Simulated Solar Irradiance Research Articles

Offline Correction of CMIP6 HighResMIP Simulated Surface Solar Irradiance With 3D Sub‐Grid Terrain Radiative Effects

AbstractThe surface solar irradiance (SSI) is crucial for the land‐atmosphere processes and remarkably affected by the topography over the rugged areas. However, the Coupled Model Intercomparison Project Phase 6 (CMIP6) HighResMIP models adopting the parallel‐plane radiative scheme without considering the sub‐grid terrain solar radiative effects (3DSTSRE) overestimate the SSI in the rugged areas and the overestimation increases with the sub‐grid terrain complexity. To reduce the biases of the SSI simulations, this study offline corrects the SSI simulations of CMIP6 HighResMIP models by a 3DSTSRE scheme. Results show that the SSI biases produced by the HighResMIP models in the rugged regions can be significantly reduced by adopting the 3DSTSRE offline correction, and the improvements increase with the sub‐grid terrain complexity, indicating that considering the 3DSTSRE in the climate models to improve the SSI simulations over rugged areas is necessary.

Influences of Cloud Microphysics on the Components of Solar Irradiance in the WRF-Solar Model

An accurate forecast of Global Horizontal solar Irradiance (GHI) and Direct Normal Irradiance (DNI) in cloudy conditions remains a major challenge in the solar energy industry. This study focuses on the impact of cloud microphysics on GHI and its partition into DNI and Diffuse Horizontal Irradiance (DHI) using the Weather Research and Forecasting model specifically designed for solar radiation applications (WRF-Solar) and seven microphysical schemes. Three stratocumulus (Sc) and five shallow cumulus (Cu) cases are simulated and evaluated against measurements at the US Department of Energy’s Atmospheric Radiation Measurement (ARM) user facility, Southern Great Plains (SGP) site. Results show that different microphysical schemes lead to spreads in simulated solar irradiance components up to 75% and 350% from their ensemble means in the Cu and Sc cases, respectively. The Cu cases have smaller microphysical sensitivity due to a limited cloud fraction and smaller domain-averaged cloud water mixing ratio compared to Sc cases. Cloud properties also influence the partition of GHI into DNI and DHI, and the model simulates better GHI than DNI and DHI due to a non-physical error compensation between DNI and DHI. The microphysical schemes that produce more accurate liquid water paths and effective radii of cloud droplets have a better overall performance.

Alumina Nanoparticle Interfacial Buffer Layer for Low‐Bandgap Lead‐Tin Perovskite Solar Cells

AbstractMixed lead‐tin (Pb:Sn) halide perovskites are promising absorbers with narrow‐bandgaps (1.25–1.4 eV) suitable for high‐efficiency all‐perovskite tandem solar cells. However, solution processing of optimally thick Pb:Sn perovskite films is notoriously difficult in comparison with their neat‐Pb counterparts. This is partly due to the rapid crystallization of Sn‐based perovskites, resulting in films that have a high degree of roughness. Rougher films are harder to coat conformally with subsequent layers using solution‐based processing techniques leading to contact between the absorber and the top metal electrode in completed devices, resulting in a loss of VOC, fill factor, efficiency, and stability. Herein, this study employs a non‐continuous layer of alumina nanoparticles distributed on the surface of rough Pb:Sn perovskite films. Using this approach, the conformality of the subsequent electron‐transport layer, which is only tens of nanometres in thickness is improved. The overall maximum‐power‐point‐tracked efficiency improves by 65% and the steady‐state VOC improves by 28%. Application of the alumina nanoparticles as an interfacial buffer layer also results in highly reproducible Pb:Sn solar cell devices while simultaneously improving device stability at 65 °C under full spectrum simulated solar irradiance. Aged devices show a six‐fold improvement in stability over pristine Pb:Sn devices, increasing their lifetime to 120 h.

