Cell Fabrication Process Research Articles

Zr and Y co-doped SrFe0.8Zr0.1Y0.1O3-δ perovskite oxide as a stable, high-performance symmetrical electrode for solid oxide cells

Symmetrical solid oxide cells (SSOCs), which use the same material for both anode and cathode, simplify the cell fabrication process and effectively resist carbon deposition and sulfur poisoning. In this study, Zr, Y co-doped SrFe0.8Zr0.1Y0.1O3-δ (SFZY) perovskite oxide is synthesized and evaluated its properties as an SSOFCs electrode. Density functional theory (DFT) indicates that the local state density of SFZY is lower than that of SrFeO3-δ (SFO). SFZY has good chemical compatibility with La0.8Sr0.2Ga0.83Mg0.17O3−δ (LSGM) electrolyte below cell operating temperature. Zr, Y co-doped SrFe0.8Zr0.1Y0.1O3-δ maintains structural stability in H2 atmosphere. At 750 ℃, the polarization resistance (Rp) of SFZY is 0.11 and 1.06 Ω cm2 in air and hydrogen atmosphere, respectively. During the Rp stability test, SFZY exhibits better stability than that of SrFeO3-δ in air and hydrogen atmosphere. At 750 ℃, the maximum power density of SFZY/LSGM/SFZY fuel cell reaches 420.1 and 258.31 mWcm−2 using H2 and wet C3H8 as fuel, respectively. In electrolytic mode, the current density of SFZY/LSGM/SFZY electrolysis cell reaches -0.55 A cm−2 at 1.3V for electrolysis of pure CO2 at 750 ℃. In summary, SFZY has a great potential as SSOCs electrode.

Enhancing performance of low-temperature fabricated inverted planar perovskite solar cells through triple-cation perovskite optimization

Perovskite solar cells have garnered significant attention due to the rapidly advancing power conversion efficiency(PCE). Recently, there has been significant interest in enhancing the performance of perovskite solar cells through Cs+ doping. However, the optimal concentration of Cs+ varies between inverted and positive structures, influenced by factors such as cell design, fabrication processes, and performance optimization requirements. In this study, we designed and prepared a novel inverted structure triple cations FA/MA/Cs perovskite solar cell at a low temperature. We observed that the quality of perovskite films can be obviously improved by doping an appropriate amount of Cs+, but excessive Cs+ will destabilize the perovskite structure, leading to rapid film decomposition in ambient air. Our results indicate that employing higher concentrations of Cs+, specifically 10 % and 15 %, leads to superior performance and enhanced stability. Notably, the perovskite solar cell incorporating 10%-Cs exhibits larger grain sizes, uniform particle distribution, and its highest PCE achieves 16.41 %. Our research provides a straightforward and cost-effective strategy for improving the performance of inverted perovskite solar cells utilizing triple cations.

Protonic Ceramic Electrochemical Cell Manufacturing at Idaho National Laboratory

Protonic Ceramic Electrochemical Cells (PCECs), operating at intermediate temperatures of 400-600oC, show great potential for hydrogen production and versatile chemical manufacturing. As this technology rapidly evolves, scaling up production in both quantity and size is crucial. This step bridges the gap between fundamental academic research on small button cells (e.g., 10 mm to 1 inch) and higher-technology readiness level development of industry-standard units (> 10x10 cm2) for stack assembly. At Idaho National Laboratory, we've made significant strides in this transition by applying advanced manufacturing technologies and our expertise in materials science and engineering. Our approach integrates materials, structural, and interface engineering research and development into the cell fabrication process, guided by a stringent quality assurance and quality control (QA&QC) system. This ensures the reliable, repeatable, and durable performance of PCECs.

Fine tuning of Nb-incorporated TiO2 thin films by atomic layer deposition and application as efficient electron transport layer in perovskite solar cells

