Flexible Optoelectronic Applications Research Articles

Observation of anomalously large Nernst effects in conducting polymers

As a fundamental thermoelectric phenomenon in many solid-state materials, the Nernst effect has yet to be observed in conducting polymers. This knowledge could provide important insight into their elusive mechanism, which are crucial for flexible optoelectronic and thermoelectric applications. However, within the Landau’s Fermi-liquid picture, the Nernst coefficient has demonstrated to be proportional to the charge mobility, and thus should be negligible in less ordered polymers with inherent low mobility. Here, we challenge this notion by observing an anomalously large Nernst effect in a range of conducting polymers. Specially, the Nernst coefficients in these doped polymers exceed the Fermi-liquid predictions by 2-3 orders of magnitudes with negative mobility dependence. These intriguing observations are attributed to the intrinsic quasi-one-dimensional transport nature in conjugated polymers and their unique chemical doping mechanism. Our research not only provides experimental insights into the non-Fermi-liquid charge transport nature of polymers, but also suggests its universality for other quasi-one-dimensional materials and/or less ordered systems, and opens up exciting possibilities for developing transverse organic thermoelectric applications.

Laser-Micro-Annealing of Microcrystalline Ni-Rich NCM Oxide: Towards Micro-Cathodes Integrated on Polyethylene Terephthalate Flexible Substrates

Here in this work, we report on micro-Raman spectroscopy investigations performed on freestanding Ni-rich NCM (LixNi0.83Co0.11Mn0.06O2) microcrystals transferred to flexible polyethylene terephthalate (PET) host substrates. This technological procedure introduces a first building block for future on-chip-integrated micro-accumulators for applications in flexible optoelectronics, sensors, microbiology, and human medicine. An after-synthesis thermal treatment was used to help improve the material homogeneity and perfection of the cathode material. To this end, a local laser micro-annealing process was applied to the freestanding Ni-rich NCM microcrystals. The thermally initialized structural processes in the singular micro-cathode units were characterized and determined by micro-Raman spectroscopy. Micro-Raman mapping images revealed the evolution of a recrystallization process after the local annealing procedure. Furthermore, laser micro-annealing led to the suppression of the pristine “polycrystalline morphology” of the investigated micro-cathode regions. Besides the dominant characteristic Raman mode at ~1085 cm−1, most likely ascribed to lithium carbonate, metal oxides with Raman modes around ~550 cm−1 were identified. This highly efficient transfer and integration technology represents a basic building block towards micrometer-sized accumulators for a large range of emerging applications.

Stretchable Blue Phase Liquid Crystal Lasers with Optical Stability Based on Small-Strain Nonlinear 3D Asymmetric Deformation.

Blue phase liquid crystal (BPLC) lasers exhibit exceptional optical quality and tunability to external stimuli, holding significant promise for innovative developments in the field of flexible optoelectronics. However, there remain challenges for BPLC elastomer (BPLCE) lasers in maintaining good optical stability during stretching and varying temperature conditions. In this work, a stretchable laser is developed based on a well-designed BPLCE with a combination of partially and fully crosslinked networks, which can output a single-peak laser under small deformation (44.429nm lasing shift at 32% strain) and a broad-temperature range (from -20 to 100°C). The superior performance can be attributed to the nonlinear 3D asymmetric deformation exhibited by the BPI lattice during stretching, particularly at low deformation rates below 40% strain, which effectively maintains the stability of the body-centered cubic structure (with the maximum strain of this BPLCE up to 220%). Moreover, the BPLCE exhibits excellent thermal stability over a temperature range from -180 to 70°C with a stopband shift of less than ±10nm. As a proof-of-concept, the application of BPLCE laser for morphology sensing and 3D mechanical perception is demonstrated, which paves the way for potential applications of flexible optoelectronics.

Stretchable Ag2S-MXene Photodetector Designed for Enhanced Electrical Durability and High Sensitivity.

