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Influence of RbF post deposition treatment on heterojunction and grain boundaries in high efficient (21.1%) Cu(In,Ga)Se2 solar cells
摘要： Post deposition treatments (PDT) by alkali fluorides applied to chalcopyrite-based absorbers have produced record efficiencies in thin-film solar devices in the past few years and recently the efficiency of 22.6 % was achieved with Cu(In,Ga)Se2 (CIGS) using rubidium fluoride (RbF) PDT. However, the effects of RbF-PDT towards changes in its interfacial and grain boundary (GB) properties are still not fully understood. In this work, cells with efficiency higher than 21% are investigated by combination of atom probe tomography (APT) and transmission electron microscopy (TEM) to show how changes in GB and interface chemistry may facilitate high efficiencies. APT studies, carried out at the interface between CIGS absorber and solution-grown CdS buffer layer, show In enrichment and Cu depletion along with traces of Rb. Our APT studies reveal higher amounts of Rb (1.5 at. %) and lower amounts of Na and K (<0.5 at. %) at GBs as compared with previous studies (on non-PDT samples) thus indicating substitution of Na and K by Rb. However, concentration of all alkali elements inside the grain bulk is below detection limit of APT. The concentration of Rb at the GBs in CIGS is measured depth-dependent using both APT and TEM, which consistently shows the increase in Rb towards the Mo back contact. In addition, a pronounced Cu depletion is observed at the GBs which might enhance hole-barrier properties of the GBs, thus improving charge carrier collection and hence the overall efficiency of the device. Thus, understanding effects of RbF-PDT at the atomic scale provides new insights concerning the further improvement of CIGS absorber and interfaces.
关键词： Cu(In,Ga)Se2,Thin-film solar cell,heterojunction,atom probe tomography,post deposition treatments,transmission electron microscopy
更新于2025-11-21 11:20:48
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Electric field assisted spray coated lead free bismuth iodide perovskite thin film for solar cell application
摘要： Solution-processed Methylammonium iodo bismuthate (MBI) perovskite solar cell is fabricated by spray technique with changed applied voltages from 0 to 1000 V during the deposition of MBI thin film. The morphology and surface roughness of MBI films are influenced significantly by the electric field during film deposition. It is attributed to improve the atomization of spray droplets due to process of coulomb fission. The surface roughness of MBI film is reduced from 39 to 19 nm with increased applied voltages during the deposition from 0 V and 1000 V, respectively. A strong absorption band is observed ～500 nm for all MBI films. The MBI perovskite solar cell is showed enhancement in the efficiency with the maximum current density 2.33 mA/cm2 at 1000 V applied voltage during the deposition. The improvement in photovoltaic characteristics with applied voltage during the film deposition is attributed to the formation of more uniform film with improved surface morphology and roughness, resulting in efficient electron transfer and reduced recombination of charge carrier at grain boundaries.
关键词： Methyl ammonium bismuth (III) iodide,Spray deposition,Perovskite solar cell,Electric filed,Lead free perovskite
更新于2025-11-21 11:18:25
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Enhanced working efficiency of Si solar cell by water induced nano-porous thermal cooling layer
摘要： Nano-porous thermal cooling layer (TCL) of thickness 14 mm beneath a Si solar cell reduces its working temperature from 82 °C to 68 °C This reduced working temperature increase its absolute working ef?ciency by 0.75%. X-Ray diffraction analysis of the material used in TCL shows its amorphous nature. The SEM images con?rm interconnected carbon particles are forming micro-channels within the TCL. Further FESEM analysis has been done to examine the in-depth structure of the carbon particles and shows the nano-porous topography within the particle. The porosity of used TCL is examined by BET measurement which con?rms the highly porous nature of the TCL having surface area of the order of 798.35 m2 g?1 with average pore size of 2.3 nm. The induced water concentration (0.049 to 0.49 ml cm?3) dependent enhanced cooling ef?ciency of nano-porous TCL has been studied in detail. The use of water saturated (0.49 ml cm?3) TCL (14 mm thick) further decreases the working temperature of the device from 68 °C to 58 °C and the device works below this temperature for around three hours. Further, in order to enhance the effective time duration, the TCL thickness (4 mm to 26 mm) dependent cooling ef?ciency of water saturated TCL has been analyzed in detail. Use of optimized water saturated TCL beneath the solar cell improve its working ef?ciency from 11.4% (at 82 °C) to 12.69% (at 58 °C) which shows an absolute and relative enhancement of 1.29% and 11.32%, respectively in cell ef?ciency. Finally, thermal analyses of TCL and water cooling mechanism in it have been discussed in detail.