Access to finely tuned thin films that can act as electron transport layer (ETL) and adapt to the absorber composition and whole cell fabrication process is key to achieve efficient perovskite-based solar cells. In this study, the growth of mixed niobium-titanium oxide (Nb-TiO2) thin films by atomic layer deposition and its use to extract photogenerated electrons is reported. Films were obtained at 200 °C from titanium (IV) i-propoxide, (t-butylimido)tris(diethylamido)niobium(V), and water by introducing Nb2O5 growth cycle in a TiO2 matrix. Process parameters (order of precursor introduction, cycle ratio) were optimized; the growth mechanism and the effective Nb incorporation were investigated by an in situ quartz crystal microbalance and x-ray photoelectron spectroscopy. The composition, morphology, structural, and optoelectronic properties of the as-deposited films were determined using a variety of characterization techniques. As a result, a fine control of the film properties (between TiO2 and Nb2O5 ones) could be achieved by tuning Nb content. To allow a successful implementation in solar devices, a comprehensive annealing study under several conditions (temperatures, various atmospheres) was conducted leading to an evolution of the optical properties due to a morphological change. Ultimately, the incorporation of these 15 nm-thick films in mesoscopic perovskite solar cells as ETL shows an improvement of the cell performances and of their stability with increasing Nb content, in comparison of both TiO2 and Nb2O5 pure compounds, reaching power conversion efficiency up to 18.3% and a stability above 80% of its nominal value after 138 h under illumination.

Printing PEDOT:PSS optimized using Response surface method (RSM) and genetic algorithm (ga) via modified 3D printer for perovskite solar cell applications

Despite significant improvements in solar cell fabrication processes, there are still significant challenges in the fabrication technology owing to poor production efficiency, large equipment and preparatory costs, substrate dependencies, material limitation, etc. This research proposes the use of a modified extrusion-based three-dimensional (3D) printing technology to print thin films of PEDOT:PSS (Poly 3,4-ethylenedioxythiophene:poly styrene sulfonate) for perovskite solar cell (PSC) applications and beyond. The main objective of the research is to induce the benefits of 3D printing technology into thin film printing for PSC applications. The central composite design (CCD) of the response surface method (RSM) in design expert software (Design Expert V13) and a genetic algorithm (GA) in MATLAB software are used to design and optimize the experiment, respectively. Accordingly, a uniformly thin PEDOT:PSS film with a 115 nm thickness is printed with the modified 3D printer at a print speed of 82 mm/s, a bed temperature of 80 °C, and an extrusion start position of 160 mm with a 0.1 mm inner diameter blunt needle and a 0.25 mm x-distance offset. To validate the printed PEDOT:PSS film for PSC application, other PSC layers, except for aluminum electrodes, are spin-coated on top of the 3D-printed PEDOT:PSS film, and the PSC is tested for its performance using a solar simulator. From the test, a competitive open-circuit voltage of 860 mV was produced. In general, printing PSC layers by modifying a cheap and easily available 3D printer has the benefits of excellent material utilization, substrate independence, rapid design, manufacture, and testing of solar cells in the electronic industry.

Unraveling the pivotal role of heterointerfaces on oxide ion transport in solid oxide fuel cells

Overcoming fundamental key issues affecting performance and stability has been recognized as the most important challenge for the commercialization of solid oxide fuel cells (SOFCs). Here, we employed a multipronged approach based on advanced nanoscale analyses coupled with electrochemical evaluation to elucidate the interrelation among ohmic resistance, oxide ion transport, and cation interdiffusion mainly occurring at the interlayer-electrolyte heterointerfaces. The presence of an interdiffusion layer (IDL), formed from the interdiffusion of Ce, Gd, and Zr during high-temperature sintering of conventional screen-printed gadolinia-doped ceria (GDC) interlayer on yttria-stabilized zirconia (YSZ) electrolyte, inadvertently acts as a major barrier to oxide ion transport and results in a significant increase of the ohmic resistance. An effective way to suppress the IDL formation and its oxide ion blocking effect is by alternatively fabricating the GDC interlayer using pulsed laser deposition (PLD), whereby dense layers prepared at a relatively lower deposition temperature without post-growth sintering can be obtained. Consequently, the cell's ohmic resistance is drastically lowered and a significant improvement in cell performance is achieved. These results have major implications for the selection and optimization of cell fabrication processes to mitigate degradation issues associated to heterointerfaces.

