The integration of inorganic-organic hybrid heterostructures offers a promising route toward efficient optoelectronic devices by combining the complementary properties of wide-band-gap semiconductors and conducting polymers. Herein, we report for the first time the direct growth of vertically aligned anatase TiO2 nanopillars on electrodeposited poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) thin films using glancing angle deposition (GLAD) at substrate temperatures below 70 degrees C. This controlled temperature approach preserves the structural integrity of PEDOT:PSS while enabling nanopillar crystallisation. The comprehensive structural, chemical, optical, and photophysical characterisation confirms the successful formation of TiO2/PEDOT:PSS heterostructures. The Raman analysis reveals intensity redistribution and a red shift of characteristic polymer peaks, indicating strong polymer-oxide coupling. The UV-Vis spectroscopy demonstrates enhanced light absorption and reduced band gaps (3.15 eV for nanopillars) compared with pristine TiO2. The photoluminescence (PL) quenching and time-correlated single-photon counting confirm efficient interfacial charge transfer, most pronounced in the nanopillar heterostructure. The demonstrated strategy provides a scalable pathway for hybrid nanostructures demonstrating significant potential in photovoltaics, photocatalysis, and photodetection.

This study explores the influence of surface capping on the defect states, structural, optical, and photocatalytic properties of PVP-capped ZnO nanosheets. The work focuses on the underlying photophysical phenomenon, Forster resonance energy transfer (FRET), which controls luminescence and impacts photocatalytic performance. X-ray diffraction (XRD) reveals a positive shift and slight increase in ZnO diffraction peaks as PVP content rises. Fourier transform infrared (FTIR) spectroscopy confirms the interaction between PVP chains and the ZnO surface, while scanning electron microscopy (SEM) shows a nanosheet-like structure. X-ray photoelectron spectroscopy (XPS) demonstrates a reduction in defect densities, including oxygen vacancies and zinc interstitials, following PVP capping. Emission spectra exhibit a shift from visible to UV peaks at 0.08 g PVP due to inter donoracceptor FRET, with a significant overall emission increase at higher PVP concentrations, attributed to competing inter and intra-acceptor FRET processes. In terms of photocatalysis, PVP-capped ZnO shows lower UV-lightdriven performance compared to uncapped ZnO. This reduction is associated with fewer oxygen vacancies, exciton recombination, and FRET between ZnO and PVP. Photo decolourization efficiency decreases as PVP content increases, which aligns with enhanced UV emission, increased FRET efficiency, and reduced surface oxygen vacancies.

Highly active novel ZnO/Fe-TiO2 composite catalysts with p-n junction heterostructure have been fabricated by adding commercial ZnO and sol–gel derived Fe-TiO2 nano-powders controlled by grinding and drying. This work reported that doped Fe (III) with TiO2 form a p-type semiconductor and whereas ZnO is an n-type semiconductor. The slight variation of electronegativity between ZnO and TiO2 causes a strong rectifying action for the formation of an interface between ZnO and Fe-TiO2. The occurrence of red shift phenomenon in absorption spectrum of the samples suggest the outcome of d-d transition of Fe3+ (2T2g → 2A2g, 2T1g) and the charge transfer transition between interacting Fe3+ ions (Fe3+ + Fe3+ → Fe4+ + Fe2+). These Fe3+ 3d states in addition to oxygen vacancies and Ti3+ centers create band states, thereby favouring the electronic transition to these levels and resulting in narrowing of TiO2 band gap. A direct confirmation is the increase of Urbach energy with the lowering in the band gap of ZnO/Fe-TiO2.The crystal field splitting of d orbitals (5 degenerate orbitals) of Fe3+ and the approach of free ligand ions which split into two sets and Fe3+ ligand field transition is discussed schematically. The photocatalytic activities of these heterostructure photocatalysts were evaluated by degrading toxic cationic organic dyes such as Methylene Blue (MB) and Malachite Green Oxalate (MG) under visible light. The mechanism of photocatalysis has been recommended which is based on the relative band structure of the semiconductor and integrated heterostructure. The formation of a spike barrier in the CB at the interface gives rise to trap sites that capture the migration of charge carriers and occurs recombination of electron-hole pair at higher Fe(III) doping concentration. The dark adsorption property of the catalysts sample has been also studied.