关键词： ef?ciency enhancement,Si solar cell,thermal cooling layer,cooling plateau,cooling agent,nano-porous
更新于2025-11-21 11:18:25
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A carbon nanotube-iron (III) oxide nanocomposite as a cathode in dye-sensitized solar cells: Computational modeling and electrochemical investigations
摘要： Here is the evaluating result on the applicability of the multi-walled carbon nanotube (MWCNT) and a-iron (III) oxide (a-Fe2O3) nanocomposite as a cathode material in dye-sensitized solar cells (DSCs). The morphology and the structure of the MWCNT/a-Fe2O3 nanocomposite have characterized by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and X-ray elemental mapping analysis. Moreover, the electrochemical performance of the nanocomposite has studied toward the activity of Iˉ/I3ˉ redox couple which represents high current density, low peak-to-peak separation, low charge-transfer resistance, and almost 100% stable response signal. Furthermore, the computational modeling employing the molecular mechanics (MM) and the restricted-Hartree Fock/semiempirical parameterization (RHF/PM6) methods reveals that the highest occupied molecular orbital (HOMO), the lowest unoccupied molecular orbital (LUMO), and the HOMO-LUMO energy gap of the modeled nanocomposite are as (cid:1)6.88, (cid:1)3.62, and 3.26 eV, respectively. These properties match with the electronic-level domino of the DSC structure. Finally, the DSC device has fabricated using N719-sensitized TiO2 photoanode and MWCNT/a-Fe2O3 counter electrode, presenting the open-circuit potential, the short-circuit current density, and the power-conversion ef?ciency of 0.7 V, 20.37 mA cmˉ2, and 6.0%, respectively. This study successfully approves the potential of the nanocomposite as a cathode material in iodine-based dye-sensitized solar cells.
关键词： Dye-sensitized solar cell,Nanocomposite,Carbon nanotube,Molecular mechanics,RHF/PM6,Iron (III) oxide
更新于2025-11-21 11:18:25
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Transparent Platinum Counter Electrode Prepared by Polyol Reduction for Bifacial, Dye-Sensitized Solar Cells
摘要： Pt catalytic nanoparticles on F-doped SnO2/glass substrates were prepared by polyol reduction below 200 °C. The polyol reduction resulted in better transparency of the counter electrode and high power-conversion efficiency (PCE) of the resultant dye-sensitized solar cells (DSSCs) compared to conventional thermal reduction. The PCEs of the DSSCs with 5 μm-thick TiO2 photoanodes were 6.55% and 5.01% under front and back illumination conditions, respectively. The back/front efficiency ratio is very promising for efficient bifacial DSSCs.
关键词： dye-sensitized solar cell,platinum,bifacial,ethylene glycol,counter electrode
更新于2025-11-21 11:01:37
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UV-ozone induced surface passivation to enhance the performance of Cu2ZnSnS4 solar cells
摘要： Interface property has been considered one of the most critical factors affecting the performance of semiconductor devices. In this work, we demonstrate an efficient surface passivation for the interface between Cu2ZnSnS4 (CZTS) and CdS buffer layer by using UV-ozone treatment at room temperature. The passivation led to a significant enhancement of short circuit current density (Jsc) of the device from 11.70 mA/cm2 to 18.34 mA/cm2 and thus efficiency of the CZTS solar cells from 3.18% to 5.55%. The study of surface chemistry has revealed that the UV-ozone exposure led to formation of a Sn–O rich surface on CZTS, which passivates the dangling bonds and forms an ultra-thin energy barrier layer at the interface of CZTS/CdS. The barrier is considered to be responsible for the reduction of non-radiative recombination loss in the solar cells as confirmed by photoluminescence (PL) measurement. The elongated lifetime of minority carriers in the CZTS solar cells by time-resolved PL has further verified the interface passivation effect induced by UV-ozone treatment. This work provides a fast, simple yet very effective approach for surface passivation of CZTS film to boost the performance of CZTS solar cells.
