Aspect Ratio Of Nanorods Research Articles

Impact of tip curvature and edge rounding on the plasmonic properties of gold nanorods and their silver-coated counterparts.

Colloidal solutions of gold nanorods and silver-coated gold nanorods were prepared. The seeded growth synthesis protocols were improved by adding a flocculation purification step. The resulting populations of pure gold nanorods and Au@Ag core-shell cuboids were characterized by very low dispersion in size and shape. UV-vis-near-infrared absorption measurements were performed on several batches of well-calibrated nano-objects, supported by calculations based on the discrete dipole approximation, allowed to highlight the impact of various morphological features on the optical response. In addition to the well-known effect of the nanorod aspect ratio on the shift of the longitudinal surface plasmon resonance mode, special attention was paid to changing either the rounding of the nanorod end-caps or that of the edges of the coating silver shell. Nanorods and cuboids were modeled as superellipsoids. This approach enabled us to model precisely their complex shapes using just a few simple parameters and analyze the evolution of their extinction spectra as a function of the rounding of their tips and edges. Such nano-objects are widely used for various applications in fields such as biomedical, biosensing, or surface-enhanced Raman spectroscopy, thus making it crucial to precisely assess the impact of each morphological feature for optimizing their performance.

Controlled Etching of Gold Nanorods Within Mesoporous Silica Shells at Mild Conditions

AbstractSurface plasmon resonance of precious metal gold nanorods can be tuned by controlling the aspect ratio, and they find widespread applications in biotechnology, imaging, sensing, optoelectronics, photonics, and catalysis. Here, a method is proposed for the controlled etching of gold nanorods within mesoporous silica shells by using a certain concentration of H2O2 at room temperature. In the experiments, the amount of HCl is varied to adjust the acidity and/or change the amount of H2O2 to control the speed of corrosion, achieving controllable adjustment of the aspect ratio of the gold nanorods. The extinction spectra show that under the action of H2O2 and HCl, the longitudinal plasmonic resonance of the gold nanorods shifted to shorter wavelengths, and the intensity of the longitudinal plasmonic resonance decreased. The more hydrochloric acid or hydrogen peroxide added, the faster the corrosion rate of the gold nanorods, and the faster the blue shift of the longitudinal plasmonic resonance. In addition, the intensity of the extinction spectra at 320 nm increased linearly versus time, which can also be used to monitor the etching process. By corroding gold nanorods to control the plasmonic resonances, gold nanorods can find broader applications.

Growth of variable aspect ratio ZnO nanorods by hydrothermal technique

Zinc oxide (ZnO) nanorods were successfully prepared by hydrothermal process. The influence of the solution temperature on the ZnO nanorods aspect ratio is investigated in the present work. The x-ray diffraction (XRD) and scanning electron microscopy (SEM) results and analysis reveal the formation of ZnO nanorods owing hexagonal Wurtzite structure with preferential orientation along the c-axis. We found that the solution temperature is a key parameter controlling the aspect ratio of the formed ZnO nanorods. The later increases linearly with the preparation temperature. The rod length is thermally activated with an activation energy of 0.48 eV, which corresponds to the activation energy of the reaction forming ZnO, indicating that the nanorods growth is controlled by the surface reaction rather than by mass transport. While, the rods diameter is reduced with increasing temperature, its activation energy of 0.23 eV is equal to the species diffusion activation energy in the solution and to the crystallite size activation energy suggesting, thereafter that the rod diameter variation is controlled by the nucleation dynamic.

Influence of chemical strains on the electrocaloric response, polarization morphology, tetragonality, and negative-capacitance effect of ferroelectric core-shell nanorods and nanowires