The structural, optical properties and underlying photophysical phenomena controlling the luminescence of PPy modified ZnO nanoplates are discussed in details here. Scanning electron micrographs reveal that the size of ZnO nanoplates prepared in presence of PPy decreases as compared to that of pristine ZnO. The crystallite size obtained from XRD for the PPy modified ZnO nanoplates also decreases as compared to that of pristine ZnO. O1s core level XPS spectra of ZnO synthesised in presence of PPy as well as pure ZnO show that oxygen vacancy in ZnO decreases in presence of PPy than that of pure ZnO. This in turn helps to reduce the visible emission and enhance UV emission from the ZnO nanoplates obtained in presence of PPy. The overall emission intensity of PPy modified ZnO samples decreases as compared to pristine ZnO. This indicates that apart from the modification of defect states of ZnO, different photophysical interactions like Forster Resonance Energy Transfer (FRET) as well as charge transfer also come into play to quench the overall luminescence of PPy modified ZnO.

This study employs oxidative polymerization, co-precipitation, and ex-situ surface capping techniques to fabricate pristine PMMA, ZnO, and PMMA-capped ZnO specimens with varying PMMA concentrations. X-ray diffraction reveals reduced directional growth of ZnO, while Fourier transform infrared spectroscopy confirms PMMA chain bonding with ZnO in PMMA-capped specimens. Scanning electron microscopy illustrates decreased average length and thickness of ZnO nanoplates post-surface modification, indicating a robust interaction between PMMA and ZnO. X-ray photoelectron spectroscopy identifies suppressed defects, including zinc interstitials and oxygen vacancies, affirming ZnO surface capping by PMMA. Absorption spectra display a blue shift in band-edge or increased bandgap, attributed to the combined effects of band alignment offset and reduced oxygen vacancy states. Luminescence spectra show gradual quenching linked to PMMA content increase, with defect-related emission suppression attributed to ZnO surface capping. UV emission suppression is ascribed to donor concentration-dependent Förster resonance energy transfer (FRET) from PMMA to ZnO. Photocatalytic tests reveal enhanced efficiency in PMMA-capped ZnO catalysts attributed to synergies involving charge separation, bulk recombination centers, oxygen vacancy states, and FRET. Efficiency improves with higher PMMA content, aligning with changes in emission intensity. The study demonstrates emission intensities' tunability through surface capping and donor concentration-dependent FRET, ultimately influencing degradation efficiency.

Electrodeposited nickel-carbon (Ni-C) nanocomposite thin films are found to have varying mechanical and tribological properties. Ni-C nanocomposites thin films of varying nickel content were synthesized by a simple electrodeposition method. Annealed thin films possess a relatively hard and adherent subsurface layer. In order to have an understanding of the mechanical and tribological characteristics of the subsurface layer, the relatively soft and fragile outer layer of the thin films was removed by scraping. The sp2 and sp3 bondings of carbon atoms in the thin films were explored by Raman spectroscopy. The Fourier-transform infrared spectra of the diamond-like carbon (DLC) and Ni-C thin films also consist of sp2 and sp3 hybridized carbon bonds. Nanocrystalline nickel nanoparticles distributed in carbon matrix were observed in Transmission electron microscopy study of the films. Decrease in coefficient of friction of the films is observed with increase in nickel content in thin films having DLC structure. The highest nickel content Ni-C composite thin film shows the maximum hardness of 7.6 GPa while the amorphous DLC thin film possesses the least hardness of 2.19 GPa. The subsurface layers demonstrate a clear demarcation of mechanical properties with unmodified overlayer pointing towards an extra care must be exercised before applying these electrodeposited coating on technological appliances.

Excitation wavelength-dependent visible emissions from ZnO nanostructures demonstrate that defect states are insufficient to explain their optical properties.

ZnO quantum dots (QDs) are potential candidates for high-efficiency emitters and photocatalysts. High efficiency demands high recombination of carriers, while high photocatalytic efficiency demands charge carrier separation. Here, we report an unexplored approach for achieving these opposite properties simultaneously by incorporating interface states in the ZnO QDs through a new strategy. We have used TEOS with Zinc acetate as synthesis precursors to prepare SiO2 encapsulated 5-6 nm ZnO QDs (ZnO@SiO2 QDs). X-ray photoelectron spectroscopy (XPS), FTIR and negative photoconductivity test confirmed the formation of interface states due to Zn - O - Si bonds between the SiO2 matrix and ZnO quantum dots. The ZnO@SiO2 QDs possess remarkable photocatalytic dye degradation properties, e.g., stability, efficiency and recyclability that outperform even the uncoated and commercially available ZnO beside high quantum yield varying between 46.1 % to 56.4 %, simultaneously. The photocatalytic mechanism has been further verified using the radical scavenger test. Thus, the work outlines designers' material design perspectives and discusses the detailed photophysical mechanisms for guiding the development of next-generation high-efficiency emitters and photocatalysts.

