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The SSIS SEL Brief + Mental Health Scales (SSIS SELb+MHS) are multi-informant assessments developed in the United States to assess the social and emotional learning (SEL) competencies and emotional behavior concerns (EBCs) of school-age youth. Although there are translations of the SEL items of the SSIS SELb+MHS available in other languages, a German translation has never been completed and validated, despite the growing need for SEL and mental health assessment in German-speaking countries. To address this need, this study's primary purpose was the examination of a German translation of the assessment with a specific focus on measurement invariance and concurrent validity invariance testing with 821 3rd through 6th-grade students in Austria and Germany. Results indicated that the SELb+MHS items clustered into 2 SEL factors and 2 EBC factors. With regard to measurement invariance, the SELb+MHS functioned similarly across both Austria and Germany and full scalar invariance was achieved. Additionally, the overall pattern of concurrent validity relationships was as expected and similar across countries. Implications and future directions are discussed.

The perovskite/silicon tandem solar cell represents one of the most promising avenues for exceeding the Shockley-Queisser limit for single-junction solar cells at a reasonable cost. Remarkably, its efficiency has rapidly increased from 13.7% in 2015 to 34.6% in 2024. Despite the significant research efforts dedicated to this topic, the "secret" to achieving high-performance perovskite/silicon tandem solar cells seems to be confined to a few research groups. Additionally, the discrepancies in preparation and characterization between single-junction and tandem solar cells continue to impede the transition from efficient single-junction to efficient tandem solar cells. This review first revisits the key milestones in the development of monolithic perovskite/silicon tandem solar cells over the past decade. Then, a comprehensive analysis of the background, advancements, and challenges in perovskite/silicon tandem solar cells is provided, following the sequence of the tandem fabrication process. The progress and limitations of the prevalent stability measurements for tandem devices are also discussed. Finally, a roadmap for designing efficient, scalable, and stable perovskite/silicon tandem solar cells is outlined. This review takes the growth history into consideration while charting the future course of perovskite/silicon tandem research., (© 2024 Wiley‐VCH GmbH.)

At present, the global photovoltaic (PV) market is dominated by crystalline silicon (c-Si) solar cell technology, and silicon heterojunction solar (SHJ) cells have been developed rapidly after the concept was proposed, which is one of the most promising technologies for the next generation of passivating contact solar cells, using a c-Si substrate and two hydrogenated amorphous silicon (a-Si:H) thin films. SHJ solar cells not only have the advantages of high conversion efficiency and high open-circuit voltage, but also have a low temperature coefficient and free from potential induced degradation. For SHJ solar cells, the passivation contact effect of the c-Si interface is the core of the entire cell manufacturing process. To approach the single-junction Shockley–Queisser limit, it is necessary to passivate monocrystalline silicon well to reduce the efficiency loss caused by recombination. Recently, the successful development of silicon heterojunction technology has significantly increased the power conversion efficiency (PCE) of crystalline silicon solar cells to 27.30%. This review firstly summarizes the development history and current situation of high efficiency c-Si heterojunction solar cells, and the main physical mechanisms affecting the performance of SHJ are analyzed. Subsequently, an overview is provided on the selection and application of passivation contact layer materials, with particular emphasis on distinguishing between various types of passivation materials and their respective roles in facilitating selective carrier transportation. Then, other components of SHJ solar cells are reviewed, including the selection and application of transparent conductive electrode materials that can reduce or replace indium element use. The application of copper plating technology and laser transfer printing (LTP) technology in the industrial development of SHJ solar cell technology is discussed. Finally, the development status of SHJ-based tandem solar cells is discussed, and also the prospects, challenges, as well as potential solutions for industrial development of SHJ solar cells are outlooked. [ABSTRACT FROM AUTHOR]

Organic–inorganic lead halide perovskite (OLHP) semiconductors have garnered significant attention for their versatile applications in solar cells, LEDs, photodetectors, and transistors, owing to their remarkable optoelectronic properties and facile solution-based fabrication. Understanding the fundamental physicochemical properties of OLHPs remains challenging due to their soft lattice structures and dynamic structural vibrations with molecular motions. It often results in extraordinary charge transporting and energy transfer, which can be found in many devices. Raman spectroscopy emerges as a vital tool for probing these structural properties due to its high resolution and non-destructive nature. This paper reviews Raman spectral analysis for OLHPs, highlighting the complexities in interpreting low and high-frequency vibrational modes associated with PbX₆ octahedra and organic/molecular cations, respectively. We identify the challenges posed by laser-induced degradation and phase transitions during resonance Raman measurements. Our study proposes improved Raman measurement strategies, emphasizing non-resonance conditions and careful selection of laser wavelengths to mitigate artifacts. These strategies aim to enhance the accuracy of Raman spectra and deepen our understanding of the structural dynamics of OLHPs, which is crucial for advancing their application in next-generation optoelectronic devices. [ABSTRACT FROM AUTHOR]