Using Landau-Ginzburg-Devonshire (LGD) approach, we proposed the analytical description of the influence of chemical strains on spontaneous polarization and the electrocaloric response in ferroelectric core-shell nanorods. We postulate that the nanorod core presents a defect-free single-crystalline ferroelectric material, and elastic defects are accumulated in the ultrathin shell, where they can induce tensile or compressive chemical strains. Finite-element modeling (FEM) based on the LGD approach reveals transitions of domain-structure morphology induced by chemical strains in the BaTiO3 nanorods. Namely, tensile chemical strains induce and support the single-domain state in the central part of the nanorod, while the curled domain structures appear near the unscreened or partially screened ends of the rod. The vortexlike domains propagate toward the central part of the rod and fill it entirely, when the rod is covered by a shell with compressive chemical strains above some critical value. The critical value depends on the nanorod sizes, aspect ratio, and screening conditions at its ends. Both analytical theory and FEM predict that the tensile chemical strains in the shell increase the nanorod polarization, lattice tetragonality, and electrocaloric response well above the values corresponding to the bulk material. The physical reason for the increase is strong electrostriction coupling between the mismatch-type elastic strains induced in the core by chemical strains in the shell. Comparison with earlier XRD data confirmed an increase of the tetragonality ratio in tensile BaTiO3 nanorods compared to the bulk material. Obtained analytical expressions, which are suitable for the description of strain-induced changes in a wide range of multiaxial ferroelectric core-shell nanorods and nanowires, can be useful for strain engineering of advanced ferroelectric nanomaterials for energy storage, harvesting, electrocaloric applications, and negative capacitance elements. Published by the American Physical Society 2024

Surface-Enhanced Raman Scattering for Probe Detection via Gold Nanorods and AuNRs@SiO2 Composites

In this paper, a self-assembly method was used to prepare gold nanorod composites, and a seed-growth method was used to adjust the amount of AgNO3 solution, enabling the preparation of gold nanorods with different aspect ratios. AuNRs@SiO2 nanocomposite particles were then prepared by using the Stöber method to coat the gold nanorod surface with silica. Transmission electron microscopy showed that the maximum aspect ratio of the gold nanorods was 4.53, which was achieved using 2 mL of 10 mM AgNO3 solution. The Raman-scattering intensity of the gold nanorods was studied using rhodamine 6G, thiram, melamine, and piroxicam, and detection limits of 10−8 M, 10−5 M, and 10−3 M were, respectively, achieved. As a substrate, these gold nanorods showed good repeatability and reproducibility, and trace detection was successfully achieved. A transmission electron microscopy analysis shows that the SiO2 shell became thicker with increasing tetraethyl orthosilicate addition. Using AuNRs@SiO2 as the base and R6G, thiram, and piroxicam as the probes, measurable detection limits of 10−9 M, 10−6 M, and 10−5 M were achieved, and this composite also showed excellent repeatability and reproducibility.

Effect of aspect ratio on the nonlinear optical properties of ZnO nanorods

In this work, we synthesized ZnO nanorods with two different aspect ratios using the solution method. Morphological and crystalline structures were investigated using TEM and XRD analysis. Also investigated the effect of aspect ratio on the optical properties of ZnO nanorods. With an increasing aspect ratio of the nanorods, the absorption peak is red-shifted and near-band edge emission is suppressed. The nonlinear absorption is enhanced with the increasing aspect ratio of ZnO nanorods.

Carbon quantum dots and gold nanostructures on photothermal therapy for cancer treatment

This study focuses on the comparison of the photothermal (PT) properties of the new carbon quantum dots with two types of gold nanostructures including gold nanoparticles and gold nanorods.We prepared and characterized CQDs doped with copper from ascorbic acid precursor (Cu-aCQDs) with 3 nm diameter and citric acid precursor (Cu-cCQDs) with 5 nm diameter by hydrothermal method, Gold nanoparticles (GNP) were synthesized using sodium sulfide reduction and Gold nanorods (GNR) (aspect ratio of 5) by growth methods. UV–Vis spectrophotometry, spectrofluorimetry, dynamic light scattering (DLS), and transmission electron microscopy (TEM) were used to analyze the optical and morphological properties of the nanoparticles. The fluorescence quantum yields of 2.14 % and 1.55 % were obtained for Cu-aCQDs and Cu-cCQDs respectively. The photothermal conversion efficiencies of 44 %, 66 %, 42 % and 57 % were obtained for Cu-aCQDs, Cu-cCQDs, GNPs and GNRs respectively. We also evaluated the toxicity and the photothermal therapy (PTT) performance of the nanoparticles on MCF-7 breast cancer cells. The ratio of the cell death (from photothermal agent) in the presence of LASER irradiation to its absence for Cu-aCQDs, Cu-cCQDs, GNPS and gold nanorods were 2.5, 5.3, 1.75 and 1.9 respectively. The CQDs had very low toxicity in the absence of LASER irradiation and only 15 % toxicity was obtained for 14.0 mg/mL of Cu-aCQDs and Cu-cCQDs, 350 μg/mL of GNPs and 87.5 of μg/mL gold nano rods. These results indicate that CQDs are less harmful than gold nanostructures in the absence of LASER irradiation and more effective than gold nanostructures when LASER irradiation is applied.