This article addresses the synthesis of Fe3+doped TiO2nanoparticles with variations of molar concentrations of Fe3+and their adequate use as potential photocatalysts for Photocatalysis applications. Synthesized photocatalysts were characterized thoroughly by different analytical techniques in terms of morphological, chemical, structural, crystalline, optical, electronic structure, surface area etc properties. The occurrence of red shift phenomenon of the energy band gap attributes to the transfer of charges and transition between the d electrons of dopant and conduction band (CB) or valence band (VB) of TiO2. The doping of Fe3+ions generates more trap sites for charge carriers with the surface trap sites. Thorough experimental conclusions revealed that the Fe3+ions necessarily regulate the catalytic property of TiO2nanomaterial. The obtained total degradation efficiency rate of Methylene Blue (MB) was 93.3% in the presence of 0.1 M Fe3+in the host material and for Malachite Green Oxalate the efficiency was 100% in the presence of 0.05 M and 0.1 M Fe3+in the host material. In both the cases the total visible light irradiation time was 90 min. The adsorption properties of the photocatalysts have been also performed in a dark for 90 min in the presence of MB dye. However, till now there are hardly reported photocatalysts which shows complete degradation of these toxic organic dyes by visible light driven photocatalysis. of potential values of valence and conduction band shows the production of active oxidizing species for hydrogen yield and the possible mechanism of the Schottky barrier has been proposed. A schematic diagram of visible light driven Photocatalysis has been pictured showing degradation activity of Fe3+-TiO2catalysts sample.

The role of Fo & BULL;rster resonance energy transfer (FRET) and charge transfer on controlling the overall luminescence of the nanocomposites based on PPy and ZnO is discussed here. Polypyrrole-ZnO (PPy-ZnO) nanocomposites have been synthesised with the variation of ZnO content (10 wt %, 30 wt % and 50 wt %) in the nanocomposite through chemical oxidative polymerization method. Nanowires of PPy and PPy-ZnO nanocomposites are observed from SEM and TEM images. The diameters of nanowires in PPy-ZnO nanocomposites are found to vary with ZnO content. Ordering in the polymer chain with the incorporation of ZnO is observed from XRD spectra. Red shift of the absorption peak of PPy in PPy-ZnO nanocomposites gives the evidence of increase in order of the polymer chain which in turn increases the singlet exciton diffusion through the polymer chain. Two photophysical phenomena i.e. FRET and charge transfer have significant impact on controlling the overall luminescence of the composites depending upon the ZnO content in the composite. At lower amount of ZnO (10 wt %), FRET occurs predominantly from defect states of ZnO to PPy and overall enhancement of luminescence is noticed. But no significant enhanced luminescence is observed when higher amount of ZnO is added to the composite. This happens due to dominant charge transfer between PPy and ZnO since they have type II band alignment. When the amount of ZnO is high in the composite, the interfacial area between PPy and ZnO get increased. XPS spectra reveals that ratio of polaron to neutral nitrogen in PPy chain also increases in the composite with higher amount of ZnO which results in the modification of band structure of PPy. Thus high interfacial area between PPy and ZnO as well as modification of band structure in PPy increases the rate of charge transfer between PPy and ZnO. Therefore, inspite of possibility of FRET, charge transfer occurs more efficiently in the nanocomposite when the ZnO content is high in the composite. This ultimately prohibits the radiative recombination of singlet exciton inside the composite with higher amount of ZnO. Hence the Photoluminescence (PL) intensity quenches considerably. Thus optimizing the amount of ZnO in the composite, the photophysical phenomena as well as luminescence of the composite can be controlled for the potential application of different optoelectronic devices like solar cell.

