Resonance Raman Spectroscopy Research Articles

Unique and redundant spectral fingerprints of docosahexaenoic, alpha-linolenic and gamma-linolenic acids in binary mixtures

The polyunsaturated fatty acids docosahexaenoic acid (DHA; 22:6n-3), docosapentaenoic acid (n-3DPA; 22:5n-3), and eicosapentaenoic acid (EPA; 20:5n-3) contain nearly identical structural moieties, but differ vastly in their biological activities and in their utilization in mammalian tissues. Most importantly, DHA cannot be substituted for in fast signal processing tissues such as neural retinal, cardiac and spermatogenic. Over 600 million years of evolution the difference of just a single double bond has not been overcome—DHA reigns supreme. These dramatic differences among polyunsaturated fatty acids are at least in part conformational. Binary 3:1 mixtures of DHA with either alpha-linolenic acid (18:3n-3; ALA) or gamma linolenic acid (18:3n-6; γ-LN) and both Nuclear Magnetic Resonance and Gradient Temperature Raman Spectroscopy were utilized to probe DHA in the liquid state. Raman modes at 1970, 1778 and 1578 cm−1 definitively demonstrate DHA, since absent in γ-LN and ALA. However, the latter two modes are also absent in 3:1 mixtures. This is evidence for a conformational change in DHA and of the capacity of structural analogs to disrupt the packing of DHA at the molecular level. NMR confirms chemical shifts in the middle of the DHA double bond region in the mixtures are not the same as the pure DHA chemical shifts.We propose asymmetry in torsion among =C-C-Ha, =C-C-Hb, Ha-C-C= and Hb-C-C= sites in each six carbon atom backbone moiety in =C″-C-C=C-C-C′= results in the observed non-uniformity of twisting observed spectroscopically. The distance C″-C′ is minimum when the six atom moiety is fully planar, and maximum when twisting involving C″ and C′ is in opposite directions from the double bond. For DHA -(H-C=C-H)-CH2- and -CH2-(H-C=C-H)- peaks are conformationally identical only at C17=C16: C19″ and C14′ both twist C″ and C′ to the same side of C17=C16. At C14=C13 and C8=C7, torsion is similar to that at C16=C15 in ALA. Torsion related to C″-C′ distances stepwise from C2 to C22 results in planar structure more “O” shaped then “U” shaped. In 3 + 1 mixtures, γ-LN predominantly disrupts peaks at the C′ half of DHA; ALA alters the conformation of the C″ half of DHA.

Chiral electronic excitations in the quasi-two-dimensional Rashba system BiTeI

The optical transitions between spin-polarized bands of the quasi-two dimensional Rashba system BiTeI are investigated using polarization resolved resonant Raman spectroscopy. We detect chiral excitations between states with opposite helicity and compare spectra to calculations within a three-band model. Using the resonant Raman excitation profile, we deduce the Rashba parameters and band gaps of the higher conduction bands near the Fermi level, and compare the parameters to values obtained by ab initio density function theory (DFT).

Dependence of Vibrational Energy Transfer on Distance in a Four-Helix Bundle Protein: Equidistant Increments with the Periodicity of α Helices.

Vibrational energy exchanges between various degrees of freedom are critical to barrier-crossing processes in proteins. Heme proteins are highly suitable for studies of the vibrational energy exchanges in proteins. The migration of excess energy released by heme in a protein moiety can be observed using time-resolved anti-Stokes ultraviolet resonance Raman spectroscopy. The anti-Stokes resonance Raman intensity of a tryptophan residue is an excellent probe for the excess energy and the spatial resolution of a single amino acid residue can be achieved. Here, we studied dependence of vibrational energy transfer on the distance in cytochrome b562, which is a heme-containing, four-helix bundle protein. The vibrational energy transfer from the heme group to a single tryptophan residue introduced by site-directed mutagenesis was examined for different heme-tryptophan distances by a quasi-constant length with the periodicity of α helices. Taken together with structural data obtained by molecular dynamics simulations, the energy transfer could be well described by the model of classical thermal diffusion, which suggests that continuum media provide a good approximation of the protein interior, of which the atomic packing density is very high.

Oxygen Activation by a Copper Complex with Sulfur-Only Coordination Relevant to the Formylglycine Generating Enzyme.

