WE PROPOSE THE SYNTHESIS OF ?-TRIKETONATE COMPLEXES OF ZN(II) AND CU(II) AS PRECURSORS IN THE PHOTO-DEPOSITION OF ZNO FILMS LOADED WITH CUO, WHICH ARE SUBSEQUENTLY CALCINED AT 600 ?C. THE ZNO/CUO HETEROJUNCTION SYSTEM WAS ANALYZED BY XRD, SEM AND XPS; THE RESULTS DEMONSTRATE LOW CRYSTALLINITY OF THE FILMS AND THE FORMATION OF ZNO AND CUO. THE RESULTS OF OPTICAL PROPERTIES CONFIRM A GRADUAL REDUCTION OF THE OPTICAL BANDGAP WHEN CUO LOADING IS INCREASED IN THE ZNO MATRIX AND THE PHOTOLUMINESCENCE TESTS FOUND A DECREASE IN THE EMISSION BANDS OF THE ZNO MATRIX WITH THE INSERTION OF CUO. THE MAXIMUM PHOTO-DEGRADATION EFFICIENCY IS ACHIEVED FOR ZNO FILMS LOADED WITH CUO AT 1 MOL%, OBTAINING 75.4 AND 68.3% FOR RHODAMINE B AND RHODAMINE 6G, RESPECTIVELY. WE PROPOSE THAT ZNO IS RESPONSIBLE FOR THE FORMATION OF SUPEROXIDE RADICALS AS THE MAIN REACTIVE SPECIES IN THE DEGRADATION OF BOTH RHODAMINES.

ZNAL2O4 AND MGAL2O4 THIN FILMS WERE GROWN ON SI(100) AND QUARTZ PLATE SUBSTRATES USING A PHOTOCHEMICAL METHOD IN THE SOLID PHASE WITH THIN FILMS OF BETA-DIKETONATE COMPLEXES AS THE PRECURSORS. THE FILMS WERE DEPOSITED BY SPIN-COATING AND SUBSEQUENTLY PHOTOLYZED AT ROOM TEMPERATURE USING 254 NM UV LIGHT. THE PHOTOLYSIS OF THESE FILMS RESULTS IN THE DEPOSITION OF METAL OXIDE THIN FILMS AND FRAGMENTATION OF THE LIGANDS FROM THE COORDINATION SPHERE OF THE COMPLEXES. THE OBTAINED SAMPLES WERE POST-ANNEALED AT DIFFERENT TEMPERATURES (350?1100 °C) FOR 2 H AND CHARACTERIZED BY FT-INFRARED SPECTROSCOPY, X-RAY DIFFRACTION (XRD), X-RAY PHOTOELECTRON SPECTROSCOPY (XPS), ATOMIC FORCE MISCROSCOPY (AFM), AND UV?VIS SPECTROSCOPY. THE RESULTS INDICATE THE FORMATION OF SPINEL-TYPE STRUCTURES AND OTHER PHASES. THESE CHARACTERISTICS DETERMINED THE QUALITY OF THE FILMS, WHICH WERE OBTAINED FROM THE PHOTODEPOSITION OF TERNARY METAL OXIDES.

IN THIS ARTICLE, WE PROPOSE A SIMPLE PHOTOCHEMICAL METHOD TO SYNTHESIZE PURE LA2TI2O7 FLMS AND LA2TI2O7 FLMS DOPED WITH SILVER AT 1.0, 3.0, AND 5.0 MOL%. AFTER ANNEALING THE PHOTO-DEPOSITED FLMS AT 900 °C, XRD, SEM, AND XPS ANALYSES SHOWED THE FORMATION OF A MONOCLINIC LA2TI2O7 PHASE AND THE PRESENCE OF AG AND AGO IN DOPED SAMPLES. PHOTOCATALYTIC TESTS FOR CONGO RED DEGRADATION DEMONSTRATED THAT PURE LA2TI2O7 ACHIEVED 25.4% DEGRADATION, WHILE DOPED SAMPLES REACHED A MAXIMUM OF 92.7% DEGRADATION. MOREOVER, INCREASING SILVER DOPING ON LA2TI2O7 FLMS SIGNIFCANTLY REDUCED THE GROWTH OF STAPHYLOCOCCUS AUREUS, INDICATING POTENTIAL ANTIBACTERIAL PROPERTIES. THE ENHANCED PHOTOACTIVITY WAS ATTRIBUTED TO THE FORMATION OF A TYPE I HETEROJUNCTION BETWEEN LA2TI2O7 AND AGO, AND A DEGRADATION MECHANISM WAS PROPOSED BASED ON CONGO RED DEGRADATION.