Portable solar-powered dual storage integrated system: A versatile solution for emergency

Increasing climate change-caused natural disasters calls for mobile self-powered backup solutions for rescue and survival. However, existing portable solar systems rely on single storage with high risk of suspension in emergency and prolonged cloudy period. This work presents a portable solar-dual storage system, which enables essential loads to function continuously regardless of weather. The system operates with a supercapacitor to buffer fluctuating solar power in the Direct mode, a battery-supercapacitor integration to enable extended low light load usage in the Off-grid mode, and a developed mode selector controller for overall energy management. Optimum size of the supercapacitor was determined to buffer the load and quickly recharge within the average low light period of 5–12 min. The simulated solar irradiance from 400-1000 W/m2 was utilized to verify automatic selection between two independent modes: direct and off-grid. Furthermore, outdoor behavior of the system has been investigated on a representative sunny, cloudy, and mixed day. Moreover, different combinations of DC and AC loads including an 80 W notebook with a power larger than the solar panel (20 W) have been demonstrated to function steadily for a few hours outdoor. This system’s signatures include manual mode selection possibility by users and automatic switching ability to a direct mode for when the battery is completely discharged or malfunction for continuous operation of the loads. This portable solar-powered system can be used in variety of scenarios and provides clean solar energy to essential electrical appliances for lighting, communication etc., thus increasing the chance of survival during emergency.

Investigation on photocatalytic activity of g-C3N4 decorated α-Fe2O3 nanostructure synthesized by hydrothermal method for the visible-light assisted degradation of organic pollutant

In recent decades, heterostructured photocatalysts have gained the great interest for their ability to possess higher photocatalytic activity. In this investigation, we synthesized g-C3N4 decorated α-Fe2O3 nanostructure by hydrothermal method to develop heterostructure. XRD, SEM, TEM, UV-DRS characterizations on the prepared sample revealed that g-C3N4 nanoparticles with 5–10 nm were decorated on the surface of the α-Fe2O3 spherical nanoparticles having the dimension of 50–100 nm. The designed g-C3N4@α-Fe3O4 heterostructure exhibit better photodegradation towards methyl orange under visible light exposure than pristine α-Fe2O3 with pseudo-first-order kinetics. The pseudo-first-order kinetic rate constant (k) for α-Fe2O3, and g-C3N4@α-Fe2O3, was determined to be 0.0171 min−1 and 0.02899 min−1, respectively. The g-C3N4@α-Fe2O3 exhibited greater photocurrent density than that of the α-Fe2O3 sample under simulated solar irradiance. In comparison with pristine α-Fe2O3 (83%), S-scheme g-C3N4@α-Fe2O3 heterostructure exhibited higher photodegradation efficiency (94%) since it had narrow bandgap energy, enhanced charged transportation, and reduced charges recombination owing to engineered heterostructure. The mechanism for the improved photodegradation efficiency of g-C3N4@α-Fe2O3 was discussed and found that O2– radicals participate a major function in the photodegradation of methyl orange dye, followed by OH− radicals. The designed g-C3N4 decorated α-Fe2O3 heterostructure may be a possible material for the treatment of textile effluents.

Photocatalytic degradation of imidacloprid in the flat-plate photoreactor under UVA and simulated solar irradiance conditions—The influence of operating conditions, kinetics and degradation pathway

This work reports the effectiveness of TiO2 photocatalysts modified by defect engineering methods. The prepared photocatalysts were characterized by X-ray diffraction (XRD), UV–Vis diffuse reflectance spectroscopy (DRS), photoluminescence (PL) measurements and electron spin resonance (ESR) technique. The immobilized photocatalyst layer was prepared using an abrasive material as a support and a mineral binder. To the best of our knowledge, this is the first time that such type of the immobilized photocatalytic layer has been prepared and tested. A home-made flat-plate photoreactor (FPP) with artificial light sources was used for the degradation of an aqueous solution of imidacloprid using an immobilized TiO2. The effects of different operating variables such as irradiation source, recirculation flow rate, irradiated surface area and photoreactor volume on the photocatalytic performances were investigated. The hydrodynamic behavior of the flat-plate photoreactor (FPP) was studied utilizing a residence time distribution (RTD) technique using the axial dispersion model. Based on kinetic measurements it was found that the photocatalytic degradation of imidacloprid under the conditions used in this study can be described by a complex kinetic model that follows pseudo-zero order kinetics at the beginning of the degradation, and with the progress of the reaction at higher irradiation times changes to the pseudo-first order. Liquid chromatography - quadrupole time‐of‐flight mass spectrometry (LC‐QTOF‐MS) was used to identify imidacloprid degradation by-products as a function of irradiation time. Theoretical modeling of the geometry and electronic structure of imidacloprid in aqueous solution was performed using density functional theory (DFT) calculation. Based on the results of theoretical simulations and experimental measurements, the possible pathway for photodegradation of imidacloprid in aqueous phase after irradiation with UVA was proposed and discussed.