Synthesizing hydrosulfido Cu thiolate complexes is quite challenging. In this report, two new and rare hydrosulfido Cu thiolate complexes, [Et4N]2[(mnt)Cu-SH] (2, mnt = maleonitrile dithiolene = S2C2(CN)2) and [Et4N]3[(mnt)Cu-(μ-SH)-Cu(mnt)] (3), have been synthesized. Coordination sites and O2 activation by complex 2 resemble the formylglycine generating enzyme (FGE), an enzyme recently crystallographically characterized with sulfur-only coordination around Cu (three thiolate ligands). The function of this enzyme (and complex 2) is surprising because vulnerable thiolates should not be well suited for O2 activation rationally. Indeed, activation of oxygen by such an all-sulfur-coordinated Cu complex 2 is lacking in the literature. Aerial O2 (ambient O2 from the air) activation by complex 2 could proceed through a superoxide radical intermediate and a sulfur radical intermediate detected by resonance Raman (rR) spectroscopy and electron paramagnetic resonance (EPR) spectroscopy, respectively. The chemistry of 2 has been examined by its reactivity, crystal structure, and spectroscopic and cyclic voltammetric analyses. In addition, the results have been complemented with density functional theory (DFT) and time-dependent DFT (TD-DFT) calculations.

Recent advances in optical label-free characterization of extracellular vesicles.

Extracellular vesicles (EVs) are complex biological nanoparticles endogenously secreted by all eukaryotic cells. EVs carry a specific molecular cargo of proteins, lipids, and nucleic acids derived from cells of origin and play a significant role in the physiology and pathology of cells, organs, and organisms. Upon release, they may be found in different body fluids that can be easily accessed via noninvasive methodologies. Due to the unique information encoded in their molecular cargo, they may reflect the state of the parent cell and therefore EVs are recognized as a rich source of biomarkers for early diagnostics involving liquid biopsy. However, body fluids contain a mixture of EVs released by different types of healthy and diseased cells, making the detection of the EVs of interest very challenging. Recent research efforts have been focused on the detection and characterization of diagnostically relevant subpopulations of EVs, with emphasis on label-free methods that simplify sample preparation and are free of interfering signals. Therefore, in this paper, we review the recent progress of the label-free optical methods employed for the detection, counting, and morphological and chemical characterization of EVs. We will first briefly discuss the biology and functions of EVs, and then introduce different optical label-free techniques for rapid, precise, and nondestructive characterization of EVs such as nanoparticle tracking analysis, dynamic light scattering, atomic force microscopy, surface plasmon resonance spectroscopy, Raman spectroscopy, and SERS spectroscopy. In the end, we will discuss their applications in the detection of neurodegenerative diseases and cancer and provide an outlook on the future impact and challenges of these technologies to the field of liquid biopsy via EVs.

Heterogeneous development of micro- and meso-pores in shale kerogen: New insights from chemical structure analysis

The development of the pore network during the thermal cracking of organic matter in shale plays an important role in the storage and transport of gas. There are several reports concerning the relationships between pore development and chemical composition in kerogen, however, little research has been performed to investigate how the transformation of the chemical structure affects the heterogeneous development of pores. In this study, kerogen isolation was performed on nine Longmaxi Formation shale samples with different maturities, then the chemical structure and pore development of isolated kerogens were studied using low-pressure gas adsorption, 13C Nuclear Magnetic Resonance spectroscopy, Raman spectroscopy, and high-resolution transmission electron microscopy. Results show that the reduction in micropores (< 2 nm pore diameter) at Ro < 1.55% mainly results from the cleavage of the aliphatic –CH and –CH2, while the increase in micropores at Ro > 1.55% is primarily derived from the condensation of aromatic rings. The development of mesopores (2–50 nm) with increasing maturity could be the result of two different mechanisms: one is developed at the edges of the aromatic layers; another is formation in the space between structural clusters with different orientations. The development of mesopores is related to the compositions and disorder degree of chemical structure. Meanwhile, changes in chemical compositions can affect the surface and structural heterogeneities by altering the surface chemical properties and pore geometry, while variations in spatial arrangement only affect the structural heterogeneity by altering the distribution of void space. Transformation of the chemical structure not only reveals the inherent mechanism of pore heterogeneity in shale kerogens but also provides some microscopic insights for understanding the occurrence and transport behaviors of fluids.