Nanoparticle Size Influences the Self-Assembly of Gold Nanorods Using Flexible Streptavidin-Biotin Linkages.

The self-assembly of colloidal nanocrystals remains of robust interest due to its potential in creating hierarchical nanomaterials that have advanced function. For gold nanocrystals, junctions between nanoparticles yield large enhancements in local electric fields under resonant illumination, which is suitable for surface-enhanced spectroscopies for molecular sensors. Gold nanorods can provide such plasmonic fields at near-infrared wavelengths of light for longitudinal excitation. Through the use of careful concentration and stoichiometric control, a method is reported herein for selective biotinylation of the ends of gold nanorods for simple, consistent, and high-yielding self-assembly upon addition of the biotin-binding protein streptavidin. This method was applied to four different sized nanorods of similar aspect ratio and analyzed through UV-vis spectroscopy for qualitative confirmation of self-assembly and transmission electron microscopy to determine the degree of self-assembly in end-linked nanorods. The yield of end-linked assemblies approaches 90% for the largest nanorods and approaches 0% for the smallest nanorods. The number of nanorods linked in one chain also increases with an increased nanoparticle size. The results support the notion that the lower ligand density at the ends of the larger nanorods yields preferential substitution reactions at those ends and hence preferential end-to-end assembly, while the smallest nanorods have a relatively uniform ligand density across their surfaces, leading to spatially random substitution reactions.

ZnO nanorod incorporated nematic liquid crystal for high multiplexing and high refresh rate displays

Zinc oxide nanorods incorporated in nematic liquid crystal matrix (NLC) are observed to improve physical properties of NLC and its device parameters, especially, for displays. In this article, we present the results of effect of incorporation of zinc oxide nanorods of various sizes but similar aspect ratio on physical properties of NLC. Zinc oxide nanorods (ZR) of similar aspect ratio (4–5) but different sizes (diameter: length) abbreviated as., ZR1 (10:50 nm), ZR2 (50:200 nm) and ZR3 (1:5 μm) are synthesized. Nanocomposites of synthesized nanorods with wide temperature range NLC are prepared. Smaller nanorods (ZR1) are expected to form chain like structures in host NLC matrix leading to softening of order parameter at the isotropic-nematic (I–N) transition. As the size of the nanorods increases the discontinuity of order parameter at I–N transition is observed to increase. Enhancement of dielectric anisotropy as well as birefringence which in turn indicates increase in the order parameter of the system is observed with the incorporation of zinc oxide nanorods. Reduction of threshold voltage, electro-optic response time and bulk ac conductivity and enhanced bend to splay elastic constant ratio of the nanocomposite samples as compared to pure NLC is observed with the incorporation of ZR in host NLC. Observed results show that nanorods of size ∼ 50: 200 nm are the most suitable to be incorporated in NLC for high multiplexing display devices.

Varying aspect ratios of Au nanorods with LSPR effect for efficient enhanced upconversion luminescence

Varying aspect ratios of Au nanorods with LSPR effect for efficient enhanced upconversion luminescence

Facile growth of perovskite nanoparticles confined on dimension-controlled Si nanorod arrays for various promising photophysical applications

In this study, a facile growth of hybrid perovskite nanoparticles (NPs) has been demonstrated on mesoporous, high-aspect ratio, morphology-controlled Si nanorod (NR) arrays. A generic method of directly confining perovskite nanocrystallites (average size <7 nm) on a mesoporous substrate without the use of colloidal stabilization was introduced. The perovskite NPs coated on dimension-and position-controlled Si NR arrays were systematically investigated by their various photophysical properties such as optical reflectance, cathodoluminescence (CL), and photoluminescence (PL) behaviors at both room temperature and low temperature. The dimension and position of the Si NR arrays were controlled by e-beam lithography followed by selective metal-assisted chemical etching (MACE). Organic-inorganic perovskite NPs were synthesized on the surface of Si NR array by spin coating of perovskite precursor solution and followed by annealing. The porous and rough sites on the surface of the NR arrays acted as nucleation centers for the formation of perovskite NPs. Due to the excitonic recombination of CH3NH3PbBr3, the NPs confined on the various NR templates exhibited strong PL emission in the 505–510 nm region. Furthermore, due to greater radiative recombination and lesser carrier trapping in the NPs, the PL and CL emission intensities of the perovskite NPs localized on the surface of the NR array were dramatically increased (PL enhancement factor ∼ 7.7, when NR aspect ratio ∼ 17.2) as compared to the bulk perovskite microcrystals. The low-temperature PL study revealed higher exciton binding energy of the NPs as compared to the bulk microcrystalline film. A systematic investigation revealed that the optical absorption, as well as the emission color of the perovskite NPs, can be tuned by the aspect ratio of the Si NR arrays. The results of our studies indicate the application of bandgap engineering of perovskite nanocrystals through confinement in a mesoporous, well-organized, regularly-ordered template as a powerful tool for tuning the emission wavelength in next-generation photonic sources. Furthermore, the important findings on the periodic array of photoactive nanoscale materials introduced in this manuscript may open up huge opportunities in numerous cutting-edge applications such as light emitting diode arrays, photodetector arrays, individually addressable devices, display devices with controlled pixel size and pixel density, etc.