A novel autothermal fluidized bed reactor for concentrated solar thermal applications

In the present study a novel directly-irradiated fluidized bed autothermal reactor (DIFBAR) for solar-driven chemical processing is presented. The reactor exploits the very concept of the autothermal reactor applied to multiphase flow of fluidized solids: a gas-solid suspension is preheated in a tubular riser prior to being exposed to radiative flux and further heated up in a concentrated solar receiver. Preheating is accomplished by solids leaving the receiver as they flow countercurrently in an annular dipleg coaxial to the riser. The dipleg may be designed so as to make the receiver section gas leak-tight with respect to the other zones of the reactor. An experimental campaign was performed under non-reactive conditions and at moderate radiative flux, hence moderate temperatures, with the purpose of demonstrating the feasibility and operability of the autothermal reactor, as a preliminary step toward a full proof-of-concept. Solids circulation rates and temperatures were measured as a function of the gas superficial velocity in the riser under given simulated solar irradiance. Infrared thermography was applied to further characterize multiphase flow and thermal patterns in the receiver. Experimental data were worked out to calculate the annulus-to-riser heat transfer coefficients. The reactor demonstrated excellent “autothermal” operation, thanks to very efficient heat transfer across the riser-annulus interface. Collection of solar energy was fairly good, with maximum thermal efficiency close to 70%, despite the design of the receiver was not specifically optimized to minimize radiative and convection losses. A preliminary analysis aimed at the scale-up of the autothermal reactor is presented. Altogether, results obtained are quite promising and stimulate further research on the development of reactors based on the proposed design for solar chemistry applications.

Assessment of Simulated Solar Irradiance on Days of High Intermittency Using WRF-Solar

Improvements in the short-term predictability of irradiance in numerical weather prediction models can assist grid operators in managing intermittent solar-generated electricity. In this study, the performance of the Weather Research and Forecasting (WRF) model when simulating different components of solar irradiance was tested under days of high intermittency at Mildura, a site located on the border of New South Wales and Victoria, Australia. Initially, four intermittent and clear case days were chosen, later extending to a full year study in 2005. A specific configuration and augmentation of the WRF model (version 3.6.1) designed for solar energy applications (WRF-Solar) with an optimum physics ensemble derived from literature over Australia was used to simulate solar irradiance with four nested domains nudged to ERA-Interim boundary conditions at grid resolutions (45, 15, 5, and 1.7 km) centred over Mildura. The Bureau of Meteorology (BOM) station dataset available at minute timescales and hourly derived satellite irradiance products were used to validate the simulated products. Results showed that on days of high intermittency, simulated solar irradiance at finer resolution was affected by errors in simulated humidity and winds (speed and direction) affecting clouds and circulation, but the latter improves at coarser resolutions; this is most likely from reduced displacement errors in clouds.

Hydrophobic lithiated titania floating film for efficient solar-driven water evaporation

Abstract Recently, the development of new photothermal materials for seawater desalination based on air–water interfacial solar heating has become a new research hotspot. In this paper, hydrophobic lithiated titania was synthesized by lithium reaction with amorphous titania followed by surface modification with a thin 1H,1H,2H,2H-perfluorooctyltrichlorosilane (PFOTS) monolayer. The hydrophobic lithiated titania was used as a photothermal material for seawater evaporation based on this new process. A thin lithiated titania floating film was assembled under simulated solar light irradiance due to the combined actions of water surface tension and the water molecules' thermal motion. The formation of the thin floating film significantly promoted water evaporation. The water evaporation rate by the lithiated titania floating film was 0.87 kg·m−2·h−1 under 2.0 sun solar irradiance, which was 2.4 times higher than that of pure water. Parameters affecting the solar evaporation process such as lithiated titania dose, solar light intensity, and storage time were investigated. Finally, the quality of the condensed fresh water was tested to evaluate the potential application of the lithiated titania floating film in practical settings of seawater desalinization.

