Phase angle encoded upconversion luminescent nanocrystals for multiplexing applications

Liu, Haichun; Jayakumar, Muthu Kumara Gnanasammandhan; Huang, Kai; Wang, Zi; Zheng, Xiang; Ågren, Hans; Zhang, Yong

doi:10.1039/c6nr09349c

Cited by 71 publications

(91 citation statements)

References 57 publications

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“…This difference is ascribed to the rise process of the upconversion luminescence. The phase angle of upconversion luminescence has also been studied by numerical simulations based on a rate equation model to mimic the harmonic response of a practical upconversion system involving complex energy transfer processes, i.e., a Yb 3 + /Er 3 + ‐codoped system . The simulated results also confirmed the easy accessibility of

> 90^{\circ}

phase angle for upconversion luminescence.…”

Section: Optical Responses Of Upconversion Systems To External Stimulimentioning

confidence: 74%

“…However, it should be clarified that such an interpretation is not accurate. The theoretical analyses performed by us and by others reveal that these observed time constants generally refer to the temporal response of the whole upconversion system rather than to properties of any individual energy state …”

Section: Optical Responses Of Upconversion Systems To External Stimulimentioning

confidence: 88%

“…In our recent study, we used a simplified rate equation model to investigate the temporal behavior of a model two‐photon upconversion system composed of two different types of ions, acting as sensitizers and activators, respectively ( Figure ) . Our results reveal that both the rise and decay times are impacted by the lifetimes of the involved energy states and also by the energy transfer between the sensitizers and activators . Assuming weak excitation, the decay time constant primarily reflects the lifetime of the activator's upper emitting state, while the rise time constant is mainly governed by the lifetimes of the sensitizers' excited state and the activator's intermediate state as well as by the energy transfer rate from the sensitizers to the activators …”

Section: Optical Responses Of Upconversion Systems To External Stimulimentioning

confidence: 96%

Section: Optical Responses Of Upconversion Systems To External Stimulimentioning

confidence: 96%

“…Both the rise and decay processes influence the time lag between the light absorption and emission. We recently investigated the phase angle of upconversion luminescence by means of a theoretical analysis . By considering the impulse response function described in equation , we found that the phase angle for the upconversion luminescence (ϕ u ) can be described by:

ϕ_{normalu} = arccos [\frac{1 - ω^{2} τ_{d} τ_{r}}{\sqrt{{(1 - ω^{2} τ_{normald} τ_{normalr})}^{2} + ω^{2} {(τ_{normald} + τ_{normalr})}^{2}}}] .

It is notable here that the phase angle for upconversion luminescence easily exceeds 90° and approaches 180° (Figure b), in stark contrast to downconversion fluorophores, whose phase angle is some fraction of 90° independent of the modulation frequency.…”

Section: Optical Responses Of Upconversion Systems To External Stimulimentioning

confidence: 99%

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Photon Upconversion Kinetic Nanosystems and Their Optical Response

Liu

Huang

Valiev

et al. 2017

Laser & Photonics Reviews

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Lanthanide-doped photon upconversion nanoparticles (UCNPs) are capable of converting low-intensity near-infrared light to UV and visible emission through the synergistic effects of light excitation and mutual interactions between doped ions. UCNPs have attracted strong interest as unique spectrum converters and found a multitude of applications in areas like biomedical imaging, energy harvesting and information technology. UCNPs are distinct from many other types of luminescent materials in terms of the involvement of a host lattice and multiple optical centers, i.e., trivalent lanthanide ions with manyfolds of accessible long-lived energy states, in individual nanoparticles. The mutual interactions between these optical centers, i.e., sequential energy transfers, make them operate as an integrated unit and co-determine the luminescence kinetics and other optical properties of the individual nanoparticle. Thus, each nanoparticle consititutes a kinetic optical system. In this work, we explore UCNPs from the outset of being such kinetic optical systems and review their physical formation, the underlying photophysics, macroscopic statistical description, and their response to various optical stimuli in the spectral, polarization, intensity, temporal and frequency domains, and demonstrate ways that their optical output can be optimized by manipulating the excitation schemes. Our review highlights upconversion nanotechnology as an interdisciplinary field across chemistry, physics and biomedical engineering, with great future possibilities, flexibility and ramifications. We outline some of the potential directions of upconversion nanoparticle research.

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> 90^{\circ}

phase angle for upconversion luminescence.…”

Section: Optical Responses Of Upconversion Systems To External Stimulimentioning

confidence: 74%

Section: Optical Responses Of Upconversion Systems To External Stimulimentioning

confidence: 88%

Section: Optical Responses Of Upconversion Systems To External Stimulimentioning

confidence: 96%

Section: Optical Responses Of Upconversion Systems To External Stimulimentioning

confidence: 96%

ϕ_{normalu} = arccos [\frac{1 - ω^{2} τ_{d} τ_{r}}{\sqrt{{(1 - ω^{2} τ_{normald} τ_{normalr})}^{2} + ω^{2} {(τ_{normald} + τ_{normalr})}^{2}}}] .