Perovskite solar cells (PSCs) have rapidly emerged as a promising photovoltaic technology, with power conversion efficiencies (PCEs) improving from 3% to over 26% within a decade. This progress positions PSCs as a competitive alternative to traditional silicon-based cells, offering advantages in performance, cost-effectiveness, and flexible applications. The unique ABX3 crystal structure of perovskites enables tunable optoelectronic properties, making them ideal for a broad spectrum of solar and optoelectronic applications. The high absorption coefficient, long diffusion lengths, and high charge-carrier mobility of PSCs have accelerated their development. However, challenges such as environmental instability and toxic solvent use hinder commercialization. Current research focuses on enhancing stability through passivation, encapsulation, and eco-friendly fabrication methods using solvents like γ-valerolactone. In addition to solar cells, perovskite materials show promise in photodetectors, LEDs, and memristors, making them central to next-generation optoelectronic devices. This review highlights the potential of PSCs while addressing the technological advancements needed for their commercial viability. [ABSTRACT FROM AUTHOR]

Tunnel oxide passivating contact (TOPCon) solar cells (SCs) as one of the most competitive crystalline silicon (c-Si) technologies for the TW-scaled photovoltaic (PV) market require higher passivation performance to further improve their device efficiencies. Here, the successful construction of a double-layered polycrystalline silicon (poly-Si) TOPCon structure is reported using an in situ nitrogen (N)-doped poly-Si covered by a normal poly-Si, which achieves excellent passivation and contact properties simultaneously. The new design exhibits the highest implied open-circuit voltage of 755 mV and the lowest single-sided recombination current density (J 0 ) of ≈0.7 fA cm⁻ 2 for a TOPCon structure and a low contact resistivity of less than 5 mΩ·cm 2 , resulting in a high selectivity factor of ≈16. The mechanisms of passivation improvement are disclosed, which suggest that the introduction of N atoms into poly-Si restrains H overflow by forming stronger Si-N and N-H bonds, reduces interfacial defects, and induces favorable energy bending. Proof-of-concept TOPCon SCs with such a design receive a remarkable certified efficiency of 25.53%., (© 2023 Wiley-VCH GmbH.)

The photovoltaic signal is an important characteristic of photodetectors, including but not limited to those that are based on p–n or p–i–n photodiodes. In an open-circuit configuration, pulsed excitation of the detector with ultrafast (femto or nanosecond) pulses leads to a photovoltaic signal that decays slowly (micro-second time scale). If the physics in the detector is dominated by the recombination of the photo-excited charge carriers, one expects the signal to decay without changing its sign. However, some experiments using short-pulse excitation have found that photovoltaic signals can undergo a sign change as a function of time following excitation, with positive signals immediately following the excitation, turning to negative signals several microseconds later. Here, we study various physical effects (density, temperature, electrostriction, pressure, photostriction, and bandgap renormalization) and determine their effect on photovoltaic signals. If, following ultrafast excitation, the carrier density and temperature are increased, and during relaxation the system reaches a state sufficiently close to the quasi-thermal equilibrium in which the carrier density is still elevated, but smaller than the intrinsic thermal equilibrium density at the elevated temperature, then the signal can become negative. [ABSTRACT FROM AUTHOR]