THIS STUDY REPORTS THE ANTIBACTERIAL ACTIVITY OF AN OLIGOSACCHARIDE, PREPARED BY PARTIAL ACID HYDROLYSIS OF A NATIVE PAECILOMYCES SP. EXOPOLYSACCHARIDE, AND OF ITS AMINOGLYCOSYLATED DERIVATIVE, PREPARED BY REDUCTIVE ALKYLATION OF THE OLIGOSACCHARIDE, AGAINST E. COLI AND S. AUREUS.

IN THIS STUDY, WE EVALUATED THE PHOTOCATALYTIC EFFICACY OF PURE Y2TI2O7 FILMS INCORPORATING VARYING AGO RATIOS (1.0, 3.0, AND 5.0 MOL%) IN THE DEGRADATION PROCESS OF BRILLIANT GREEN DYE AND IN THE BACTERIAL DISINFECTION OF ESCHERICHIA COLI UNDER UV?VISIBLE ILLUMINATION. THE FILMS WERE PREPARED UTILIZING A PHOTOCHEMICAL METHODOLOGY INVOLVING ?-DIKETONATE COMPLEXES OF Y(DBM)3, TI(DBM)4, AND AG(ACAC) AS STARTING MATERIALS. FOLLOWING SYNTHESIS, THE PHOTO-DEPOSITS UNDERWENT CALCINATION AT 900 °C FOR 2 H AND WERE SUBSEQUENTLY ANALYZED USING FOURIER TRANSFORM INFRARED SPECTROSCOPY, X-RAY DIFFRACTION, SCANNING ELECTRON MICROSCOPY - ENERGY DISPERSIVE X-RAY SPECTROSCOPY, AND X-RAY PHOTOELECTRON SPECTROSCOPY. THE OUTCOMES OF THESE CHARACTERIZATIONS INDICATE THE FORMATION OF A PYROCHLORE Y2TI2O7 CUBIC PHASE, WITH THE EMERGENCE OF AGO IN THE DOPED SAMPLES. PHOTOCATALYTIC PERFORMANCE YIELDED SIGNIFICANT RESULTS, WITH A 94.9 % DEGRADATION OF BRILLIANT GREEN OBSERVED FOR Y2TI2O7 SAMPLES DOPED AT 3.0 MOL%, AND A 98.4 % INHIBITION OF ESCHERICHIA COLI CULTURES OBSERVED FOR Y2TI2O7 SAMPLES DOPED AT 1.0 MOL%. THEORETICAL CALCULATIONS WERE EMPLOYED TO DETERMINE THE BAND EDGE POTENTIALS OF BOTH OXIDES, SUPPORTING THE ESTABLISHMENT OF A TYPE I HETEROJUNCTION BETWEEN THE Y2TI2O7 PHASE AND AGO. A DEGRADATION MECHANISM HAS BEEN POSTULATED BASED ON ASSAYS INVOLVING THE BLOCKING OF REACTIVE OXYGEN SPECIES AND CHARGE CARRIERS THROUGH THE USE OF SPECIFIC

