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The effect of process-induced defects on the photo-generated charge-carrier lifetime and solar cell performance is critical, which will help optimize the process recipe. In this work, we attempt to quantify the effects of process-induced defects during boron implantation on the n-type silicon wafer in different annealing ambiences. We have evaluated the role of defects that can be formed during oxygen and inert ambience annealing on n-type bifacial passivated emitter rear totally diffused solar cells using a recombination current prefactor (J0). The numerically calculated J0 is calibrated with the reported experimental J0 values using two different methods: (i) Shockley–Read–Hall lifetime and (ii) effective trap-density method. In the latter method, we used the simulated defect density profiles. Both methods capture the process-induced degradation. We observed that the process-induced defects could deteriorate by almost 1% absolute efficiency for the considered annealing conditions. We found that dislocation loops alone cause an ignorable effect on terminal characteristics, but other process-induced mechanisms could dominantly degrade the cell's performance. To further support, we show that independent defects (apart from coupled defects) other than dislocation loops could explain the experimentally reported boron-implanted diodes' J–V curves under reverse bias conditions. [ABSTRACT FROM AUTHOR]

Tandem solar cells are rationally designed and fabricated by stacking multiple subcells to achieve power conversion efficiency well above the Shockley‐Queisser (SQ) limit. There is a large selection pool for the subcell candidates, such as Si, III–V, Kesterite, Perovskite, and organic solar cells. A series of different combinations of these subcells have been successfully demonstrated in practical tandem solar cell devices. However, there has not been a systematic summary of how to connect subcells in a tandem solar cell using a practical, cost‐effective, and efficiency‐beneficial fashion. In this work, the connection manners of subcells within a tandem cell are classified into three main categories, performing sequential growth, using the physical connection, and applying an intermediate layer, focusing on systematical description of intermediate layers using different materials. The advantages and disadvantages of these connection methods and their applicability to tandem cell types are further elaborated using two typical example models, III–V/Si and Perovskite inclusive tandem cell devices. Eventually, this work can provide useful guidance on how to carry out a suitable intermediate connection in the design of tandem solar cells depending on the selected subcells and device structure. [ABSTRACT FROM AUTHOR]

Multi‐absorbers, and tandem solar cells (TSCs), have enticed research focus with their competitive advantage of crossing the limits posed by Shockley–Queisser efficiency by single‐junction solar cell (SC). Perovskite solar cells (PSC) with their bandgap tunability and ease of solution processing at low temperatures for securing high efficiency (25.8%) provide an ideal candidate for top cell in TSC. Simultaneously, Si SCs with a 95% market share and their ideal low bandgap (1.12 eV) for capturing high‐energy photons in the near‐infrared (NIR) can assume bottom cell in TSC. This review highlights the research perspective for perovskite/Si TSCs to expedite its emergence as future TSC. The 4T device architecture of perovskite/Si TSC optically couples the subcells whereas the 2T configuration ensures the optical and electrical coupling among the constituent subcells. The semitransparency of the top cell, flat as well as textured Si bottom cell, matching of the current between the subcell through the recombination and tunnel junction layers, and modification of perovskites through‐thickness variation are few worth‐considering factors that contribute toward highly efficient perovskite/Si TSC. Finally, the research insight about perovskite/Si and all‐perovskite TSC is analyzed with reference to the ideal choice for the bottom cell. [ABSTRACT FROM AUTHOR]

Redox chemistry transpiring at the interface of NiOx hole transport layer (HTL) and perovskite absorber is a critical phenomenon leading to relatively low values of open circuit voltage (VOC) and fill factor (FF), in turn hampering the overall device performance and stability. In this work, for the first time, the hard acid electronic nature of vanadium (V) dopant in nickel oxide HTL is opportunely exploited to mitigate the undesirable Lewis acid–base reactions occurring at the HTL/mixed-cation perovskite interface. The findings of the study show that vanadium doping results in improved interfacial energetics along with decreased VOC loss, confirming that despite the increase in Ni3+/Ni2+ ratio with the vanadium dopant, the redox reaction catalyzed by Ni3+ ions is kept under check. Vanadium doping also aided in the realization of superior perovskite films with lower Urbach energy, which translated into one order increase in maximum photoinduced carrier generation rate per unit volume. Carrier dynamics investigations show fewer defect states (lower VTFL) and trap-assisted recombination (lower diode ideality factor), which optimize the devices' photovoltaic performance. These benefits collectively contribute to low-loss charge transfer across the NiOx/mixed-cation perovskite interface, which increases the relative efficiency by ∼30% for 5 wt% V-doped NiOx devices compared to pristine NiOx devices, augmented by an increase in device J–V parameters like open circuit voltage (VOC), short circuit current density (JSC), and fill factor (FF). [ABSTRACT FROM AUTHOR]

The silicon photovoltaic industry is rapidly expanding production capacity for TOPCon solar cells and surveys such as the ITRPV 2024 forecast worldwide market dominance for this cell concept from the year 2024 and beyond. Already now, approaches such as laser doped selective emitter and alternative methods for contact formation such as laser-enhanced contact optimization (LECO) are increasingly used in industry to reduce metal induced recombination at the cell front side. However, in order to fully avoid recombination at the front contacts the application of local passivated contacts under the metal fingers would be desirable as final evolutionary step of both-side-contacted single-junction silicon solar cells via the high-temperature route. The present paper proposes a lean fabrication process to achieve this goal and provides detailed experimental results for solar cells with polycrystalline silicon passivated contacts for both polarities. It is shown that local passivated contacts can be integrated into standard TOPCon cells by adding only a few additional process steps to the current industrial baseline process. Crucially, it is shown that this cell concept can achieve vanishing metal induced charge carrier recombination with differences below 2 mV between implied open-circuit voltage of the non-metalized cell precursor and the external open-circuit voltage of the final solar cell. In the present study this enables a champion device with an external open-circuit voltage of 719 mV and an efficiency of 23.4%. While these results mark an important milestone on the way towards a fully passivated TOPCon cell, the paper also details the challenges related to the development and integration of local passivated contacts and the shortcomings that have to be addressed in order to achieve a relevant efficiency gain over standard TOPCon cells. [ABSTRACT FROM AUTHOR]

Flexible perovskite solar cells (f‐PSCs) as a promising power source have grabbed surging attention from academia and industry specialists by integrating with different wearable and portable electronics. With the development of low‐temperature solution preparation technology and the application of different engineering strategies, the power conversion efficiency of f‐PSCs has approached 24%. Due to the inherent properties and application scenarios of f‐PSCs, the study of strain in these devices is recognized as one of the key factors in obtaining ideal devices and promoting commercialization. The strains mainly from the change of bond and lattice volume can promote phase transformation, induce decomposition of perovskite film, decrease mechanical stability, etc. However, the effect of strain on the performance of f‐PSCs has not been systematically summarized yet. Herein, the sources of strain, evaluation methods, impacts on f‐PSCs, and the engineering strategies to modulate strain are summarized. Furthermore, the problems and future challenges in this regard are raised, and solutions and outlooks are offered. This review is dedicated to summarizing and enhancing the research into the strain of f‐PSCs to provide some new insights that can further improve the optoelectronic performance and stability of flexible devices. [ABSTRACT FROM AUTHOR]