Nanowire-based smart windows combining electro- and thermochromics for dynamic regulation of solar radiation

Smart window is an attractive option for efficient heat management to minimize energy consumption and improve indoor living comfort owing to their optical properties of adjusting sunlight. To effectively improve the sunlight modulation and heat management capability of smart windows, here, we propose a co-assembly strategy to fabricate the electrochromic and thermochromic smart windows with tunable components and ordered structures for the dynamic regulation of solar radiation. Firstly, to enhance both illumination and cooling efficiency in electrochromic windows, the aspect ratio and mixed type of Au nanorods are tuned to selectively absorb the near-infrared wavelength range of 760 to 1360 nm. Furthermore, when assembled with electrochromic W18O49 nanowires in the colored state, the Au nanorods exhibit a synergistic effect, resulting in a 90% reduction of near-infrared light and a corresponding 5 °C cooling effect under 1-sun irradiation. Secondly, to extend the fixed response temperature value to a wider range of 30–50 °C in thermochromic windows, the doping amount and mixed type of W-VO2 nanowires are carefully regulated. Last but not the least, the ordered assembly structure of the nanowires can greatly reduce the level of haze and enhance visibility in the windows.

Precise Control over Positioning and Orientation of Nanorods in Block Copolymer Nanocomposites via Regulation of Coassembly Pathways

Block copolymer nanocomposites with precise organization of nanorods are promising candidates for construction of orientation-dependent materials. Realizing position- and orientation-controllable coassembly of nanorods in the nanocomposites is thermodynamically challenging due to their slow ordering kinetics and existence of long-lived defects. Regulating the kinetic pathways of a coassembly process offers a convenient alternative to approach the equilibrium configurations of nanostructured composites. Herein, we extend the computational hybrid particle/field method to probe into the coassembly behaviors of block copolymer/nanorod mixtures in the presence of zone annealing. It is found that through regulating coassembly pathways by zone annealing, the nanocomposites have the capability to coassemble into periodically defect-free nanostructures with controllable orientation of nanorods, originating from the epitaxial characteristics of zone-annealed nanocomposites. Meantime, the preferred orientation of nanorods is finely tuned by thermodynamic variables, e.g., incompatibility, aspect ratio, and concentration of nanorods. Furthermore, the minimum free-energy pathways of orientation transition obtained from the string method are used to understand the pathway selection of orientation-controllable nanorods within a nanostructured matrix. In addition, it is revealed that the end-to-end aligned nanorods along the tensile direction are able to enhance the mechanical strength of nanostructured composites. The multiscale modeling study gives insights into how to regulate coassembly pathways to access the targeted nanostructures of nanocomposites with superior mechanical properties through designing manufacture-friendly continuous processing.

Au nanorod core in an AgPt cage: Synthesis of Au@AgPt core/cage nanoframes with rough surface and controllable geometry by galvanic replacement

Metallic nanoparticles with intricate nanoframe structures have provoked extensive attention for improving optical and catalytic properties owing to their open structures. However, how to precisely control the geometry shape and surface details of the nanoframes remains a daunting challenge. Herein, we report a novel structure of Au@AgPt core/cage nanoframes with rough surfaces and controllable geometry and surface details based on the galvanic replacement reaction between Ag shells wrapped around gold nanorods and Pt4+ ion. With the increase of Pt4+ ion, the six faces of Ag shell firstly undergo a continuous concaving process to form the concave surface, following by an asymmetric and continuous hollowing-out process started from one side of Ag shell, and in this whole process accompanied by re-deposition process of both silver and platinum on the edges and vertices. We also verify that the prepared Au@AgPt nanoframes have the characteristics of adjustable size, aspect ratio, roughness, skeleton diameter and composition ratio by changing these reaction conditions such as temperature, thickness of Ag layer, and aspect ratio of gold nanorod. This controlled shape evolution also results in abundant localized surface plasmon resonance (LSPR) modes. Multiple absorption bands could be tuned simultaneously from blue (400 nm) to near infrared (1300 nm) range.