PURE AND 10% PT-LOADED ZINC OXIDE THIN FILMS HAVE BEEN SUCCESSFULLY PREPARED BY DIRECT UV IRRADIATION OF BIS(?-DIKETONATE)ZINC(II) AND PT(II) PRECURSOR COMPLEXES SPIN-COATED ON SI(1 0 0) SUBSTRATES. THE SURFACE MORPHOLOGY OF THE FILMS WAS CHARACTERIZED USING ATOMIC FORCE MICROSCOPY (AFM) AND IT SHOWED THAT THE AS-PHOTODEPOSITED FILMS ARE AMORPHOUS AND HAVE A ROUGHER SURFACE THAN THERMALLY TREATED FILMS. THE CHEMICAL COMPOSITION OF THE FILMS WAS DETERMINED BY X-RAY PHOTOELECTRON SPECTROSCOPY (XPS). THE RESULTS INDICATED THE PRESENCE OF ZNO AND PTO ON THE SURFACE OF AS-DEPOSITED LOADED ZINC OXIDE FILMS. GAS SENSING TESTS REVEAL THAT AS-DEPOSITED 10% PT/ZNO FILMS EXHIBIT A BETTER RESPONSE THAN PURE ZNO FILMS TOWARDS 20 PPM CARBON MONOXIDE AT AN OPERATING TEMPERATURE OF 250 °C. THE SENSORS ALSO HAVE FAST RESPONSE AND RECOVERY CHARACTERISTICS.

PD-LOADED TUNGSTEN OXIDE THIN FILMS HAVE BEEN SUCCESSFULLY FABRICATED BY DIRECT UV IRRADIATION OF BIS(BETA-IKETONATE)DIOXOTUNGSTEN(VI) AND PD(II) PRECURSOR COMPLEXES SPIN-COATED ON SI(100) SUBSTRATES. X-RAY DIFFRACTION (XRD) AND X-RAY PHOTOELECTRON SPECTROSCOPY (XPS) WERE USED TO ANALYZE THE CRYSTAL STRUCTURE AND THE CHEMICAL COMPOSITION OF THE FILMS BEFORE AND AFTER ANNEALING AT 500 °C. THE RESULTS OF XRD AND AFM ANALYSIS SHOWED THAT THE AS-PHOTODEPOSITED FILMS ARE AMORPHOUS WHEREAS THERMALLY TREATED FILMS PRESENT A ROUGHER MORPHOLOGY. POST-ANNEALING OF THE FILMS IN AIR AT 500 °C TRANSFORMS THE OXIDES TO A MONOCLINIC WO3 PHASE. ANNEALED 10% PD/WO3 FILMS EXHIBITED AN EXCELLENT RESPONSE TOWARDS 50 PPM AMMONIA GAS AT AN OPERATING TEMPERATURE OF 300 °C. THE PD-LOADED SENSORS PRESENTED HIGHER SENSITIVITY AND QUICKER RESPONSE-RECOVERY RATES THAN UNLOADED WO3 FILMS.

IN SOLAR CELLS, ZNS WINDOW LAYER DEPOSITED BY CHEMICAL BATH TECHNIQUE CAN REACH THE HIGHEST CONVERSION EFFICIENCY; HOWEVER, PRECURSORS USED IN THE PROCESS NORMALLY ARE MATERIALS HIGHLY VOLATILE, TOXIC AND HARMFUL TO THE ENVIRONMENT AND HEALTH (TYPICALLY AMMONIA AND HYDRAZINE). IN THIS WORK THE CHARACTERIZATION OF ZNS THIN FILMS DEPOSITED BY CHEMICAL BATH IN A NON-TOXIC ALKALINE SOLUTION IS REPORTED. THE EFFECT OF DEPOSITION TECHNIQUE (GROWTH IN SEVERAL TIMES) ON THE PROPERTIES OF THE ZNS THIN FILM WAS STUDIED. THE FILMS EXHIBITED A HIGH PERCENTAGE OF OPTICAL TRANSMISSION (GREATER THAN 80%); AS THE DEPOSITION TIME INCREASED A DECREASING IN THE BAND GAP VALUES FROM 3.83 EV TO 3.71 EV WAS OBSERVED. FROM CHEMICAL ANALYSIS, THE PRESENCE OF ZNS AND ZN(OH)2 WAS IDENTIFIED AND X-RAY DIFFRACTION PATTERNS EXHIBITED A CLEAR PEAK CORRESPONDING TO ZNS HEXAGONAL PHASE (1 0 3) PLANE, WHICH WAS CONFIRMED BY ELECTRON DIFFRACTION PATTERNS. FROM MORPHOLOGICAL STUDIES, COMPACT SAMPLES WITH WELL-DEFINED PARTICLES, LOW ROUGHNESS, HOMOGENEOUS AND PINHOLE-FREE IN THE SURFACE WERE OBSERVED. FROM OBTAINED RESULTS, IT IS EVIDENT THAT DEPOSITS OF ZNS?CBD USING A NON-TOXIC SOLUTION ARE SUITABLE AS WINDOW LAYER FOR TFSC.