Conventional time-of-flight methods can be used to determine carrier mobilities for photovoltaic cells in which the transit time between electrodes is greater than the RC time constant of the device. To measure carrier drift on sub-ns timescales, we have recently developed a two-pulse time-of-flight technique capable of detecting drift velocities with 100-ps time resolution in perovskite materials. In this method, the rates of carrier transit across the active layer of a device are determined by varying the delay time between laser pulses and measuring the magnitude of the recombination-induced nonlinearity in the photocurrent. Here, we present a related experimental approach in which diffractive optic-based transient grating spectroscopy is combined with our two-pulse time-of-flight technique to simultaneously probe drift and diffusion in orthogonal directions within the active layer of a photovoltaic cell. Carrier density gratings are generated using two time-coincident pulse-pairs with passively stabilized phases. Relaxation of the grating amplitude associated with the first pulse-pair is detected by varying the delay and phase of the density grating corresponding to the second pulse-pair. The ability of the technique to reveal carrier diffusion is demonstrated with model calculations and experiments conducted using MAPbI3 photovoltaic cells. [ABSTRACT FROM AUTHOR]

The popularity of metal halide perovskites is in part the result of their versatility in numerous applications. To date, perovskites are used in their intrinsic, undoped form, as the doping of these materials is not yet adequately mastered. Herein, the recently reported electronic doping of CH3NH3PbI3 is employed to fabricate perovskite solar cells in which the interfacial electron transport layer (ETL) is replaced by n‐doping of one side of the perovskite film. The doping involves the incorporation of metastable Sm2+ ions that undergo an in situ oxidation to Sm3+, releasing electrons to the conduction band to render the perovskite n‐type. In spite of the lack of an ETL, these solar cells have the same efficiency as the samples with the ETL. The open circuit voltage of the doped solar cells increases proportionally to the doping concentration due to the narrowing of the depletion layer thickness at the interface of the perovskite and the top electrode, reaching the value of ≈1 V for the doped ETL‐free device, the same as for the reference sample. These proof‐of‐concept results represent the first step toward perovskite‐based devices incorporating a p‐n homojunction. [ABSTRACT FROM AUTHOR]

This study explores the impact of organic cations in bismuth iodide complexes on their memristive behavior in metal-insulator-metal (MIM) type thin-layer devices. The presence of electron-donating and electron withdrawing functional groups (-CN, -CH3, -NH2, and -N(CH3)2) on pyridinium cations induces morphological alterations in crystals, thus influencing the electronic or ionic conductivity of devices comprising sandwiched thin layers (thickness = 200 nm ± 50) between glass/ITO as bottom electrode (~110 nm) and copper (~80 nm) as the top electrode. It was found that the current-voltage (I-V) scans of the devices reveal characteristic pinched hysteresis loops, a distinct signature of memristors. The working voltage windows are significantly influenced by both the types of cation and the dimensionality of ionic fragments (0D or 1D) in the solid-state form. Additionally, the temperature alters the surface area of the I-V loops by affecting resistive switching mechanisms, corresponding log-log plots at three temperatures (-30 °C, room temperature and 150 °C) are fully studied. Given that a memristor can operate as a single synapse without the need for programming, aligning with the requirements of neuromorphic computing, the study investigates long-term depression, potentiation, and spike-time-dependent plasticity-a specific form of the Hebbian learning rule-to mimic biologically synaptic plasticity. Different polar pulses, such as triangle, sawtooth, and square waveforms were employed to generate Hebbian learning rules. The research demonstrates how the shape of the applied pulse series, achieved by overlapping pre- and postpulses at different time scales, in association with the composition and dimensionality of ionic fragments, lead to changes in the synaptic weight percentages of the devices. [ABSTRACT FROM AUTHOR]

Due to the unique microstructure of hydrogenated nanocrystalline silicon oxide (nc‐SiOx:H), the optoelectronic properties of this material can be tuned over a wide range, which makes it adaptable to different solar cell applications. In this work, the authors review the material properties of nc‐SiOx:H and the versatility of its applications in different types of solar cells. The review starts by introducing the growth principle of doped nc‐SiOx:H layers, the effect of oxygen content on the material properties, and the relationship between optoelectronic properties and its microstructure. A theoretical analysis of charge carrier transport mechanisms in silicon heterojunction (SHJ) solar cells with wide band gap layers is then presented. Afterwards, the authors focus on the recent developments in the implementation of nc‐SiOx:H and hydrogenated amorphous silicon oxide (a‐SiOx:H) films for SHJ, passivating contacts, and perovskite/silicon tandem devices. [ABSTRACT FROM AUTHOR]

