Here, we report the fabrication of solution processible PBTTT-C14 thin films with high molecular orientation and uniformity using a technique known as unidirectional floating film transfer method (U-FTM) for developing highly efficient organic phototransistors (OPT) for green light sensing. U- FTM fabricated PBTTT-C14 films were transferred onto octadecyl trichlorosilane (OTS) modified Si/ SiO2 substrates and annealed at different temperatures. The influence of annealing temperature on the crystallinity of PBTTT-C14 thin films have been analyzed systematically. Under the optimized condition, maximum progression in optical anisotropy and high-order crystallinity were observed in the PBTTT-C14 film. The anisotropic charge transport characteristic offered by U- FTM fabricated PBTTT-C14 film resulted in high field effect mobility in the fabricated OPTs. Under dark conditions, the device showed a charge carrier mobility of 3.57 & times; 10(-1) cm(2)/ V. s and an on/off ratio of 5.2 & times; 10(4). Achieved a high responsivity of 2638 A/W, photosensitivity of 4.6 & times;10(3) and specific detectivity of 2.5 & times;10(14) Jones under the illumination of monochromatic green light (525 nm). This work emphasis the affordable fabrication of highly efficient photodetectors for modern green light sensing applications.

Here, a solution-processed, ITO/ZnO/rr-P3HT/Ag nanowires-based self-powered broadband photodetector, with a spectral range from 300-700 nm has been demonstrated. Due to the high transparency of the Ag nanowires-based top electrode, double-sided photoresponse is achieved. Moreover, Ag nanowires' surface plasmonic resonance enhances the light-harvesting capability, which results in appreciable self-powered device performance. The device exhibits a peak photosensitivity of $10<^>{3}$ , photoresponsivity of 11.9 mA/W, and photodetectivity of $2\times 10<^>{11}$ Jones at 520 nm under low illumination power (1 mW/cm(2)). Therefore, the proposed double-sided, cost-effective, and self-powered broadband photodetector holds strong potential for integration into next-generation wearable and self-powered optoelectronic systems for sensing and communication applications.

Organic field-effect transistors (OFETs) based on conjugated polymers are promising for flexible, low-cost electronics; however, their performance is often limited by interfacial trap states and disordered molecular packing. In this work, the combined influence of fabrication method (spin coating and UFTM), dielectric interface engineering (OTS and CYTOP), and molecular orientation on the charge transport characteristics of poly(9,9-dioctylfluorene-alt-bithiophene) (F8T2)-based thin film transistors is systematically investigated. The UFTM process produces highly aligned polymer films, yielding pronounced optical anisotropy with a dichroic ratio of ~ 6.5 at an optimized annealing temperature of 120 °C. The optimized UFTM CYTOP (ǁ) device exhibits a maximum field-effect mobility of ~2.8 × 10-³ cm² V-¹ s-¹, an on/off current ratio of ~ 4 × 10⁶, improved threshold voltage, reduced subthreshold swing, excellent device-to-device reproducibility, while retaining ~ 80% of its initial mobility after 60 days under ambient conditions. These findings demonstrate a simple, low-cost, and scalable fabrication strategy for improving the electrical performance and operational reliability of F8T2-based OFETs.

This study demonstrates a notable improvement in ultraviolet (UV) photodetector (PD) performance through the integration of gold nanoparticles (Au NPs) on a 3 M ZnO thin film (TF). The Au NPs induce a localized surface plasmon resonance (LSPR) effect, which enhances light absorption and promotes efficient charge carrier generation. The device, configured in an Ag/Au:ZnO/Ag metal-semiconductor-metal (MSM) structure, exhibited a remarkable enhancement in responsivity, increasing from 43 A/W (pristine ZnO) to 1.8 & times;10(3) A/W, along with a sensitivity of 1.7 & times;10(6) . This performance boost is attributed to plasmon-induced hot carrier injection and localized near-field enhancement. In addition, the device achieved a specific detectivity of similar to 1 & times;10(15) Jones, an external quantum efficiency (EQE) of 7% & times;105 %, and a linear dynamic range (LDR) of 124 dB (at lambda(ex)=330 nm). These results demonstrate the potential of plasmonic nanostructures (NSs) in driving next-generation, high-efficiency UV PDs based on solution-processed ZnO films.