THE USE OF SOLAR RADIATION TO GENERATE ELECTRICITY IS A PROMISING SOLUTION TO THE GLOBAL ENERGY CRISIS, DUE TO ITS LOW CARBON FOOTPRINT AND GLOBAL AVAILABILITY. IN THIS SENSE, THIN FILM SOLAR CELLS ARE AN INTERESTING ALTERNATIVE BECAUSE OF ITS GOOD CONVERSION EFFICIENCIES AND THE SMALL AMOUNT OF MATERIAL NEEDED FOR THEIR MANUFACTURE [1]. ON THE OTHER HAND, NANOSTRUCTURED METAL SULFIDES HAVE BEEN EXTENSIVELY STUDIED DUE TO THEIR EXCELLENT PROPERTIES AND PROMISING APPLICATIONS IN ELECTRONIC AND OPTOELECTRONIC DEVICES, SUCH AS SOLAR CELLS, LIGHT-EMITTING DIODES, AND NON-VOLATILE MEMORIES [2]. IN THIS SENSE, CDS IS A COMMONLY USED OPTICAL WINDOW MATERIAL IN THIN FILM SOLAR CELLS, DUE TO ITS HIGH OPTICAL TRANSPARENCY, WIDE BANDGAP ENERGY (2.42 EV) AND N-TYPE CONDUCTIVITY. TO USE AS AN ABSORBER LAYER, PBS HAS INTERESTING FEATURES LIKE DIRECT BANDGAP ENERGY (0.41 EV AT 300 K) P TYPE CONDUCTIVITY, AND LARGE EXCITON RADIUS (18 NM) WHICH PROVIDES STRONG QUANTUM CONFINEMENT OF ELECTRONS AND HOLES, THUS INCREASING THE ABSORPTION FOR SOLAR RADIATION IN THE NEAR INFRARED REGION [3]. IN THIS WAY, CDS/PBS THIN FILM SOLAR CELLS WITH LAYERS DEPOSITED BY MEANS OF CHEMICAL BATH DEPOSITION HAVE BEEN INVESTIGATED BY SEVERAL AUTHORS, WHERE THEY HAVE OBTAINED GOOD EFFICIENCIES BETWEEN 0.44 % AND 4.85 % [3-6]. CURRENTLY, CHEMICAL BATH DEPOSITION (CBD) IS A LOW-COST, SCALABLE AND EASY TECHNIQUE TO SYNTHESIZE SEMICONDUCTOR THIN-FILMS [3-7]. NOW, IN BOTH SEMICONDUCTORS IT IS POSSIBLE TO MODIFY THEIR PROPERTIES BY INTRODUCING METALLIC DOPANTS INTO THEIR STRUCTURE, LIKE ITS BANDGAP VALUE AND ELECTRICAL CONDUCTIVITY. IN THIS SENSE, DOPING WITH AL HAS BEEN REPORTED FOR CHEMICALLY-DEPOSITED CDS AND PBS FILMS SHOWING IN BOTH CASES AN IMPROVEMENT IN THEIR ELECTRICAL CONDUCTIVITY AND A MODIFICATION OF ITS BANDGAP ENERGY AND CRYSTALLITE SIZE [6-9]. MOREOVER, DIFFERENT OPTOELECTRONIC DEVICES HAVE BEEN REPORTED RECENTLY USING CBD AL-DOPED CDS THIN FILMS [10-13].