With the aid of 3D full‐field finite difference time–domain simulations, model configurations for CsPbI3$\left(\text{CsPbI}\right)_{3}$ thin‐film solar cell devices that include periodically arranged TiO2$\left(\text{TiO}\right)_{2}$ microspheres, exhibiting resonating whispering gallery modes (WGMs), are proposed. The TiO2$\left(\text{TiO}\right)_{2}$ microspheres present, either immersed in perovskite or coated with perovskite layer, between the electron‐ and hole‐transport layers show enhanced current‐conversion efficiency. The presence of WGMs lead to enhancement in the absorption of CsPbI3$\left(\text{CsPbI}\right)_{3}$ layer. The incoming electromagnetic wave couples with TiO2$\left(\text{TiO}\right)_{2}$ microsphere and forms confined resonating modes. Different designs are examined for deciding the appropriate position of WGM exhibiting spheres with respect to thin‐film perovskite solar cell (PSC) featuring back reflector and optimized antireflectance coating. Since the incoupling element is lossless, energy stored in microspheres is absorbed efficiently by the underlying active material. This directly contributes to the increment in the current density of the solar cell. Thus, the devices show a higher current density of 23.62 mA cm−1, while that in planar solar cell device shows current density of 13.68 mA cm−1, for the same thickness of perovskite layer. This leads to more than 70% enhancement in the short‐circuit current density than the conventional PSCs device of similar size. [ABSTRACT FROM AUTHOR]

Halide perovskites demonstrate excellent optoelectronic characteristics such as large light absorption coefficients, long charge carrier diffusion lengths, and high charge carrier mobility. With these benefits, halide perovskites have been considered as a next-generation photoactive materials and introduced to diverse optoelectronic devices. Among them, perovskite solar cells (PSCs) and photodetectors (PPDs) have been paid attention, which have in common that they transform the light signals into photocurrent. In particular, great innovations have been achieved in improving the performance of PSCs and PPDs. With this regard, in this perspective, we have explained the development and recent progress in PSCs and PPDs. In addition, future research directions have also been outlined. This perspective summarizes the recent advances in halide perovskites for optoelectronic devices including solar cells and photodetectors and provides the guideline for further research direction in the field. [ABSTRACT FROM AUTHOR]

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]

The frequency response of the photocurrent (Iph) generated in perovskite photodetectors is a crucial issue in imaging or telecommunication applications, although it is briefly discussed in the literature. The present work obtains for the first time the complete expression of the Iph generated on MAPbI3 (MA:methylamoniumI) perovskite polycrystalline thin films. A conditioning circuit is used to extract Iph at 1 V of bias voltage under a square‐modulated laser excitation with a sensitivity smaller than 1 nW and a linear dynamic range LDR > 200 dB; It allows an accurate determination of the module of Iph together with the phase, which is not usually reported in photodetector systems. The frequency domain analysis reveals that Iph can be modeled by two fractional poles located at low (10 kHz) and high (39–250 kHz) cut‐off frequencies. Optimum geometrical parameters and excitation fluence are found for the wider response, resulting for the best device on a cut off frequency up to 250 kHz, and the reproduction of square‐modulated optical waves up to 100 kHz. These results represent an important strategy toward the electrical analysis of MAPbI3 (or other perovskite materials) for the design of posterior electronic stages, optimization of devices and determination of their figures of merit. [ABSTRACT FROM AUTHOR]

Transparent conductive oxides (TCOs) have been widely used as transparent electrodes in numerous optoelectronic devices including perovskite/silicon tandem solar cells. A significant concern regarding the application of TCOs is the sputter-induced damage to the underlying films. Understanding the source of this damage and finding ways to mitigate it are crucial to improve the design of solar cells. In this study, a systematic investigation was performed to determine the origin of TCO sputtering damage on the perovskite/C60 stack using various optical filters and a series of sample structures. Our results revealed that the steady-state photoluminescence intensity increased when the perovskite/C60 stack was only exposed to plasma radiation. This finding suggests that sputtering damage originates from ion bombardment rather than plasma radiation. X-ray diffraction analysis indicated that the plasma radiation involved in the sputtering process could release the lattice strain in the perovskite film. Furthermore, both simulations and experiments illustrated that sputtering damage was associated with the formation of defects in the C60 layer and the dissociation of C＝N bonds at the perovskite surface due to ion-bombardment-induced phonon propagation. A method to mitigate this damage using a SnOx buffer layer was experimentally confirmed, and its working mechanism was elucidated. [ABSTRACT FROM AUTHOR]

