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The need to increase transparency in existing passivating contacts for crystalline silicon solar cells has motivated the development of transparent contacts based on transition metal oxides (TMOs). Among hole‐selective materials, molybdenum oxide (MoOx) has achieved the greatest success so far. However, despite providing low contact resistivity, MoOx relies on an intrinsic hydrogenated amorphous silicon (a‐Si:H(i)) interlayer to achieve high levels of surface passivation and thus high open‐circuit voltage at a device level, partially defeating the objective of improved transparency. Herein, we report unprecedented performance for a‐Si:H‐free MoOx‐based contacts by employing an alternative passivating interlayer based on a well‐engineered chlorine‐containing Al‐alloyed titanium oxide/titanium dioxide (AlyTiOx/TiO2)stack. The resulting AlyTiOx/TiO2/MoOx stack achieved record levels of passivation, reaching J0 values as low as 16 fA cm−2, closer to values reported for a‐Si:H‐based contacts, while maintaining lower contact resistivity, well below 100 mΩ cm−2. Additionally, the stack presents improved transparency compared to a‐Si:H‐based contacts, with gains in short‐circuit current density of at least 0.8 mA cm−2. The work pushes the performance of hole‐selective passivating contacts based on TMOs to new levels, enabling a record efficiency of 22.53% for cells with fully transparent hole‐selective passivating contacts. This work serves as an important stepping stone toward low‐thermal‐budget, simple manufacturing of high‐efficiency solar cells. [ABSTRACT FROM AUTHOR]

Silicon heterojunction (SHJ) technology marks a notable development in the photovoltaic sector, paving the way for solar cells with very high efficiency. At its core, SHJ technology is characterized by the formation of a heterojunction between crystalline silicon (c-Si) and carrier-selective materials, which are not necessarily based on intrinsic/doped a-Si:H. In this research, a transparent conductive multilayer structure consisting of MoOx/Ag/MoOx is utilized on the front illuminated side as hole-selective contacts, while a metal/organic polymer Al/C60 is employed as a full-area rear electron-selective contact. This configuration results in an Ag/MoOx/Ag/MoOx/n-Si/C60/Al heterojunction solar cell. The device was extensively investigated electrically under varying temperatures using techniques such as impedance spectroscopy, capacitance–voltage, and current–voltage measurements in dark conditions. Furthermore, the SHJ solar cell achieved an efficiency of 7.8% under 1 sun illumination, demonstrating its potential in the field of photovoltaics. These findings underscore the potential of this multilayer structure to enhance SHJ solar cell performance, marking a step forward in photovoltaic technology with implications for more efficient and cost-effective solar energy solutions. [ABSTRACT FROM AUTHOR]

With the aid of the atomic layer deposition (ALD) technique, TiOx-based electron-selective contacts have been produced with high optical transparency and excellent passivation of silicon surfaces. These contacts are now considered to be on par with commercially available, optically absorbing Si-based contacts such as a-Si:H and poly-Si. On the other hand, these contacts have shown four stability challenges that prevent their commercialization: (1) degradation after metallization; (2) degradation following sputtering; (3) degradation over time; and (4) degradation at high temperatures. Although several approaches to overcoming some of these obstacles have been proposed in the literature, these impediments have remained unresolved over the past decade. Herein, the aforementioned problems have been successfully addressed by constructing an AlyTiOx/TiyZnOx/TiOx/ZnO/ITO multilayer structure, which includes an AlyTiOx/TiyZnOx/TiOx stack for surface passivation, an ALD ZnO buffer layer to minimize sputtering damage and hence enable recovery, and a sputtered indium tin oxide (ITO) capping layer to shield the passivation stack from moisture, act as a barrier for chlorine and hydrogen effusion, and eliminate TiOx-metal electrode interaction. Through systematic investigation, the key factors that degrade the performance of these layers are identified and resolved. This breakthrough in achieving highly stable and outstanding passivation performance using wide-bandgap transition metal oxides is a key step towards the development of highly efficient crystalline silicon (c-Si) solar cells that combine high open-circuit voltages and short-circuit current densities. [ABSTRACT FROM AUTHOR]

Doped polysilicon (poly-Si) passivating contacts have emerged as a key technology for the next generation of silicon solar cells in mass production, owing to their excellent performance and high compatibility with the existing passivated emitter and rear cell technology. However, the current solar cell architecture based on a rear-side electron-selective (n+) poly-Si contact is also approaching its practical limit (∼26%) in mass production. The full potential of doped poly-Si passivating contacts can only be realized through incorporation of both electron-selective and hole-selective (p+) poly-Si contacts. While studies of both p+ and n+ poly-Si contacts commenced simultaneously, significant performance differences have arisen. Phosphorus-doped poly-Si contacts consistently outperform boron-doped counterparts, displaying typically lower recombination current density (J0) values (1 – 5 fA/cm2 vs 7 – 15 fA/cm2). This discrepancy can be attributed to inadequate optimization of p+ poly-Si contacts and fundamental limitations related to boron doping. The poorer passivation of p+ poly-Si contacts can be at least partly attributed to boron segregation into the interfacial oxide layers, compromising the interfacial oxide integrity and reducing the chemical passivation effectiveness. This review critically examines the progress of p+ poly-Si contacts characterized by cell efficiency and J0 values, delves into existing challenges, identifies potential solutions, and explores some potential solar cell architectures to enhance efficiency by incorporating p+ poly-Si contacts. [ABSTRACT FROM AUTHOR]