The development of a high-efficiency polymer light-emitting diode is strongly hindered by injected charge carriers in the emissive polymer layer. But real-time identification of the interactions that quench the photo-luminescence is extremely difficult owing to the complex photophysics of polymers involved in it. Here, we have synthesized the polyaniline nanotubes to study interactions at the nanoscale within the emissive layer. Acid doping of PAni helped us to quantify the processes that suppress the emission, e.g., Fo & BULL;rster resonance energy transfer (FRET) and charge transfer (CT). We have developed a material design perspective by demonstrating how an effective increase in conjugation length of PAni nanochain through 1D nanostructure growth can avoid the undesired emission quenching due to exciton quenching by the polarons. We have demonstrated how this approach helped us to preserve up to 95 % of the emission, which would otherwise be lost by exciton-polaron quenching interaction. Exploration of this new strategy could be a way forward for both fundamental and application aspects to enhance the emission efficiency of the conducting conjugate polymers and emissive layers in flexible polymer light-emitting diodes (PLEDs).

Synthesis of nanoparticles (NPs) is gaining attention as a cost-effective and environmentally acceptable alternative to remove the pollutant by facile photocatalysis process. Role of hydrothermal treatment on Zinc-oxide (ZnO) nanostructures were investigated using non-ionic surfactant diethanolamine (DEA). Further, in order to investigate the effect of DEA on morphological variation different concentration of DEA was used. The samples were thoroughly characterized by XRD, Rietveld analysis, FESEM and TEM to get insight idea about the ZnO structural and morphological properties. Moreover, XPS spectra reveal the variation of surface oxygen defects as hydrothermal treatment induced more defects to ZnO material. BET measurement reveals the alteration of surface area and pore size of ZnO sample. The surface defect-states (mostly oxygen vacancies) of the catalyst nanoparticles can influence the photocatalytic degradation of MB dye activated by ZnO nanoflowers via a non-radiative energy transfer pathway. A steady-state photoluminescence analysis validated the photoinduced electron transport from ZnO to MB dye. Steady state photoluminesence emission spectra established one to one correlation between the defects and colour emission from ZnO. Spectral overlap between donor (ZnO) to acceptor (MB dye) also enhanced greatly after hydrothermal treatment ascribing more Förster resonance energy transfer (FRET) which accelerates photocatalytic degradation efficiency of methylene blue (MB) dye under UV light irradiation. The defect-engineered ZnO nanoparticles synthesized through facile hydrothermal treatment led to an efficient decolourization of MB dye which was strengthened by FRET based on a correlation of photocatalytic degradation and defect mediated colour emission.

Anatase titania thin films were prepared by hydrothermal assisted sol-gel dip coating at two different hydrothermal temperatures: 90 °C and 180 °C for 12 h each. Some of the as-deposited films were annealed at 500 °C for 6 h. Both as-deposited and annealed films consisted of tiny spherical particles. Crystallite size and particle size increased with increased hydrothermal temperature and annealing. Atomic force microscopy showed that root mean square and average surface roughness increased with increased hydrothermal temperature and annealing. The prepared films exhibited almost zero transmittance in the violet-ultraviolet transition region with a gradual rise in the visible region up to a maximum value of ~40% at the near infrared. The transmission decreased for annealed films and as hydrothermal temperature was increased. Band gap values did not show any significant difference before and after annealing, although they decreased with increased hydrothermal temperature. Improved crystallinity and greater packing density at higher hydrothermal temperature and annealing led to a corresponding increase in the refractive index. The intensity of photoluminescence peaks was quenched when samples were annealed and as the hydrothermal temperature increased, because of annihilation of oxygen vacant states by the ambient oxygen. Improved crystallinity diminished the number of defect sites in the films, thus reducing the amount of radiative recombination of the e‒/h+ pair. Annealed samples and those prepared from sols processed at higher hydrothermal temperature showed better photocatalytic activity. The maximum degradation efficiency of 62.8% was demonstrated by annealed thin films prepared from sols hydrothermally processed at180 °C after 90 minutes of UV irradiation.