In this work, the kinetics of phase separation in ultrathin non-stoichiometric Si oxide (SiOx, x < 2) films during high-temperature annealing is studied by Monte Carlo simulations on a two-dimensional lattice. The separation of Si and Si oxide phases by redistribution of oxygen atoms between the neighboring Si-OaSi4-a (0 = a = 4) complexes composing the SiOx microstructure is considered. The net direction of oxygen redistribution corresponds to the decrease of the penalty energy of the participating complexes, which is taken into account by applying the Metropolis algorithm. As a result, the dependence of the morphology of the Si nano-structures formed in the Si oxide matrix on the initial SiOx stoichiometry is obtained. Isolated Si nanoparticles with irregular shapes form at x = 1. A progressive increase of the excess Si content leads to the formation of noodle-like and branched Si particles, local Si networks and finally fully percolated Si structures at the percolation threshold x ~ 0.7. [ABSTRACT FROM AUTHOR]

Conventional time-of-flight (TOF) measurements yield charge carrier mobilities in photovoltaic cells with time resolution limited by the RC time constant of the device, which is on the order of 0.1–1 µs for the systems targeted in the present work. We have recently developed an alternate TOF method, termed nonlinear photocurrent spectroscopy (NLPC), in which carrier drift velocities are determined with picosecond time resolution by applying a pair of laser pulses to a device with an experimentally controlled delay time. In this technique, carriers photoexcited by the first laser pulse are "probed" by way of recombination processes involving carriers associated with the second laser pulse. Here, we report NLPC measurements conducted with a simplified experimental apparatus in which synchronized 40 ps diode lasers enable delay times up to 100 µs at 5 kHz repetition rates. Carrier mobilities of ∼0.025 cm2/V/s are determined for MAPbI3 photovoltaic cells with active layer thicknesses of 240 and 460 nm using this instrument. Our experiments and model calculations suggest that the nonlinear response of the photocurrent weakens as the carrier densities photoexcited by the first laser pulse trap and broaden while traversing the active layer of a device. Based on this aspect of the signal generation mechanism, experiments conducted with co-propagating and counter-propagating laser beam geometries are leveraged to determine a 60 nm length scale of drift velocity dispersion in MAPbI3 films. Contributions from localized states induced by thermal fluctuations are consistent with drift velocity dispersion on this length scale. [ABSTRACT FROM AUTHOR]

The elongation of spherical Au nanoparticles embedded in SiO 2 under swift heavy ion (SHI) irradiation is an extensively studied phenomenon. The use of a TEM grid as a substrate facilitates the identification of the same nanoparticle before and after the irradiation. Since the underdensification of SiO 2 inside the ion track plays a key role, the elongation is sensitive to the matrix material properties. Therefore, we studied the elongation process of SHI irradiated Au spherical nanoparticles of various diameters (5–80 nm) embedded either in atomic layer deposition (ALD) or plasma-enhanced chemical vapor deposition (PECVD) SiO 2. The results show that a different elongation ratio is achieved depending on the particle initial size, ion fluence, and a different SiO 2 deposition method. The embedded nanoparticles in ALD SiO 2 elongate roughly 100% more than the nanoparticles embedded in PECVD SiO 2 at the biggest applied fluence (5 × 10 14 ions / cm 2). On the other hand, at fluences lower than 10 14 ions / cm 2 , nanoparticles elongate slightly more when they are embedded in PECVD SiO 2. [ABSTRACT FROM AUTHOR]

Metal halide perovskite solar cells (PSCs) have emerged as one of the most promising candidates for next-generation photovoltaic technologies. However, perovskite films deposited by blade-coating usually exhibit inferior film morphology compared to those fabricated by spin-coating, which hinders the power conversion efficiency (PCE) and stability of the scalable perovskite solar modules (PSMs). Herein, ellipsoidal colloids are tailored in the perovskite precursor solution by incorporating perovskite colloids and polymer additives. Compared to unregulated spherical colloids, the ellipsoidal colloids demonstrate more oriented packing during the blade-coating process, which is due to the anisotropic driven force from the fluidic flow in the meniscus. As a result of the improved film morphology, the regulated PSCs and PSMs achieve superior PCE of 24.31% and 21.67% (21.37% certified), respectively, for aperture areas of 0.09 and 13.94 cm 2 , and 89% initial PCE after 600 h continuous operation., (© 2025 Wiley‐VCH GmbH.)