Passivating contacts based on transition metal oxides are of great interest for applications in crystalline silicon (c-Si) solar cells due to their improved optical transparency and potential cost reduction. In this work, the contact resistivity and passivation for thermally evaporated Cu2O are investigated and optimized, with and without an Al2O3 interlayer, as a hole-selective contact to c-Si. Additionally, we implement an AlyTiOx/TiO2 stack as a novel passivating tunnel interlayer for hole-selective contacts, achieving an implied open-circuit voltage iVoc of 630 mV and a record-low J0 of 212 fA cm-2 while maintaining a contact resistivity ρc of 62mΩ cm². A record-low ρc of 8mΩ cm² for Cu2O-based contacts is also demonstrated at the expense of passivation. The addition of the interlayer resulted in a 2% absolute improvement in the efficiency of proof-of-concept c-Si cells with full-area rear Cu2O contacts, reaching 19.1%.The demonstration of this novel interlayer stack provides new avenues to improve the performance also of other hole-selective passivating contacts. [ABSTRACT FROM AUTHOR]

For innovative application in wastewater treatment techniques, MnO-Fe2O3 nanocomposites were successfully synthesized using the sol–gel auto-combustion method at different temperatures for the adsorption of 137Cs and 60Co radionuclides from aqueous solution. The characterization of these nanocomposites was carried out through FT-IR, SEM-EDX, and X-ray diffraction. These nanocomposites were employed as adsorbent materials for the removal of 137Cs and 60Co radionuclides from simulated radioactive waste solutions. The study involved a series of experiments aiming to demonstrate the MnO-Fe2O3 nanoparticles' exceptional adsorption potential concerning 137Cs and 60Co. Additionally, the investigation delved into how variations in temperature, dose amount, contact time, and pH value influence the adsorption dynamics. Due to their high specific surface area, the synthesized MnO-Fe2O3 nanoparticles had high adsorption capacity of more than 60% and 90% for 137Cs and 60Co, respectively. By investigation of kinetics and adsorption isotherms, pseudo-second-order reaction and the Langmuir model turned out to fit well for the adsorption of 137Cs and 60Co onto the MnO-Fe2O3 nanocomposites. Moreover, a thermodynamic analysis revealed that the adsorption process was spontaneous for both target metals and the adsorption of 60Co was endothermic, whereas the adsorption of 137Cs was exothermic. [ABSTRACT FROM AUTHOR]

Passivating contact technologies are essential for fabricating high‐efficiency crystalline silicon (c‐Si) solar cells, and their application and incorporation into manufacturing lines has ranked as a hot topic of research. Generally, ideal passivating contacts should combine excellent electrical contact, outstanding surface passivation, and high optical transparency. However, addressing all these criteria concurrently is challenging since it is unlikely for any single material to exhibit both efficient carrier transport and surface‐defect passivation while demonstrating negligible parasitic absorption. In this work, several earth‐abundant, wide‐bandgap materials are combined to engineer high‐quality transparent electron‐selective passivating contact structures capable of overcoming these obstacles. A highly transparent AlyTiOx/ZnO/TiO2 stack with a total thickness of 3 nm, prepared by atomic layer deposition, is shown to provide a close‐to‐ideal passivating contact to Si surfaces by enabling dual functions of remarkable silicon surface passivation (with an effective minority carrier lifetime of 12.3 ms, an implied open‐circuit voltage of 730 mV, and a surface recombination current density prefactor of 2.6 fA cm−2), combined with efficient carrier transport with a very low contact resistivity of 3.4 mΩ cm2. These results demonstrate that low‐cost silicon interface‐engineering strategiesbased on transition metal oxides can push c‐Si solar cell performance to its theoretical limits. [ABSTRACT FROM AUTHOR]

III–V semiconductors are among the highest performing materials for solar energy conversion devices. Exposing III–V semiconductors to a hydrogen plasma can improve optoelectronic properties and is a critical step in fabricating efficient InP solar cells. However, there is a limited understanding of the changes induced by hydrogen plasma exposure to the surface and in the bulk of III–V semiconductors. Herein, it is demonstrated that a 19.3% efficient p‐InP solar cell with a TiO2 electron selective contact layer can be achieved by exposing the InP substrate to hydrogen plasma. Detailed investigations employing ultraviolet photoelectron spectroscopy and capacitance–voltage measurement unveil that the hydrogen plasma exposure on p‐InP leads to charge carrier polarity inversion in the near‐surface region (charge inversion layer) while simultaneously reducing the carrier concentration (charge‐depleted layer) in the bulk. The study provides important insights into the impact of hydrogen plasma exposures on InP which may lead to more efficient optoelectronic devices such as solar cells, photodetectors, light‐emitting diodes, and photoelectrochemical cells. [ABSTRACT FROM AUTHOR]