Conventional semi‐transparent perovskite solar cells (ST‐PSCs) generally exhibit inferior performance and stability relative to opaque PSCs. However, a comprehensive understanding of the origins of inferior performance and stability of ST‐PSCs and a practical solution to these challenges are both lacking. Here, it is shown for the first time that lithium ions from a lithium bis(trifluoromethanesulfonyl)imide (LiTFSI)‐doped 2,2′,7,7′‐tetrakis[N,N‐di(4‐methoxyphenyl)amino]−9,9′‐spirobifluorene (Spiro‐MeOTAD) hole‐transport layer (HTL) can diffuse into the molybdenum trioxide buffer layer at their interface, yielding ST‐PSCs with lower efficiency and accelerated degradation. It is also demonstrated that this undesired Li‐ion diffusion can be avoided by HTL surface modification with stable lithium oxides. Using this approach, the constructed ST‐PSC exhibits a new record power conversion efficiency (PCE) of 22.02% (21.68% certified) and a fill factor of >80%, with >99% shelf‐stability after 400 h and >99% operational stability for 240 h, which clears away this longstanding limitation of the performance and stability of ST‐PSCs. This strategy is also applied to fabricate four‐ and two‐terminal perovskite/silicon tandem solar cells with bifacial equivalent efficiencies of 31.5% and 26.34%, respectively, at 20% albedo. [ABSTRACT FROM AUTHOR]

Among all‐inorganic perovskites, CsPbIBr2 has become a potential candidate in semitransparent perovskite solar cells (ST‐PSCs) due to its excellent thermal stability and suitable bandgap. Herein, by optimizing the ambient temperature in an N2‐filled glovebox, the growth process of CsPbIBr2 crystals is regulated to avoid the generation of pinholes and improve the photoelectric conversion capacity of perovskite cells. When the ambient temperature is around 25 °C, the champion power conversion efficiency (PCE) of 10.82% with opaque n–i–p structure is achieved. Based on MoOx/Ag/MoOx (20/12/20 nm) multilayer top electrode, the ST‐PSC device achieves a maximum PCE of 7.06% at the fluorine‐doped tin oxide side under the simulated 1 sun illumination condition and a PCE of 23.96% at MoOx/Ag/MoOx electrode side under the intensity of 1000 lux (≈350 μW cm−2) provided by a white light‐emitting diode lamp, along with an average visible transmittance of 29.25%. The resulting perovskite solar cell is the first bifacial inorganic ST‐PSC that could be used under both sunlight and indoor light, which is an important step toward all‐day power generation of inorganic ST‐PSCs and building‐integrated photovoltaics. [ABSTRACT FROM AUTHOR]

Semitransparent photovoltaic (STPV) solar cells offer an immense opportunity to expand the scope of photovoltaics to special applications such as windows, facades, skylights, and so on. These new opportunities have encouraged researchers to develop STPVs using traditional thin‐film solar cell technologies (amorphous‐Si, CdTe, and CIGS or emerging solar cells (organic, perovskites, and dye‐sensitized). There are considerable improvements in both power conversion efficiency (PCE) and semitransparency of these STPV devices. This review studies the device structure of state‐of‐the‐art STPV devices and thereby analyzes the different approaches toward maximizing the product of PCE and average visible transmittance. The origins of PCE losses during the opaque‐to‐semitransparent transition in the different STPV technologies are discussed. In addition, critical practical aspects relevant to all STPV devices, such as compatibility of the top transparent electrode with the device structure, buffer layer optimization, light management engineering, scale‐up, and stability, are also reported. This overview is expected to facilitate researchers across different technologies to identify and overcome the challenges toward achieving higher light utilization efficiencies in STPVs. [ABSTRACT FROM AUTHOR]

Opto‐electronic models that seek to predict the performance of perovskite and tandem solar cells (PSCs/TSCs) often keep the optical and recombination parameters (ORPs) constant in subsequent studies. During fabrication of PSCs, however, these parameters can vary significantly. To account for the inherent fabrication variability, a comprehensive opto‐electronic‐electric model to predict the current–voltage characteristics of four‐terminal (4T) TSCs is developed. This model is calibrated with forty‐eight in‐house fabricated transparent PSCs with perovskite layer thickness of 420, 550, and 700 nm and corresponding median efficiencies of 20.6%, 21.1%, and 21.0%, respectively; a CIS bottom cell with stand‐alone efficiency of 17.5%; and combined 4T TSCs with a median efficiency of 29.0%. After fitting and validation, the functional forms of the ORPs are captured to estimate how they change with perovskite layer thickness. Finally, the errors with models assuming constant ORPs are demonstrated and how to improve the TSCs efficiency to more than 30% is discussed. [ABSTRACT FROM AUTHOR]

We present a new statistical study to optimize the manufacturing conditions of hybrid perovskite-based photovoltaic cells (ITO/PEDOT:PSS/CH3NH3PbI3/PCBM/Ag). The parameters were varied at three levels; high, medium, and low, i.e., the rotation speed of the spin coating, ω , to deposit the organic–inorganic perovskite (CH3NH3PbI3) film, the concentration of the holes conductor polymer (PCBM), C , and the solvents, dimethyl sulfoxide, N,N-dimethylformamide, and diethyl-ether evaporation time, t . The best performing device obtained a J SC of 19.04 mA/cm2, V OC of 0.971 mV, with a fill factor, FF of 46.54%, resulting in a photovoltaic efficiency (η) of 8.6%. These solar cell parameters were obtained with a medium-speed rotation at 4500 rpm, with a high concentration of PCBM (25 mg/mL), and leaving 10 min as the maximum evaporating time. Statistical analysis suggests this good performance is due to an optimum PCBM thickness layer ,avoiding leakage and recombination processes and promoting fast charge carrier transport. At the same time, the perovskite layer is thick enough to promote good photogeneration without increasing the recombination processes, reaching an equilibrium between photogeneration, transport, and recombination. [ABSTRACT FROM AUTHOR]

Owing to the bandgap‐bowing effect, mixed lead‐tin halide perovskites provide ideal bandgaps for the bottom subcell of all‐perovskite tandem photovoltaic devices that offer fundamentally elevated power‐conversion efficiencies. However, these materials suffer from degradation in ambient air, which worsens their optoelectronic properties and hinders their usability for photovoltaic applications. Such degradation pathways are not yet fully understood, especially for the perovskites in the middle of the APbxSn1‐xI3 solid solution line, which offer the narrowest bandgaps across the range. This study unravels the degradation mechanisms of APbxSn1‐xI3 perovskites, reporting clear differences between mixed lead‐tin (x = 0.5) and tin‐only (x = 0) perovskites. The dynamic optoelectronic properties, electronic structure, crystal structure, and decomposition products of the perovskite thin films are examined in situ during air exposure. Both perovskite compositions suffer from the formation of defects over the timescale of hours, as indicated by a significant reduction in their charge‐carrier diffusion lengths. For tin‐only perovskite, degradation predominantly causes the formation of energetically shallow tin vacancies and hole doping. However, for mixed lead‐tin perovskite, deep trap states are formed that significantly accelerate charge‐carrier recombination, yet leave mobilities relatively unaffected. These findings highlight the need for passivation strategies tailored specifically to mixed lead‐tin iodide perovskites. [ABSTRACT FROM AUTHOR]

