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Electrodeposition (ED) from ionic liquid (IL) medium is of much importance because a variety of architectures can be synthesized by IL assisted growth. However, these liquids are relatively new for the fabrication of compounds and alloys with a great control over the stoichiometry and thickness. In this regard a well-defined route needs to be established for their wider acceptance as greener alternatives to deposit materials like CdTe, CdS, CdSe, etc. via ED. In this article, we have discussed the prerequisites, tricks and methodology to develop stoichiometric CdTe thin films from IL medium with required thicknesses in a highly controlled way compared to conventional ED techniques. This method provides a greener alternative to aqueous electrolytes which are considered to be hazardous media for the ED of CdTe films. We have found that the required precursor ratio of Te:Cd can be lower down to 1:10 for [Bmim]Cl IL medium which is 1:1000 for the aqueous electrolytes. As-grown nanostructured CdTe films can be directly utilized for the devices like IR sensors, Schottky rectifiers and Solar cells without any post-annealing. Moreover, the aspect ratio of nanostructures can be tuned by changing the precursors’ ratio in IL bath. Nevertheless, IL can be reused multiple times to develop identical thin films which guarantee the low cost pathway.

In this paper, we have studied the effect of nanocrystalline TiO2 functional layer on the performance of Si photodetectors. It was found that the electron affinity of the deposited TiO2 films is much lower (3.2 eV) than the conventional films of the value 3.9 eV. In addition, the band gap of these newly developed films was found to be 3.6 eV which makes the films transparent for band to band optical absorption. However, a very high absorption co efficient of the value 4.6 × 105 cm−1 and excitonic dissociation facilitate charge generation and transfer mechanisms in such films. It was found that the photodetector parameters like internal gain, response time, responsivity, detectivity, sensitivity and noise can be improved by inserting functional TiO2 layer to make either anisotype or isotype heterojunction with Si photodetectors. The major phenomena for such enhancements were found to be decrease in tunneling length and increased charge generation/transfer due to TiO2 nanocrystals. By this modified design, TiO2/p-Si hybrid device offer high responsivity of the value 23.07 A/W and detectivity of 4.5 × 1012 Jones for red light (620 nm) at an incident power of 1 mW/cm2. Furthermore, it was confirmed that faster devices with rise time of only 30 μs in broadband region from 425 to 620 nm can be made out of TiO2/n-Si configuration which allows slower diffusion of charge carriers. This study will provide a pathway to design ultramodern, highly responsive/sensitive and broadband Si photodetectors.

The extraction of petroleum fluids from sub-surface accumulations mandates the drilling of a well into the formation containing the accumulation. The drilling techniques have evolved over time to overcome several challenges while some of the issues still prevail with the currently used drilling practices like loss circulation, large tripping time to change bottom hole assembly, stuck pipe problems and low well bore stability, to name a few. These decrease the drilling efficiency and increase the Non-Productive Time (NPT) of this highly capital-intensive industry encouraging the Petroleum Industry to look for new technology. Casing while Drilling (CwD) is a technique of drilling which has been proven to alleviate many of the problems faced while drilling. In this method, drilling and casing of a well bore is carried out simultaneously, which improves the drilling efficiency by reducing the NPT. It has proven to be beneficial in controlling loss circulation and improving wellbore stability by ‘Plastering’ effect, high quality cement job and increased rig floor safety. It uses smaller rig and less fuel thereby reducing carbon footprint in the environment. This paper studies comprehensive well control and casing string design consideration. Economics encourages its application that has been discussed in the paper. A case study on the application of CwD in Malay basin for top hole drilling is presented. Finally, the paper briefly outlines the technical challenges that need attention to get better results from CwD. Keywords: Casing while drilling, Non productive time, Plastering effect, Well control

