Browsing by Author "Li, Yilin"
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Item High‐performance hybrid luminescent‐scattering solar concentrators based on a luminescent conjugated polymer(Wiley, 2021) Li, Yilin; Sun, Yujian; Zhang, Yongcao; Li, Yuxin; Verduzco, RafaelLuminescent solar concentrators (LSCs) are considered a promising building‐integrated photovoltaic technology. Over the past decade, numerous luminophores have been developed for LSCs. However, conjugated polymers are rarely reported for LSCs despite their wide application in other fields. In this study, we investigated a luminescent conjugated polymer, poly(naphthalene‐alt‐vinylene) (PNV), for LSCs. PNV exhibits an absorption wavelength (λabs) of 535 nm, an emission wavelength (λem) of 632 nm and a photoluminescence quantum yield of 0.40 in a poly(methyl methacrylate) matrix. When tested under outdoor direct sunlight (1000 W m−2 ± 10%) and indoor diffuse light‐emitting diode (LED) light (10 W m−2 ± 10%), the PNV‐based LSCs with a size of 12 in. (30.48 cm) exhibited power conversion efficiencies (ηLSC) of up to 2.9% and 3.6%, respectively, and concentration ratios (C) of up to 1.49 and 3.53, respectively. The external quantum efficiencies of the LSCs and the edge emission spectra of the luminescent waveguides were analyzed to reveal the impact of surface scattering treatment on device performance. Monte Carlo ray‐tracing simulation was employed to project the performance of large‐area LSCs with sizes of up to 120 in. (304.8 cm). For the LSCs under outdoor direct sunlight and indoor diffuse LED light, the projected ηLSC values were 1.29% and 0.88%, respectively, and the projected C values were 6.73 and 8.62, respectively. This study suggests that high‐performance LSCs can be achieved through luminescent conjugated polymers.Item Rapid, Ambient Temperature Synthesis of Imine Covalent Organic Frameworks Catalyzed by Transition-Metal Nitrates(American Chemical Society, 2021) Zhu, Dongyang; Zhang, Zhuqing; Alemany, Lawrence B.; Li, Yilin; Nnorom, Njideka; Barnes, Morgan; Khalil, Safiya; Rahman, Muhammad M.; Ajayan, Pulickel M.; Verduzco, RafaelCovalent organic frameworks (COFs) are crystalline, porous organic materials that are promising for applications including catalysis, energy storage, electronics, gas storage, water treatment, and drug delivery. Conventional solvothermal synthesis approaches require elevated temperatures, inert environments, and long reaction times. Herein, we show that transition-metal nitrates can catalyze the rapid synthesis of imine COFs under ambient conditions. We first tested a series of transition metals for the synthesis of a model COF and found that all transition-metal nitrates tested produced crystalline COF products even in the presence of oxygen. Fe(NO3)3·9H2O was found to produce the most crystalline product, and crystalline COFs could be produced within 10 min by optimizing the catalyst loading. Fe(NO3)3·9H2O was further tested as a catalyst for six different COF targets varying in linker lengths, substituents, and stabilities, and it effectively catalyzed the synthesis of all imine COFs tested. This catalyst was also successful in the synthesis of 2D imine COFs with different geometries, 3D COFs, and azine-linked COFs. This work demonstrates a simple, low-cost approach for the synthesis of imine COFs and will significantly lower the barrier for the development of imine COFs for applications.Item Side‐Chain Engineering for High‐Performance Conjugated Polymer Batteries(Wiley, 2021) Li, Xiaoyi; Li, Yilin; Sarang, Kasturi; Lutkenhaus, Jodie; Verduzco, RafaelConjugated polymers are attractive for energy storage but typically require significant amounts of conductive additives to successfully operate with thin electrodes. Here, side‐chain engineering is used to improve the electrochemical performance of conjugated polymer electrodes. Naphthalene dicarboximide (NDI)‐based conjugated polymers with ion‐conducting ethylene glycol (EG) side chains (PNDI‐T2EG) and non‐ion‐conducting 2‐octyldodecyl side chains (PNDI‐T2) are synthesized, tested, and compared. For thick (20 µm, 1.28 mg cm−2) electrodes with a 60 wt% polymer, the PNDI‐T2EG electrodes exhibit 66% of the theoretical capacity at an ultrafast charge–discharge rate of 100C (72 s per cycle), while the PNDI‐T2 electrodes exhibit only 23% of the theoretical