Label-free in vivo assessment of brain mitochondrial redox states during the development of diabetic cognitive impairment using Raman spectroscopy

Mitochondrial redox imbalance has been recognized as a unifying cause for diabetic cognitive impairment. Currently, a robust method for the in vivo assessment of brain mitochondrial redox imbalance is still lacking. Here, we conducted a spectral study to assess brain mitochondrial redox imbalance in the process of diabetic cognitive impairment by using label-free resonance Raman spectroscopy (RRS). Our findings showed that mitochondrial redox imbalance in cultured neurons and organotypic cortical slices exposed to high glucose were quantified by the reduction of Raman peak area at 750 cm-1 and 1128 cm-1, which were also associated with synaptic injury and neuron apoptosis. Raman peak area at 750 cm-1 and 1128 cm-1 were also decreased in db/db mice at the age of 8, 16 and 24 weeks, and had a high correlation with the mitochondrial NAD+/NADH redox couple. Of note, this mitochondrial redox imbalance occurred before measurable cognitive decline in 8-week-old diabetic mice, and might signal impending diabetic cognitive impairment. In summary, RRS-based mitochondrial redox states assay enabled the in vivo assessment of brain mitochondrial redox imbalance, and might provide an early indicator to enhance the prediction of diabetic cognitive impairment and inform on the response to therapies targeting mitochondrial redox imbalance.

Computational hints for the simultaneous spectroscopic detection of common contaminants in water

In this work, we present a reliable computational methodology with the capability to aid in the identification of ionic water contaminants, such as nitrite, nitrate, and thiocyanate ions, based on the use of Resonance Raman (RR) spectroscopy. The method combines an exhaustive configurational sampling that fully captures the structural complexity inherent to aqueous solutions with state–of–the–art computational techniques that accurately simulate the response properties originating Resonance Raman signals of molecules in solution. Our computational findings show that it is possible to limit the quantum mechanical treatment to only a few explicit water molecules in order to capture the relevant interactions, and thus reproduce the available experimental spectra for NO2- and NO3-. Once validated, the methodology is applied to the prediction of the RR spectrum of aqueous SCN−. Our results indicate that by using an incident wavelength of 210 nm, the three emerging contaminants can be simultaneously detected in an aqueous matrix, thus avoiding the laborious indirect measurements used in current protocols. The designed protocol offers generalized explicit benefits: simultaneous detection of pollutants whose absorption spectra overlap, and because of the very nature of RR, pushes detection limits to lower concentrations.

Light‐Driven Multi‐Charge Separation in a Push‐Pull Ruthenium‐Based Photosensitizer – Assessed by RASSCF and TDDFT Simulations

AbstractThe performance of photosensitizers in the field of, for example, solar energy conversion, relies on their light‐harvesting efficiency in the visible region, population of long‐lived charge‐separated intermediates, as well as their charge‐accumulation capacity amongst other properties. In this computational study, we investigate the photophysical properties of a bis(bipyridyl)ruthenium(II)‐based black dye (Ru) incorporating a chromophoric unit based on a thiazole donor‐acceptor push‐pull motif. The combination of two light‐harvesting units, that is, the Ru(II)polypyridyl and the thiazole‐based organic dye, yields close‐lying metal‐to‐ligand charge transfer (MLCT) states, involving both ligand spheres as well as intra‐ligand charge transfer (ILCT) states of the organic dye. Due to the combination of inorganic and organic chromophores the computational modelling of the photophysics of Ru is challenging. To this aim, time‐dependent density functional theory and multiconfigurational methods are applied. The excited‐state properties obtained for the states of interest are rationalized by electronic absorption and resonance Raman spectroscopies. The CAM‐B3LYP functional was found to accurately describe the ground‐ and excited‐state properties of Ru. Finally, excited‐state relaxation pathways and the multi‐charge‐accumulation capacity were addressed. Despite the unidirectional nature of the MLCTthia and ILCTthia transitions, the thiazole unit is merely capable to store one redox equivalent.

Crystallinity effects on the vibrational spectral features of saponite: Implications for characterizing variable crystalline phyllosilicates on Mars