Transparent and flexible photodetector was realized by effective interfacial design methods. Silver nanowires (AgNWs) were networked onto a colorless polyimide (cPI) substrate to ensure the transparent conductive front electrode of Ni/ZnO/AgNWs/cPI photodetector. Under UV illumination, remarkable performances were obtained for quick responses (rise time = 0.987 ms and fall time = 2.49 ms) and ultrahigh responsivity (1.46 × 10 4 A/W). Due to the merit of AgNW-networks, an enhanced interfacial surface was established for the ZnO film, simultaneously providing efficiently short pathways for the collection of photo-generated carriers. The AgNWs-embedding Schottky photodetector gave an excellent noise equivalent power of 4.38 × 10 −15 W/Hz 1/2 , which is suitable for femtowatt-level photodetection. We demonstrate that the active adoption of metallic nanowires would provide high-degree of freedom for high-performing photoelectric devices with satisfying flexible and transparent features.

Transparent UV-photodetectors exhibiting very high responsivity and fast operation are discussed. Schottky contact photoelectric devices utilizing wide band gap TiO2 absorber layer were evaluated for their performances as UV-photodetectors. Three different work function metals Cu, Mo and Ni were used to realize Schottky barrier with TiO2. Ni Schottky contacts were found to be most suitable to fabricate high responsivity (2.034 A/W) photodetector with faster rise time (0.14 ms) and wide linear dynamic range (128 dB) operating at small applied reverse bias of −1 V. However, higher barrier height in the case of Mo/TiO2 interface resulted in lowest dark current density of the value 2.21×10−8 A/cm2 with quick fall time of 0.52 ms. The modulation of the barrier height would provide a route for designing fast and high responsive Schottky photodetector with broad linear dynamic range performance.

A record-high efficiency of 16.92% was realized by using microscale-patterned Si solar cells. Si microwire (SiMW) solar cells were designed to compare their performances with the standard flat-Si solar cell. The diameter and period of SiMWs were tuned to investigate the effects on the operation and the electrical properties of the solar cells. The highest efficiency SiMW solar cell has a width of 1.57 µm to provide the significantly enhanced efficiency of 16.92% from 10.15% of the flat-Si solar cell, due to the improved values of open circuit voltage (608 mV), short circuit current density (36.47 mA/cm 2 ) and fill factor (76.29%). Impedance spectroscopy and capacitance-voltage studies were carried out to obtain series and shunt resistances, built-in potential, acceptor carrier density, depletion width and flat band potential. Optical properties of SiMW solar cells were analyzed by external and internal quantum efficiencies. The carrier lifetime was measured by using open circuit voltage decay technique. Systematic analyses were performed to reveal the optical and electrical features of SiMW solar cells. These findings may provide efficient design schemes for high-performing solar cells using structured platforms.

We demonstrate the transparent Schottky photodetector of the configuration Cu/TiO 2 /FTO unveiling superior photodetection properties. The improved performance of fabricated photodetector was ascribed to high quality rutile-nanocrystalline TiO 2 films with very high absorption coefficient (~6×10 5 cm −1 ) and excitonic localized states. The existence of such localized states in TiO 2 Schottky device offered fastest response time of 1.12 ms suggesting their application in fast switching photodetectors. In addition, the photodetectors showed high responsivity of the value 0.897 A/W and detectivity 4.5×10 12 Jones. This transparent TiO 2 design would provide a functional route for various photoelectric device applications.

Electrodeposition (ED) from ionic liquid (IL) medium is of much importance due to a variety of architectures can be synthesized by IL assisted growth. However, these liquids are relatively new for the fabrication of compounds and alloys with a great control over the stoichiometry and thickness. In this regard a well-defined route needs to be established for their wider acceptance as greener alternatives to deposit materials like CdTe, CdS, CdSe, etc. via ED. In this MethodsX article, we have discussed the prerequisites, tricks and methodology to develop stoichiometric CdTe thin films from IL medium with required thicknesses in a highly controlled way compared to conventional ED techniques. This method provides a greener alternative to aqueous electrolytes which are considered to be hazardous media for the ED of CdTe films. We have found that the required precursor ratio of Te:Cd can be lower down to 1:10 for [Bmim]Cl IL medium which is 1:1000 for the aqueous electrolytes. As-grown nanostructured CdTe films can be directly utilized for the devices like IR sensors, schottky rectifiers and solar cells without any post-annealing. Moreover, the aspect ratio of nanostructures can be tuned by changing the precursors’ ratio in IL bath. Nevertheless, IL can be reused multiple times to develop identical thin films which guarantee the low cost pathway. • Nanostructured CdTe thin films • Low cost • Reuse of ionic liquid