Section: Optical Responses Of Upconversion Systems To External Stimulimentioning

confidence: 99%

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Photon Upconversion Kinetic Nanosystems and Their Optical Response

Liu

Huang

Valiev

et al. 2017

Laser & Photonics Reviews

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Enhancing Light and X‐Ray Charging in Persistent Luminescence Nanocrystals for Orthogonal Afterglow Anti‐Counterfeiting

Huang

Dou

Zhang

et al. 2021

Adv Funct Materials

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Persistent luminescence nanoparticles (PLNPs) are an emerging type of optical nanomaterial that possess long-lasting afterglow after the excitation has stopped. Recently, bottom-up synthesis of PLNPs has offered uniform and small nanocrystals that are desirable for various bioapplications. However, the lack of a simple method to enhance the afterglow of these PLNPs is one of the key obstacles hindering their further development and applications. Herein, a simple strategy is demonstrated that can amplify both light and X-ray charged persistent luminescence in monodispersed Zn 2 GeO 4 :Mn PLNPs via the non-equivalency substitution of zinc ions with lithium ions in the lattice matrix and concomitant to the electron traps tailoring. It is significant that, in addition to increasing the intensity of the afterglow, this nanoscale atomic level substitution can preserve the desirable uniform size and morphology of the PLNPs. Furthermore, since the two excitations (light and X-ray) are independent of each other, a light/X-ray orthogonally encrypted spatio-temporal dual-dimensional afterglow anti-counterfeiting is demonstrated via these nanoparticles. It is believed that this simple method offers a foundation for new opportunities to unleash the optical performance in PLNPs. This will also pave the way to the development of such PLNPs for numerous photonic and bioapplications, which are limited in existing methods.

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Optical Nanomaterials and Enabling Technologies for High‐Security‐Level Anticounterfeiting

et al. 2019

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by 2023 the global anticounterfeiting packaging market is projected to reach 208.4 billion USD. [9] The field of anticounterfeiting has a moving target. Initially, for example, almost every country implemented watermarks or fluorescence labels on banknotes to deter copying. [1] Nowadays, a broad range of optical nanomaterials, including metallic nanoparticles, organic dyes, semiconducting quantum dots, and lanthanide-doped nanoparticles (Figure 1) are available to be explored for developing next-generation anticounterfeiting technologies. Thanks to the rapid development of material science, wet-chemistry methods are available for highly controllable synthesis, allowing a large range of nanoparticles with distinguished optical features to be employed as anticounterfeiting taggants. Among them, lanthanide-doped upconversion nanoparticles (UCNPs) are outstanding for the feasibility to tune their optical properties in multiple dimensions. Here, we survey the recent progress in anticounterfeiting applications using new collections of optical nanomaterials as security inks and point out that UCNPs are one of the most promising candidates for high-security-level anticounterfeiting applications. [10] Moreover, we present an outlook for future trends in encryption and decryption devices and technologies toward their real-world adoptions. Nanoparticles for Anticounterfeiting ApplicationsGenerally, anticounterfeiting is done by verifying authentic information that can be either covert or overt. In a typical decoding process, the retrieved information may manifest itself as fluorescence color and intensity in patterns that are varying in the time and space domains. As a crucial element of anticounterfeiting technology, an encoding material serves as a carrier of distinct authentic information. [15] Hence, to achieve a high anticounterfeiting level, the encoding material should be able to offer abundant optical states that can be tailored to carry unique information. In this regard, nanoparticle materials (Table 1) have attracted tremendous interest owing to their exceptional stability, controllability, and diversity in tuning their optical properties in multiple dimensions, e.g., fluorescence color, intensity, and lifetime value. We surveyed and summarized several key fundamental optical features including reflection, absorption, scattering, and fluorescence that can be Optical nanomaterials have been widely used in anticounterfeiting applications. There have been significant developments powered by recent advances in material science, printing technologies, and the availability of smartphone-based decoding technology. Recent progress in this field is surveyed, including the availability of optical reflection, absorption, scattering, and luminescent nanoparticles. It is demonstrated that advances in the design and synthesis of lanthanide-doped upconversion nanoparticles will lead to the next generation of anticounterfeiting technologies. Their tunable optical properties and optical responses to a range of external stimuli a...

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Phase angle encoded upconversion luminescent nanocrystals for multiplexing applications

Cited by 71 publications

References 57 publications

Photon Upconversion Kinetic Nanosystems and Their Optical Response

Photon Upconversion Kinetic Nanosystems and Their Optical Response

Enhancing Light and X‐Ray Charging in Persistent Luminescence Nanocrystals for Orthogonal Afterglow Anti‐Counterfeiting

Optical Nanomaterials and Enabling Technologies for High‐Security‐Level Anticounterfeiting

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