| 1. |
- Alsufyani, Maryam, et al.
(author)
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Lactone Backbone Density in Rigid Electron-Deficient Semiconducting Polymers Enabling High n-type Organic Thermoelectric Performance
- 2022
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In: Angewandte Chemie International Edition. - : WILEY-V C H VERLAG GMBH. - 1433-7851 .- 1521-3773. ; 61:7
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Journal article (peer-reviewed)abstract
- Three lactone-based rigid semiconducting polymers were designed to overcome major limitations in the development of n-type organic thermoelectrics, namely electrical conductivity and air stability. Experimental and theoretical investigations demonstrated that increasing the lactone group density by increasing the benzene content from 0 % benzene (P-0), to 50 % (P-50), and 75 % (P-75) resulted in progressively larger electron affinities (up to 4.37 eV), suggesting a more favorable doping process, when employing (N-DMBI) as the dopant. Larger polaron delocalization was also evident, due to the more planarized conformation, which is proposed to lead to a lower hopping energy barrier. As a consequence, the electrical conductivity increased by three orders of magnitude, to achieve values of up to 12 S cm and Power factors of 13.2 mu Wm(-1) K-2 were thereby enabled. These findings present new insights into material design guidelines for the future development of air stable n-type organic thermoelectrics.
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| 2. |
- Dongo, Patrice D., et al.
(author)
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Detection of Ice Formation With the Polymeric Mixed Ionic-Electronic Conductor PEDOT: PSS for Aeronautics
- 2023
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In: Advanced Electronic Materials. - : WILEY. - 2199-160X.
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Journal article (peer-reviewed)abstract
- Ice formation detection is important in telecommunications and aeronautics, e.g., ice on the wings of an aircraft affects its aerodynamic performance and leads to fatal accidents. While many types of sensors exist, resistive sensors for ice detection have been poorly explored. They are however attractive because of their simplicity and the possibility to install an array of sensors on large areas to map the ice formation on wings. Hygroscopic ionic conductors have been demonstrated for resistive ice sensing but their high resistance prevents the readout of sensor arrays. In this work, mixed ionic-electronic polymer conductors (MIEC) are considered for the first time for ice detection. The polymer blend poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) is solution deposited on a pair of electrodes. The sensor displays an abrupt rise in electrical resistance during the transition phase between water liquid to solid. It is proposed that the morphology and electronic transport in PEDOT are affected by the freezing event because the absorbed water in the PSS-rich phase undergoes dilatation upon forming ice crystals. For the aeronautics application, successful tests of integration of sensing layer in pre-preg layers of aeronautical grade and freezing detection are carried out to validate the ice detection principle.
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| 3. |
- Li, Qifan, et al.
(author)
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A Highly Conductive n-Type Conjugated Polymer Synthesized in Water
- 2024
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In: Journal of the American Chemical Society. - : AMER CHEMICAL SOC. - 0002-7863 .- 1520-5126.
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Journal article (peer-reviewed)abstract
- Poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) is a benchmark hole-transporting (p-type) polymer that finds applications in diverse electronic devices. Most of its success is due to its facile synthesis in water, exceptional processability from aqueous solutions, and outstanding electrical performance in ambient. Applications in fields like (opto-)electronics, bioelectronics, and energy harvesting/storage devices often necessitate the complementary use of both p-type and n-type (electron-transporting) materials. However, the availability of n-type materials amenable to water-based polymerization and processing remains limited. Herein, we present a novel synthesis method enabling direct polymerization in water, yielding a highly conductive, water-processable n-type conjugated polymer, namely, poly[(2,2 '-(2,5-dihydroxy-1,4-phenylene)diacetic acid)-stat-3,7-dihydrobenzo[1,2-b:4,5-b ']difuran-2,6-dione] (PDADF), with remarkable electrical conductivity as high as 66 S cm(-1), ranking among the highest for n-type polymers processed using green solvents. The new n-type polymer PDADF also exhibits outstanding stability, maintaining 90% of its initial conductivity after 146 days of storage in air. Our synthetic approach, along with the novel polymer it yields, promises significant advancements for the sustainable development of organic electronic materials and devices.
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| 4. |
- Liu, Tiefeng, et al.