In this data in brief (DIB) article, major photodetector (PD) characteristics of anisotype (Ag/n-TiO2/p-Si/Al), isotype (Ag/n-TiO2/n-Si/Ag) and M-S-M type (Ag/p-Si/Al) structures under reverse bias conditions (−1 to −5 V) over a broad spectral region (300–800 nm) have been presented. Critical figures of merit like current-voltage (IV), responsivity (R), detectivity (D), gain, sensitivity (S), linear dynamic range (LDR), normalized photo to dark current ratio (NPDR) and noise equivalent power (NEP) of TiO2 embedded Si PDs are presented in graphical forms. I–V characteristics of PDs under dark and monochromatic illuminations (365, 425, 515 and 600 nm) were acquired by using source measure unit (Kithley). Internal gain was deduced from photoresponse spectra which were recorded with the help of Potentiostat/Galvanostat (PGSTAT302N, Autolab) under monochromatic illumination at 100 Hz chopping frequency. Quantum efficiency instrument supplied by Optosolar was utilized to accurately measure the spectral responsivity and detectivity of PDs in wide spectral region (300–1100 nm). Please refer our main article [1] to understand the role of functional nanocrystalline TiO2 films on the performance of the photodetectors.

A semitransparent CuO film was applied for photoelectrochemical (PEC) cell to produce the record-high photocurrent (6.4 mA/cm2) for nanocrystalline monoclinic CuO photocathode. Large-scale affordable reactive-sputtering method was effectively formed Cu oxide films and sequential thermal processes efficiently controlled the Cu oxide phases with enhanced optical-transparency of Cu oxide films. Structural, physical, optical, and electrical properties of various Cu oxide films (CuO, Cu4O3, and Cu2O) were systematically investigated according to the sputtering condition and thermal processes. It was found that the energy band gap of CuO can be tuned from 1.7 to 1.9 eV by modulating the oxygen flow for reactive sputtering. Mott–Schottky analyses revealed the flat band potential close to the 0.96 V versus reversible hydrogen electrode and energy band edges of Cu oxide films. This state-of-the-art CuO photocathode would provide a strong potential for wide applications of the transparent PEC system of on-site energy generation.

Diversion of treatment fluid is the major attribute of successful refracturing treatment. This paper provides a comprehensive review of near wellbore and far-field diversion application and the selection parameters of chemical particulate diverters during refracturing treatment. Furthermore, this paper highlights laboratory tests for the performance evaluation and monitoring techniques during the treatments. The case studies are presented to support the concept and to demonstrate recent developments, challenges and future scope of improvement. Significant insight into the diversion technology and the guidelines for its successful application are provided to help engineers to increase the effectiveness of refracturing treatment.

The passive frequency Filters are mainly made up of ceramics or piezoelectric materials that are mainly used in receivers, mixers and radio transmitters. Very limited studies have been done to obtain filters by a simple configuration of R-C elements which are the basis of these devices. In this study, 2 component passive filters were realized by using the Schottky junction between FTO and CdTe nanostructured thin film. CdTe nanostructured thin films were directly deposited on FTO substrate via electrodeposition from ionic liquid medium. A simple configuration of Cu : FTO : CdTe : Cu was utilized to attenuate the frequencies from 7 kHz to 0.7 MHz. Interestingly we have found that by changing the dimensions of CdTe nanostructures, the cut off frequency as well as band width of such filters can be varied. This study is first of its kind which shows the direct relationship between dimension of CdTe nanostructures and their frequency response