In this work, we present a facile and straightforward approach for fabricating highly stretchable photodetectors based on Ag2S and Ti3C2Tx MXene hybrid materials. These devices exhibit exceptional mechanical resilience, maintaining stable electrical and optical performance even after 10 000 cycles of 30% strain. The incorporation of MXene not only enhances the device's electrical durability but also ensures the retention of conductivity under significant mechanical deformation, positioning MXene as a critical material for the advancement of flexible electronics. These devices demonstrate strong photoresponses across a broad wavelength range, from visible to infrared, confirming their potential for use in flexible and stretchable optoelectronic applications. This study highlights the advantage of utilizing MXene in stretchable electronics and offers a promising route for developing durable, flexible devices for next-generation wearable technologies.

Exploring the electronic and mechanical properties of the recently synthesized nitrogen-doped amorphous monolayer carbon.

The recent synthesis of nitrogen-doped amorphous monolayer carbon (NAMC) opens new possibilities for multifunctional materials. In this study, we have investigated the nitrogen doping limits and their effects on NAMC's structural and electronic properties using density functional-based tight-binding simulations. Our results show that NAMC remains stable up to 35% nitrogen doping, beyond which the lattice becomes unstable. The formation energies of NAMC are higher than those of nitrogen-doped graphene for all the cases we have investigated. Both undoped MAC and NAMC exhibit metallic behavior, although only MAC features a Dirac-like cone. MAC has an estimated Young's modulus value of about 410 GPa, while NAMC's modulus can vary around 416 GPa depending on nitrogen content. MAC displays optical activity in the ultraviolet range, whereas NAMC features light absorption within the infrared and visible ranges, suggesting potential for distinct optoelectronic applications. Their structural thermal stabilities were addressed through molecular dynamics simulations. MAC melts at approximately 4900 K, while NAMC loses its structural integrity for temperatures ranging from 300 K to 3300 K, lower than graphene. These results point to potential NAMC applications in flexible electronics and optoelectronics.

Dual-Coated Antireflective Film for Flexible and Robust Multi-Environmental Optoelectronic Applications.

Artificial antireflective nanostructured surfaces, inspired by moth eyes, effectively reduce optical losses at interfaces, offering significant advantages in enhancing optical performance in various optoelectronic applications, including solar cells, light-emitting diodes, and cameras. However, their limited flexibility and low surface hardness constrain their broader use. In this study, we introduce a universal antireflective film by integrating nanostructures on both sides of a thin polycarbonate film. One side was thinly coated with Al2O3 for its high hardness, enhancing surface durability while maintaining flexibility. The opposite side was coated with SiO2 to optimize antireflective properties, making the film suitable for diverse environments (i.e., air, water, and adhesives). This dual-coating strategy resulted in a mechanically robust and flexible antireflective film with superior optical properties in various conditions. We demonstrated the universal capabilities of our antireflective film via optical simulations and experiments with the fabricated film in different environments.

Investigation of structural and optical characteristics of PVA/crystal violet dye composites for flexible smart optoelectronic applications

Investigation of structural and optical characteristics of PVA/crystal violet dye composites for flexible smart optoelectronic applications

Rapid and Scalable Synthesis of In2O3‐Decorated MXene Nanosheets for High‐Performance Flexible Broadband Photodetectorss

AbstractA promising flexible photodetector based on hybrid nanocomposites of 2D MXene and In2O3 nanoparticles (NPs) has been developed, demonstrating excellent ultraviolet (UV) light responsivity. In this work, In2O3‐decorated MXene nanosheets (In2O3MX) are synthesized via a simple one‐step sonochemical method using ultrasonication, rapidly producing the composites in a short time. The synthesized material shows efficacy across broadband wavelengths (UV, Vis, NIR). Notably, the photodetector using In2O3MX exhibits a responsivity (R) of 121.6 A W−1 and a specific detectivity (D*) of 106.4 × 10¹⁰ Jones in the UV range, and confirming enhanced electrical properties and the feasibility of low‐voltage detection with tau plots. Additionally, the electrical and optical characteristics remain unchanged after bending the device up to 10,000 times with a bending radius of 6.0 mm, highlighting its suitability for flexible optoelectronic applications. Overall, this study introduces a novel approach to the simple synthesis of 2D MXene nanocomposites and provides valuable insights into the development of flexible photodetectors using these materials.