Transparent photovoltaics (TPVs) can be integrated into the surfaces of buildings and vehicles to provide point‐of‐use power without impacting aesthetics. Unlike TPVs that target the photon‐rich near‐infrared portion of the solar spectrum, TPVs that harvest ultraviolet (UV) photons can have significantly higher transparency and color neutrality, offering a superior solution for low‐power electronics with stringent aesthetic tolerance. In addition to being highly transparent and colorless, an ideal UV‐absorbing TPV should also be operationally stable and scalable over large areas while still outputting sufficient power for its specified application. None of today's TPVs meet all these criteria simultaneously. Here, the first UV‐absorbing TPV is demonstrated that satisfies all four criteria by using CsPbCl2.5Br0.5 as the absorber. By precisely tuning the halide ratio during thermal co‐evaporation, high‐quality large‐area perovskite films can be accessed with an ideal absorption cutoff for aesthetic performance. The resulting TPVs exhibit a record average visible transmittance of 84.6% and a color rendering index of 96.5, while maintaining an output power density of 11 W m−2 under one‐sun illumination. Further, the large‐area prototypes up to 25 cm2 are demonstrated, that are operationally stable with extrapolated lifetimes of >20 yrs under outdoor conditions. [ABSTRACT FROM AUTHOR]

Wide bandgap perovskites are being widely studied in view of their potential applications in tandem devices and other semitransparent photovoltaics. Vacuum deposition of perovskite thin films is advantageous as it allows the fabrication of multilayer devices, fine control over thickness and purity, and it can be upscaled to meet production needs. However, the vacuum processing of multicomponent perovskites (typically used to achieve wide bandgaps) is not straightforward, because one needs to simultaneously control several thermal sources during the deposition. Here a simplified dual‐source vacuum deposition method to obtain wide bandgap perovskite films is shown. The solar cells obtained with these materials have similar or even larger efficiency as those including multiple A‐cations, but are much more thermally stable, up to 3500 h at 85 °C for a perovskite with a bandgap of 1.64 eV. With optimized thickness, record efficiency of >19% and semitransparent devices with stabilized power output in excess of 17% are achieved. [ABSTRACT FROM AUTHOR]

Carrier‐selective contact is an essential strategy to improve the power conversion efficiency (PCE) of crystalline silicon (c‐Si) solar cells by enhancing carrier transport and reducing recombination. Many two‐dimensional transition metal carbides/nitrides (MXene) possess excellent electrical conductivity and tunable work function, enabling them as potential carrier‐selective contact materials for c‐Si solar cells. Herein, low work function (3.71 eV) monolayer Ti3C2Tx thin films are fabricated with an ordered arrangement of nanosheets by interfacial self‐assembly method, and the Ti3C2Tx/n‐type c‐Si heterostructure achieves extremely low contact resistivity (22.64 mΩ cm2). Dopant‐free heterojunction crystalline silicon solar cell with self‐assembled monolayer Ti3C2Tx electron‐selective contact is reported for the first time, showing the highest PCE of 16.46% among MXene monolayer‐based c‐Si solar cells, which is mainly attributed to the greatly increased fill factor and open circuit voltage by the accession of self‐assembled monolayer Ti3C2Tx as electron transport layer. This work opens up the possibility of applying MXene as electron transport material for photovoltaic devices. [ABSTRACT FROM AUTHOR]

Nickel oxide (NiOx$\left(\text{NiO}\right)_{x}$) is a promising hole transport material for perovskite/Si tandem solar cells. Various silicon cell architectures may be used as bottom cells. The polycrystalline (poly‐Si) p+/n+$\left(\text{p}\right)^{+} / \left(\text{n}\right)^{+}$ tunnel diode is expected to be a high‐efficiency interconnection scheme between the two subcells of monolithic tandems in p‐i‐n configuration with a high thermal budget, excellent passivation properties, and low contact resistivity. However, NiOx$\left(\text{NiO}\right)_{x}$ is then interfaced to poly‐Si(p+$\left(\text{p}\right)^{+}$) and the chemical integrity of the interface due to the necessity of annealing treatments has to be questioned. For this purpose, the NiOx$\left(\text{NiO}\right)_{x}$/poly‐Si contact resistivity for different annealing temperatures is investigated between 100 and 500 °C, and two different NiOx$\left(\text{NiO}\right)_{x}$ deposition techniques, namely, wet‐chemically applied and sputter‐deposited NiOx$\left(\text{NiO}\right)_{x}$. The values of more than 1 Ω cm2$1 \textrm{ } \Omega \textrm{ } \left(\text{cm}\right)^{2}$ are obtained. The insertion of a nm‐thin metallic Ni interlayer is shown to enable a tremendous decrease of the contact resistivity by 2–3 orders of magnitude. The formation of NiSi2$\left(\text{NiSi}\right)_{2}$ is proven by highly resolved (scanning) transmission electron microscopy ((S)TEM) coupled with energy‐dispersive X‐ray spectroscopy (EDXS). This interfacial engineering approach is expected to provide an effective way of improving the contact properties and integrability of NiOx$\left(\text{NiO}\right)_{x}$ into various tandem cell processes. [ABSTRACT FROM AUTHOR]

In aerospace applications, SiOx deposition on perovskite solar cells makes them more stable. However, the reflectance of the light changes and the current density decreases can lower the efficiency of the solar cell. The thickness of the perovskite material, ETL, and HTL must be re-optimized, and testing the number of cases experimentally takes a long time and costs a lot of money. In this paper, an OPAL2 simulation was used to find the thickness and material of ETL and HTL that reduces the amount of light reflected by the perovskite material in a perovskite solar cell with a silicon oxide film. In our simulations, we used an air/SiO2/AZO/transport layer/perovskite structure to find the ratio of incident light to the current density generated by the perovskite material and the thickness of the transport layer to maximize the current density. The results showed that when 7 nm of ZnS material was used for CH3NH3PbI3-nanocrystalline perovskite material, a high ratio of 95.3% was achieved. In the case of CsFAPbIBr with a band gap of 1.70 eV, a high ratio of 94.89% was shown when ZnS was used. [ABSTRACT FROM AUTHOR]

Silicon (Si) is a low‐cost, stable photovoltaic market contributor which is approaching its single‐junction theoretical efficiency limit. To further elevate the efficiency of crystalline Si (c‐Si) afterward, Si solar cells (SCs) need a proper top cell absorber in Si tandem SCs. Herein, the top cell absorber is studied by evaluating their current state of the art, the existing challenges, and possible future solutions which can enhance their efficiency. The progress of perovskite/Si tandem SC both for monolithic and four terminals is exceptional but still many challenges limit their commercialization. In view of these challenges, the relative's solutions are prescribed in detail to make possible their realization. III–V semiconductors being mature candidates still face a growth/fabrication problem, which makes them a costly option for III–V/Si tandem SCs. Effective growth strategies along with technical solutions are discussed in detail. Emerging chalcogenides are considered the future of tandem technology. Recent developments in the chalcogenides/Si tandem SC are highlighted and the possible options are presented. In the end, a short note is given on the near future tandem materials for Si tandem SCs. [ABSTRACT FROM AUTHOR]