In this study, we have used impedance spectroscopy to understand the current mechanisms in photovoltaic cells of non-stoichiometric PbOx/Au-Pd. Potential pulse anodization technique was used to synthesis PbOx films which also enabled nanowall assemblies all over the substrate. The first ever solar cells of PbOx showed an overall efficiency of 0.38% with a high open circuit voltage of 0.7 V and short circuit current density of 2.04 mA/cm2 for 10 nm thick Au/Pd Schottky contact. However, the device suffered with a low fill factor of 26% and DC analysis only gave an approximate idea about the physical phenomena behind it. Impedance spectroscopy is an important tool to analyze critical and complex interfaces either of solid-liquid or solid-solid interfaces. In this technique, a small A.C. signal is applied over the scanned potential range to perturb the junctions. After fitting an appropriate distributed circuit model to the recorded data and variation of each element of the circuit was plotted against applied bias. With the use of this tool, we were able to understand the charge transport at each and individual interface of the device and hence to know about the shunting sites which hindered the performance of the cell. The variations of various interfacial resistances and capacitive loads have been discussed in detail to understand the functioning of the device. This study will be helpful in determining the loads in the actual devices and work upon it to improve the overall efficiency of the solar cells. Figure 1

In this study, we have fabricated type-I straddling gap heterojunction solar cells of Ag/CuOx/TiO2/FTO configuration utilizing extremely thin p-n junction of 150 nm. We have studied four unique devices by varying the oxygen vacancies in CuOx and its effect on the overall performance of the cells. The average transmittance of 28–52% made these devices semitransparent for visual perception and transparent for visible spectrum of the Sun. The solar cell characteristics were recorded for 365 nm UV light which showed a linear increase in open circuit voltage (Voc) from 0.266 to 1.01 V while changing CuOx phases from Cu2O to CuO. However, a non-linear trend was observed for the photocurrent density and that has been discussed in detail by considering both material and device aspects. The optimized solar cell with CuO active layer possessed Voc of 1.01 V with 3.48 mA/cm2 current density and fill factor (FF) of 31% which sums up to an overall efficiency of 16.22% for an input power of 7 mW/cm2. The electrical parameters of solar cells were analyzed by using a two-diode model and the influence of TiO2 buffer layer has been discussed by the charge transfer mechanisms using the band diagrams. It was found that CuO/TiO2 device offered highest efficiency due to large Δ E c which increased the tunneling probability of minority charge carriers and reduced the recombination process at the interface. This study is the first experimental report on CuOx/TiO2 heterojunction solar cell which may find applications to design fancy and semitransparent power generating windows with colors yellow to brown by varying CuOx stoichiometry.

Specific adsorption of ions of ionic liquids on an electrode plays an important role in controlling the mass and/or charge transport phenomena in electrochemical techniques. Insufficient experimental evidences put limit on wider acceptance and usage of ionic liquids in the field of energy devices. In the present study, two different photoelectrochemical cells (PECs) having configurations as (i) PbOx/Fe(CN)6 -4/-3/Pt and (ii) PbOx/[Bmim]Tf2N/Pt were utilized to provide the experimental pathway and to unveil the adsorption characteristics of ion-pairs of any ionic liquid. The photoresponse curves of PECs under chopped light illumination conditions were used to extract the flatband potential of PbOx film. The band edge positions and electron affinity of PbOx films were calculated with the help of Mott-Schottky plots. It is well known that the adsorption properties of electrolytes can be understood by calculating the point of zero charge (pHpzc). Hence, this parameter was calculated by analyzing the temperature dependent flatband potential which further unveiled the adsorption characteristics of ionic liquids. This study is an unexplored approach to get closer to the understanding of inherent properties of ionic liquids which can be of utmost interest to either basic or applied field researchers.