Synthesizing, characterizing, and cold plasma treating of Cr2O3/CuO nanomaterials doped PMMA/PEO for flexible optoelectronic applications

Synthesizing, characterizing, and cold plasma treating of Cr2O3/CuO nanomaterials doped PMMA/PEO for flexible optoelectronic applications

One-step pulsed laser deposition of carbon/metal oxynitride composites for supercapacitor application

Abstract Advanced material composite of nanocarbons and metal-based materials provides a synergistic effect to obtain excellent electrochemical charge-storage performance and other properties. Herein, 3D porous carbon-metal oxynitride nanocomposites with tunable carbon/metal and oxygen/nitrogen ratio are synthesized uniquely by simultaneous ablation from two different targets by single-step pulsed laser deposition at room temperature. Co-ablation of titanium and vanadium nitride targets together with graphite allowed us to synthesize carbon-metal oxynitride porous nanocomposite and exploit them as a binder-free thin film supercapacitor electrode in aqueous electrolyte. We show that the elemental composition ratio and hence the structural properties can be tuned by selecting target configuration and by manipulating the ablation position. We investigate how this tuning capability impacts their charge-storage performances. We anticipate the utilization of as-synthesized various composites in a single PLD production run as next-generation active materials for flexible energy storage and optoelectronic applications.

The Effect of Concentration of Aluminum on Structural, Optical, and Electrical Properties of Aluminum‐doped ZnO Nanostructures Electrochemically Deposited on Polyimide

AbstractAluminum‐doped ZnO (AZO) were successfully prepared on polyimide (PI) film using electrochemical deposition. Field emission scanning electron microscopy (FESEM) analysis revealed that as the aluminum concentration increased, the morphology of AZO nanostructures changed from pellets to nanorods. X‐ray photoelectron spectrometry (XPS) was employed to study the chemical states of undoped and Al‐doped ZnO on a polyimide substrate. The X‐ray diffraction (XRD) patterns of the PI/AZO nanostructures showed a polycrystalline wurtzite structure with a crystallographic orientation along the (002) plane. The XRD analysis also indicated that the average crystallite size decreased from 50.5 nm to 31.0 nm with increasing aluminum concentration (from 0.05 mM to 10 mM). Transmittance analysis revealed that with increasing aluminum concentration, the average optical transmittance in the visible region decreased from 90 % to 75 %. The aluminum concentration has a significant effect on the electrical properties of the samples, as shown by current‐voltage (I–V) and Hall measurements. Among the samples, the AZO/PI film prepared with 5 mM aluminum concentration exhibited the minimum electrical resistivity (4.14×10−2 Ω.cm), the highest carrier density (1.10×1021 cm−3) and the Hall mobility (5.40 cm2 V−1 s−1). We also discuss the possible mechanisms underlying these results compared to undoped ZnO films. This study contributes to the potential applications in flexible electronics and optoelectronics by demonstrating the tunability of AZO nanostructures on a flexible polyimide substrate through controlled aluminum doping.

Polyvinyl alcohol/carboxymethyl cellulose blended polymers doped with PPy/milled MWCNTs filler for Flexible optoelectronic and Energy Storage Applications

Polyvinyl alcohol/carboxymethyl cellulose blended polymers doped with PPy/milled MWCNTs filler for Flexible optoelectronic and Energy Storage Applications

Patterned flexible Silver Nanowire/2D MXene transparent conducting electrode for organic light-emitting diodes

Patterned flexible Silver Nanowire/2D MXene transparent conducting electrode for organic light-emitting diodes

Fabrication and characteristics of PMMA–PEG/SiO2–SiC quaternary nanocomposites for gamma ray shielding and flexible optoelectronics applications