capacity. Electrochemical impedance spectroscopy measurements on thin (5 µm, 0.32 mg cm−2), high‐polymer‐content (80 wt%) electrodes reveal that PNDI‐T2EG exhibits much higher lithium‐ion diffusivity (DLi+ = 7.01 × 10−12 cm2 s−1) than PNDI‐T2 (DLi+ = 3.96 × 10−12 cm2 s−1). PNDI‐T2EG outperforms most previously reported materials in thick, high‐polymer‐content electrodes in terms of rate performance. The results demonstrate that the rate performance and capacity are significantly improved through the incorporation of EG side chains, and this work demonstrates a route for increasing the rate of ion transport in conjugated polymers and improving the performance and capacity of conjugated‐polymer‐based electrodes.Item Solution-Deposited and Patternable Conductive Polymer Thin-Film Electrodes for Microbial Bioelectronics(Wiley, 2022) Tseng, Chia-Ping; Liu, Fangxin; Zhang, Xu; Huang, Po-Chun; Campbell, Ian; Li, Yilin; Atkinson, Joshua T.; Terlier, Tanguy; Ajo-Franklin, Caroline M.; Silberg, Jonathan J.; Verduzco, RafaelMicrobial bioelectronic devices integrate naturally occurring or synthetically engineered electroactive microbes with microelectronics. These devices have a broad range of potential applications, but engineering the biotic–abiotic interface for biocompatibility, adhesion, electron transfer, and maximum surface area remains a challenge. Prior approaches to interface modification lack simple processability, the ability to pattern the materials, and/or a significant enhancement in currents. Here, a novel conductive polymer coating that significantly enhances current densities relative to unmodified electrodes in microbial bioelectronics is reported. The coating is based on a blend of poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) crosslinked with poly(2-hydroxyethylacrylate) (PHEA) along with a thin polydopamine (PDA) layer for adhesion to an underlying indium tin oxide (ITO) electrode. When used as an interface layer with the current-producing bacterium Shewanella oneidensis MR-1, this material produces a 178-fold increase in the current density compared to unmodified electrodes, a current gain that is higher than previously reported thin-film 2D coatings and 3D conductive polymer coatings. The chemistry, morphology, and electronic properties of the coatings are characterized and the implementation of these coated electrodes for use in microbial fuel cells, multiplexed bioelectronic devices, and organic electrochemical transistor based microbial sensors are demonstrated. It is envisioned that this simple coating will advance the development of microbial bioelectronic devices.Item Transformation of One-Dimensional Linear Polymers into Two-Dimensional Covalent Organic Frameworks Through Sequential Reversible and Irreversible Chemistries(American Chemical Society, 2021) Zhu, Dongyang; Li, Xiaoyi; Li, Yilin; Barnes, Morgan; Tseng, Chia-Ping; Khalil, Safiya; Rahman, Muhammad M.; Ajayan, Pulickel M.; Verduzco, RafaelCovalent organic frameworks (COFs) are crystalline porous materials linked by dynamic covalent bonds. Dynamic chemistries enable the transformation of an initially amorphous network into a porous and crystalline COF. While dynamic chemistries have been leveraged to realize transformations between different types of COFs, including transformations from two-dimensional (2D) to three-dimensional (3D) COFs and insertion of different linking groups, the transformation of linear polymers into COFs has not yet been reported. Herein, we demonstrate an approach to transform linear imine-linked polymers into ketone-linked COFs through a linker replacement strategy with triformylphloroglucinol (TPG). TPG first reacts through dynamic chemistry to replace linkers in the linear polymers and then undergoes irreversible tautomerism to produce ketone linkages. We have analyzed the time-dependent transformation from the linear polymer into COF through powder X-ray diffraction, Fourier-transform infrared spectroscopy (FT-IR), and scanning electron microscopy (SEM) to understand the transition and substitution mechanisms. This work demonstrates another route to produce COFs through sequential reversible and irreversible chemistries and provides a potential approach to synthesizing COFs through the solution processing of linear polymers followed by transformation into the desired COF structure.