IN THIS WORK, WE REPORT THE INFLUENCE OF ANNEALING TEMPERATURE ON THE STRUCTURAL, MORPHOLOGICAL AND OPTICAL PROPERTIES OF THO2 THIN FILMS DEPOSITED ON FUSED QUARTZ AND (100) SILICON SUBSTRATES BY PHOTOCHEMICAL METAL?ORGANIC DEPOSITION (PMOD) USING HINOKITIOLATE THORIUM (IV) COMPLEX AS THE PRECURSOR. X-RAY PHOTOELECTRON SPECTROSCOPY (XPS) CONFIRMED THE DEPOSITION OF THE THO2 FILMS. THE EFFECT OF THERMAL ANNEALING (FROM 300?°C TO 1100?°C) ON THE STRUCTURAL PROPERTIES OF THE THO2 FILMS WAS EVALUATED WITH X-RAY DIFFRACTION (XRD), UV?VIS TRANSMITTANCE SPECTROSCOPY, SPECTROSCOPIC ELLIPSOMETRY AND ATOMIC FORCE MICROSCOPY (AFM). XRD PATTERNS OF THE FILMS ANNEALED ABOVE 300?°C REVEALED THAT ALL DIFFRACTION PEAKS BELONG TO A CUBIC THO2 STRUCTURE WITHOUT PREFERENTIAL ORIENTATION. THE AVERAGE CRYSTALLITE SIZE INCREASED FROM 2.3?NM TO 3.7?NM AS THE ANNEALING TEMPERATURE INCREASED FROM 300?°C TO 750?°C. ANNEALING AT 1100?°C PROMOTED THE FORMATION OF HUTTONITE (?-THSIO4) IN THE THO2 LAYER. FILMS DEPOSITED ON FUSED QUARTZ SHOWED 80% TRANSMITTANCE IN THE VISIBLE RANGE, AND THE ANNEALING TEMPERATURE DID NOT IMPACT THE BAND GAP ENERGY. THE AFM STUDIES REVEALED THAT AS THE ANNEALING TEMPERATURE INCREASED, THE FILM SURFACE ROUGHNESS DECREASED. BETWEEN 750?°C AND 950?°C, THE FILM SURFACE WAS RELATIVELY SMOOTH WITH AN OF RMS SURFACE ROUGHNESS IN THE RANGE 2.3?5.0?NM. THE VALUES OF THE REFRACTIVE INDEX OF THE FILMS WERE IN THE RANGE OF N?=?1.6 FOR THE AS-DEPOSITED FILM TO N?=?2.1 FOR THE FILMS ANNEALED AT 750?°C. THIS RESULT SUGGESTS THE POTENTIAL USE OF THO2 FILMS AS A TRANSPARENT REFLECTOR MATERIAL FOR SHORT WAVELENGTHS.

THIS PAPER PRESENTS A PHOTOCHEMICAL SYNTHESIS METHOD FOR PRODUCING PURE CEO2 DEPOSITS AND CEO2 DEPOSITS LOADED WITH VARYING PROPORTIONS OF FE2O3. THE DEPOSITS WERE CALCINED AT 950 °C AND CHARACTERIZED STRUCTURALLY, COMPOSITIONALLY, AND MORPHOLOGICALLY USING XRD, XPS, SEM, FT-IR, AND RAMAN SPECTROSCOPY TECHNIQUES. CERIANITE AND HEMATITE PHASES WERE IDENTIFIED IN CEO2/FE2O3 SAMPLES, INDICATING HETEROGENEOUS SURFACE DEPOSITS. PHOTOCATALYTIC TESTING UNDER UV?VIS ILLUMINATION FOR 5 H DEMONSTRATED PROMISING RESULTS. FOR THE DEGRADATION OF BRIGHT GREEN DYE, EFFICIENCIES OF 78.9 % AND 90.1 % WERE ACHIEVED FOR PURE CEO2 AND CEO2 SAMPLES LOADED WITH 1.0 MOL% FE2O3, RESPECTIVELY. SIMILARLY, FOR OXYTETRACYCLINE DRUG DEGRADATION, PERFORMANCE RATES OF 35.3 % AND 67.0 % WERE OBSERVED FOR CEO2 AND CEO2 SAMPLES LOADED WITH 1.0 MOL% FE2O3, RESPECTIVELY. RECYCLABILITY TESTS SHOWED A GRADUAL DECLINE IN PHOTOCATALYTIC PERFORMANCE OVER SUCCESSIVE CYCLES DUE TO BY-PRODUCT ACCUMULATION CONTAMINATING THE CATALYST.