We report a one-pot, surfactant-free and catalyst-free electrochemical synthesis of CdTe spindle like nanostructures directly on the substrate from a single ionic liquid electrolytic bath. The growth mechanism of CdTe nanostructures is revealed by investigating the structural growth in different deposition time domains. The physical dimensions of CdTe nanostructures were varied by changing the Te : Cd ratio in the bath and maintaining 1 : 1 stoichiometry of Te : Cd in the growing thin film. Maintaining the stoichiometry is necessary for its use in the solar photovoltaic devices. A simple configuration Cu:FTO:p-CdTe:Cu was utilized to study the impact of CdTe structures on the electrical properties of the diode. The I–V measurements and admittance spectroscopy revealed that the electrical properties of the diode improve systematically by increasing the diameter and length of the CdTe nanostructures. We also show efficient reuse and optimized use of the ionic liquid for the electrodeposition of CdTe nanostructures.

In this data in brief (DIB) article, major photodetector (PD) characteristics of anisotype (Ag/n-TiO2/p-Si/Al), isotype (Ag/n-TiO2/n-Si/Ag) and M-S-M type (Ag/p-Si/Al) structures under reverse bias conditions (−1 to −5 V) over a broad spectral region (300–800 nm) have been presented. Critical figures of merit like current-voltage (IV), responsivity (R), detectivity (D), gain, sensitivity (S), linear dynamic range (LDR), normalized photo to dark current ratio (NPDR) and noise equivalent power (NEP) of TiO2 embedded Si PDs are presented in graphical forms. I–V characteristics of PDs under dark and monochromatic illuminations (365, 425, 515 and 600 nm) were acquired by using source measure unit (Kithley). Internal gain was deduced from photoresponse spectra which were recorded with the help of Potentiostat/Galvanostat (PGSTAT302N, Autolab) under monochromatic illumination at 100 Hz chopping frequency. Quantum efficiency instrument supplied by Optosolar was utilized to accurately measure the spectral responsivity and detectivity of PDs in wide spectral region (300–1100 nm). Please refer our main article [1] to understand the role of functional nanocrystalline TiO2 films on the performance of the photodetectors.

Ionic liquid based electrolytes are gaining great interest in the field of photoenergy conversion. We have found that the ionic liquids namely BMIm Cl, BMIm PF6 and BMIm Tf2N inherently offer redox activity. The device performance of the photoelectrochemical (PEC) cells of the configuration PbOx (0.25 cm(2))|blank ionic liquids|platinum (2 cm(2)) was analyzed in detail to get insights into the working principle of such systems. It was found that partially reversible redox ion pairs diminish the performance of such cells as power generating devices. The partial redox activity of the ionic liquids was confirmed by a number of observations derived from the PEC spectra. The important parameter, Vredox, which determines the performance of any PEC cell was also calculated for all the ionic liquids. The difficulties that arise in high frequency C-V measurements for ionic liquid systems were overcome by choosing the appropriate probing frequency. The evaluated Vredox of BMIm Cl, BMIm PF6 and BMIm Tf2N ionic liquids was found to be -0.30, -0.20 and -0.78 V (vs. NHE), respectively. This study will be beneficial to understand the role of ionic liquids as redox active electrolyte media in several applications.

