Browsing by Author "Liao, Yu-Ming"

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Intrinsic Ultralow-Threshold Laser Action from Rationally Molecular Design of Metal-Organic Framework Materials
(2020-08-12)
Bera, Krishna Prasad
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Kamal, Saqib
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Inamdar, Arif I.
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Sainbileg, Batjargal
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Lin, Hung-, I
Metal-organic frameworks (MOFs) are superior for multiple applications including drug delivery, sensing, and gas storage because of their tunable physiochemical properties and fascinating architectures. Optoelectronic application of MOFs is difficult because of their porous geometry and conductivity issues. Recently, a few optoelectronic devices have been fabricated by a suitable design of integrating MOFs with other materials. However, demonstration of laser action arising from MOFs as intrinsic gain media still remains challenging, even though some studies endeavor on encapsulating luminescence organic laser dyes into the porous skeleton of MOFs to achieve laser action. Unfortunately, the aggregation of such unstable laser dyes causes photoluminescence quenching and energy loss, which limits their practical application. In this research, unprecedently, we demonstrated ultralow-threshold (similar to 13 nJ/cm(2)) MOF laser action by a judicious choice of metal nodes and organic linkers during synthesis of MOFs. Importantly, we also demonstrated that the white random lasing from the beautiful microflowers of organic linkers possesses a porous network, which is utilized to synthesize the MOFs. The highly luminescent broad-band organic linker 1,4-NDC, which itself exhibits a strong white random laser, is used not only to achieve the stimulated emission in MOFs but also to reduce the lasing threshold. Such white lasing has multiple applications from bioimaging to the recently developed versatile Li-Fi technology. In addition, we showed that the smooth facets of MOF microcrystals can show Fabry-Perot resonant cavities having a high quality factor of similar to 10(3) with excellent photostability. Our unique discovery of stable, nontoxic, high-performance MOF laser action will open up a new route for the development of new optoelectronic devices.
Plasmonic Carbon-Dot-Decorated Nanostructured Semiconductors for Efficient and Tunable Random Laser Action
(2018-01-01)
Liao, Wei-Cheng
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Liao, Yu-Ming
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Su, Chuan-Tsung
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Perumal, Packiyaraj
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Lin, Shih-Yao
Carbon dots have emerged as popular materials in various research fields, including biological and photovoltaic areas, while significant reports are lacking related to their applications in laser devices, which play a significant role in our daily life. In this work, we demonstrate the first controllable random laser assisted by the surface plasmon effect of carbon dots. Briefly, carbon dots derived from candle soot are randomly deposited on the surface of gallium nitride (GaN) nanorods to enhance the ultraviolet fluorescence of GaN and generate plasmonically enhanced random laser action with coherent feedback. Furthermore, potentially useful functionalities of tunable lasing threshold and controllable optical modes are achieved by adjusting the numbers of carbon dots, enabling applications in optical communication and identification technologies. In addition to providing an efficient alternative for plasmonically enhanced random laser devices with simple fabrication and low cost, our work also paves a useful route for the application of environmentally friendly carbon dots in optoelectronic devices.
Self-Powered, Self-Healed, and Shape-Adaptive Ultraviolet Photodetectors
(2020-02-26)
Tsai, Meng-Shian
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Shen, Tien-Lin
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Wu, Hsing-Mei
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Liao, Yu-Ming
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Liao, Yu-Kuang
The emergence of self-healing devices in recent years has drawn a great amount of attention in both academics and industry. Self-healed devices can autonomically restore a rupture as unexpected destruction occurs, which can efficiently prolong the life span of the devices; hence, they have an enhanced durability and decreased replacement cost. As a result, integration of wearable devices with self-healed electronics has become an indispensable issue in smart wearable devices. In this study, we present the first self-powered, self-healed, and wearable ultraviolet (UV) photodetector based on the integration of agarose/poly(vinyl alcohol) (PVA) double network (DN) hydrogels, which have the advantages of good mechanical strength, self-healing ability, and tolerability of multiple types of damage. With the integration of a DN hydrogel substrate, the photodetector enables 90% of the initial efficiency to be restored after five healing cycles, and each rapid healing time is suppressed to only 10 s. The proposed device has several merits, including having an all spray coating, self-sustainability, biocompatibility, good sensitivity, mechanical flexibility, and an outstanding healing ability, which are all essential to build smart electronic systems. The unprecedented self-healed photodetector expands the future scope of electronic skin design, and it also offers a new platform for the development of next-generation wearable electronics.