关键词： CZTS solar cell,UV-Ozone treatment,Interface modification,Surface passivation
更新于2025-11-21 11:01:37
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Nano-mirror embedded back reflector layer (BRL) for advanced light management in thin silicon solar cells
摘要： This work illustrates a technology for advanced light management by introducing a nonconventional back reflector layer (BRL) in amorphous silicon (a-Si:H) solar cells. To meet this, silver sulfide (Ag2S) nanoparticles with ~50 nm diameter have been chosen as the nano-mirror owing to its low parasitic absorption loss over a broad wavelength (300 to 1100 nm) region. The Ag2S NPs were sandwiched between two indium tin oxide (ITO) layer and placed as the back reflector layer of an a-Si:H solar cell to achieve better light trapping within the active layers. The embedded structure exhibited high reflectance (up to 93%) in the red and near-infrared region, the main working zone of a-Si:H cells. With the incorporation of such state of the art back reflector structure in a-Si:H solar cells, a photo-conversion efficiency of 10.58% has been achieved; which is one of the best in this class.
关键词： a-Si:H solar cell,Back reflection,theoretical validation,high efficiency,nano-mirror
更新于2025-11-21 11:01:37
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Cu(In,Ga)Se2 monograin powders with different Ga content for solar cells
摘要： Monograin layer (MGL) solar cell technology based on CuIn1-xGaxSe2 (CIGSe) monograin powder crystals is a promising approach for the future low-cost production of flexible solar panels. In this study, CuIn1-xGaxSe2 monograin powders (0 ≤ x ≤ 1) were prepared from binary compounds in the liquid phase of potassium iodide as flux material in evacuated quartz ampoules at 720 °C. The crystal structure and the lattice parameters of the CIGSe monograin powder crystals were determined by using X-ray diffraction analysis. A linear decrease of the lattice parameters with increasing Ga concentration was detected. The photoluminescence (PL) spectra of the CIGSe crystals were dominated by the edge emission band that shifted towards higher energies with increasing Ga content. Moreover, additional deep PL band (below 1.0 eV) appeared for Ga contents above x = 0.21 showing higher relative intensity with increasing Ga content. The effective bandgap energy of the CIGSe monograin powder materials ranged from 1.0 eV to 1.68 eV as the [Ga]/([In] + [Ga]) ratio increased from 0 to 1.0. An efficiency of 12.8% (active area) was obtained with the MGL solar cell based on CuIn1-xGaxSe2 monograin powder with Ga content of x = 0.21.
关键词： Cu(In,Ga)Se2,Solar cell,Crystalline powder,Crystal growth
更新于2025-11-21 10:59:37
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Iodine Induced PbI <sub/>2</sub> Porous Morphology Manipulation for High-Performance Planar Perovskite Solar Cells
摘要： The quality of the perovskite film has a vital influence on the performance of perovskite solar cells and it is quite desirable to simultaneously manipulate the crystallization and morphology of the perovskite film. In this study, conventional PbI2 is replaced with a PbI2/I2 mixed precursor during the first step of sequential deposition, causing the formation of a PbI2 porous nanostructure. By changing the content of I2 in the precursor, the morphology of the PbI2 film as well as the resulting perovskite film can be successfully modulated. With an optimal content of I2, a high-quality perovskite film with a pure phase and smooth surface can be achieved. As a result, the conversion efficiency of perovskite solar cells using a PbI2/I2 mixed precursor can be as high as 18.63%, compared to 16.89% for the reference device through traditional sequential deposition with a pure PbI2 precursor.
关键词： porous PbI2,iodine,perovskite,sequential deposition,solar cell
更新于2025-11-20 15:33:11
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Demonstration of Photovoltaic Action and Enhanced Stability from a Quasi-Two-Dimensional Hybrid Organic–Inorganic Copper–Halide Material Incorporating Divalent Organic Groups
摘要： Commercialization of solar cells based on photoactive lead–halide perovskites is in-part limited by their toxicity and instability. In this study, new and related copper–halide hybrid organic–inorganic materials containing dicationic 1,6-hexanediammonium (+H3N-C6H12-NH3+) demonstrated superior stability to heat and moisture in comparison to the analogous material containing monocationic 1-propylammonium (C3H7-NH3+) in twice the stoichiometry. Electronic absorption spectra taken of the materials were consistent with an indirect optical bandgap of ~1.8 eV, making them well-suited for application as the photoactive layer in the top cell of a tandem solar cell with silicon. The best-performing single-junction solar cells containing the dicationic material as the photoactive layer exhibited an open-circuit photovoltage in excess of 400 mV and a short-circuit photocurrent density of ~30 μA/cm2. These values are similar to those reported for state-of-the-art copper–halide hybrid organic–inorganic materials containing organic monocations and motivate further research on this class of materials.
关键词： photovoltaic,two-dimensional material,dications,solar cell,copper halide,hybrid material,stability,perovskite
更新于2025-11-19 16:56:42