Effects of the aspect ratio of plasmonic gold nanorods on the inhibition of lysozyme amyloid formation.

Amyloid formation due to altered protein folding and aggregation has gained significant attention due to its association with neurodegenerative disorders such as Alzheimer's disease, Parkinson's disease, Huntington's disease, and systemic lysozyme amyloidosis. Amyloids are characterized by parallel and anti-parallel cross-β-strands arranged to form stacks of sheets that provide stability and rigidity to the amyloid core. The prototypic protein Hen Egg White Lysozyme (HEWL) has been extensively used to understand protein hydrolysis, fragmentation, folding, misfolding, and amyloid formation. In the present study, we have examined the efficacy of plasmonic gold nanorods (GNRs) as an anti-amyloid agent against HEWL amyloids. Our results reveal that (i) the amyloid inhibition by plasmonic GNRs is dependent on their aspect ratio, (ii) the large aspect ratio GNRs ameliorate amyloid assembly completely, and (iii) GNRs interfere at several stages along the lysozyme fibril-formation pathway and block the conversion of monomeric and oligomeric intermediates into mature fibrils. Using a multi-parametric approach, we demonstrate that GNRs drive HEWL into off-pathway and amyloid-incompetent forms. To establish GNRs as generic amyloid inhibitors, we extended our studies to another archetypal protein, Bovine Serum Albumin (BSA), and observed similar results of GNRs inhibiting BSA aggregation. We believe that our results will pave the way for the potential use of GNRs with current therapeutics to reduce the burden of amyloid-related diseases.

Effect of small amounts of akaganeite (β-FeOOH) nanorods on the gelation, phase behaviour and injectability of thermoresponsive Pluronic F127.

Pluronic F127 (PF127) is a copolymer with an amphiphilic nature and can self-assemble to form micelles and, beyond 20% (w/v), form a thermoresponsive physical gel state. However, they are mechanically weak and easily dissolve in physiological environments, which limits their use in load-bearing in specific biomedical applications. Therefore, we propose a pluronic-based hydrogel with enhanced stability by incorporating small amounts of paramagnetic nanorods, akaganeite (β-FeOOH) nanorods (NRs) of aspect ratio ∼7, with PF127. Due to their weak magnetic properties, β-FeOOH NRs have been used as a precursor for preparing stable iron-oxide states (e.g., hematite and magnetite), and the studies on β-FeOOH NRs to be used as a primary component in hydrogels are at the nascent stage. Here we report a method to synthesize β-FeOOH NRs on a gram scale using a simple sol-gel process and characterize the NRs with various techniques. A phase diagram and thermoresponsive behaviour based on rheological experiments and visual observations are proposed for 20% (w/v) PF127 with low concentrations (0.1-1.0% (w/v)) of β-FeOOH NRs. We observe a unique non-monotonous behaviour in the gel network represented by various rheological parameters like storage modulus, yield stress, fragility, high-frequency modulus plateau, and characteristic relaxation time as a function of nanorod concentration. A plausible physical mechanism is proposed to fundamentally understand the observed phase behaviour in the composite gels. These gels show thermoresponsiveness and enhanced injectability, and could find applications in tissue engineering and drug delivery.

Nanoscale deformation of crystalline metals: Experiments and simulations

In the present work, we performed experiments and molecular dynamic simulations to study the atomic physical process and deformation mechanism involved in nanoscale deformation of crystalline metals. By contact deforming bulk metals using hard molds with different cavity sizes at various temperatures and different stress levels, the flow of metals (e.g., Au and Ag) into nanocavities is quantified by the aspect ratio of molded micro-/nanorods, based on which the dependence of deformability on cavity size, temperature and stress is revealed. It is found that the critical forming pressure is determined by the entering barrier. Once the entering barrier can be overcome, quantified by the aspect ratio of metal nanorods, the molding efficiency increases with the cavity size decreasing. Moreover, three deformation modes are uncovered in the nanoscale plastic flow of metals and directly related with the atomic physical processes, i.e. atomic diffusion, dislocation nucleation, multiplication and movement. In the dislocation dominated temperature regime, a transition of deformation mode from burst growth to continuous growth is observed as the cavity size increases. When the mold cavity size is very small (100-101 nm), the metal atoms flowing in a mold cavity will arrange amorphously even at low temperature, which usually only occurs at high temperature for large cavity sizes. Therefore, reducing the size shows the same effect as increasing the temperature, making nanomolding easier.