In this paper, we have shown a complete methodology to scrutinize the electrodeposition of stoichiometric and nanostructured CdTe thin films from an ionic liquid bath, namely 1-butyl-3-methylimidazolium chloride ([Bmim]Cl). A detailed cyclic voltammetric study using paused potentials has been carried out to identify various redox processes of an unknown complex system. As-deposited 1 μm CdTe films possessed spindle like nanostructures of cubic phase and very high absorption coefficient of 6 × 10 4 cm −1 . Looking at the cost of ionic liquids, we have suggested a way-out procedure to reuse the ionic liquid without any recycling. A miniature ionic liquid bath of 5 mL having only 1:10 (Te:Cd) precursor concentration can be utilized for fabricating four identical 0.5 cm 2 CdTe thin films of 1 μm thickness by applying −1.65 V (vs. Fc/Fc + ) at 80 °C. The reuse of ionic liquid decreases deposition time in 4th run to only 555 s, which is the shortest deposition time from any electrolytic bath till date. The bottleneck in adopting ionic liquids for commercial use lies in their cost and this crucial issue was dealt with a simple idea proposed in the present work. This study will be important to open up a new era of “Green” and low cost alternatives to develop nanostructured thin films of any compound material for their utilization in modern photoelectric devices.

Since the beginning of the era of third generation solar cells, researchers are motivated to explore varioussemiconductor-metal con“gurations for the ecient solar energy conversion. We “rst time report the use ofnon-stoichiometric PbO x electrodes in the Schottky junction solar cell. This metal oxide makes an ecientSchottky junction with the high work function alloy of Au-Pd. It was found that thin “lms of anodized leadmetal prepared via potential pulse technique result in the nanowall assemblies. When a few nanometer layer ofAu-Pd was sputtered on these assemblies, we obtained a core-shell Schottky junction solar cells of PbO x /Au-Pd.With these newly developed structures, we obtained highest J sc of 2.04 mA/cm 2 with V oc of 707 mV achievingan overall ec iency of 0.384%. The performance of solar cell was assessed by D.C. and A.C. techniques. Anequivalent circuit model is also presented for understanding the charge transfer mechanisms in such solar cells.Keywords: Schottky junction solar cell, PbO

One dimensional superstructures are of great interest in the field of optics, opto-electronics and photonics. Over a period of time, researchers have developed various new and low cost techniques to prepare nanostructures of metals as well as semiconductors. We found that ionic liquid can be used to synthesis nanostructured film directly on the substrate by means of electrodeposition. It was found that spindle like CdTe superstructure assemblies over the commercial F:SnO 2 substrate gives a Schottky junction, resulting in the highest rectification ratio of 6000. It was also possible to manipulate the dimensions of structures by changing the precursor molar ratio in the ionic liquid bath. It was observed that by varying the structure size, electrical properties of the diodes improve significantly. The admittance measurements reveal that by increasing the length and diameter of the structures, the conductance of the diode increases linearly. We believe that proper arrangement of the fabricated CdTe thin films will find many applications in near future.

An intensive electrochemical impedance study was carried out to understand the charge-transfer processes in photoelectrochemical (PEC) cells based on ionic liquid (IL) electrolytes. Three different electrolytes were utilized to understand the role of redox species as well as the medium on the charge-transfer mechanism. The negligible diffusion resistance, despite the presence of two different redox species in the case of Fe(CN)(6) (-4/-3) in IL, was explained on the basis of charge transfer between species of two different redox couples. Accordingly, the redox species are not required to travel through the bulk of the electrolyte for the removal of accumulated charges, as short-range charge transfer between the IL and the Fe(CN)(6) (-4/-3) species facilitates the removal of accumulated charges. It is also shown that PEC cells utilizing dual redox couples are highly stable with larger photoelectrochmeical windows, >3 V.