This study entails the examination of tunnel oxide passivated contact on p‐type silicon wafers (p‐TOPCon) passivated with n‐polysilicon for a solar cell by using Quokka‐3, a numerical simulation program. The effects of the thickness, bulk lifetime, resistivity, and selectivity of charge carriers due to the polysilicon passivated contact are investigated. Through such n‐polysilicon passivated contact, the back‐emitter solar cells engender higher internal power owing to enhanced surface passivation. This further reduces the shading loss due to front metallization; however, the reduced minority carrier lifetime of the p‐type Czochralski (Cz) wafer restricts the possibilities for high efficiency. Subsequently, the minority charge carrier lifetime of the p‐type wafer conceivably becomes an obstacle to realizing TOPCon solar cells with a high conversion efficiency. This study demonstrates that a configuration suitable for the industrial manufacturing of high‐efficiency solar cells is a crystalline silicon solar cell on a p‐type wafer through a rear‐emitter n‐polysilicon passivated contact. A roadmap toward 24.87% of the p‐TOPCon solar cells through the n‐type polysilicon passivated contact is also devised. [ABSTRACT FROM AUTHOR]

Today, it has become an important task to modify existing traditional silicon-based solar cell factory to produce high-efficiency silicon-based heterojunction solar cells, at a lower cost. Therefore, the aim of this paper is to analyze CH3NH3PbI3 and ZnO materials as an emitter layer for p-type silicon wafer-based heterojunction solar cells. CH3NH3PbI3 and ZnO can be synthesized using the cheap Sol-Gel method and can form n-type semiconductor. We propose to combine these two materials since CH3NH3PbI3 is a great light absorber and ZnO has an optimal complex refractive index which can be used as antireflection material. The photoelectric parameters of n-CH3NH3PbI3/p-Si, n-ZnO/p-Si, and n-Si/p-Si solar cells have been studied in the range of 20-200 nm of emitter layer thickness. It has been found that the short circuit current for CH3NH3PbI3/p-Si and n-ZnO/p-Si solar cells is almost the same when the emitter layer thickness is in the range of 20-100 nm. Additionally, when the emitter layer thickness is greater than 100 nm, the short circuit current of CH3NH3PbI3/p-Si exceeds that of n-ZnO/p-Si. The optimal emitter layer thickness for n-CH3NH3PbI3/p-Si and n-ZnO/p-Si was found equal to 80 nm. Using this value, the short-circuit current and the fill factor were estimated around 18.27 mA/cm2 and 0.77 for n-CH3NH3PbI3/p-Si and 18.06 mA/cm2 and 0.73 for n-ZnO/p-Si. Results show that the efficiency of n-CH3NH3PbI3/p-Si and n-ZnO/p-Si solar cells with an emitter layer thickness of 80 nm are 1.314 and 1.298 times greater than efficiency of traditional n-Si/p-Si for the same sizes. These findings will help perovskites materials to be more appealing in the PV industry and accelerate their development to become a viable alternative in the renewable energy sector. [ABSTRACT FROM AUTHOR]

A comprehensive algorithm for calculating the energy yield (EY) is used as the most important figure‐of‐merit in determining the capabilities of PV devices in realistic operation. The model is based on advanced optical modeling and extensive opto‐thermo‐electrical characterization. It takes the realistic environmental and device installation data fully into account, as well as the complete set of device specifications including all relevant temperature‐induced variations. A detailed analysis and optimization of two‐terminal perovskite‐silicon tandem devices are done in terms of long‐term electrical energy production at different geographical locations from distinct Köppen–Geiger–Photovoltaic climate zones (KGPV). It is shown that the optimal perovskite bandgap (EG,PK) in a tandem device operating under realistic conditions is in all cases higher than the one optimized under STC, yet does not differ significantly from location to location, which is beneficial from the manufacturing point of view. The optimal EG,PK is influenced primarily by the spectral distribution of incident irradiance, and not so much by the operating temperature conditions. Moreover, a clear linear dependency between the optimal EG,PK and the weighted average photon energy of the incident irradiance is demonstrated, which presents an important rule for rapid tandem design. [ABSTRACT FROM AUTHOR]

The interfacial defects or imperfections in the multilayer perovskite solar cells (PSCs) are detrimental for efficient and stable devices. To produce highly efficient and stable PSCs, a bilayer between the interfaces of electron‐transport material/perovskite and perovskite/hole‐transport material can be useful for suppressing recombinations at these interfaces. To passivate the interfacial defects at the perovskite/SnO2 and perovskite/Spiro‐OMeTAD for three absorber materials (CsPbI3, FAPbI3, and Cs0.05(FA0.83MA0.17)0.95Pb(I0.83Br0.17)3), a thin layer of WO3 and poly‐bathocuproine interfacial layer is explored using solar cell capacitance simulation in 1D. The optimized device photovoltaic performances significantly improve using bilayers. The power conversion efficiency for the FAPbI3‐based PSCs in bilayer configuration is more than 12% as compared to pristine, whereas open‐circuit voltage is improved by over 13%. The enhancement in device performance is attributed to the reduction of interfacial defects at both the electron transport layer/perovskite and perovskite/hole transport layer interfaces. The proposed interface modification strategy provides a novel approach for fabricating efficient perovskite devices. [ABSTRACT FROM AUTHOR]

To overcome the efficiency limit of perovskite single-junction solar cells, it is vital to develop various types of tandem solar cells. Especially, wide-bandgap (WBG) perovskite solar cells (PSCs) have played an important role in high-efficiency tandem solar cells. Herein, an indium zinc oxide-based interfacial structure is developed to improve the performance of a WBG PSC and used as the transparent electrode for semitransparent (ST) PSCs. This approach minimizes ohmic contact between the electron-transport layer and metallic electrode, which also accelerates electron transfer and suppresses trap-assisted carrier recombination. As a result, the WBG PSC (1.71 eV) shows the best power conversion efficiency of 19.26% and improves operational stability. When the optimized ST-PSC is used as the ST-top cell, perovskite/CdTe four-terminal and perovskite/silicon (doubleside polished) two-terminal tandem solar cells achieve a maximum efficiency of 22.59% and 26.34%, respectively. [ABSTRACT FROM AUTHOR]

The development of vacuum‐deposited perovskite materials and devices is partially slowed down by the minor research effort in this direction, due to the high cost of the required research tools. But there is also another factor, thermal co‐deposition in high vacuum involves the simultaneous sublimation of several precursors with an overall deposition rate in the range of few Å s−1. This leads to a deposition time of hours with only a single set of process parameters per batch, hence to a long timeframe to optimize even a single perovskite composition. Here we report the combinatorial vacuum deposition of wide bandgap perovskites using 4 sources and a non‐rotating sample holder. By using small pixel substrates, more than 100 solar cells can be produced with different perovskite absorbers in a single deposition run. The materials are characterized by spatially resolved methods, including optical, morphological, and structural techniques. By fine‐tuning of the deposition rates, the gradient can be altered and the best‐performing formulations in standard depositions with rotation can be reproduced. This is viewed as an approach that can serve as a basis to prototype other compositions, overcoming the current limitations of vacuum deposition as a research tool for perovskite films. [ABSTRACT FROM AUTHOR]

