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The potential performance of silicon heterojunction solar cells applying transparent passivating contact (TPC) at the front side, based on a nc‐SiC:H/SiO2 layer stack, is modeled and investigated. Herein, a complete multiscale electro‐optical device model of TPC solar cells is developed. The model is then used to understand and analyze such cells and search for potential conversion efficiency improvement paths. The influences of contact layer thicknesses and other properties on device performance are studied. An algorithm‐based optimization of cell electro‐optical performance is performed. It is implemented by coupling a genetic algorithm with a finite element method‐based TPC solar cell device model. Optimum front contact layer thicknesses are calculated. For optically optimized TPC contact layer thicknesses, an optical improvement of around 0.5 mA cm−2 is found. Moreover, for complete electro‐optical optimization of TPC layers, about 0.27% absolute value increment in power conversion efficiency is calculated. At the rear side, proper designing of optimizing carrier transport using active dopant concentration of p‐type a‐Si:H layer and indium tin oxide layer has shown a potential to reach power conversion efficiency beyond 25%. [ABSTRACT FROM AUTHOR]

In this work, we propose a route to achieve a certified efficiency of up to 24.51% for silicon heterojunction (SHJ) solar cell on a full‐size n‐type M2 monocrystalline‐silicon Cz wafer (total area, 244.53 cm2) by mainly improving the design of the hydrogenated intrinsic amorphous silicon (a‐Si:H) on the rear side of the solar cell and the back reflector. A dense second intrinsic a‐Si:H layer with an optimized thickness can improve the vertical carrier transport, resulting in an improved fill factor (FF). In order to reduce the plasmonic absorption at the back reflector, a low‐refractive‐index magnesium fluoride (MgF2) is deposited before the Ag layer; this leads to an improved gain of short circuit current density (Jsc). In total, together with MgF2 double antireflection coating and other fine optimizations during cell fabrication process, ~1% absolute efficiency enhancement is finally obtained. A detailed loss analysis based on Quokka3 simulation is presented to confirm the design principles, which also gives an outlook of how to improve the efficiency further. [ABSTRACT FROM AUTHOR]

Hot‐wire chemical vapor deposition was utilized to develop rapidly grown and high‐quality phosphorus‐doped amorphous silicon (a‐Si:H) thin films for poly‐crystalline silicon on tunnel oxide carrier‐selective passivating contacts. Deposition rates higher than 150 nm/min were obtained for the in situ phosphorus‐doped a‐Si:H layers. To optimize the passivating contact performance, material properties such as microstructures as well as hydrogen content were characterized and analyzed for these phosphorus‐doped a‐Si:H films. The results show that a certain microstructure of the films is crucial for the passivation quality and the conductance of passivating contacts. Porous silicon layers were severely oxidized during high‐temperature crystallization, giving rise to very low conductance. The insufficient effective doping concentration in these layers also yields inferior passivation quality due to lack of field‐effect passivation. On the other hand, dense silicon layers are insensitive to oxidation but very sensitive to blistering of the films during the subsequent high‐temperature process steps. By optimizing the deposition parameters, a firing‐stable‐implied open‐circuit voltage of 737 mV and a contact resistivity of 10 mΩ·cm2 were achieved at a high deposition rate of 100 nm/min while 733 mV and 90 mΩ·cm2 were achieved at an even higher deposition rate of 150 nm/min. [ABSTRACT FROM AUTHOR]

One of the challenges in fabricating high‐performance n‐type silicon heterojunction (SHJ) solar cells is developing a high‐quality transparent conductive oxide (TCO) electrode. Herein, the development and application of low‐temperature sputtered titanium‐doped indium oxide (ITiO) in n‐type, rear junction SHJ solar cells as a function of the oxygen flow ratio is presented. The microstructure, morphology, and optoelectronic properties are analyzed. The grain size of ITiO thin films decreases rapidly as the oxygen flow ratio is increased. Compared with an indium tin oxide (ITO) thin film, ITiO shows a superior balance in achieving excellent optoelectronic properties by reducing film resistivity but maintaining weak absorption. Higher fill factor is obtained by substituting ITiO for ITO as the front electrode in SHJ solar cells, which is mainly due to the improved carrier transport. Resistivity contributions of front‐side vertical and lateral carrier transport are disclosed by Quokka3 simulation. A champion cell efficiency of 23.81% with ITiO is achieved, which is so far the highest efficiency among the application of ITiO in SHJ solar cells to the best of our knowledge. The study demonstrates that ITiO is a promising TCO candidate for SHJ solar cells. [ABSTRACT FROM AUTHOR]

N‐type microcrystalline silicon carbide (μc‐SiC:H(n)) is a wide bandgap material that is very promising for the use on the front side of crystalline silicon (c‐Si) solar cells. It offers a high optical transparency and a suitable refractive index that reduces parasitic absorption and reflection losses, respectively. In this work, we investigate the potential of hot wire chemical vapor deposition (HWCVD)–grown μc‐SiC:H(n) for c‐Si solar cells with interdigitated back contacts (IBC). We demonstrate outstanding passivation quality of μc‐SiC:H(n) on tunnel oxide (SiO2)–passivated c‐Si with an implied open‐circuit voltage of 742 mV and a saturation current density of 3.6 fA/cm2. This excellent passivation quality is achieved directly after the HWCVD deposition of μc‐SiC:H(n) at 250°C heater temperature without any further treatments like recrystallization or hydrogenation. Additionally, we developed magnesium fluoride (MgF2)/silicon nitride (SiNx:H)/silicon carbide antireflection coatings that reduce optical losses on the front side to only 0.47 mA/cm2 with MgF2/SiNx:H/μc‐SiC:H(n) and 0.62 mA/cm2 with MgF2/μc‐SiC:H(n). Finally, calculations with Sentaurus TCAD simulation using MgF2/μc‐SiC:H(n)/SiO2/c‐Si as front side layer stack in an IBC solar cell reveal a short‐circuit current density of 42.2 mA/cm2, an open‐circuit voltage of 738 mV, a fill factor of 85.2% and a maximum power conversion efficiency of 26.6%. [ABSTRACT FROM AUTHOR]

Conductive hydrogenated silicon carbide (SiC x :H) is discovered as a promising hydrogenation material for tunnel oxide passivating contacts (TOPCon) solar cells. The proposed SiC x :H layer enables a good passivation quality and features a good electrical conductivity, which eliminates the need of etching back of SiN x :H and indium tin oxide (ITO)/Ag deposition for metallization and reduces the number of process steps. The SiC x :H is deposited by hot wire chemical vapor deposition (HWCVD) and the filament temperature ( T f ) during deposition is systematically investigated. Via tuning the SiC x :H layer, implied open-circuit voltages (i V oc ) up to 742 ± 0.5 mV and a contact resistivity (ρ c ) of 21.1 ± 5.4 mΩ·cm 2 is achieved using SiC x :H on top of poly-Si(n)/SiO x /c-Si(n) stack at T f of 2000 °C. Electrochemical capacitance-voltage (ECV) and secondary ion mass spectrometry (SIMS) measurements were conducted to investigate the passivation mechanism. Results show that the hydrogenation at the SiO x /c-Si(n) interface is responsible for the high passivation quality. To assess its validity, the TOPCon stack was incorporated as rear electron selective-contact in a proof-of-concept n-type solar cells featuring ITO/a-Si:H(p)/a-Si:H(i) as front hole selective-contact, which demonstrates a conversion efficiency up to 21.4%, a noticeable open-circuit voltage ( V oc ) of 724 mV and a fill factor (FF) of 80%.