Fabrication and characteristics of PMMA–PEG/SiO2–SiC quaternary nanocomposites for gamma ray shielding and flexible optoelectronics applications

Revealing the photo-sensing capabilities of a super-flexible, paper-based wearable a-Ga2O3 self-driven ultra-high-performance solar-blind photodetector

Revealing the photo-sensing capabilities of a super-flexible, paper-based wearable a-Ga2O3 self-driven ultra-high-performance solar-blind photodetector

Enhanced photodetection in organic semiconductor single crystal sensitized by a tailored synergistic absorption of capsule-shaped chlorophyll derived CQDs

Enhanced photodetection in organic semiconductor single crystal sensitized by a tailored synergistic absorption of capsule-shaped chlorophyll derived CQDs

Enormous and Tunable Bulk Charge/Spin Photovoltaic Effect in Piezoelectric Binary Materials T-IV-VI and T-V-V.

Understanding the nonlinear response of light and materials is crucial for fundamental physics and next-generation electronic devices. In this work, we have investigated the second-order nonlinear bulk photovoltaic (BPV) and bulk spin photovoltaic (BSPV) effects in the piezoelectric binary materials T-IV-VI and T-V-V (IV = Ge, Sn; VI = S, Se; and V = P, As, Sb, Bi). The independent nonzero conductivity tensors of charge current are derived for these binaries through the symmetry analysis, along with the mechanism for generating pure spin current. These binaries, with their unique folded structure, exhibit significant charge and spin currents under illumination. Furthermore, we find that strain engineering can effectively modulate charge/spin currents by influencing charge density distribution and built-in electric field due to the piezoelectric effect. Our research suggests that the piezoelectric binary materials possess enormous and tunable charge/spin currents, underscoring their potential for applications in nonlinear flexible optoelectronics and spintronics.

Developing polymer nanocomposite films of ZnO/NiFe2O4 nanohybrids, polyvinyl pyrrolidone, and chitosan for flexible electromagnetic applications and energy storage devices

Developing polymer nanocomposite films of ZnO/NiFe2O4 nanohybrids, polyvinyl pyrrolidone, and chitosan for flexible electromagnetic applications and energy storage devices

Tailoring the optical properties of dye–polymer composite films based on polyvinyl alcohol doped with phenol red toward flexible optoelectronic applications

The composite films of polyvinyl alcohol (PVA) incorporating varying concentrations of phenol red (PR) dye were fabricated using the solution casting method. Structural characteristics of the prepared films were explored through XRD and FTIR spectroscopy analyses. The inclusion of PR dye within the PVA matrix induced cross-linking, enhancing the amorphous nature of the doped PVA samples, as evidenced by XRD patterns. In the presence of PR dopants, the FTIR peaks for PVA exhibited altered intensities and increased width, indicating physical interactions between the functional groups of PVA and PR dopants. The impact of PR additives on the optical properties of PVA was investigated across the spectral range of 190–2500 nm. The PVA/phenol red composite demonstrated enhanced UV blocking in the 190–400 nm wavelength range, rendering it suitable for applications such as UV notch filters, including laser blocking filters. The indirect and direct optical band-gaps of PVA polymer films were reduced from 5.20 eV and 5.78 eV to 4.30 eV and 5.28 eV, respectively, with an increase in the PR filling ratio from 0 wt% to 1.8 wt%. The dispersion region of the refractive index was analyzed using the single oscillator model (Wemple-DiDomenico). Calculation and discussion of values such as dispersion and oscillation energies (Ed and Eo), permittivity at infinite frequency (ε ∞), and lattice contribution to the dielectric function (ε L) of PVA/PR composite films were conducted. These advancements position PVA/PR composite films for potential applications in flexible optoelectronic devices, including light-emitting diodes and photodetectors.

Molybdenum doped indium oxide thin films grown on mica substrates with high near-infrared transparency and electron mobility for flexible optoelectronic and spintronic applications

Molybdenum doped indium oxide thin films grown on mica substrates with high near-infrared transparency and electron mobility for flexible optoelectronic and spintronic applications