THIS STUDY WAS CONDUCTED TO ASSESS THE CATALYTIC ELECTRODE SURFACE ADSORPTION AND CAPTURE PROPERTIES OF DIFFERENT METAL CHITOSAN DERIVATIVES IN AQUEOUS PHOSPHATE BUFFER SOLUTION (PH?=?7.3). EARLY, RECENT WORK SHOWED THAT THE RESPONSE OF IRON CHITOSAN COMPLEX WITH R?=?-CH3 ON THE PERIPHERY, OVER BLOOD RED CELLS IN PRESENCE OF SPHINGOMYELINASE C WAS PROTECTED. THE EFFECT OF OTHERS SUBSTITUENT (R?=?-BR, -CL, -F, NO2, -OCH3, -H) ON THE PERIPHERY OF THE SCHIFF BASE LIGAND DID NOT SHOW CORRELATION WITH THE OXIDATION OF SPHINGOMYELINASE C AND ITS BIOLOGICAL RESPONSE. FOR THIS REASON, VARIOUS ADSORBED METAL (M?=?FE OF RECENT WORK, CU, NI AND CO) COMPLEXES OF CHITOSAN AND SCHIFF BASES ON GLASSY CARBON ELECTRODE FOR THE OXIDATION OF SPHINGOMYELINASE C WERE INVESTIGATED AND COMPARED, EACH ONE WITH -CH3 GROUP ON THE PERIPHERY OF THE SCHIFF BASE. UV?VIS AND IR-TF SPECTROSCOPIES, ELECTROCHEMISTRY AND MICROSCOPY ASSAY WERE PERFORMED; THEN, THE METAL EFFECT UNDERLYING. FOR THE SCHIFF BASE, COBALT AND COPPER COMPLEXES DID NOT PROVED TO BE A REMARKABLE CELLULAR PROTECTOR IN PRESENCE OF THE ENZYME, BUT THE NICKEL COMPLEX SHOWED TO BE A CELLULAR PROTECTOR AT SHORT TIME, THIS CONCLUSION HELP TO PROPOSAL A REACTION MECHANISM FOR THE ELECTROCHEMICAL AND BIOLOGICAL STUDIES.

A ONE-STEP ELECTRODEPOSITION PROCESS WAS USED TO OBTAIN CUINS2 (CIS) FILMS ON A MOLYBDENUM SUBSTRATE BY VARYING THE SUPPORTING ELECTROLYTE (LITHIUM CHLORIDE, LICL) CONCENTRATION. THE AS-DEPOSITED SAMPLES WERE CHARACTERIZED BY SCANNING ELECTRON MICROSCOPY, ENERGY-DISPERSIVE SPECTROSCOPY, PROFILOMETRY, AND DIFFUSE REFLECTANCE SPECTROSCOPY. FROM CHARACTERIZATION, IT WAS FOUND THAT DIFFERENT CONCENTRATIONS OF LICL MAINLY LEAD TO A MORPHOLOGICAL CHANGE IN THE OBTAINED CIS FILMS. MOREOVER, THEIR CHEMICAL COMPOSITION SHIFTED TO THE STOICHIOMETRIC COMPOSITION FOR HIGH CONCENTRATIONS OF THE SUPPORTING ELECTROLYTE. AFTER ANNEALING, THE STRUCTURAL ANALYSIS FROM X-RAY DIFFRACTION REVEALED THAT ALL SAMPLES CRYSTALLIZED IN THE TETRAGONAL PHASE OF CIS. IN ADDITION, IT WAS FOUND THAT THE CRYSTALLITE SIZE INCREASED FOR SAMPLES GROWN AT HIGHER CONCENTRATIONS OF LICL. OPTICAL STUDIES CARRIED OUT BY DIFFUSE REFLECTANCE SPECTROSCOPY REVEALED THAT THE BAND GAP VALUES INCREASED FROM ~ 1.40 TO ~ 1.45 EV (AVERAGE) AFTER THE ANNEALING PROCESS. FINALLY, ZINC SULFIDE (ZNS) THIN FILMS WERE CHEMICALLY DEPOSITED ONTO ELECTRODEPOSITED CIS FILMS IN ORDER TO EVALUATE THE PHOTOVOLTAIC RESPONSE OF ZNS/CIS BILAYER SYSTEMS. WE DISCOVERED THAT ZNS THIN FILMS COVERED THE SURFACE OF CIS MORE EFFECTIVELY FOR THE HIGHEST CONCENTRATION OF LICL AND THAT ONLY THE ZNS/CIS BILAYER WITH THE CIS FILM OBTAINED AT THE HIGHEST CONCENTRATION OF LICL SHOWED A PHOTOVOLTAIC RESPONSE.