In monolithic perovskite/silicon tandem solar cells, it is important to know which subcells are limiting the overall current to adapt the perovskite absorber thickness and bandgap accordingly. The current matching situation is usually analyzed by integrating measured external quantum efficiencies. However, this method can lead to significant errors and misinterpretations if metastable perovskite solar cells are involved. Herein, spectrometric characterization is presented as an alternative approach avoiding these errors. Current–voltage curves are recorded under different spectral conditions. Spectral irradiance settings are varied in a systematic way from redshifted spectra (the perovskite top solar cell limits the current) to blueshifted spectra (the silicon bottom solar cell limits the current) around the air mass 1.5 global (AM1.5G) spectrum. This method not only allows for accurate determination of the current matching point, but also gives quantitative insight in the behavior of the single subcells and their influence on the tandem performance. As different current mismatching also influences other global cell parameters, an example is presented where the current loss due to the current mismatch is partly compensated by a strong fill factor increase when the silicon solar cell limits the current, resulting in a high‐power output also at the AM1.5G condition. [ABSTRACT FROM AUTHOR]

The wide‐bandgap perovskite solar cell is a crucial part of perovskite/silicon tandem solar cells, which offer an avenue for surpassing the power conversion efficiency (PCE) limit of single‐junction silicon solar cells. However, the actual efficiency of such tandem solar cells today is diminished by the nonradiative recombination losses in the wide‐bandgap perovskite subcells. Here, this work reports a grain regrowth and bifacial passivation (GRBP) strategy to reduce recombination losses at the grain boundaries and perovskite/charge transport layer interfaces simultaneously. This is achieved by a posttreatment of perovskite films with a mixture of methylammonium thiocyanate (MASCN) and phenethylammonium iodide (PEAI). The MASCN induces the regrowth of perovskite grains and simultaneously facilitates the penetration of PEAI into the hole‐transport‐layer (HTL)/perovskite bottom interface. Thereby, the bulk and interface nonradiative recombination losses are reduced and the open‐circuit voltage in solar cells is considerably increased. PCEs of 21.9% and 19.9% for the 1.65‐eV bandgap opaque and semitransparent perovskite solar cells, respectively, are obtained. The encapsulated semitransparent perovskite solar cells retain their initial efficiency following 500 h of operation under one‐sun illumination in ambient conditions. The perovskite/silicon 4‐terminal (4‐T) tandem cells are fabricated with impressive PCEs 29.8% and 28.5% for 0.049 cm2 and 1 cm2 devices, respectively. [ABSTRACT FROM AUTHOR]

Today, it has become an important task to modify existing traditional silicon-based solar cell factory to produce high-efficiency silicon-based heterojunction solar cells, at a lower cost. Therefore, the aim of this paper is to analyze CH3NH3PbI3 and ZnO materials as an emitter layer for p-type silicon wafer-based heterojunction solar cells. CH3NH3PbI3 and ZnO can be synthesized using the cheap Sol-Gel method and can form n-type semiconductor. We propose to combine these two materials since CH3NH3PbI3 is a great light absorber and ZnO has an optimal complex refractive index which can be used as antireflection material. The photoelectric parameters of n-CH3NH3PbI3/p-Si, n-ZnO/p-Si, and n-Si/p-Si solar cells have been studied in the range of 20–200 nm of emitter layer thickness. It has been found that the short circuit current for CH3NH3PbI3/p-Si and n-ZnO/p-Si solar cells is almost the same when the emitter layer thickness is in the range of 20–100 nm. Additionally, when the emitter layer thickness is greater than 100 nm, the short circuit current of CH3NH3PbI3/p-Si exceeds that of n-ZnO/p-Si. The optimal emitter layer thickness for n-CH3NH3PbI3/p-Si and n-ZnO/p-Si was found equal to 80 nm. Using this value, the short-circuit current and the fill factor were estimated around 18.27 mA/cm2 and 0.77 for n-CH3NH3PbI3/p-Si and 18.06 mA/cm² and 0.73 for n-ZnO/p-Si. Results show that the efficiency of n-CH3NH3PbI3/p-Si and n-ZnO/p-Si solar cells with an emitter layer thickness of 80 nm are 1.314 and 1.298 times greater than efficiency of traditional n-Si/p-Si for the same sizes. These findings will help perovskites materials to be more appealing in the PV industry and accelerate their development to become a viable alternative in the renewable energy sector. [ABSTRACT FROM AUTHOR]

Light‐trapping elements play an important role in solar cells to enhance their light‐harvesting efficiency. Pyramidal‐shaped nano‐microstructures and gradient metasurfaces are mostly used as light‐trapping elements in solar cells. There is, however, one major concern with nanostructured solar cells: a larger surface area resulting in a larger surface recombination loss. In this article, a novel thin‐film wedge tandem‐solar cell made of perovskites and silicon is designed where the bottom cell itself works as a light‐trapping element. Optical and electrical simulations are performed to estimate performance metrics of the wedge tandem‐solar cell and compare with typically used unpatterned planar tandem‐solar cell. In terms of optical and electrical performance, wedge geometry outperforms planar geometry and shows 17.18% higher efficiency. Compared to a typical planar tandem cell, such a design can lead to thin and low‐weight tandem solar cells, which can be very useful in space applications. The proposed design can be fabricated using an optimized electrospray deposition process. [ABSTRACT FROM AUTHOR]

Regulation of Lewis acid‐base adduct intermediate is more critical for the dual metal ions of Sn2+ and Pb2+ than for the single metal ion such as Pb2+ in preparing high quality perovskite films. It has been reported here that the photovoltaic performance of Sn‐Pb alloyed perovskite solar cells is dependent on the interaction between metal ions and Lewis base additives. Urea and thiourea are selected as an O‐ and a S‐donor, respectively, which is used as an additive in the precursor solution including equimolar SnI2 and PbI2 together with organic iodides of formamidinium iodide and methylammonium iodide, forming a nominal composition of FA0.5MA0.5Pb0.5Sn0.5I3. Open‐circuit voltage (Voc) is increased while maintaining short‐circuit photocurrent density (Jsc) after the addition of urea. On the other hand, both Jsc and Voc are simultaneously increased by adding thiourea, leading to a considerable increase in power conversion efficiency from 14.58% (control) to 18.59%. A strong interaction between the relatively soft Sn2+, compared to Sn4+, and the soft sulfur in thiourea, associated with hard and soft acid and base theory, suppresses effectively a disproportionation reaction of 2Sn2+→ Sn4+ + Sn0, which results in a substantial enhancement of carrier lifetime and consequently photovoltaic performance. [ABSTRACT FROM AUTHOR]

Fullerene is one of the most critical materials that are widely used to improve and examine the inverted perovskite solar cells (PSCs, p‐i‐n structure). Fullerenes are known to improve the stability, lower the hysteresis, and increase the power conversion efficiency of the PSCs. Fullerene and its derivatives are often used in constructing effective PSCs. Several properties and performance of fullerenes are the key bases for testing and making effective alternatives that can improve the performance of PSCs. This review summarizes some of the most important fullerenes (i.e., fullerene and its derivatives) that are employed in inverted (p‐i‐n) PSCs and their physical properties that can overcome the well‐known shortcomings in perovskite materials. The current density–voltage hysteresis in PSC and the fullerenes role in lowering the hysteresis are discussed. Moreover, fullerenes are also reviewed as electron transport layer, cathode buffer layer, and additives for perovskites. Enhanced stability by using fullerene derivatives is illustrated. Additionally, fullerenes in flexible and tandem PSCs as well as advantages and disadvantages of fullerenes are briefly discussed. Finally, an overview of the fullerene future in PSCs is discussed with alternative nonfullerene materials used in PSC. [ABSTRACT FROM AUTHOR]