(author)
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Ground-state electron transfer in all-polymer donor:acceptor blends enables aqueous processing of water-insoluble conjugated polymers
- 2023
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In: Nature Communications. - : NATURE PORTFOLIO. - 2041-1723. ; 14:1
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Journal article (peer-reviewed)abstract
- Water-based conductive inks are vital for the sustainable manufacturing and widespread adoption of organic electronic devices. Traditional methods to produce waterborne conductive polymers involve modifying their backbone with hydrophilic side chains or using surfactants to form and stabilize aqueous nanoparticle dispersions. However, these chemical approaches are not always feasible and can lead to poor material/device performance. Here, we demonstrate that ground-state electron transfer (GSET) between donor and acceptor polymers allows the processing of water-insoluble polymers from water. This approach enables macromolecular charge-transfer salts with 10,000x higher electrical conductivities than pristine polymers, low work function, and excellent thermal/solvent stability. These waterborne conductive films have technological implications for realizing high-performance organic solar cells, with efficiency and stability superior to conventional metal oxide electron transport layers, and organic electrochemical neurons with biorealistic firing frequency. Our findings demonstrate that GSET offers a promising avenue to develop water-based conductive inks for various applications in organic electronics. Chemical approaches to improve aqueous dispersions of conjugated polymers are limited by the feasibility of modifying the backbone or lead to poor performance. Here, Liu et al. show that ground-state electron transfer in donor:acceptor blends aids aqueous dispersion, for high conductivity and solubility.
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| 5. |
- Wu, Hanyan, et al.
(author)
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Influence of Molecular Weight on the Organic Electrochemical Transistor Performance of Ladder-Type Conjugated Polymers
- 2022
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In: Advanced Materials. - : Wiley-V C H Verlag GMBH. - 0935-9648 .- 1521-4095. ; 34:4
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Journal article (peer-reviewed)abstract
- Organic electrochemical transistors (OECTs) hold promise for developing a variety of high-performance (bio-)electronic devices/circuits. While OECTs based on p-type semiconductors have achieved tremendous progress in recent years, n-type OECTs still suffer from low performance, hampering the development of power-efficient electronics. Here, it is demonstrated that fine-tuning the molecular weight of the rigid, ladder-type n-type polymer poly(benzimidazobenzophenanthroline) (BBL) by only one order of magnitude (from 4.9 to 51 kDa) enables the development of n-type OECTs with record-high geometry-normalized transconductance (g(m,norm) approximate to 11 S cm(-1)) and electron mobility x volumetric capacitance (mu C* approximate to 26 F cm(-1) V-1 s(-1)), fast temporal response (0.38 ms), and low threshold voltage (0.15 V). This enhancement in OECT performance is ascribed to a more efficient intermolecular charge transport in high-molecular-weight BBL than in the low-molecular-weight counterpart. OECT-based complementary inverters are also demonstrated with record-high voltage gains of up to 100 V V-1 and ultralow power consumption down to 0.32 nW, depending on the supply voltage. These devices are among the best sub-1 V complementary inverters reported to date. These findings demonstrate the importance of molecular weight in optimizing the OECT performance of rigid organic mixed ionic-electronic conductors and open for a new generation of power-efficient organic (bio-)electronic devices.
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| 6. |
- Wu, Hanyan, et al.
(author)
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Stable organic electrochemical neurons based on p-type and n-type ladder polymers
- 2023
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In: Materials Horizons. - : ROYAL SOC CHEMISTRY. - 2051-6347 .- 2051-6355. ; :10, s. 4213-4223
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Journal article (peer-reviewed)abstract
- Organic electrochemical transistors (OECTs) are a rapidly advancing technology that plays a crucial role in the development of next-generation bioelectronic devices. Recent advances in p-type/n-type organic mixed ionic-electronic conductors (OMIECs) have enabled power-efficient complementary OECT technologies for various applications, such as chemical/biological sensing, large-scale logic gates, and neuromorphic computing. However, ensuring long-term operational stability remains a significant challenge that hinders their widespread adoption. While p-type OMIECs are generally more stable than n-type OMIECs, they still face limitations, especially during prolonged operations. Here, we demonstrate that simple methylation of the pyrrole-benzothiazine-based (PBBT) ladder polymer backbone results in stable and high-performance p-type OECTs. The methylated PBBT (PBBT-Me) exhibits a 25-fold increase in OECT mobility and an impressive 36-fold increase in & mu;C* (mobility x volumetric capacitance) compared to the non-methylated PBBT-H polymer. Combining the newly developed PBBT-Me with the ladder n-type poly(benzimidazobenzophenanthroline) (BBL), we developed complementary inverters with a record-high DC gain of 194 V V-1 and excellent stability. These state-of-the-art complementary inverters were used to demonstrate leaky integrate-and-fire type organic electrochemical neurons (LIF-OECNs) capable of biologically relevant firing frequencies of about 2 Hz and of operating continuously for up to 6.5 h. This achievement represents a significant improvement over previous results and holds great potential for developing stable bioelectronic circuits capable of in-sensor computing.