WE PROPOSE THE USE OF ALKOXIDE ?-DIKETONATES OF CE(III), ER(III), PR(III) AND YB(III) AS PRECURSORS FOR PHOTOCHEMICAL DEPOSITION OF CEO2:ER AND CEO2:ER/LN (LN = PR OR YB) THIN FILMS, FOLLOWED BY SUBSEQUENT ANNEALING AT 950 °C. THE MEASUREMENTS OF LUMINESCENT PROPERTIES REVEALED THAT CEO2:ER SAMPLES UNDER EXCITATION AT 980 NM EXHIBIT UP-CONVERSION EMISSIONS AT 540 NM AND NEAR INFRARED EMISSIONS CENTERED AT 1550 NM. WHEN CO-DOPING IS PERFORMED ON THE CEO2 FILMS, CEO2:ER/PR REDUCES ITS UP-CONVERSION CHARACTERISTICS AND THE NIR EMISSIONS INCREASE. HOWEVER, THE CEO2:ER/YB SAMPLES SIGNIFICANTLY INCREASE THE UP-CONVERSION PROPERTIES AND INHIBIT NIR EMISSIONS. DIFFERENT MECHANISMS BASED ON ENERGY TRANSFER PROCESSES ARE PROPOSED TO EXPLAIN THESE DIFFERENCES IN THE DEGREE OF INTENSITY OF THESE EMISSIONS.

BECAUSE OF THE MASSIVE INCREMENT IN SOLAR PLANTS LOCATED IN EXTREME ENVIRONMENTS, STUDYING THE ASSOCIATION OF CLIMATE PARAMETERS AND SOILING IN NATURAL CONDITIONS HAS BEEN NECESSARY. IN THIS WORK, SOLAR GLASS COUPONS WERE EXPOSED TO ENVIRONMENTAL CONDITIONS IN SALVADOR SOLAR PLANT, IN THE ATACAMA DESERT, DURING SUMMER AND WINTER CAMPAIGNS. THE SOILING WAS QUANTIFIED AND CHARACTERIZED, AND THE DEGRADATION OF OPTICAL PROPERTIES OF SOILED COUPONS WAS ALSO MEASURED. REGARDING THE REDUCTION OF THE OPTICAL PROPERTIES OF THE GLASS COUPONS, IT WAS OBSERVED THAT THE DETRIMENTAL EFFECT WAS HIGHER IN SUMMER THAN IN WINTER. A STATICAL ANALYSIS FOUND THAT THIS DIFFERENCE IN SOILING PERFORMANCE IS RELATED TO THE RELATIVE HUMIDITY AND WIND SPEED PRESENT IN EACH CAMPAIGN, MAINLY DUE TO THE DAILY VARIATIONS OF THESE PARAMETERS. PROLONGED PERIODS OF RELATIVE HUMIDITY CLOSE TO 30% PROMOTE THE ADHESION OF PARTICLES TO THE PV GLASS SURFACE AND INHIBIT THEIR RESUSPENSION BY THE ACTION OF THE WIND, I.E., MORE DUST MASS ACCUMULATES. SINCE THE EFFECT OF SOILING IS MORE CRITICAL DURING THE SUMMER PERIOD, THE USE OF A PREVENTING SOILING MITIGATION SYSTEM IS HIGHLY ENCOURAGED, AND THE ADJUSTMENT OF THE CLEANING SCHEDULE ACCORDING TO THE SEASONALITY OF SOILING.