Over the past decade, semiconducting halide perovskite lasers have emerged as a transformative platform in optoelectronics, owing to unique properties such as high photoluminescence quantum yields, tunable bandgaps, and low-cost fabrication processes. This review systematically examines the advancements in halide perovskite lasers, covering diverse laser architectures, such as whispering gallery mode, Fabry-Pérot, plasmonic, bound states in the continuum (BIC), quantum dot, and polariton lasers. The mechanisms of optical gain, the role of material engineering in optimizing lasing performance, and the challenges associated with continuous-wave (CW) pumping and electrically driven lasing are discussed. Furthermore, recent progress in improving the stability and scalability of perovskite lasers, essential for their integration into practical applications in displays, optical communications, sensing, and integrated photonics is highlighted. Finally, future research directions are discussed, emphasizing the potential of perovskite lasers to revolutionize various technological domains by enabling the development of next-generation photonic devices., (© 2025 Wiley‐VCH GmbH.)

Tin-based halide perovskites (ASnX 3 ) have garnered substantial interest due to their unique photoelectric properties and environmentally friendly features. The A-site ions tuning strategy has been proven to promote material performance. However, there is a lack of systematic research on the optical properties, lattice structure variation, and band structure evolution in tin-based perovskites when the A-site ions tune from organic to inorganic. Herein, MA 1-x Cs x SnBr 3 and MA 1-x Cs x SnI 3 (0≤x≤1) flakes are synthesized through a one-pot reaction method. By controlling the Cs ratio, a tunable photoluminescence (PL) emission covering a wide range of 560-685 nm can be observed in MA 1-x Cs x SnBr 3 , with bandgap tuned from 1.8 to 2.15 eV, while the PL ranges from 900 to 950 nm with the bandgap 1.2-1.3 eV for MA 1-x Cs x SnI 3 . Besides, the PL intensity of MA 1-x Cs x SnBr 3 significantly enhances with the increasing Cs ratio. First-principles calculations reveal that the octahedron shrinks gradually as the Cs ratio increases. It increases the orbital overlap between Sn and Br and causes a symmetry variation, thus decreasing the bandgap and increasing emission intensity. This work reveals the photophysical mechanism of improved optical properties and bandgap variation in tin-based perovskites, paving the way for their future applications., (© 2025 Wiley‐VCH GmbH.)

The development of efficient electron-collecting monolayer materials is desired to lower manufacturing costs and improve the performance of regular (negative-intrinsic-positive, n-i-p) type perovskite solar cells (PSCs). Here, we designed and synthesized four electron-collecting monolayer materials based on thiazolidinone skeletons, with different lowest-unoccupied molecular orbital (LUMO) levels (rhodanine or thiazolidinedione) and different anchoring groups to the transparent electrode (phosphonic acid or carboxylic acid). These molecules, when adsorbed on indium tin oxide (ITO) substrates, lower the work function of ITO, decreasing the energy barrier for electron extraction at the ITO/perovskite interface and improving the device performance. The shift of work function, rather than the LUMO levels of the molecules themselves, was found to be correlated with the performance of the perovskite solar cells., (© 2025 Wiley-VCH GmbH.)

Hole-transport layers (HTL) in perovskite solar cells (PSCs) with an n-i-p structure are commonly doped by bis(trifluoromethane)sulfonimide (TFSI) salts to enhance hole conduction. While lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) dopant is a widely used and effective dopant, it has significant limitations, including the need for additional solvents and additives, environmental sensitivity, unintended oxidation, and dopant migration, which can lead to lower stability of PSCs. A novel ionic liquid, 1-(2-methoxyethyl)-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)amide (MMPyTFSI), is explored as an alternative dopant for 2,2',7,7'-tetrakis(N,N-di-p-methoxyphenylamino)-9,9'-spirobifluorene (spiro-OMeTAD). MMPy ions act as a surface passivator, reducing defects on the perovskite surface, while TFSI ions facilitate p-type doping. MMPyTFSI functions as an efficient dopant, maintaining excellent performance even when tetrahydrofuran (THF) is utilized as a solvent in place of chlorobenzene (CB), while significantly reducing the environmental impact of the process. The optimized PSC achieves a power conversion efficiency (PCE) of 23.10% and demonstrates enhanced long-term stability in all aging tests for over 1000 h in a humid atmosphere, at high temperature, and under simulated sunlight illumination. These results demonstrate that MMPyTFSI is an effective and environmentally friendly dopant for producing stable and efficient PSCs., (© 2025 The Author(s). Advanced Science published by Wiley‐VCH GmbH.)