Rationally Designed Conversion‐Type Lithium Metal Protective Layer for All‐Solid‐State Lithium Metal Batteries

AbstractA stable interfacial design bridging Li metal and sulfide solid electrolytes is imperative for deploying practical all‐solid‐state Li metal batteries. Despite the extensive exploration of interlayer materials, including inorganic substances, lithiophilic metals, and their composites, a comprehensive understanding of their stability and chemo‐mechanical evolution, particularly those influenced by cell fabrication processes, remains unexplored. Herein, it is meticulously investigate the formation and evolution of LiF, Mg, and conversion‐type multicomponent MgF2 ultrathin interlayers, each fabricated via thermal evaporation deposition. Unexpectedly, LiF and Mg fail to enhance cell performance, with LiF notably susceptible to external pressures during cell fabrication, leading to serious current constriction, while Mg deposition results in the formation of a Li‐rich solid solution. Remarkably, the MgF2 coatings demonstrate substantially superior performance in both Li|Li6PS5Cl|Li symmetric cells (up to 2000 h) and LiNi0.70Co0.15Mn0.15O2|Li6PS5Cl|Li full‐cells (82% capacity retention after 800 cycles) at 30 °C. These results are attributed to the in‐situ formation of LiF and LixMg nanograins through a conversion reaction, which, after repeated cycling, maintains stability and a fixed position at the interface while ensuring uniform interfacial Li+ flux. Supported by comprehensive analyses, these findings highlight the pivotal role of conversion‐type interlayers in mitigating side reactions and preventing Li penetration.

Fabrication of fuel electrode supported proton conducting SOFC via EPD of La2Ce2O7 electrolyte and its performance evaluation

The proton conducting La2Ce2O7 electrolyte has already been shown to be chemically more stable to H2O and CO2 than BaCeO3 based electrolyte materials. It has become widely popular as an alternative electrolyte for low to intermediate temperature operation in solid oxide fuel cells. Few initial studies have reported the fabrication of LCO-based fuel cells using the co-pressing process. Here, we present an alternative, simple, cost-effective and efficient method for the deposition of uniform and dense La2Ce2O7 electrolyte coatings, which is a key requirement for any fuel cell fabrication process. In this work, La2Ce2O7 is synthesized by a conventional solid state reaction route and we have established the process of fuel cell fabrication followed by its investigation for SOFC application as electrolyte material. Different alcohols (e.g. butanol, ethanol, acetone, acetyl acetone and isopropanol) are used as dispersion medium, the suspension chemistry and subsequent coating of LCO powders by electrophoretic deposition are investigated. A thin and good quality coating of about 11 μm thickness is obtained in an ethanol-based suspension under deposition conditions at 50 V for 2 min. Fuel electrode supported half cells with LCO electrolyte fabricated by electrophoretic deposition and performance test of fabricated cell is evaluated in moist H2 (∼3% H2O) as reducing medium and static air as oxidizing medium.

Fabrication processes for all‐inorganic CsPbBr3 perovskite solar cells

AbstractAll‐inorganic perovskite solar cells have shown great potential owing to their superior stability against thermal stress and moisture compared to organic–inorganic perovskite solar cells. However, there are some remaining issues in the all‐inorganic perovskite solar cell fabrication process, such as the low solubility of the perovskite precursors and the occurrence of the secondary phases. In this review, we focus on all‐inorganic CsPbBr3 perovskite solar cells and categorize them based on their fabrication process. Various processes and strategies that have been developed to solve the aforementioned issues including the general process of multistep spin coating are thoroughly investigated. Finally, a summary of the various processes for the all‐inorganic CsPbBr3 perovskite solar cells and an outlook for the development of highly efficient all‐inorganic perovskite solar cells are proposed.image

SYSTEMATIC FIELD APPLICATION OF ENHANCED PLASMONIC ORGANIC SOLAR CELL: AN OVERVIEW

Organic solar cells (OSCs) have attracted considerable research interest due to their satisfactory properties including light-weight, low-cost, low-temperature fabrication process, semi-transparency and mechanical flexibility. Recent advances in OSCs have demonstrated above 10% efficiency in single-junction cells, indicating a strong competitiveness when compared with the commercial silicon photovoltaic system. To obtain maximum efficiency, there is a trade-off between light absorption and charge transport efficiency. Plasmonic light-trapping scheme is a feasible approach to maximize light absorption while maintaining charge transport efficiency. To give an overall look at the plasmonic organic solar cells, we review the recent progress on plasmonic-enhanced OSCs devices by integration with metal plasmonic enhancers, including both experimental and theoretical works. Among the varying proposed plasmonic structures, nano particles are preferable because of their strong scattering properties, particle size tunability, shape, and dielectric environment. In addition, design approaches based on plasmonics can be used to improve absorption in solar cells, permitting a considerable reduction in the physical thickness of solar cell absorber layers, and yielding novel options for solar-cell designs. Also, the simplicity in plasmonics preparation and integration methods is easily compatible with the standard solar cell fabrication process.