PH Controlled Nanostructure and Optical Properties of ZnO and Al-Doped ZnO Nanorod Arrays Grown by Microwave-Assisted Hydrothermal Method.

The low-temperature microwave-assisted hydrothermal method was used to successfully grow pure and Al-doped ZnO (AZO) nanorod (NR) arrays on glass substrates. The combined effects of doping and pH on the structural properties, surface chemistry, and optical properties of all samples were investigated. Thermodynamic-based simulations of the growth solution were performed and a growth mechanism, that considers the effects of both the pH and Al-doping, is proposed, and discussed. Tuning the solution pH is key parameter to grow well-aligned, single crystal, highly packed, and high aspect ratio nanorod arrays. Moreover, the optical absorption in the visible range is enhanced by controlling the pH value. The PL spectra reveal a shift of the main radiative emission from the band-to-band into a transition involving deep defect levels of Zinc interstitial Zni. This shift is caused by an enhancement of the non-radiative components (phonon relaxation) at high pH values. The production of well-ordered ZnO and AZO nanorod arrays with visible-active absorption/emission centers would increase their potential use in various applications.

ZnO nanostructure fabricated by electrochemical deposition

Electrochemical deposition method was employed to fabricate ZnO nanorods on zinc foil substrate in this paper. The structural observations of ZnO nanorods with different aspect ratios were carried out by field- emission scanning electron microscopy. The microstructures of ZnO nanorods were also characterized by X-ray diffraction and the changes in surface hydroxyls with electrochemical deposition time were analyzed by X-ray photoelectron spectroscopy. The study results show the aspect ratios of ZnO nanorods and the density of their surface hydroxyls are responsible for their superhydrophobicity. The fluorinated polymer coated ZnO nanorods showed an excellent superhydrophobic behavior with 167◦ contact angle of water droplet, which is larger than that of fluorinated polymer flat surface. The more the surface hydroxyls are, the more hydrophilic the surfaces are. Meanwhile, the larger the aspect ratio of ZnO nanorod arrays is, the larger its drophobicity is. The results of this study might have a simple and feasibility pathway to the fabrication of superhydrophobic cleaning materials used in engineering fields.

Liquefied petroleum gas sensing performance of solochemically synthesized ZnO nanorods: Role of precursors and fractal analysis

Nanorods of ZnO were grown successfully using a template free solochemical route using zinc chloride, zinc nitrate and zinc acetate precursors at 70 °C. The structural and morphological analysis of synthesized all ZnO samples were tested by X-ray diffraction (XRD), Fourier transform infrared (FTIR), transmission electron microscopy (TEM) techniques. Whole pattern fitting of XRD patterns shows less strain in unit cell is observed in case of ZnO sample synthesized from zinc chloride precursor. Variations in aspect ratios of ZnO nanorods synthesized using different precursors were observed from TEM results. The ZnO nanorods composed thin films were fabricated via spin coating technique and its liquefied petroleum gas (LPG) sensing performance was investigated. The surface topographical studies and fractal analysis of these films were examined by atomic force microscopy (AFM). These results reveals that thin film composed ZnO nanorods prepared using zinc chloride precursor possess average roughness ~133 nm and fractal dimension ~ 2.42, which is higher than other films. This film exhibits maximum gas response ~502 towards 50 ppm LPG, along with low response and recovery time, repeatability, great selectivity as compared with thin films synthesized from other precursors. The reason of enhancement of gas response for ZnO thin film synthesized using precursor zinc chloride as compared to zinc acetate and zinc nitrate is explained on the basis of aspect ratio and fractal roughness. The LPG sensing mechanism towards ZnO nanorod is also discussed. • ZnO nanorods are prepared by a simple and low-cost solochemical method. • Excellent LPG performance of spin- coated films using ZnO nanorods explored. • Effect of precursors on LPG sensing and fractal analysis evaluated. • The sensor exhibits a fast response (~6–7 s) and a quick recovery (~6–7 s). • Role of precursors during gas sensing performance assessed on the basis of fractal analysis.