Renewal of aerosol data for ALADIN-HIRLAM radiation parametrizations

Abstract. Radiative transfer calculations in numerical weather prediction (NWP) and climate models require reliable information about aerosol concentration in the atmosphere, combined with data on aerosol optical properties. Replacement of the default input data on vertically integrated climatological aerosol optical depth at 550 nm (AOD550, Tegen climatology) with newer data, based on those available from Copernicus atmosphere monitoring service (CAMS), led to minor differences in the simulated solar irradiance and screen-level temperature in the regional climate model HCLIM-ALARO simulations over Scandinavia and in a clear-sky case study using HARMONIE-AROME NWP model over the Iberian peninsula. In the case study, replacement of the climatological AOD550 with that based on three-dimensional near-real-time aerosol mass mixing ratio resulted in a maximum reduction of the order of 150 W m−2 in the simulated local solar irradiance at noon. Corresponding maximum reduction of the screen-level temperature by almost two degrees was found. The large differences were due to a dust intrusion from Sahara, which is obviously not represented in the average climatological distribution of dust aerosol. Further studies are needed in order to introdude updated aerosol optical properties of all available aerosol types at different wavelengths, make them available for the radiation schemes of ALADIN-HIRLAM and test the impact on the predicted radiation fluxes.

Model for the performance of photovoltaic systems

In this article, the future in photovoltaic energy productivity (PVE) is evaluated using climate variables simulated aerosol clearness index and solar irradiance, it is a model for the performance of photovoltaic systems. The analysis indicates that the aerosol emission reductions in the near future result in an increase in global warming with a significant response of the solar surface radiation and associated PVE productivity. Changes in radiation surface and productivity of solar PVE are related to overall reduction in aerosol effects on the circulation and large scale associated with cloud coverage pattern, rather than local atmospheric effects on optical properties. PVE evaluation is then discussed in the context of the current situation and the PV market highlighting the effects on productivity induced by industrial and public policies, while technological development are comparable to the effects related to the weather. The results presented encourage the improvement and further use of climate models in the assessment of future availability for renewable energy.

Scalable and low-cost synthesis of black amorphous Al-Ti-O nanostructure for high-efficient photothermal desalination

Sunlight provides us with enough renewable energy resource being potentially converted into heat for steam generation, residential water heating, desalination, and wastewater treatment, while the exploration of low-cost but high-efficiency photothermal materials still remains a grand challenge. We here reported a new Al-Ti-O nanostructure with tunable colors from gray to black, which couples the features of plasmonic effects in Al nanoparticles and high photoactivity in black TiO2, enabling the optimized black Al-Ti-O nanostructure shows a broad light absorption capability with almost covering 90.32% of solar spectrum. Inspiringly, the black Al-Ti-O hybrid were assembled into a microporous membrane that can naturally float on the surface of water for photothermal desalination application, manifesting a high efficiency of 77.52% for desalination under simulated solar light irradiance, as well as an outstanding durability upon continuous running. A solar seawater desalination system was designed and manufactured to demonstrate its potential for practical application, which can produce purified water with a rate of ~ 0.50kgm−2h−1, or ~ 4Lm−2day−1, given that the effective sunshine time is 8h per day under current solar irradiation (~ 820Wm−2). The numerous advantages in the present black Al-Ti-O hybrid, including high photothermal efficiency, viable scalable synthesis, and low cost, may build step stone for commercial solar desalination application.

Exoskeleton may influence the internal body temperatures of Neotropical dung beetles (Col. Scarabaeinae).

The insect exoskeleton is a multifunctional coat with a continuum of mechanical and structural properties constituting the barrier between electromagnetic waves and the internal body parts. This paper examines the ability of beetle exoskeleton to regulate internal body temperature considering its thermal permeability or isolation to simulated solar irradiance and infrared radiation. Seven Neotropical species of dung beetles (Coleoptera, Scarabaeinae) differing in colour, surface sculptures, size, sexual dimorphism, period of activity, guild category and altitudinal distribution were studied. Specimens were repeatedly subjected to heating trials under simulated solar irradiance and infrared radiation using a halogen neodymium bulb light with a balanced daylight spectrum and a ceramic infrared heat emitter. The volume of exoskeleton and its weight per volume unit were significantly more important for the heating rate at the beginning of the heating process than for the asymptotic maximum temperature reached at the end of the trials: larger beetles with relatively thicker exoskeletons heated more slowly. The source of radiation greatly influences the asymptotic temperature reached, but has a negligible effect in determining the rate of heat gain by beetles: they reached higher temperatures under artificial sunlight than under infrared radiation. Interspecific differences were negligible in the heating rate but had a large magnitude effect on the asymptotic temperature, only detectable under simulated sun irradiance. The fact that sun irradiance is differentially absorbed dorsally and transformed into heat among species opens the possibility that differences in dorsal exoskeleton would facilitate the heat gain under restrictive environmental temperatures below the preferred ones. The findings provided by this study support the important role played by the exoskeleton in the heating process of beetles, a cuticle able to act passively in the thermal control of body temperature without implying energetic costs and metabolic changes.