Efficiency enhancement of natural cocktail dyes in a TiO2-based dye-sensitized solar cell and performance of electron kinetics on the TiO2 surface

In this study, natural dye extracts were prepared from the dried leaves of Andrographis paniculata and Psidium guajava (APPG). The study’s objective was to increase the light harvesting phenomenon from solar energy utilizing natural dye from APPG, and the problem statement was to harvest the optimum solar radiation and convert it into electrical energy. Acetone and ethanol were used as solvents during the preparation process. Based on this research, the crystallite size of TiO2 nanoparticles was assessed, the impact of acetone and ethanol on APPG dye was compared, and the absorption, FTIR, and UV-Vis spectra of the solar cell fabrication process using solvents were experimentally explored. APPG leaf extract functions as a dye sensitizer. Cells are precisely sandwiched with a photoanode, TiO2 nanoparticles, an electrolyte (I/I3−), and a cathode. The JV properties of dye extracts utilizing acetone and ethanol were measured using a solar simulator equipped with a 100 mW/cm2 Xenon light and a Keithley 2400 Graphical Series SMU. An experimental DSSC with dye extraction and utilizing acetone solvent yielded a maximum photo-conversion efficiency of 0.6914%, while ethanol yielded a photo-conversion efficiency of 0.5630%. Furthermore, an energy-level diagram was used to explain the electron kinetics of DSSC, and the time required for transfer electron injection in the TiO2 surface from a dye-excited state was 150 ps.

External Gettering of Metallic Impurities by Black Silicon Layer

Black silicon (b‐Si) has many attractive properties and is currently being adopted in various fields of semiconductor technology. It is shown here that b‐Si during thermal activation may serve as an external gettering layer to remove metallic impurities and associated defects from bulk Si. The gettering efficiency by b‐Si is estimated according to the results of studying the resistivity, defect density, interstitial iron concentration, and effective minority carrier lifetime on gettered test and ungettered reference Si samples. It is shown that in the thermal oxidation process, the b‐Si layer serves as an effective drain for excess iron atoms and other fast‐diffusing impurities, thereby significantly reducing the density of oxidation‐induced stacking faults in Si. In addition, the resistivity of the substrates decreases, and the bulk carrier lifetime increases significantly. Finally, gettering by b‐Si is introduced into the solar cells fabrication process and its effect on solar cell current–voltage characteristics is investigated. It has been shown that all electronic parameters of the solar cells are improved. The conversion efficiency of ungettered solar cells is 16.8%, and for gettered solar cells, depending on the oxidation temperature, it increases by 1.36–1.96%.

Area-dependent performance variation of ultrasonic spray-coated organic solar cells

Here, a comparative study has been performed to understand the scalability of as developed ultrasonic spray deposition process for large-area organic solar cell fabrication. It was observed that the performance of the devices reduces with increasing active area dimensions. The short circuit current density and power conversion efficiency got decreased by more than 70% on increasing the device area from 0.04 to 1.5 cm2. In the case of small-area devices, the low electrical resistance owing to fewer droplet boundaries and negligible pinholes of the spray-coated film leads to better device performance. Whereas, upon scaling up the device area, the non-uniformity of the spray-coated film starts dominating and is found to be responsible for the reduction in overall device performance. The non-homogeneous film morphology in the case of larger-area devices greatly affects the charge generation, as it decreased from 4.77 × 1021 to 1.92 × 1021 cm−3 s−1 for large-area devices compared to small-area ones. The results suggest that the spray-deposited films greatly suffer from the limitation of droplet boundaries and pin-holes, which need to be addressed further with post-deposition treatments, in order to fabricate commercially viable large-area devices.