A facile additive-assisted hydrothermal route is demonstrated to realize high-performance ZnO ultraviolet (UV) photodetectors. Incorporation of trisodium citrate and potassium dichromate into the growth solution enables the selective formation of ZnO nanowalls and nanorods. X-ray photoelectron spectroscopy confirms Cr(3+ )incorporation and associated defect-state modulation in the ZnO lattice. The nanowall device exhibits high responsivity (similar to 1.4 & times; 10(3) A/W), photosensitivity (similar to 3.7 & times; 10(6)), and detectivity (similar to 1.3 & times; 10(15) Jones), attributed to efficient lateral charge transport and reduced carrier trapping, whereas nanorods display a distinct dual-band photoresponse near similar to 330 and similar to 370 nm due to additive-induced sub-bandgap states. This simple, low-temperature, and cost-effective approach provides a scalable route for tailoring ZnO nanostructures for high-sensitivity and dual UV-A-band photodetection, enabling applications in environmental monitoring, flame detection, secure optical communication, and wearable health diagnostics.

In conjugated polymers, it is challenging to realize a rigid coplanar conformation without involving complex and judicious molecular level design and synthesis. In this work, we demonstrate planarization of the backbone of a thiophene-based liquid crystalline conjugated polymer PBTTT-C14 thin films fabricated by unidirectional floating film transfer method (U-FTM) on fluoropolymer-based surface passivated substrates. The U-FTM fabricated thin films are known to exhibit good optical anisotropy with edge-on orientation. Annealing PBTTT-C14 film at its mesophase on fluorine-rich CYTOP reduced the torsional disorder in the conjugated backbone, which resulted in extension of conjugation length and improved crystallinity, showcasing a significant band edge red-shift of 25 nm, peak shift of 16 nm in the absorption spectra. The increased interdigitation of alkyl chains and stacking with edge-on orientation is utilized in conducting polymer-based organic field-effect transistors (OFETs) and achieved a high mobility of 0.16 cm2/V.s.

In this work, the influence of additive chemistry and growth duration on the morphology and photoresponse of hydrothermally grown ZnO nanostructures was systematically investigated. Potassium dichromate (K2Cr2O7) and trisodium citrate (Na3C6H5O7) were introduced into the precursor solution to regulate nucleation dynamics, crystal growth orientation, and surface morphology. The synergistic effect of these additives facilitated the formation of well-defined ZnO nanoplates with improved surface uniformity and strong adhesion to the substrate. The optimized device (ZKC3) exhibited a remarkable photocurrent of 3.6 × 10−3 A, a dark current of 2.5 × 10−10 A, a high responsivity of 3613 A/W, and a photosensitivity of 1.4 × 10−7 at 320 nm under a 20 V bias, demonstrating excellent UV detection performance. These results emphasize that optimizing additive chemistry and growth duration plays a pivotal role in achieving tailored ZnO morphology and enhanced device performance, offering a viable route toward cost-effective and scalable optoelectronic device fabrication.

We report a high-performance dual UV-A band photodetector based on sodium (Na)-doped zinc oxide (ZnO) nanostructures (NSs) synthesized via a hydrothermal method. Undoped and Na-doped ZnO samples (5-30 mM) were grown on glass substrates, where Na incorporation during growth modified the crystal quality and defect states, leading to two distinct absorption peaks at similar to 330 and similar to 360 nm, unlike pristine ZnO (PZO), which showed only the band-edge response at similar to 360 nm. FESEM analysis revealed vertically aligned nanorods (NRs) with uniform surface coverage, while XRD confirmed that both undoped and Na-doped ZnO possess a hexagonal wurtzite structure with preferential (002) orientation; however, the (002) peak intensity decreased with Na doping, indicating increased defect density and strain. energy-dispersive X-ray analysis (EDX) and X-ray photoelectron spectroscopy (XPS) verified successful Na incorporation within the ZnO lattice, consistent with compositional tuning. The optimized NZO5 device exhibited a maximum responsivity of 406 A/W, sensitivity of 3.3 x 10(6), detectivity of similar to 6.4 x 10(14) Jones, EQE of 1.53 x 10(5) %, linear dynamic range (LDR) of 130 dB, and rise/decay times of 30/45 s at excitation wavelength of 330 nm and applied bias of 20 V, with clear dual responsivity peaks at similar to 330 and similar to 360 nm. These results establish Na doping as a simple and effective route to engineer defect states in ZnO and realize selective, dual UV-A band photodetectors with superior responsivity and detectivity.