X-ray diffraction patterns of Martian mudstones acquired by Chemistry & Mineralogy X-Ray Diffraction (CheMin) aboard Mars Science Laboratory (MSL) suggest that the smectites detected in Gale crater have poor crystallinity. This finding poses an urgent question about the structural ordering of phyllosilicates found globally by Visible/Near-Infrared (VIS-NIR) spectroscopic orbital remote sensing on Mars, linked to their formation conditions. In this study, we synthesized saponite (Nz+x/z[M6][Si8-xAlx]O20(OH)4·nH2O, where M and N correspond to the divalent octahedral cations and the interlayer cations, respectively) with variable crystallinity, which bear structural similarities to the smectite discovered at Gale crater. Synthetic saponite was characterized using Field Emission Scanning Electron Microscopy (FE-SEM), powder X-ray diffraction (XRD), then studied the spectral features of these samples using nuclear magnetic resonance spectroscopy (NMR), Raman spectroscopy, and VIS-NIR reflectance spectroscopy. Our study revealed that the crystallinity of these saponite samples increased (as shown in the FWHM of XRD (060) peak), and is accompanied by (1) improved T-O-T layer stacking along the c axis (specified by the intensity and width of the XRD (001) peak); (2) increased uniformity of the SiO4 unit in tetrahedral sheets (based on the peak widths of Raman spectra and the well-resolved 29Si NMR peaks); (3) improved regularity in the distribution of Mg2+ in octahedral sites and thus the regularity of metal-OH bonds in octahedral sheet (based on the resolution of the NIR 2.2–2.4 μm band and the peak width of the XRD (060,330) peak); and (4) the increased Al in tetrahedral sites and decrease of Al in octahedral sites (the width of 27Al NMR peak), the crystallinity of saponite raised. Based on experimental observations, the first derivative spectra of metal-OH absorptions were proposed as a crystallinity index for smectite on Mars. Our results indicate that different vibration spectroscopy techniques can constrain the structural ordering of smectite on Mars and provide insight into their formation conditions.

The effect of C60 fullerene polymerization processes on the mechanical properties of clusters forming ultrahard structures of 3D C60 polymers

We observed the effect of high (up to 80 GPa) pressure, catalyst (CS2) and laser irradiation on the process of three-dimensional (3D) polymerization of fullerene C60 and the mechanical properties of the 3D C60 samples. The studies were carried out using resonant Raman spectroscopy and piezospectroscopy, high resolution transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy. We have revealed that the 3D C60 structure consists of at least two types of clusters formed by covalent bonds with a different set of force constants, while C60 molecules, as one of the elements of the 3D C60 structure (clusters), are preserved at least up to a pressure of 80 GPa. The intensity of Raman scattering depends on the wavelength of the exciting radiation (resonance effect) and a set of force constants: the higher their values, the shorter-wavelength exiting radiation is required for Raman scattering observation by such clusters. Clusters with bulk moduli from 454 GPa to 644 GPa are formed depending on methods of C60 polymerization. According to the set of clusters, 3D C60 samples with bulk moduli from 506 GPa to 608 GPa were obtained.

De Novo Synthesis of Bacteriochlorins Bearing Four Trideuteriomethyl Groups

Site-specific introduction of isotopes in tetrapyrrole macrocycles provides the foundation for probing physicochemical features germane to photosynthetic energy-transduction processes, but has chiefly been done with porphyrins rather than the more biologically relevant hydroporphyrin analogues of native photosynthetic pigments. A prior study incorporated pairwise 13C or 15N atoms in the skeleton of a bacteriochlorin containing a gem-dimethyl group in each pyrroline ring. Here, a complementary effort is reported that installs deuterium atoms in substituents at the perimeter of a bacteriochlorin. Thus, perdeuteriated 3-methyl-2,4-pentanedione was converted in an 8-step synthesis via the intermediacy of tert-butyl 5-formyl-3,4-bis(trideuteriomethyl)pyrrole-2-carboxylate to the 2,3,12,13-tetrakis(trideuteriomethyl)-8,8,18,18-tetramethylbacteriochlorin (BC-2). The fidelity of isotope substitution was maintained throughout the synthesis. Resonance Raman spectroscopy of the copper chelate (CuBC-2) revealed that addition of the four β-pyrrolic substituents alone is not sufficient to account for the vibronic complexity observed for the copper chelate of bacteriochlorophyll a (CuBChl a). The increased vibronic activity exhibited by the natural pigments and CuBChl a must arise from the increased structural complexity of the macrocycle.

Aluminum-black silicon plasmonic nano-eggs structure for deep-UV surface-enhanced resonance Raman spectroscopy

By combining surface-enhanced Raman spectroscopy together with resonance Raman effects in the deep-UV region, ultra-sensitive and selective molecule detection can be achieved by deep-UV surface-enhanced resonance Raman spectroscopy (SERRS). Here, we report a deep-UV plasmonic nano-eggs structure consisting of elongated Al nanoparticles on black Si (BSi) for use in deep-UV SERRS characterization of biomolecules. The Al/BSi nano-eggs structure can be easily fabricated over a large area via conventional techniques including inductively coupled-plasma reactive ion etching on a Si substrate and Al sputtering without the need for accurate thickness control. A home-built deep-UV SERRS setup with the excitation wavelength of 266 nm is used to characterize adenine deposited on Al/BSi nano-eggs structures. High-intensity and reproducible Raman signals for adenine are obtained. A low-cost and easy-to-fabricate Al/BSi nano-eggs structure provides a convenient means to achieve deep-UV SERRS characterization, and it is thought to be beneficial for the development of ultra-sensitive molecule detection schemes.