TiO 2 is considered a promising candidate for catalysis applications. The addition of acetic acid and its variation creates a strong bond with oxide surfaces, which generates various oxidizing agents. X-ray diffraction analysis of the prepared TiO 2 nanoparticles reveals their semicrystalline nature. The results show that holes are captured by the surface and subsurface, producing ≡ T i IV − O H . , ≡ T i IV − O . − − T i IV ≡ and the reducing agent = T i III − , which act as active oxidizers during photocatalysis, thus confirming the occurrence of an OH radical via an advanced oxidation process. Increasing the acetic acid amount leads to disordered structural defects below the conduction band (CB). X-ray photoelectron spectroscopy analysis shows the induction of hydroxylation of surface defects, such as Ti–OH. The results indicate that an oxygen vacancy is favourable due to a large number of surface defects. Detailed discussion of the energy band structure with the concept of a valence band (VB) and a CB maximum is implemented. The electron-withdrawing carboxylic group can affect oxygen vacancies and acetate ligands on the photocatalyst surface. The formation of a bidentate acetate adstructure with a lower acetic acid concentration leads to an explanation for higher visible-light-driven methylene blue degradation. The mechanism for the formation of an additional Ti–O–Ti bond by a condensation process is also illustrated elaborately. Theoretical calculations of the potentials of the VB and CB show the effects of active sites on degradation and can be associated with redox reactions for water splitting abilities. A possible model of sensitized photocatalysis for hydrogen production with hydrogen and oxygen evolution sites is also proposed in this article. Thus, TiO 2 nanoparticles with acetic acid variation are promising sources for photocatalytic/catalytic applications.

Pure ZnO and a group of Cu2+-ion-doped (4, 6, and 8 wt%) ZnO nanomaterials are synthesized using the co-precipitation technique. X-ray diffraction and Fourier transform infrared spectroscopy confirm both the substitution of Zn2+ ions by Cu2+ ions in the ZnO lattice and formation of the ZnO/CuO composite. The divalent oxidation state of Cu is confirmed using X-ray photoelectron spectroscopy. A suppression in the oxygen vacancy density is observed up to a doping level of 6 wt%, but beyond that it increases. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) show a cross-linked nanoflower-like structure. The presence of a separate CuO phase is also confirmed via TEM. Absorption spectroscopy yields a reduction in the bandgap up to 6 wt%, after which it is increased for 8 wt%. An enhanced plasmon band in the spectra reveals the presence of CuO. The photoluminescence is quenched for doping up to 6 wt%, and with further doping the emission is enhanced. These observations are explained by the doping-concentration-dependent Förster resonance energy transfer (FRET) phenomenon between the ZnO (donor) and the CuO (acceptor). For the highest doping concentration, the emission profile shows a sudden enhancement resulting from the simultaneous competition of two FRET mechanisms (the intra-acceptor mechanism and the inter-donor-acceptor mechanism). By contrast, for other doped nanomaterials, the inter-donor-acceptor FRET mechanism with doping-concentration dependence is able to explain the suppression of the emission intensity. All doped nanomaterials show an improved visible-light-driven photocatalytic efficiency compared with pure ZnO for methylene blue, which results from the synergistic effects of a reduction in the concentration of bulk defects, enhanced charge separation, and FRET. The highest photocatalytic performance is demonstrated by the 6 wt% nanomaterial due to its optimum doping concentration. However, beyond this concentration, the formation of excessive CuO on the surface of ZnO increases the concentration of bulk defects, and the simultaneous occurrence of the inter-donor-acceptor FRET and intra-acceptor FRET mechanisms takes place leading to the rapid recombination of electron-hole pairs and reduced photocatalytic activity.

The effects of surface modification on the defect state densities, optical properties, and photocatalytic and quantum efficiencies of zinc oxide (ZnO) nanoplates were studied in this work. The aim of this study is to identify the photophysical processes that dictate the quenching of emission from defect states upon surface modification and the role of different defects such as zinc interstitials (Zni) or oxygen vacancies (VO) beside the photophysical processes in determining the photocatalytic efficiency of plate-like ZnO nanostructures. For controlling the intrinsic defect state densities of ZnO nanoplates, which is difficult to achieve, their surface was modified using different polymers such as PMMA and PVA. X-ray photoelectron spectroscopy (XPS) and photoluminescence (PL) emission spectroscopy were employed to identify and quantify the defect states. The analysis of relative defect state densities of Zni or VO showed that Zni significantly impacts the photocatalytic activity (PCA) besides VO, but it has a lower influence than VO because of the difference in the accessibility and intrinsic nature of these two defects. Synchronous quenching of emission from different defect states with different formation energies and its correlation with the photocatalytic activity led us to conclude that photophysical processes such as concentration-dependent Förster resonance energy transfer (FRET), charge transfer (CT) and Zni defects play a significant role behind PCA, which has been previously reported to be influenced by VO only. FRET and CT also play a critical role behind emission quenching upon surface modification. Upon the surface modification of nanoplates, a drop in the quantum efficiency from 12.14% to 4.44% was observed with the fine-tuning of emission colour from bluish-white to blue. Besides the defect states, FRET and CT phenomena are dominant in reducing the quantum efficiency of hybrid light-emitting diodes (HyLEDs) and photocatalytic efficiency. Therefore, the work outlines the reason behind the suppression of luminescence and photocatalytic efficiency of ZnO nanoparticles after surface modification and how to optimise them for their applications as an emissive layer in HyLEDs and efficient photocatalysts.