In this paper, we have carefully investigated the operation of a photoelectrochemical (PEC) cell configured of PbOx|Fe(CN)6(-4/-3)|Pt in the accumulation, flat band, depletion, inversion and deep-depletion regions using impedance measurements. The increases in the photocurrent for the different regions differ in their nature: a logarithmic increase in the depletion region, a linear increase in the inversion region along with a linear increase in the dark current and an exponential increase in the photo- and dark current in the deep-depletion region. All these variations are studied in detail to correlate these observations to the charge transfer mechanisms. The characteristics of the impedance spectrum itself can be assigned to the mentioned regions. We have found that the maximum photocurrent of the PEC cell, in the present investigation, can be extracted when the cell is working in the inversion region, while the maximum rate of the increase in photocurrent is found when the junction behaves as an ideal Schottky diode with a single RC element. Systematic experiments are suggested to establish a correlation between the observations obtained from the photocurrent, impedance, conductance, low frequency and high frequency capacitance measurements. It was found that light induced trap states in the semiconductor limit the photocurrent which has a linear dependency on the irradiance. A detailed investigation with A.C. conductivity measurements showed that the trap states actively participate in the current mechanism via a hopping phenomenon with small activation energies of 0.2 and 0.8 meV. The hopping rate increased exponentially with the applied bias under dark and illumination conditions. We also show a new way of finding the potential at which the maximum photocurrent will be extracted from the PEC cell, wherein the hopping via trap states is a dominating charge transfer mechanism. This study will help in pin pointing the key affecting parameters which limit the charge transfer process in the cell.

An optically transparent and electrically conductive p-NiO layer was deposited on a conventional n-Si/p-Si solar cell, which improved the device performance. The transmittance and reflectance properties of the p-NiO layer were found to be much better than the SiNx layer in the visible light region. Impedance spectroscopic study under varying bias and illumination conditions was carried out to understand the underlying mechanisms governing the device performance. An AC signal analysis revealed that the p-NiO layer acted as a front surface field region for majority charge carriers. In addition, the p-NiO layer significantly improved Si solar cell performances due to the improved properties of parasitic resistances. The optically transparent NiO layered Si device (p-NiO/n-Si/p-Si) spontaneously enhanced the electrical properties, resulting in the substantially improved fill factor value of 74% from 34.3% of the bare n-Si/p-Si device. The existence of a front surface field increased the lifetime of carriers to 92 μs for the p-NiO/n-Si/p-Si solar cell compared to only 43 μs for an n-Si/p-Si cell. We may suggest a functional NiO layer to the efficient designs for Si solar cells.

The 2D nanostructures are gaining lot of interest in the field of electronics and solar photovoltaics. We have recently developed new shape and architecture of CdTe nanostructures on low cost F:SnO2 (FTO) substrate by electrodeposition from ionic liquid medium. It was observed that the ionic liquid medium facilitate the fabrication of nanostructured thin film directly on the substrate. By using two different substrates, FTO and CdS coated FTO it was possible to fabricate Schottky and p-n junction solar cells out of developed CdTe nanostructured films. It was interesting to observe that the Schottky junction solar cells of such nanostructured films result in higher Voc of 805 mV which is a quite high value for such solar cells. However, low connectivity between nanostructures resulted in lower Jsc values. On the other hand we found that the growth of semiconductor films from ionic liquid medium is highly substrate dependent. It was found that stoichiometric CdTe films can only be deposited on 50 nm thick film of CdS. Increasing the thickness of CdS layer always lead to non stoichiometric CdTe films which no longer can be utilized in solar cells. The first ever successful deposition of stoichiometric CdTe film on CdS buffer layer resulted in a solar cell with Voc of 150 mV, Jsc of 500 μA/cm2, FF of 27% and efficiency of 0.02%. This initial study will be helpful in understanding the growth of binary alloy on different substrates from ionic liquid medium. Figure 1

A simple, low cost and reproducible way of fabricating solid state Schottky junction solar cells utilizing non-stoichiometric PbOx films is discussed for the first time. A high work function metal alloy of Au-Pd was used to realize the non linear junction characteristic. We found a noticeable difference in the performances of devices made out of PbOx films prepared via potentiodynamic and potential pulse techniques where the required thicknesses of Au-Pd alloy for the optimum performance of the devices were found to be only 1 and 10 nm respectively. With the potential pulsed PbOx/Au-Pd cell, we achieved highest Jsc of 2.04 mA cm−2 with Voc of 707 mV giving an overall efficiency of 0.384% . All the electrical parameters were derived from the analysis of dark I-V, C-V and ρ-T measurements.