The single‐crystalline silicon solar cell with tunnel oxide passivating poly‐Si contact (TOPCon) has developed into one of the most promising and high‐performance n‐type Si‐based solar cells in their mass production way because of its high conversion efficiency and robustness. Owing to its unique device structure, TOPCon shows superior advantages over amorphous Si‐based heterojunction one (HJT) in developing high‐performance monolithic perovskite/silicon tandem solar cell because TOPCon may have better tolerance than HJT to the particle bombardments and plasma fluorescence irradiations in the sputtering deposition process of transparent conductive oxide (TCO) recombination layer. Herein, bathocuproine (BCP):silver complex is introduced as a buffer recombination contact between TCO and poly‐SiCX, to modulate the tunneling junction between perovskite/TOPCon. Depending on fine film thickness and derived energy level tuning, BCP:Ag buffer layer can effectively prevent the sputter bombardments and passivate the interface of TCO/poly‐SiCX(n)/SiOX contact, as well as enhancing electron transport. As a result, a certified conversion efficiency of 25.84% is achieved in the monolithic perovskite/TOPCon silicon tandem solar cell. This work definitely paves a new and promising way to develop high‐performance monolithic perovskite/c‐Si tandem solar cells. [ABSTRACT FROM AUTHOR]

Over the past decade, the impressive progress in power conversion efficiency (PCE) of organometallic halide perovskite solar cells (PSCs), coupled with their ready integration into tandem solar cells, has led them to approach PCEs of 30% for tandem solar cells with a silicon bottom subcell. However, the complementary technology of perovskite/copper indium gallium selenide (CIGS) tandem solar cells has been thus far unable to reach similar efficiency values. Herein, a further advance in the efficiency of 4T perovskite/CIGS tandems is demonstrated, increasing the PCE up to 27.3% via systematic optimization of the top semitransparent PSC. Improvements in light management through the optimization of anti‐reflection coatings, coupled with the development of transparent conductive oxides that incur very low parasitic absorption are reported. It is revealed that both are crucial for maximizing efficiency and, by utilizing additional optical simulations, a detailed loss analysis that enables us to outline a path toward approaching 30% PCE for 4T perovskite/CIGS tandem devices is developed. [ABSTRACT FROM AUTHOR]

Lead-free perovskite solar cells (PSCs) have sparked considerable interest in the optoelectronics research community and gained recognition in recent years due to their practical use in solar energy. The primary obstacles in producing PSCs are stability and toxicity due to the immersion of organic-cation and lead in perovskite material. This study presents an electrical simulation of a caesium–indium-based lead-free hybrid PSC using SCAPS-1D software. Spiro-MeOTAD is a typical hole transport material (HTM) used in PSC, although it has not always been suggested because of its high design cost and stability constraints. This study aims to evaluate the performance of lead-free double perovskite material as an absorber layer along with different hole transport materials (HTM). We discovered that the lead-free double perovskite combined with graphene-oxide (GO) and reduced graphene oxide (rGO) produces the best results. Furthermore, the light-harvesting layer and HTM layer has optimized via thickness, defects, doping concentration, and temperature. The improved PSC structure achieves power conversion efficiency (PCE) of more than 24%, and the results of the optimized PSC have compared to the results of the experimentally implemented PSC. This work also used C–V measurements on the optimized structure to determine the device contact potential and doping concentration. The optimized results suggest a feasible future route for creating lead-free PSC with high productivity and free from stability or toxicity issues. [ABSTRACT FROM AUTHOR]

Multi‐junction solar cells connecting two or more cells with significantly different bandgaps have a lot of promise for exceeding the Shockley Queisser (S‐Q) efficiency limit of single‐junction‐based photovoltaic devices. In this article, a new class of tandem devices has been proposed and investigated for improved efficiencies. The proposed tandem cell is connected in monolithic two‐terminal tandem configurations with wide bandgap formamidinium (FA) based perovskite absorber (FA0.85 Cs0.15 Pb (I0.85 Br0.15)3) (1.6 eV) (Cs15/Br15)) on the top cell and low bandgap gallium free chalcogenide (CuInSe2) absorber on the bottom cell. Doped FA‐based perovskite material is preferred over commonly used FAPbI3 as it is a proven fact that adding modest quantities of cesium and bromine stabilizes the optically active black phase of FAPbI3 Perovskite and increases overall device performance. In contrast, bottom CuInSe2 (CIS) absorber material is selected considering its good thermal stability and excellent light‐absorbing capabilities in a broad‐spectrum range. The feasibility of the suggested tandem configuration is assessed in two steps. First, a 1.6 eV perovskite top cell is simulated and calibrated to suit the state‐of‐the‐art power conversion efficiency of 17.5 %, followed by a 1.04 eV CuInSe2‐based bottom cell with a calibrated efficiency of 16.2 %. Both devices are tested for tandem configuration once the standalone (top and bottom) subcells have been calibrated. At varied absorber thicknesses in both the top and bottom subcells, the current matching conditions are achieved. At optimal thicknesses of 700 nm and 590 nm for the bottom and top absorbers, respectively, the overall tandem structure obtained an excellent power conversion efficiency of 25.13 %. Results reported in this study may pave the way for the development of high‐efficiency perovskite/CIS based tandem solar cells in the future. [ABSTRACT FROM AUTHOR]

Semi‐transparent perovskite solar cells (ST‐PeSCs) have tremendous potential as solar windows owing to their higher efficiency and visible transmittance. However, studies toward this application are still nascent, particularly in unraveling the interplay between how the perovskite composition impacts the achievable device performance and stability. Here, the role of A‐ and X‐site modification in APbX3 perovskites is studied to understand their influence on these factors. Through detailed experimental and simulation work, it is found that a perovskite composition consisting of cesium (Cs) and formamidinium (FA) at the A‐site delivers the best device performance over a range of band gaps, which are tuned by changes to the X‐site anion. Using this optimized perovskite composition, power conversion efficiencies of 15.5% and 4.1% are achieved for ST‐PeSCs with average visible transmittance values between 20.7% and 52.4%, respectively. Furthermore, the CsFA‐based ST‐PeSCs show excellent long‐term stability under continuous illumination and heating. The stability of the precursor solutions across each of the studied compositions has also been considered, showing dramatic differences in the structural properties of the perovskites and their device performance for all mixed A‐site compositions possessing the archetypal methyl ammonium species, while also confirming the superior stability of the CsFA precursor solutions. [ABSTRACT FROM AUTHOR]