Raman Diagnostics of Cathode Materials for Li-Ion Batteries Using Multi-Wavelength Excitation

Lithium-ion batteries have been commonly employed as power sources in portable devices and are of great interest for large-scale energy storage. To further enhance the fundamental understanding of the electrode structure, we report on the use of multi-wavelength Raman spectroscopy for the detailed characterization of layered cathode materials for Li-ion batteries (LiCoO2, LiNixCo1−xO2, LiNi1/3Mn1/3Co1/3O2). Varying the laser excitation from the UV to the visible (257, 385, 515, 633 nm) reveals wavelength-dependent changes in the vibrational profile and overtone/combination bands, originating from resonance effects in LiCoO2. In mixed oxides, the influence of resonance effects on the vibrational profile is preserved but mitigated by the presence of Ni and/or Mn, highlighting the influence of resonance Raman spectroscopy on electronic structure changes. The use of UV laser excitation (257, 385 nm) is shown to lead to a higher scattering efficiency towards Ni in LiNi1/3Mn1/3Co1/3O2 compared to visible wavelengths, while deep UV excitation at 257 nm allows for the sensitive detection of surface species and/or precursor species reminiscent of the synthesis. Our results demonstrate the potential of multi-wavelength Raman spectroscopy for the detailed characterization of cathode materials for lithium-ion batteries, including phase/impurity identification and quantification, as well as electronic structure analysis.

Systematic Influence of Electronic Modification of Ligands on the Catalytic Rate of Water Oxidation by a Single-Site Ru-Based Catalyst.

Catalytic water oxidation is an important process for the development of clean energy solutions and energy storage. Despite the significant number of reports on active catalysts, systematic control of the catalytic activity remains elusive. In this study, descriptors are explored that can be correlated with catalytic activity. [Ru(tpy)(pic)2 (H2 O)](NO3 )2 and [Ru(EtO-tpy)(pic)2 (H2 O)](NO3 )2 (where tpy=2,2' : 6',2"-terpyridine, EtO-tpy=4'-(ethoxy)-2,2':6',2"-terpyridine, pic=4-picoline) are synthesized and characterized by NMR, UV/Vis, EPR, resonance Raman, and X-ray absorption spectroscopy, and electrochemical analysis. Addition of the ethoxy group increases the catalytic activity in chemically driven and photocatalytic water oxidation. Thus, the effect of the electron-donating group known for the [Ru(tpy)(bpy)(H2 O)]2+ family is transferable to architectures with a tpy ligand trans to the Ru-oxo unit. Under catalytic conditions, [Ru(EtO-tpy)(pic)2 (H2 O)](NO3 )2 displays new spectroscopic signals tentatively assigned to a peroxo intermediate. Reaction pathways were analyzed by using DFT calculations. [Ru(EtO-tpy)(pic)2 (H2 O)](NO3 )2 is found to be one of the most active catalysts functioning by a water nucleophilic attack mechanism.

Classical Model of Surface Enhanced Infrared Absorption (SEIRA) Spectroscopy.

The molecule-plasmon interaction is the key to the mechanisms of surface enhanced infrared absorption (SEIRA) and surface enhanced Raman scattering (SERS). Since plasmons are well described by Maxwell's equations, one fundamental treatment involves the classical interpretation of infrared absorption and resonance Raman spectroscopies. We can understand the molecule-plasmon interaction using electromagnetic theory if the classical field effect on a transition dipole moment or transition polarizability is properly described. In previous work, we derived the Raman excitation profile of a model molecule using a classical driven spring attached to a charged mass with a perturbative force constant due to vibrational oscillations. In this study we generalize the interactions of plasmons with molecules by considering the N2O asymmetric stretch SEIRA signal on a Dy doped CdO (CdO:Dy) film. This semiconductor has tunable plasmon dispersion curves throughout the near-and mid-infrared that can interact directly with vibrational absorption transitions. We have demonstrated this using the Kretschmann configuration with a CaF2 prism and a MgO substrate. The model predicts the phase behavior of SEIRA. The calculated enhancement factor relative to an Au control is 6.2, in good agreement with the value of 6.8 ± 0.5 measured under the same conditions.