Passivating contacts based on transition metal oxides (TMOs) have the potential to overcome existing performance limitations in high‐efficiency crystalline silicon (c‐Si) solar cells, which is a significant driver for continuing cost/Watt reductions of photovoltaic electricity. Herein, innovative stacks of Al‐alloyed TiOx (AlyTiOx) and pure TiOx as transparent electron‐selective passivating contacts for n‐type c‐Si surfaces are explored. An optimized stack of 2 nm AlyTiOx and 2 nm TiOx is shown to provide both record‐quality surface passivation and excellent electrical contact, with a surface recombination current density prefactor J0 of 2.4 fA cm−2 and a specific contact resistivity ρc of 15.2 mΩ cm2. The performance of this innovative stack significantly exceeds previously reported values for pure or doped TiOx single layers, SiOx/TiOx stacks, a‐Si:H/TiOx stacks, and other transparent contact technologies. Furthermore, an excellent efficiency of 21.9% is attained by incorporating the optimized stack as a full‐area rear contact in an n‐type c‐Si solar cell. The findings set a new benchmark for the passivation performance of metal oxide‐based passivating contacts, bringing it to a level on par with state‐of‐the‐art SiOx/poly‐Si contacts while greatly improving optical transparency. [ABSTRACT FROM AUTHOR]

Radiation shielding composites based on polyvinyl chloride (PVC) reinforced with different weight ratios of Pb(NO3)2 (5, 10, and 20 wt%) were prepared using the solution-casting technique. Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), scanning electron microscopy, and tensile testing method were used to characterize the PVC composite films. FTIR and XRD investigations illustrate the structural change and modification of the as-prepared PVC composites. The morphological analysis of the composite revealed that Pb(NO3)2 was dispersed uniformly within PVC polymer matrix. TGA revealed that the incorporation of Pb(NO3)2 improved the thermal stability of the investigated composites, whereas adding Pb(NO3)2 to the polymer matrix worsened its tensile properties. The as-prepared composite films were investigated for radiation-shielding of gamma-rays radioactive point sources (241Am, 133Ba, 137Cs, and 60Co). Linear attenuation coefficient (μ, cm−1), mass attenuation coefficient (μ/ρ, cm2/g), and half-value layer (HVL, cm) have been estimated from the obtained data using the MicroShield program. Reasonable agreement was attended between theoretical and experimental results. The deviation between the experiment and theoretical values of mass attenuation coefficient is being to be lower than 9%, and this can be correlated to the good distribution of Pb(NO3)2. The results revealed that adding Pb(NO3)2 to PVC polymer composites improved their mass attenuation coefficient. [ABSTRACT FROM AUTHOR]

The effects of gamma and neutron irradiations on the chemical, optical and structural properties of Bayfol CR-6-2 were investigated. The samples were irradiated by γ-rays from a 60Co source at various doses ranging between 16 and 900 kGy at room temperature in atmospheric air. For neutrons, an Am-Be neutron facility was used for the sample irradiation in thermal mode which had an activity of 185 GBq. Samples were irradiated with different doses of neutrons ranging from 15.7 to 564.2 mGy. The changes induced were analyzed using UV-Vis and Fourier transform infrared (FTIR) spectrometry. The results demonstrated an occurrence of oxidative degradation, resulting in the formation of carbonyl groups at 1700 cm -1. Simultaneous thermo-gravimetric investigation (TGA) has been performed on the samples of 0.3 mm thickness. The results obtained indicate that cross-linking predominates at small neutron doses and main chain scission happens at higher doses. [ABSTRACT FROM AUTHOR]

Amorphous thin-film TiO x prepared via atomic layer deposition (ALD) has been identified as one of the most promising materials for use in transparent passivating contacts in high-efficiency and low-cost crystalline silicon (c-Si) solar cells. As highlighted in this work, the passivation performance of ALD TiO x layers strongly depends on the metal precursor used, with films prepared using TiCl 4 recently showing the best results. However, a full understanding of how such films achieve their high level of surface passivation has not yet been demonstrated. This study provides a clear demonstration that a key part of this passivation mechanism is due to chlorine (Cl) accumulation at the Si surface. This mechanism is demonstrated to be quite general in nature by showing how 2 nm of ALD TiO x (TiCl 4 + H 2 O) can be applied as a capping layer for either ZnO or Al 2 O 3 interlayers to dramatically reduce silicon surface recombination. Cl depth profiles obtained using secondary ion mass spectrometry confirm the presence of Cl extending through the depth of the interlayers with a peak at the silicon interface. Remarkably, this diffusion of Cl is observed following low-temperature (75 °C) deposition of the TiO x capping layer, without any subsequent thermal treatment. Contrary to earlier studies that treated residual Cl in ALD films as a general contamination issue, these findings reveal unequivocally that chlorine plays a crucial role in Si surface passivation and can be classed as an effective passivation element, similar to hydrogen in its ability to passivate Si dangling bonds. The outcomes of this research emphasize the importance of residual chlorine in enhancing the passivation of buried interfaces and provide additional motivation for employing metal chloride precursors for silicon surface passivation applications.