Lab‐scale perovskite solar cells have reached efficiencies as high as the best monocrystalline silicon cells, with expectations that their manufacturing costs could be lower than those of currently commercialized cells. As a result, efforts are now directed to the production of these cells. In this sense, the use of frontal metal grids in large‐area perovskite cells and parallel‐connected modules is imperative due to the low conductivity of the transparent conductive substrate usually employed in these devices. For the insertion of grids, a trade‐off between reduced resistive losses and the increase in shadowed area must be achieved. Assessment of grid parameters is of utmost importance for the assembly of viable large‐scale cells and modules. Furthermore, a direct transfer from grid parameters previously specified for other photovoltaic technologies might not be the best option for perovskite cells. Nonetheless, investigations of grids specifically designed for these cells are still scarce in the literature. Here, grid design, both in terms of metal composition and geometric factors, is discussed, including their development for tandem cells and flexible devices. To provide further insights into the maturity level of this technology, a patent analysis regarding grid designs for perovskite modules is also presented in this review. [ABSTRACT FROM AUTHOR]

Photovoltaic (PV) technology is ready to become one of the main energy sources of, and contributers to, carbon neutrality by the mid‐21st century. In 2020, a total of 135 GW of PV modules were produced. Crystalline silicon solar cells dominate the world's PV market due to high power conversion efficiency, high stability, and low cost. Silicon heterojunction (SHJ) solar cells are one of the promising technologies for next‐generation crystalline silicon solar cells. Compared to the commercialized homojunction silicon solar cells, SHJ solar cells have higher power conversion efficiency, lower temperature coefficient, and lower manufacturing temperatures. Recently, several new record efficiencies have been achieved. To meet the continued demand for high‐efficiency solar cells, expectations for large‐scale mass production of SHJ solar cells are rising. To approach the efficiency limit and industrialization of SHJ solar cells, serious attempts have been made, yielding higher short‐circuit current, open‐circuit voltage, and fill factor. In this article, these recent advancements are reviewed, which reveals the future roadmap for approaching the efficiency limit. [ABSTRACT FROM AUTHOR]

Herein, an optical loss analysis of the recently introduced silicon carbide–based transparent passivating contact (TPC) for silicon heterojunction solar cells is presented, the most dominant losses are identified, and the potential for reducing these losses is discussed. Magnesium fluoride is applied as an antireflective coating to reduce the reflective losses by up to 0.8 mA cm−2. When applying the magnesium fluoride, the passivation quality of the layer stack degrades, but is restored after annealing on a hot plate in ambient air. Afterwards, a road map for TPC solar cells toward an efficiency of 25% is presented and discussed. The largest part in efficiency gain is achieved by reducing the finger width and by increasing the passivation quality. Furthermore, it is shown that TPC solar cells have the potential to achieve short‐circuit current densities above 42 mA cm−2 if the finger width is reduced and the front‐side indium tin oxide (ITO) layer can be replaced by an ITO silicon nitride double layer. [ABSTRACT FROM AUTHOR]

Metal halide perovskites have recently emerged as one of the most promising classes of semiconductors for various applications, especially in the field of optoelectronics. Lead-based halide perovskite materials, virtually unexploited for decades, have become prominent candidates due to their unique and intrinsic physicochemical and optical properties. Current challenges faced by the scientific community to capitalize on the properties of Pb-based perovskites are mainly associated with environmental concerns due to the toxicity of Pb and their poor stability. Under this context, over recent years, a number of new Pb-free halide perovskite (and perovskite-like) semiconductor classes have been introduced. This Perspective reviews recent developments in Pb-free halide perovskites, which specifically target their application in solar cells, light-emitting devices, and photocatalysts. Each type of Pb-free material is paired with a specific optoelectronic application, and the latest record performances are reported. Although these materials do not yet exhibit as attractive intrinsic optoelectronic properties as the Pb-based halide perovskites, their potential as alternatives for well-suited applications is discussed. [ABSTRACT FROM AUTHOR]

Optimization of carrier extraction and/or transport layers is an important factor for the development of perovskite semiconductor devices. In particular, tin dioxide, SnO2, is being frequently used as an electron transport layer (ETL) in perovskite solar cells. However, a systematic study on preparation and characterization of the SnO2-ETL is still lacking, and thus, morphological and electronic-functional roles are not fully understood. In this paper, we systematically investigate the SnO2-ETL prepared on fluorine-doped tin oxide (FTO) substrates by a spin-coating technique. Using microscopic observations, we morphologically study how the SnO2 film covers the FTO surface with large unevenness. Optical characterizations are employed for investigating an electronic band alignment of the perovskite/SnO2 interface varied with the SnO2 concentration in a solution. Furthermore, we systematically evaluate photovoltaic properties of FTO-based solar cell devices. A major finding from these investigations is the fact that while the SnO2-ETL prepared at the adequate condition exhibits an ideal band alignment, the excessive SnO2 deposition causes a poor electron extraction and device performance degradation. Furthermore, we show that the spin-coated SnO2-ETL can cover the FTO surface as an ultrathin wrapping layer. These results highlight the importance of the SnO2-ETL and pave the way for optoelectronic device applications of perovskite materials. [ABSTRACT FROM AUTHOR]

The outstanding optoelectronic properties of metal halide perovskites make them an attractive photovoltaic absorber material and has rapidly culminated in the development of highly efficient perovskite solar cells outperforming many conventional alternatives. However, the device stack still suffers from non‐negligible losses induced by various nonradiative recombination processes, which are not fully understood till date. This paper highlights recent findings attempting to understand the nature and origin of nonradiative recombination induced losses within the device stack, as well as the quantification of the magnitude and rates associated with key loss pathways mostly via steady state and transient contactless optical techniques. These studies show that nonradiative recombination processes occurring at interfaces are more dominant than those within the bulk of the perovskite absorber. However, recent findings also show that there remains room for improvement for the suppression of bulk nonradiative recombination. General routes for suppressing recombination processes within the bulk and at interfaces are discussed. Finally, current challenges are presented, which need to be overcome in order to obtain a deeper insight into the nature of defects at surfaces and within the bulk of perovskites, and ultimately enhance the power conversion efficiency of perovskite solar cells toward their thermodynamic efficiency limit. [ABSTRACT FROM AUTHOR]

The electron transport layer (ETL) is critical in perovskite solar cells (PSCs) as it controls the optics of the complete solar cell. This study uses an industrially viable RF magnetron sputtering technique to prepare the tungsten oxide (WOx) ETL for PSCs. Necessary morphological and optoelectronic investigations were carried out to ensure the high-quality WOx thin-film. The influence of the deposition power on the ETL thickness and PSC optics were systematically investigated. A three-dimensional (3D) finite-difference time-domain (FDTD) approach analyses the optics and optimization of the complete solar cell. The investigations allow the optimized planar PSC to determine the JSC of > 21 mA/cm2. The optical performance of the planar device is limited due to higher optical losses; hence, the current study proposes a PSC design embedded with Ag nanoparticles. The proposed PSC can improve the JSC by ~ 17% (up to 24.5 mA/cm2) than the planar device owing to improved light trapping, further boosting the PSC's energy conversion efficiency (ECE). A detailed discussion on film realization and solar cell optics is provided. [ABSTRACT FROM AUTHOR]