Ring Vibrations to Sense Anionic Ibuprofen in Aqueous Solution as Revealed by Resonance Raman.

We unravel the potentialities of resonance Raman spectroscopy to detect ibuprofen in diluted aqueous solutions. In particular, we exploit a fully polarizable quantum mechanics/molecular mechanics (QM/MM) methodology based on fluctuating charges coupled to molecular dynamics (MD) in order to take into account the dynamical aspects of the solvation phenomenon. Our findings, which are discussed in light of a natural bond orbital (NBO) analysis, reveal that a selective enhancement of the Raman signal due to the normal mode associated with the C–C stretching in the ring, , can be achieved by properly tuning the incident wavelength, thus facilitating the recognition of ibuprofen in water samples.

A holistic overview on corn cob biochar: A mini-review.

Corn cob is one of the agricultural waste materials subjected to improper burning, which creates pollution. It can be used for the production of green technologies for further applications. Carbonisation or slow pyrolysis could be promising alternative to burning. It has many applications, such as soil ameliorant, waste water treatment, carbon sequestration, composting, supercapacitor, fuel cell and biocomposites material. It motivated to investigate the suitability of corn cob as a potential material for biochar production and its application. The advanced form of analysis, such as thermogravimetric, scanning electron microscopy, surface area, Fourier transform infrared spectroscopy, nuclear magnetic resonance spectroscopy and Raman spectroscopy, is elaborated for in-depth knowledge of characteristics. The hypothesis is that if the available corn cob is used for biochar production, it will reduce the carbon dioxide (CO2) emission. On a global level, conversion of available corn cob into biochar is expected to reduce CO2 emission by 0.13 Gt per year. The reduction in CO2 emission also favours economy. If 1 tonne of biomass per year is converted into biochar, 0.82 tonnes of CO2 can be reduced per year and by considering the emission cost of Rs 1800 per tonne, the cost saving would be Rs 1476 per year. The presented mini-review article provides an outline of the state-of-art information on corn cob biochar and its novel application. It will be helpful to scientific domain to find new opportunities in biochar research and also the humanity will be benefitted due to reduction in greenhouse gases.

In-situ twistable bilayer graphene

The electrical and optical properties of twisted bilayer graphene (tBLG) depend sensitively on the twist angle. To study the angle dependent properties of the tBLG, currently it is required fabrication of a large number of samples with systematically varied twist angles. Here, we demonstrate the construction of in-situ twistable bilayer graphene, in which the twist angle of the two graphene monolayers can be in-situ tuned continuously in a large range with high precision. The controlled tuning of the twist angle is confirmed by a combination of real-space and spectroscopic characterizations, including atomic force microscopy (AFM) identification of crystal lattice orientation, scanning near-field optical microscopy (SNOM) imaging of superlattice domain walls, and resonant Raman spectroscopy of the largely enhanced G-mode. The developed in-situ twistable homostructure devices enable systematic investigation of the twist angle effects in a single device, thus could largely advance the research of twistronics.

Dynamic synthesis of CdTe NRs: Diameter dependent tuning of PL quenching efficiency for sensitive organic vapor detection

Cadmium telluride (CdTe) is one of the well-explored semiconductors in the history of material science research, because of its innumerable benefits in all dimensional nanostructures. However, no endeavor has been dedicated as of now to understanding the size-dependent tuning of nonradiative emission efficiency and how it influences the sensitive detection of organic vapors (ethanol and acetone) through photoluminescence (PL) quenching mechanism. Herein, the aspect ratio of CdTe nanorods (NRs) is varied by changing its diameter while keeping the axial length constant through electrodeposition into lab made anodic aluminium oxide (AAO) membranes. The growth kinetics and thermodynamics involved while electrodeposition of CdTe NR in each distinct pore diameter of AAO membrane is studied and reasoned. The surface morphology of variable diameter AAO membranes and NRs, respectively fabricated under various electrochemical parameters are observed through a field emission scanning electron microscope. The relation between NRs dimension and structural parameters like d-spacing, crystallite size, band area ratio, and exciton-phonon ratio are extracted from X-ray diffraction and Resonance Raman spectroscopy. The strongly luminescent CdTe NRs, coupled with their chemical durability and organic molecule affinity displayed a sensitive response of ~12 and 6 ppm to ethanol and acetone vapors in the range of 10–100 ppm as a PL sensor. The carrier lifetime measurement through time-correlated single photon counting spectroscopy endorses the role of increased recombination density with a decrease in the diameter of NRs.