Halide-perovskite semiconductors have a high potential for use in single-junction and tandem solar cells. Despite their unprecedented rise in power conversion efficiencies (PCEs) for photovoltaic (PV) applications, it remains unclear whether perovskite solar modules can reach a sufficient operational lifetime. In order to make perovskite solar cells (PSCs) commercially viable, a fundamental understanding of the relationship between their nanostructure, optoelectronic properties, device efficiency, and long-term operational stability/reliability needs to be established. In this review, the phase instabilities in state-of-the-art formamidinium (FA)-rich perovskite absorbers is discussed. Furhermore, the concerted efforts are summarized in this prospect, covering aspects from fundamental research to device engineering. Subsequently, a critical analysis of the dictating impact of the nanoscale landscape of perovskite materials on their resulting intrinsic stability is provided '. Finally, the remaining challenges in the field are assessed and future research directions are proposed for improving the operational lifetimes of perovskite devices. It is believed that these approaches, which bridge nanoscale structural properties to working solar cell devices, will be critical to assessing the realization of a bankable PSC product., (© 2024 Wiley‐VCH GmbH.)

Developing high-quality wide bandgap (WBG) perovskites with ≈1.7 eV bandgap (E g ) is critical to couple with silicon and create efficient silicon/perovskite tandem devices. The sufferings of large open-circuit voltage (V OC ) loss and unstable power output under operation continuously highlight the criticality to fully develop high-quality WBG perovskite films. In this study, rubidium and thiocyanate as additive regulators in WBG perovskites are incorporated, significantly reducing non-radiative recombination, ion-migration, and phase segregation. The optimized 1.66 eV E g perovskite solar cells achieved state-of-art 1.3 V V OC (0.36 V deficit), and delivered a stabilized power conversion efficiency of 24.3%, along with good device stability (20% degradation (T 80 ) after over 994 h of operation under 1 sun at ≈65°C). When integrated with a flat front side silicon cell, silicon/perovskite two-terminal tandem device (30% efficient) is obtained with a 1.97 V V OC , and T 90 operational lifetime of more than 600 h at room temperature., (© 2024 Wiley‐VCH GmbH.)

Tandem photovoltaics consisting of a wide-bandgap top cell and a narrow-bandgap bottom cell have shown great potential to exceed current single-junction photovoltaics. To maximize the dual junction benefit, significant research is needed in selecting and optimizing the structure of both solar devices. This work reports the optimization of tandem solar cells with a CIGS solar cell as the bottom cell and a 2D–3D perovskite solar cell (PSC) as the top cell via numerical simulations using SCAPS-1D. The performances of the PSCs were optimized by varying the bandgaps of the 2D–3D perovskite and the thickness of the perovskite layer. The bottom p-CIGS/n-GaSe heterojunction solar cell was also optimized in terms of the thicknesses of the p-type/n-type layer and defect densities. The top PSC and bottom CIGS solar cells individually displayed maximum power conversion efficiencies (PCEs) of ∼21.41% and ∼12.98%, respectively. This simulation study was carried out for tandem solar cells by matching the optical behavior of the bottom cells with the calculated spectra of 2D–3D PSCs. Proper matching with CIGS cells in the tandem device was performed by varying the thickness of the perovskite layer with respect to different bandgaps. With the optimized 2D–3D perovskite/CIGS tandem device, over ∼30% PCE was recorded. To the best of our knowledge, this is the first time a 2D–3D perovskite solar cell/GIGS–GaSe heterojunction solar cell based tandem device has been optimized via numerical simulation. Based on our findings, a low-cost GIGS–GaSe heterojunction solar cell can be optimized as the bottom cell to fabricate efficient 2D–3D perovskite tandem solar cells. [ABSTRACT FROM AUTHOR]