Li2Se as cathode additive to prolong the next generation high energy lithium-ion batteries

The initial lithium loss caused by the formation of solid electrolyte interface (SEI) is a critical issue that reduces the energy density of lithium-ion batteries (LIBs). In order to offset the initial capacity loss, herein we propose lithium selenide (Li2Se) as an effective cathode prelithiation agent, which has a high “donor” Li-ion capacity, poor reversibility, relatively low delithiation potential and good compatibility to the existing cell fabrication processes. In a LiNi0.8Co0.1Mn0.1O2 (NCM)/ Si-C-Gr full cell, a high initial charge capacity of 250 mAh/g is obtained with 7% Li2Se additive, and the discharge capacity is 188.2 mAh/g (10.3 mAh/g higher than that of the pristine counterpart). The released capacity from Li2Se can offset the initial capacity loss during the SEI formation, confirmed by the enhanced discharged capacity. In addition, it can serve as a “lithium bank” to compensate the Li loss caused by the ongoing SEI breakage and reformation of Si-C-Gr anodes, leading to an improved cycling stability. The reversible capacity of the full cell with Li2Se prelithiation additives remains 152 mAh/g after 150 cycles at 0.3C, with an increase of 37.1% as compared to the counterpart without the additive. Li2Se is a promising cathode prelithiation agent especially for future advanced battery systems involving high specific capacity anodes with large initial irreversible capacity and poor cycling performance.

Epitaxially Grown p‐type Silicon Wafers Ready for Cell Efficiencies Exceeding 25%

Combining the advantages of a high‐efficiency solar cell concept and a low carbon footprint base material is a promising approach for highly efficient, sustainable, and cost‐effective solar cells. In this work, we investigate the suitability of epitaxially grown p‐type silicon wafers for solar cells with tunnel oxide passivating contact rear emitter. As a first proof of principle, an efficiency limiting bulk recombination analysis of epitaxially grown p‐type silicon wafers deposited on high quality substrates (EpiRef) unveils promising cell efficiency potentials exceeding 25% for three different base resistivities of 3, 14, and 100 Ω cm. To understand the remaining limitations in detail, concentrations of metastable defects Fei, CrB and BO are assessed by lifetime‐calibrated photoluminescence imaging and their impact on the overall recombination is evaluated. The EpiRef wafers’ efficiency potential is tracked along the solar cell fabrication process to quantify the impact of high temperature treatments on the material quality. We observe large areas with few structural defects on the wafer featuring lifetimes exceeding 10 ms and an efficiency potential of 25.8% even after exposing the wafer to a thermal oxidation at 1050 °C.

(Invited) High-Temperature Electrosynthesis of Hydrogen and Syngas - Technology Status and Development Needs

High-temperature solid oxide electrolysis cell (SOEC) technology has been considered and developed for production of hydrogen (from steam) and syngas (from mixtures of steam and carbon dioxide). The SOEC, a solid oxide fuel cell (SOFC) in reverse or electrolysis operating mode, is traditionally derived from the more technologically advanced SOFC. The SOEC uses the same materials and operates in the same temperature range (600˚-800˚C) as the conventional SOFC. The SOEC therefore has the advantages shown by the SOFC such as flexibility in cell and stack designs, multiple options in cell fabrication processes, and choice in operating temperatures. In addition, at the high operating temperature of the SOEC, the electrical energy required for the electrolysis is reduced and the unavoidable Joule heat is used in the splitting process. SOEC technology has made significant progress toward practical applications in the last several years. To date, SOEC single cells, multi-cell stacks and systems have been fabricated/built and operated. However, further improvements are needed for the SOEC in several areas relating to the key drivers (efficiency, reliability and cost) to enable commercialization. This paper provides an overview on the status of SOEC technology, especially zirconia based technology, and discusses R&D needs to move the technology toward practical applications and widespread uses.

Flexible fabric-based GaAs thin-film solar cell for wearable energy harvesting applications

GaAs photovoltaic (PV) cells have been extensively studied for flexible energy harvesting devices due to their merits such as thin-film feasibility, flexibility, and high-efficiency. However, GaAs-based thin-film PV cells have a limitation for the applications in wearable platform since they are not compatible with fabric carrier. To handle this problem, we report thin-film transfer technique that involves a sacrificial layer with a double-layer structure, an Au–Au bonding technique, a Cr/Au bilayer to induce metal stress, and an etchant for fast epitaxial lift-off (ELO). In addition, a polyimide layer attached underneath the fabric substrate not only protects the fragile epi layer but also accelerates the lateral etching via spontaneous bending. The application of these techniques enables the successful transfer of GaAs thin-film PV epi structures onto fabric platform without degrading crystal quality. Fabric-based GaAs PV cells are fabricated via the standard PV cell fabrication process. The platform expansion of GaAs thin-film techniques has great potential for large-scale commercialization. • III-V epi-layers onto fabric substrate can be realized without degrading crystal quality. • The GaAs solar cells are directly integrated with fabric platform. • High efficiencies over 17.49% can be achieved on fabric platform. • Fabric-based GaAs solar cells present the stable output power with high flexibility.