Influence of building surface solar irradiance on environmental temperatures in urban neighborhoods

For buildings located in actual urban neighborhoods, modeling of outdoor airflow with Computational Fluid Dynamics (CFD) requires solar radiation at building surfaces to predict local environmental temperatures. This study conducts a parametric analysis to support the development of coupled simulations of outdoor airflow and solar radiation simulations at building surfaces. To account for different assumptions used in the outdoor modeling, this study uses OpenFOAM CFD and couples it with three different simulation engines, including EnergyPlus, Daysim, and Radiance to predict simulated outdoor solar irradiance for implementation in outdoor CFD simulations. The primary aim of selecting these three simulation engines is to evaluate tradeoffs between the model complexity and accuracy for simulated outdoor solar irradiance for outdoor CFD simulations. Examined parameters include: (i) surface representation with different mesh types, (ii) urban plan area density, and (iii) the impact of simulated solar irradiances on the simulated air temperature and velocity values in the CFD simulations. The study results showed that the surface representation has up to a 7.6% and 133% influence on the simulated outdoor global and local solar irradiances, respectively. The surface thermal boundary conditions have up to 1.5°C difference on the air temperature and negligible impacts on the air velocity.

Preparation of Carbon Nanotube/TiO2 Mesoporous Hybrid Photoanode with Iron Pyrite (FeS2) Thin Films Counter Electrodes for Dye-Sensitized Solar Cell.

Multi-walled carbon nanotube (MWCNT)/TiO2 mesoporous networks can be employed as a new alternative photoanode in dye-sensitized solar cells (DSSCs). By using the MWCNT/TiO2 mesoporous as photoanodes in DSSC, we demonstrate that the MWCNT/TiO2 mesoporous photoanode is promising alternative to standard FTO/TiO2 mesoporous based DSSC due to larger specific surface area and high electrochemical activity. We also show that iron pyrite (FeS2) thin films can be used as an efficient counter electrode (CE), an alternative to the conventional high cost Pt based CE. We are able to synthesis FeS2 nanostructures utilizing a very cheap and easy hydrothermal growth route. MWCNT/TiO2 mesoporous based DSSCs with FeS2 CE achieved a high solar conversion efficiency of 7.27% under 100 mW cm−2 (AM 1.5G 1-Sun) simulated solar irradiance which is considerably (slightly) higher than that of A-CNT/TiO2 mesoporous based DSSCs with Pt CE. Outstanding performance of the FeS2 CE makes it a very promising choice among the various CE materials used in the conventional DSSC and it is expected to be used more often to achieve higher photon-to-electron conversion efficiencies.

Photoinjection of High Potential Holes into Cu5Ta11O30 Nanoparticles by Porphyrin Dyes

Excited-state hole injection into the valence band of Cu5Ta11O30 nanoparticles (NP-Cu5Ta11O30) was investigated through sensitization with zinc porphyrin dyes using simulated solar irradiance. The Cu5Ta11O30 nanoparticles were prepared by a flux-mediated synthesis and found to have an average particle size of ∼10–15 nm by DLS and TEM. The zinc 4-(10,15,20-tris(4-pyridinyl)-porphin-5-yl)phenylphosphonic acid (D1) and its analogue, in which the pyridine groups are methylated (D2), were synthesized and found to have excited-state reduction potentials appropriate for p-type dye sensitization of the nanoparticles. The dye-sensitized NP-Cu5Ta11O30 exhibited fluorescence quenching consistent with electron transfer from the NP-Cu5Ta11O30 to the dye; forward and recombination rates were obtained by transient absorption measurements. Hole injection times of 8 ps and <100 fs were observed for D1 and D2, respectively. Nanoparticulate films of Cu5Ta11O30 were prepared and evaluated in dye-sensitized solar cells under simulated solar irradiance (AM 1.5 G, 100 mW/cm2). Measurable photocurrents and open-circuit potentials (Voc) of 200 and 110 mV were observed using D1 and D2, respectively.