This work investigates the effect of post-deposition annealing on pristine 3 M ZnO thin films for ultraviolet (UV) photodetector applications. The films were annealed in air at 450 degrees C for 1 h in a muffle furnace, and their morphology, optical, structural, and electrical properties were systematically analyzed. Field emission scanning electron microscopy (FESEM) revealed a transition from irregular grains in pristine films to well-connected, densely packed nanostructures after annealing. UV-Vis absorption showed enhanced near-band-edge absorption, while photoluminescence (PL) spectra indicated suppressed deep-level emission, confirming reduced defect density. X-ray diffraction (XRD) analysis revealed improved crystallinity with a stronger (002) peak intensity and reduced FWHM after annealing. Current-voltage (I-V) measurements under UV illumination demonstrated a dramatic enhancement in responsivity, increasing from 43 A/W (pristine) to 1700 A/W (annealed). These results confirm that thermal annealing effectively tailors ZnO thin film morphology and optoelectronic properties, enabling high-performance UV photodetectors.

Oriented and uniform thin films of solution-processable organic semiconducting copolymer PFO-DBT were fabricated using a recently developed unidirectional floating film transfer (FTM) method and used as an active semiconductor on surface passivated Si/SiO2 as gate dielectric to fabricate organic phototransistor (OPT) in the bottom gate top contact device architecture. The influence of different passivation of SiO2 such as an ultrathin spin-coated cyclic transparent optical polymer (CYTOP) and the self-assembled monolayer of hexamethyldisilazane (HMDS) on anisotropic charge transport and device performance of OPTs have been systematically investigated. FTM-processed thin films provided good optical anisotropy in thin films and electrical anisotropy in the OPTs. With improved surface properties and enhanced anisotropies, the device showed a charge carrier mobility of 7.8 x 10-3 cm2/V-sec, on/off ratio in the order of 105, and a threshold voltage of-4V under dark conditions. OPTs fabricated in this work demonstrated photosensitivity nearly of order 104 and a corresponding responsivity of 17 A/W under the illumination of 525 nm monochromatic green light with a low power density of 0.15 mW/cm2. The results are promising for making OPTs with enhanced mobility, photosensitivity and photoresponsivity in the visible region.

In this letter, we present a unique method to improve the output performance of ZnO-based flexible piezoenergy harvesters (FPEHs). Halide dopants (Cl, Br) are infused into ZnO nanorods (NRs) to increase lattice distortion along the c-axis. This facilitates charge separation, which improves the output performance of halide-doped ZnO FPEHs. This technique confirmed that the size and concentration of the dopants have a significant impact on lattice distortion along the c-axis in halogen-doped ZnO NRs. By doping the halide elements, the lattice distortion along the ZnO c-axis could be tuned from a contractive to an elastic state. This modulation was driven by the variation in ionic size and doping concentration of halide elements, which yielded an enhancement in the performance of ZnO FPEHs. The pristine ZnO NRs exhibited an output voltage of 2.24 V and a current of 272.68 nA, yielding a maximum power of 610.8 nW. In contrast, ZnO:Cl NRs demonstrated a piezoelectric voltage of 3.41 V and a piezoelectric current density of 323.43 nA/cm(2), reaching a peak power output of 1.1 mu W. ZnO:Br NRs exhibited an even higher piezoelectric voltage of 4.55 V and a current of 367.79 nA, achieving a maximum power of 1.67 mu W. Further enhancement in piezoelectric performance was observed when the NaBr doping concentration was increased to 20 mM, resulting in a piezovoltage of 4.84 V, a piezoelectric current of 447.63 nA, and a peak power of 2.17 mu W. This approach of inducing the lattice distortion via halide dopants could be applied to design piezoelectric devices with improved efficiency at a low cost.