Combining a perovskite top cell with a conventional passivated emitter and rear cell (PERC) silicon bottom cell in a monolithically integrated tandem device is an economically attractive solution to boost the power conversion efficiency (PCE) of silicon single‐junction technology. Proof‐of‐concept perovskite/silicon tandem solar cells using high‐temperature stable bottom cells featuring a polycrystalline silicon on oxide (POLO) front junction and a PERC‐type passivated rear side with local aluminum‐p+ contacts are reported. For this PERC/POLO cell, a process flow that is compatible with industrial, mainstream PERC technology is implemented. Top and bottom cells are connected via a tin‐doped indium oxide recombination layer. The recombination layer formation on the POLO front junction of the bottom cell is optimized by postdeposition annealing and mitigation of sputter damage. The perovskite top cell is monolithically integrated in a p−i−n junction device architecture. Proof‐of‐concept tandem cells demonstrate a PCE of up to 21.3%. Based on the experimental findings and supporting optical simulations, major performance enhancements by process and layer optimization are identified and a PCE potential of 29.5% for these perovskite/silicon tandem solar cells with PERC‐like bottom cell technology is estimated. [ABSTRACT FROM AUTHOR]

Two issues need to be resolved when fabricating p–i–n semitransparent perovskite solar cells (ST‐PVSCs) for four‐terminal (4 T) perovskite/silicon tandem solar cells: 1) damage to the underlying absorber (MAPbI3), electron transporting layer ([6,6]‐phenyl‐C61‐butyric acid methyl ester, PCBM), and work function (WF) modifier (polyethylenimine, PEI), resulting from the harsh sputtering conditions for the transparent electrodes (TEs) and 2) low average near‐infrared transmittance (ANT) of TEs. Herein, a unique SnO2 layer to protect the MAPbI3 and PCBM layers is developed and functions as a WF modifier for a new TE (cerium‐doped indium oxide, ICO), which exhibits an excellent ANT of 86.7% in the range of 800−1200 nm. Moreover, a MAPbI3‐based p–i–n ST‐PVSC is prepared, achieving an excellent power conversion efficiency (PCE) of 17.23%. When it is placed over the Si solar cell, a 4 T tandem solar cell with a PCE of 26.14% is obtained. [ABSTRACT FROM AUTHOR]

The commercialization of perovskite photovoltaic technology is dependent on the development of high‐efficiency, stable, and large‐area solar modules. Despite the rapid rise in efficiencies of laboratory‐scale perovskite solar cells (PSCs), there is still a big gap in the transition from small‐area devices to large‐area perovskite solar modules (PSMs). Herein, recent progresses on scaling‐up PSMs are reviewed: first, multifarious scalable preparation methods, solvent engineering, and corresponding morphology control strategies for large‐area homogeneous perovskite films are summarized. Various charge carrier transport materials, electrode materials, and their scaling methods for high‐efficiency and stable PSMs are then outlined and the device structure design of PSMs is discussed. Finally, the current strategies for optimizing the environmental stability of devices are highlighted, and packaging for reducing lead leakage during operation is discussed. [ABSTRACT FROM AUTHOR]

Over the past few years, perovskite solar cells have arisen as a technology to potentially side with mainstream silicon photovoltaics (PVs) to help drive the transition towards renewable sources of energy. The coupling of perovskites with silicon in a tandem configuration may accelerate this development due to the remarkably high power conversion efficiencies possible with such devices. However, most of the perovskite/silicon tandem achievements so far have been confined to the lab environment, with only a few reported tests under outdoor conditions, using packaged devices. Nevertheless, one of the major challenges for perovskite/silicon tandem technologies, in addition to scale‐up, lies in the cell‐to‐module (CTM) translation, which for the perovskite/silicon tandem concept is complicated by perovskite‐imposed constrains such as a low‐temperature resilience, imposing challenges regarding tabbing and lamination, as well as a high sensitivity to moisture ingress, mandating the search for adequate encapsulation materials and methods. Herein, these challenges are described and assessed in depth and a perspective on future directions toward module design, tailored for perovskite/silicon tandem PVs is given, combining high performance with excellent durability. The discussion also holds relevance for all‐perovskite and other emerging PV technologies seeking market entry. [ABSTRACT FROM AUTHOR]

Beginning with the breakthrough of solid‐state perovskite‐sensitized solar cells in 2012, the number of studies on photovoltaic devices based on halide perovskite materials has exploded. As of 2021, the certificated record power conversion efficiency (PCE) of small‐area perovskite solar cells (≈0.1 cm2 active area) is 25.5%, making them very competitive with conventional silicon solar cells (26.7%) in terms of efficiency. For commercialization and large‐scale manufacturing purposes, it is necessary to develop high‐efficiency large‐area perovskite photovoltaics with minimal PCE loss. Herein, the recent progress of perovskite solar modules (PSMs) is reviewed and a research direction toward high‐efficiency PSMs is proposed. It is important to carefully examine the materials and methods used for development of high‐efficiency scalable perovskite solar cells and modules as the uniformity and quality of large‐area perovskite film significantly affect the PCE, more so than in small‐area devices. Precursor, additive, and interface engineering are described as well as various coating methodologies for suitable PSMs. Engineering of uniform, pinhole‐free, and high‐quality large‐area perovskite films can contribute to high‐efficiency PSMs and pave the way for commercialization. The technologies used for materials and method engineering for high‐efficiency PSMs are discussed, with an eye toward commercialization. [ABSTRACT FROM AUTHOR]

Wide‐bandgap perovskites based on alloying cesium and formamidinium lead mixed halides (CsxFA1–xPb(IyBr1–y)3) have received great attention due to their potential application in high‐efficiency tandem solar cells. However, the fast crystallization of CsxFA1–xPb(IyBr1–y)3 perovskite films results in a high trap density and hinders the further enhancement of the photovoltaic performance. Herein, an intermediate engineering is developed to retard the fast crystallization of Cs0.17FA0.83PbI1.8Br1.2 wide‐bandgap perovskite by adding FACl in the precursor solution. The introduction of the FACl additive leads to the formation of a thermodynamic phase‐pure intermediate which facilitates the further crystallization of a high‐quality perovskite thin film at elevated temperature and thus enhances the ultimate device performance. The champion device achieves an efficiency over 19% and exhibits 83.8% retention after 50 days aging without encapsulation. [ABSTRACT FROM AUTHOR]

In recent years, perovskite/silicon tandem solar cells (PK/c‐Si tandem) have demonstrated high power conversion efficiency (PCE) and demonstrated great application potential in photovoltaic (PV) systems. However, the PCE of PK/c‐Si tandem devices is still below the theoretical limit. From a broader perspective, their poor stability and difficulty in large‐area realization are crucial barriers for commercial viability. In this report, the detailed constraints facing high PCE of tandem devices and the corresponding solutions are discussed. The authors propose that the main obstacle comes from the limitation of the perovskite top cell. However, careful understanding of the optical and electrical properties of each functional layer is expected to be the core process to further promote efficiency. Regarding the environmental and intrinsic instability issues, encapsulation is considered to be the most effective method to address environmental instability. Preventing ion migration is one of the fundamental methods to eliminate intrinsic instability. It is believed that low dimensional perovskite materials will become a competitive solution to simultaneously solve these two instabilities. Finally, some suggestions for reducing costs and preparation of PK/c‐Si tandem on a large‐scale are also discussed which provides guidance for further boosting the development of PK/c‐Si tandem. [ABSTRACT FROM AUTHOR]