Estimation of atmospheric turbidity and surface radiative parameters using broadband clear sky solar irradiance models in Rio de Janeiro-Brasil

The main goal of this paper is to estimate a set of optimal seasonal, daily, and hourly values of atmospheric turbidity and surface radiative parameters Angstrom’s turbidity coefficient (β), Angstrom’s wavelength exponent (α), aerosol single scattering albedo (ω o ), forward scatterance (F c ) and average surface albedo (ρ g ), using the Brute Force multidimensional minimization method to minimize the difference between measured and simulated solar irradiance components, expressed as cost functions. In order to simulate the components of short-wave solar irradiance (direct, diffuse and global) for clear sky conditions, incidents on a horizontal surface in the Metropolitan Area of Rio de Janeiro (MARJ), Brazil (22° 51′ 27″ S, 43° 13′ 58″ W), we use two parameterized broadband solar irradiance models, called CPCR2 and Iqbal C, based on synoptic information. The meteorological variables such as precipitable water (u w ) and ozone concentration (u o ) required by the broadband solar models were obtained from moderate-resolution imaging spectroradiometer (MODIS) sensor on Terra and Aqua NASA platforms. For the implementation and validation processes, we use global and diffuse solar irradiance data measured by the radiometric platform of LabMiM, located in the north area of the MARJ. The data were measured between the years 2010 and 2012 at 1-min intervals. The performance of solar irradiance models using optimal parameters was evaluated with several quantitative statistical indicators and a subset of measured solar irradiance data. Some daily results for Angstrom’s wavelength exponent α were compared with Angstrom’s parameter (440–870 nm) values obtained by aerosol robotic network (AERONET) for 11 days, showing an acceptable level of agreement. Results for Angstrom’s turbidity coefficient β, associated with the amount of aerosols in the atmosphere, show a seasonal pattern according with increased precipitation during summer months (December–February) in the MARJ.

Preliminary Wrf-Arw Model Analysis of Global Solar Irradiation Forecasting

Abstract The purpose of this research is focused on the evaluation of short term global solar irradiation forecasting performance in order to assess the outcome of photovoltaic power stations. The paper presents a comparative analysis between the predicted irradiation obtained by numerical simulation and measurements. The simulation data is obtained from WRF-ARW model (Weather Research Forecasting-Advanced Research WRF), whose initial and boundary conditions are provided by the global forecasting model GFS. Taking into account the complexity of options for the physics models provided with WRF, we embarked upon a parametric analysis of the simulated solar irradiance. This complex task provides a better insight among the coupling of various physics options and enables us to find the best fit with the measured data for a specified site and time period. The present preliminary analysis shows that the accuracy of the computed global solar irradiance can be improved by choosing the appropriate built-in physics models. A combination of physics models providing the best results has been identified.

SEVO ON THE GROUND: DESIGN OF A LABORATORY SOLAR SIMULATION IN SUPPORT OF THE O/OREOS MISSION

This technical note describes a novel solar simulation experiment designed to mimic the solar radiation experienced by the Organism/Organics Exposure to Orbital Stresses (O/OREOS) nanosatellite in low-Earth orbit. Thin films of organic compounds within hermetically sealed sample cells (identical to the films and cells of the spaceflight mission) were exposed to simulated AM0 solar radiation in the laboratory for a total of 6 months, and monitored for spectral changes at two-week intervals. The laboratory experiment accurately simulated ultraviolet and visible solar irradiance to within 2% from 200‐1000 nm and the Ly! (121.6 nm) emission line radiation to within 8%. Design and calibration parameters for the experiment are discussed in detail for this ground-based laboratory irradiation experiment, which was built as a complement to, and as scientific validation of, the O/OREOS SEVO experiment in space.

Transparent front contact optimization in dye sensitized solar cells: use of cadmium stannate and titanium oxide by sputtering

A reliable transparent front contact of cadmium stannate (CTO) and titanium oxide (TiO2) entirely deposited by magnetron sputtering has been studied and applied to build standard dye-sensitized solar cell. CTO gives very high average optical transmittance (Tavg≥90%) along with competitive sheet resistance (Rsheet≤15 Ω/sq), while a very thin layer of TiO2 (thickness<5nm) acts as buffer layer to prevent charge recombination. The matched materials allow achievement of good performances of the cells, in terms of short circuit current and power conversion efficiency. UV-visible spectrophotometry, glancing incident X-rays diffraction and X-rays reflectivity techniques were used to characterize thin films before cell realization; sealed solar cells were tested under simulated solar irradiance at 1 Sun to determine functional properties.