To improve the organic field‐effect transistor (OFET) performance, the advantages of the unidirectional floating film transfer method (UFTM) are utilized to fabricate uniaxially aligned thin film of a liquid crystalline semiconducting polymer (SCP) upon a SiO 2 surface modified with a self‐assembled monolayer (SAM) of alkyl‐silane. We deposited the SAM of octadecyl‐triethoxy silane (OTES) by spin coating onto the SiO 2 gate dielectric surface to make the surface hydrophobic and promote the molecular self‐assembly of aligned SCP. The electrical anisotropy of the UFTM fabricated thin films of poly [2,5‐bis (3‐tetradecylthiophen‐2‐yl) thieno [3,2‐b] thiophene] (PBTTT) C‐14 were studied by constructing parallel and perpendicular OFETs. Parallel OFET exhibits a mobility of 0.13 cm 2 V −1 sec −1 , a dark on‐off ratio of 2.6 × 10 5 , and 0V V th . Further, OFETs are utilized as organic phototransistors (OPTs) under monochromatic green light (525 nm) illumination at an intensity of 3 mWcm −2 . The photosensitivity and responsivity of parallel OPT are 6.3 × 10 4 and 81 AW −1 , respectively, which are much more pronounced compared to that of the corresponding perpendicular OPT with the photosensitivity and responsivity of 2 × 10 2 and 6.2 AW −1 , respectively. This work contributes to the advancement of organic photodetector technology, offering valuable guidance for future device development and applications.

Solid state sensor characteristics of NiTi and Cu based shape memory alloys (SMAs) are reported for both high and low temperatures (−50 ℃ to 250 ℃). The effect of two different alloys on the martensitic transformation (MT) are demonstrated at low and high temperature ranges. The sensor was fabricated with novel technique of SMA coating on optical fiber through flash evaporation process. The morphology, phase transformation, and actuation characteristics of such coated optical fibers were studied through optical microscopy, differential scanning calorimetry, and laser displacement sensor respectively. The effects of different materials on characteristic transformation temperatures, enthalpy and entropy values were investigated. During heating we have observed that both SMA coated fiber straightened with respect to the initial state. However, more bending was observed during cooling for the SMA coated fibers. Such sensing behavior arises due to induced strain of thin SMA coating on optical fiber during exposure at different temperature ranges. We have observed maximum actuation of 8 mm during heating and 5 mm during cooling for NiTi rich samples, whereas 4 mm during heating and 12 mm during cooling was detected for Cu rich SMAs. This sensing behavior of the SMA coated optical fiber affects the intensity of optical signal passing through it. NiTi rich SMA coated fiber shows better sensitivity during heating while Cu rich SMA shows better response for cooling cycles. Hence, we can conclude that SMA coated optical fiber can potentially be used for sensing and monitoring applications at varying temperature ranges.

This study is focused on utilizing laser technology as a versatile energy source in device fabrication for energy harvesting applications. Dual utilization of CO2 laser is employed for graphene synthesis and selective deposition of ZnO piezo ceramic by laser mu-3D printing. A Piezo-Tribo hybrid nanogenerator is fabricated through selectively transferring ZnO ceramic onto porous laser-induced graphene followed by hydrothermal growth. The Laser decal transfer successfully yields uniform ZnO within porous graphene, facilitating the consistent growth of nanorods in pores. A FEP-ZnO-LIG device is fashioned, synergizing tribo-electricity from FEP-LIG and piezoelectricity due to the presence of ZnO, focusing on energy harvesting to consistently power sensors. ZnO piezo device demonstrates the least voltage and current output (9 V and 270 nA), while the FEP-LIG pair exhibits a higher output of 36 V voltage and 410 nA current. The combination of piezoelectric and electrostatic charge transfer mechanisms in a cascading fashion produces enhanced output voltage (75 V) and current (1.06 mu A) compared to individual sum of piezo and tribo pairs. This enhanced performance is possibly attributed to synergistic interaction between ZnO nanostructures and graphene, enhancing charge flow during continuous contact and separation. This technique extends beyond its application for fine-tuning of functional performance in device fabrication.

In this study, we report a high-quality ZnO thin film synthesized using the sol-gel method for developing a spectrally selective UV photodetector with enhanced detectivity and LDR. The effect of varying precursor concentrations from 1 M to 3 M was systematically examined, with 3 M identified as the optimal concentration. The 3 M ZnO thin film-based planar Ag/ZnO/Ag Metal-Semiconductor-Metal (MSM) structure device has demonstrated dominant photosensitivity of 2.2x10(6) at 350 nm (UV-A) radiation and 20 V applied bias. Additionally, the device exhibited a maximum responsivity of 43 A/W with a full width at half maxima (FWHM) of 38 nm, detectivity of 7.4x10(13) Jones, external quantum efficiency (EQE) of 15444%, and a linear dynamic range (LDR) of 112 dB at 350 nm (UV-A) radiation and 20 V applied bias. This work presents a cost-effective alternative to traditional methods, highlighting the strong potential of the 3 M ZnO thin film for advanced UV photodetector applications.