Ni-TiO2 catalysts have been successfully developed by simple sol–gel techniques with variations in Ni2+ concentration. The reduced bandgap suggests the appearance of the intragap various localized defect states and oxygen vacancies. The formation of oxygen vacancies and its effect on photocatalysis with the presence of the colour centres (F, F+, F++) in the photocatalytic mechanism by replacement of anion vacancy and electron pair displacement are discussed. The low concentration (0.02 M) of Ni2+ doping represents a large amount of oxygen vacancy, which assures the high capability of visible light absorbance. The chemical reaction mechanism of oxidation/hydrogenation-induced photocatalytic behaviour through formation of Leuco-MB is also established. The design of anatase/rutile heterostructure and the proposed mechanism of Schottky induced charge transfer phenomenon under visible light irradiation are also embedded in our work. In comparison with many other early reports, our results show that the 0.02 M concentration of Ni2+ doping has an outstanding photocatalytic activity with complete decolouration with evolution of Leuco-methylene blue and thus obtained 100

H+ and Al3+ co-doped Polyaniline thin films have been synthesized by electropolymerization method with the variation of aluminium nitrate salt (Al2(NO3)3, 9H2O) into the electrolyte. FESEM, atomic force microscopy and UV–Vis-NIR spectrophotometry were used to characterize the nanostructured polyaniline thin films. FESEM showed nanowire like structures of the thin films. AFM study indicated an enhancement of surface roughness with increase in Al3+ concentration. Enhancement in photoluminescent emission was also observed with the increase of Al3+ amount into the electrolyte solutions. Supercapacitive behaviour of the films was investigated using cyclic voltammetry; areal capacitance showed an increasing trend with increase of Al3+ concentration. Electropolymerized PAni doped with Al3+ can be used as electrode materials for supercapacitor application.

TiO 2 photocatalysts were synthesized by facile sol–gel process with compensation of cetyltrimethylammonium bromide (CTAB). We report the influence of CTAB addition on morphological, electronic properties, stoichiometric and photocatalytic activity of anatase-enriched CTAB–TiO 2 . Here CTAB acts as a good surface modifier. Observed quenched photoluminescence (PL) intensity signifies high charge separation rate and reduced recombination probability of charge carriers. CTAB takes part in trapping electrons, which hinders the recombination of electron–hole pairs. X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy analyses show the formation of oxygen vacancies and Ti 3+ -defect states. These defect states are also confirmed from PL analysis. X-ray diffraction pattern reveals the increase of crystallinity of the catalyst sample on increasing CTAB amount in the TiO 2 matrix. The estimated decreasing nature of particle size of the samples claimed that agglomeration of particles was destroyed with addition of CTAB and the surface area increases accordingly. The broadening of XRD patterns for higher CTAB-assisted samples was attributed to the formation of point defects. Here, results show that the bridging oxygen vacancies and other defect states played a crucial role by interacting with water molecules and dissociation of the Ti-O bonds to form titanium ions. Photocatalytic activity of methylene blue degradation in UV light by varying catalyst loading was investigated. Kinetic modelling of degradation has been established in this study. Photodegradation of dye increases at higher amounts of catalysts due to the presence of more OH . radicals in the active sites.

Morphological and optical properties have been investigated for electrochemically deposited polyaniline (PAni) thin films on various substrates, having different transparent conducting oxides (TCO) layer viz. ITO and FTO. Different substrates have facilate the nucleation formation for the growth of nanostructures and control the length of the diameter of nanofibrils. Diameter of the nano-fibrils can facilate the transfer of ions and electrons and hence it affects the pseudocapacitor nature of thin films. Contact angle measurements of thin films depict that hydrophilic nature of PAni thin films also depend on different substrates. Moreover, morphology dependent electrochemical performances of PAni thin films were investigated using cyclic voltametry. Photoluminescence emission has shown pronounce effect due to the variation of substrate. PAni thin films can be used as supercapacitors by tuning their capacitance by varying substrate used as working electrode.