Important Impact of the Slurry Mixing Speed on Water-Processed Li4Ti5O12 Lithium-Ion Anodes in the Presence of H3PO4 as the Processing Additive.

The aqueous processing of lithium transition metal oxides into battery electrodes is attracting a lot of attention as it would allow for avoiding the use of harmful N-methyl-2-pyrrolidone (NMP) from the cell fabrication process and, thus, render it more sustainable. The addition of slurry additives, for instance phosphoric acid (PA), has been proven to be highly effective for overcoming the corresponding challenges such as aluminum current collector corrosion and stabilization of the active material particle. Herein, a comprehensive investigation of the effect of the ball-milling speed on the effectiveness of PA as a slurry additive is reported using Li4Ti5O12 (LTO) as an exemplary lithium transition metal oxide. Interestingly, at elevated ball-milling speeds, rod-shaped lithium phosphate particles are formed, which remain absent at lower ball-milling speeds. A detailed surface characterization by means of SEM, EDX, HRTEM, STEM-EDX, XPS, and EIS revealed that in the latter case, a thin protective phosphate layer is formed on the LTO particles, leading to an improved electrochemical performance. As a result, the corresponding lithium-ion cells comprising LTO anodes and LiNi0.5Mn0.3Co0.2O2 (NMC532) cathodes reveal greater long-term cycling stability and higher capacity retention after more than 800 cycles. This superior performance originates from the less resistive electrode-electrolyte interphase evolving upon cycling, owing to the interface-stabilizing effect of the lithium phosphate coating formed during electrode preparation. The results highlight the importance of commonly neglected─frequently not even reported─electrode preparation parameters.

Facile preparation of electrodes of efficient electrolyte-supported solid oxide fuel cells using a direct assembly approach

Solid oxide fuel cells (SOFCs) are the most efficient energy conversion technology to convert the chemical energy of fuels like hydrogen, natural gas, etc. to electricity. However, one of the limiting factors in the commercial viability of SOFCs technologies is the time-consuming and high-cost multiple cell fabrication processes. Here, we report the development of a facile procedure for the preparation of an electrolyte-supported cell with a Ni-Gd0.1Ce0.9O1.95 composite anode and a La0.6Sr0.4Co0.2Fe0.8O3-δ cathode, and the fabrication procedure of the electrodes decreases from four steps of screen-printing and sintering of conventional cell preparation processes to two steps of screen-printing using a direct assembly approach without the high-temperature sintering steps. The most important observation is the simultaneous formation of the electrode/electrolyte interfaces of both the anode and cathode by in situ passing a current through the directly assembled cells at 800 ℃. The power density of the directly assembled cell reaches 0.41 W cm−2 at a voltage of 0.7 V and 800 ℃, close to 0.46 W cm−2 of the sintered cell. The directly assembled cell shows comparable operational stability to the sintered cell at 800 ℃ for 100 h. This work sheds light on the facile fabrication of electrolyte-supported cells with substantially simplified preparation procedures and reduced costs.

In situ modulated photoluminescence study of the hydrogenation processes of tunnel oxide passivating contacts during plasma processes

AbstractCompared to current c‐Si solar cell technologies, fired passivating contacts (FPCs) can reduce the thermal budget of the solar cell fabrication process. In this study, a simplified process flow for the fabrication of these contacts is investigated along with the use of two hole transport materials: p‐type nanocrystalline silicon ((p) nc‐Si:H) and nanocrystalline silicon oxide ((p) nc‐SiOx:H). More specifically, the passivation properties provided by the FPC stack are assessed at different stages of the manufacturing. The hydrogenation process is studied using in situ modulated photoluminescence (MPL) which allows to measure in real time the effective minority carrier lifetime in the sample during a process step. The increase of passivation observed during the deposition of the capping silicon‐nitride (a‐SiNx:H) layer by plasma‐enhanced chemical vapor deposition is shown to be due to both annealing of the sample and the deposition in presence of silane in the plasma, while the exposure to an NH3 and H2 plasma is mostly detrimental for the passivation properties. The in situ MPL measurements additionally allow us to show that the improvement of the passivation properties happens during the first few minutes of a‐SiNx:H deposition.