A novel bimorph-integrated-optical fiber structure has been proposed for sensing the temperature with linearity within a broad range. Shape memory alloy-coated Kapton-polyimide sheet was used as a bimorph. Its displacement with temperature rise proportionally impacts the optical signal and inculcates a linear sensing behavior in the optical fiber. Significant optical intensity changes have been recorded with good linearity within 40 degrees C-120 degrees C. Sensitivity of similar to 14.8 mV/ degrees C in martensite while similar to 21.2 mV/ degrees C in the austenite phase transition range was observed with an accuracy error of +/- 0.014 degrees C. Linear intensity changes were also confirmed from the spectral analysis within two regions, however, there was a sharp deflection in wavelength of similar to 1.6 nm. The technology offers an economical sensing solution with the potential for integration with the Internet of Things. It has capability for smart sensing, thereby serving contemporary industrial requirements.

Cryogenic shape memory actuators are beneficial for various device applications, such as gas liquefiers (hydrogen, helium, and LNG storage and transportation), gas separation devices, compressors, cryostats, temperature controllers, and liquid pumps. Especially, shape memory alloys (SMA) are ideal actuator materials used for aforementioned applications in extreme environments. SMA actuator converts thermal energy into mechanical energy due to its unique characteristic of temperature-dependent actuation. Here, we have studied the extremely low-temperature actuation capability of Cu-based SMA bimorph. The CuAlMn SMAs with two different compositions (Cu-9Al-12.6Mn, Cu-9Al-11.8 M) were prepared and coated on a polyimide substrate (bimorph) by the thermal evaporation method. The varying compositions have a strong effect on achieving the martensitic transformation (MT) at similar to 77 K where only a few SMAs can exhibit such transformation temperature below the boiling point of liquid nitrogen (LN2). Hence, the results indicated that the CuAlMn SMA could be favorable for cryogenic actuation and super-elastic applications. Moreover, we have observed maximum actuation of SMA bimorph of similar to 4.5 mm during low-temperature (up to 77 K) exposure. Further, we have recorded that the response time of the actuator during cryogenic exposure is similar to 60 msec which is quite faster than other actuation devices.

In Laser decal transfer process, the materials are printed in micron-sized dots without changing its phase from thin film coated substrate (donor substrate). The pulsed laser irradiates the donor substrate opposite to the coated side and transfers the material in the same phase to another substrate kept very close to donor substrate. The process has shown its potential for printing micro sensors without any changes in physical and functional properties during the printing process for the electronics components. Generally, ZnO-based patterned structure is still challenging for the existing manufacturing techniques without hampering its functionality in the sensing application. In this work, an attempt has been made to print ZnO structure in solid phase using maskless based µ-3D printing using a long-pulsed CO 2 laser. A two-dimensional numerical model in COMSOL Multiphysics is developed to estimate the temperature induced by the laser irradiation on the sacrificial layer, and energy conservation is applied to estimate the particle's velocity. A deformed mess geometry is used to predict the ablation depth of the sacrificial layer after the laser irradiation. The deformed geometry shows the ablated area in the sacrificial layer and the temperature induces different time frame. The ZnO ceramic film is coated on the sacrificial layer followed by the laser µ-3D printing of ZnO on silicon wafer using CO 2 laser at three laser fluence i.e., 530 mJ/cm 2 , 1030 mJ/cm 2 , 1530 mJ/cm 2 with 90% pulse overlap. The ejection of ZnO from substrate is visualized using the high-speed camera by shadowgraphy techniques. The ejection mode is defined based on the deviation of the particle from the laser beam direction.

High flexibility and solution processability have made all polymer organic pho-totransistors (AP-OPTs) a suitable candidate for various wearable and smart home applications. However, fabrication of the AP-OPTs via the solution process is still challenging owing to the possible degradation of the polymer gate dielectric layer by the solvent of the organic semiconductor, resulting in hampered device performance. To circumvent this issue, the unidirectional floating film transfer method, having the least impact on the underlying organic dielectric film, has been used to obtain highly oriented poly (3-hexylthiophene) (P3HT) thin film. Further, the effect of P3HT film orientation with respect to the channel has been investigated. Results revealed that the device with parallel orientation performed better with photosensitivity of 5 x 10(3) and photoresponsivity of 133 A/W.