use of white electroluminescent organic light-emitting devices, owing to their potential for significantly improved efficiency over incandescent sources combined with low-cost, high-throughput manufacturability. The most impressive characteristics of such devices reported to date have been achieved in all-phosphor-doped devices, which have the potential for 100 per cent internal quantum efficiency: the phosphorescent molecules harness the triplet excitons that constitute three-quarters of the bound electron-hole pairs that form during charge injection, and which (unlike the remaining singlet excitons) would otherwise recombine non-radiatively. Here we introduce a different device concept that exploits a blue fluorescent molecule in exchange for a phosphorescent dopant, in combination with green and red phosphor dopants, to yield high power efficiency and stable colour balance, while maintaining the potential for unity internal quantum efficiency. Two distinct modes of energy transfer within this device serve to channel nearly all of the triplet energy to the phosphorescent dopants, retaining the singlet energy exclusively on the blue fluorescent dopant. Additionally, eliminating the exchange energy loss to the blue fluorophore allows for roughly 20 per cent increased power efficiency compared to a fully phosphorescent device. Our device challenges incandescent sources by exhibiting total external quantum and power efficiencies that peak at 18.7 +/- 0.5 per cent and 37.6 +/- 0.6 lm W(-1), respectively, decreasing to 18.4 +/- 0.5 per cent and 23.8 +/- 0.5 lm W(-1) at a high luminance of 500 cd m(-2).

2,118 citations

Journal ArticleDOI
17 Feb 2000-Nature
TL;DR: This work uses the mechanism for energetic coupling between phosphorescent and fluorescent molecular species is a long-range, non-radiative energy transfer: the internal efficiency of fluorescence can be as high as 100%.
Abstract: To obtain the maximum luminous efficiency from an organic material, it is necessary to harness both the spin-symmetric and anti-symmetric molecular excitations (bound electron-hole pairs, or excitons) that result from electrical pumping This is possible if the material is phosphorescent, and high efficiencies have been observed in phosphorescent organic light-emitting devices However, phosphorescence in organic molecules is rare at room temperature The alternative radiative process of fluorescence is more common, but it is approximately 75% less efficient, due to the requirement of spin-symmetry conservation Here, we demonstrate that this deficiency can be overcome by using a phosphorescent sensitizer to excite a fluorescent dye The mechanism for energetic coupling between phosphorescent and fluorescent molecular species is a long-range, non-radiative energy transfer: the internal efficiency of fluorescence can be as high as 100% As an example, we use this approach to nearly quadruple the efficiency of a fluorescent red organic light-emitting device

2,050 citations

Journal ArticleDOI
TL;DR: A new class of organic nanoparticles (CN-MBE nanoparticles) with a mean diameter of ca.
Abstract: A new class of organic nanoparticles (CN-MBE nanoparticles) with a mean diameter of ca. 30−40 nm, which exhibit a strongly enhanced fluorescence emission, were prepared by a simple reprecipitation method. CN-MBE (1-cyano-trans-1,2-bis-(4‘-methylbiphenyl)ethylene) is very weakly fluorescent in solution, but the intensity is increased by almost 700 times in the nanoparticles. Enhanced emission in CN-MBE nanoparticles is attributed to the synergetic effect of intramolecular planarization and J-type aggregate formation (restricted excimer formation) in nanopaticles. On/off fluorescence switching for organic vapor was demonstrated with CN-MBE nanoparticles.

1,770 citations