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| 7. |
- Yang, Chiyuan, et al.
(author)
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A high-conductivity n-type polymeric ink for printed electronics
- 2021
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In: Nature Communications. - : Nature Research. - 2041-1723. ; 12:1
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Journal article (peer-reviewed)abstract
- Conducting polymers, such as the p-doped poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS), have enabled the development of an array of opto- and bio-electronics devices. However, to make these technologies truly pervasive, stable and easily processable, n-doped conducting polymers are also needed. Despite major efforts, no n-type equivalents to the benchmark PEDOT:PSS exist to date. Here, we report on the development of poly(benzimidazobenzophenanthroline):poly(ethyleneimine) (BBL:PEI) as an ethanol-based n-type conductive ink. BBL:PEI thin films yield an n-type electrical conductivity reaching 8Scm(-1), along with excellent thermal, ambient, and solvent stability. This printable n-type mixed ion-electron conductor has several technological implications for realizing high-performance organic electronic devices, as demonstrated for organic thermoelectric generators with record high power output and n-type organic electrochemical transistors with a unique depletion mode of operation. BBL:PEI inks hold promise for the development of next-generation bioelectronics and wearable devices, in particular targeting novel functionality, efficiency, and power performance. The development of n-type conductive polymer inks is critical for the development of next-generation opto-electronic devices that rely on efficient hole and electron transport. Here, the authors report an alcohol-based, high performance and stable n-type conductive ink for printed electronics.
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| 8. |
- Yang, Chi Yuan, et al.
(author)
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Low-Power/High-Gain Flexible Complementary Circuits Based on Printed Organic Electrochemical Transistors
- 2022
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In: Advanced Electronic Materials. - : Wiley. - 2199-160X .- 2199-160X. ; 8:3
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Journal article (peer-reviewed)abstract
- The ability to accurately extract low-amplitude voltage signals is crucial in several fields, ranging from single-use diagnostics and medical technology to robotics and the Internet of Things (IoT). The organic electrochemical transistor (OECT), which features large transconductance values at low operating voltages, is ideal for monitoring small signals. Here, low-power and high-gain flexible circuits based on printed complementary OECTs are reported. This work leverages the low threshold voltage of both p-type and n-type enhancement-mode OECTs to develop complementary voltage amplifiers that can sense voltages as low as 100 µV, with gains of 30.4 dB and at a power consumption of 0.1–2.7 µW (single-stage amplifier). At the optimal operating conditions, the voltage gain normalized to power consumption reaches 169 dB µW−1, which is >50 times larger than state-of-the-art OECT-based amplifiers. In a monolithically integrated two-stage configuration, these complementary voltage amplifiers reach voltage gains of 193 V/V, which are among the highest for emerging complementary metal-oxide-semiconductor-like technologies operating at supply voltages below 1 V. These flexible complementary circuits based on printed OECTs define a new power-efficient platform for sensing and amplifying low-amplitude voltage signals in several emerging beyond-silicon applications.
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| 9. |
- Zhang, Silan, et al.
(author)
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Toward Stable p-Type Thiophene-Based Organic Electrochemical Transistors
- 2023
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In: Advanced Functional Materials. - : WILEY-V C H VERLAG GMBH. - 1616-301X .- 1616-3028. ; 33:40
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Journal article (peer-reviewed)abstract
- Operational stability is essential for the success of organic electrochemical transistors (OECTs) in bioelectronics. The oxygen reduction reaction (ORR) is a common electrochemical side reaction that can compromise the stability of OECTs, but the relationship between ORR and materials degradation is poorly understood. In this study, the impact of ORR on the stability and degradation mechanisms of thiophene-based OECTs is investigated. The findings show that an increase in pH during ORR leads to the degradation of the polymer backbone. By using a protective polymer glue layer between the semiconductor channel and the aqueous electrolyte, ORR is effectively suppressed and the stability of the OECTs is significantly improved, resulting in current retention of nearly 90% for & AP;2 h cycling in the saturation regime.
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