The reliability of oxide‐semiconductor (OS) thin‐film transistors (TFTs) is significantly influenced by the gate insulator (GI). During electrical bias stress, the defect sites near the semiconductor/GI interface and/or within the GI may trap electrons, which makes the threshold voltage (Vth) shift toward positive values. On the other hand, carbon (C) or hydrogen (H) atoms may diffuse from the GI into the active layer, and act as shallow donors, which induce negative Vth shifts (ΔVth). In this paper, an in situ atomic layer deposition (ALD)‐based GI heterostructure is introduced, which consists of a stack of two complementary materials, namely Al2O3 and SiO2. Here, a competition occurs between electron trapping in Al2O3 (positive ΔVth) and carrier generation from H atoms in SiO2 (negative ΔVth) which allows the achievement of nearly zero ΔVth under positive bias temperature stress (PBTS). This strategy is successfully applied to a high‐mobility (>50 cm2 Vs−1) ALD‐based indium‐gallium‐zinc oxide (IGZO) device, resulting in a net ∆Vth of −0.02 V under PBTS and drain current variation (∆ID) of +0.49% under constant current stress (CCS). The application of an in situ ALD process thus offers valuable insights to resolve the mobility versus reliability trade‐off in high‐performance oxide TFTs. [ABSTRACT FROM AUTHOR]

Tunable bandgaps make halide perovskites promising candidates for developing tandem solar cells (TSCs), a strategy to break the radiative limit of 33.7% for single‐junction solar cells. Combining perovskites with market‐dominant crystalline silicon (c‐Si) is particularly attractive; simple estimates based on the bandgap matching indicate that the efficiency limit in such tandem device is as high as 46%. However, state‐of‐the‐art perovskite/c‐Si TSCs only achieve an efficiency of ~32.5%, implying significant challenges and also rich opportunities. In this review, we start with the operating mechanism and efficiency limit of TSCs, followed by systematical discussions on wide‐bandgap perovskite front cells, interface selective contacts, and electrical interconnection layer, as well as photon management for highly efficient perovskite/c‐Si TSCs. We highlight the challenges in this field and provide our understanding of future research directions toward highly efficient and stable large‐scale wide‐bandgap perovskite front cells for the commercialization of perovskite/c‐Si TSCs. [ABSTRACT FROM AUTHOR]

The ability to characterise perovskite phases non-destructively is key on the route to ensuring their long-term stability in operando. Raman spectroscopy holds the promise to play an important role in this task. Among all perovskites, formamidinium lead iodide (FAPbI3) has emerged as one of the most promising candidates for single-junction photovoltaic cells. However, Raman spectroscopy of FAPbI3 remains challenging as is evidenced by conflicting reports in the literature. Here, we demonstrate that due to the vulnerability of FAPbI3 to laser-induced degradation, the detected Raman spectrum depends strongly on the experimental conditions. This can lead to conflicting results and is revealed as the origin of discrepancies in the literature. We overcome this issue by deploying defocused Raman spectroscopy, preventing laser-induced damage to the sample and simultaneously improving the signal-to-noise ratio, allowing us to furthermore resolve much weaker Raman modes than was previously possible. We offer step-by-step instructions on how to apply this technique to a given spectrometer. Non-destructive characterisation of the FAPbI3 phases further enables us to quantify the phase stability of pristine FAPbI3 crystals and FAPbI3 grown with the high-performance additive methylenediammonium chloride (MDACl2). This shows that the neat crystals fully degrade within two weeks, whereas in samples grown with the additive only about 2% of the crystal bulk is in the δ-phase after 400 days. This establishes defocused Raman spectroscopy as a powerful tool for the characterisation of FAPbI3 and other perovskite materials. [ABSTRACT FROM AUTHOR]

The rapid emergence of organic-inorganic lead halide perovskites for low-cost and high-efficiency photovoltaics promises to impact new photovoltaic concepts. Their high power conversion efficiencies, ability to coat perovskite layers on glass via various scalable deposition techniques, excellent optoelectronic properties, and synthetic versatility for modulating transparency and color allow perovskite solar cells (PSCs) to be an ideal solution for building-integrated photovoltaics (BIPVs), which transforms windows or façades into electric power generators. In this review, the unique features and properties of PSCs for BIPV application are accessed. Device engineering and optical management strategies of active layers, interlayers, and electrodes for semitransparent, bifacial, and colorful PSCs are also discussed. The performance of PSCs under conditions that are relevant for BIPV such as different operational temperature, light intensity, and light incident angle are also reviewed. Recent outdoor stability testing of PSCs in different countries and other demonstration of scalability and deployment of PSCs are also spotlighted. Finally, the current challenges and future opportunities for realizing perovskite-based BIPV are discussed., (© 2022 Wiley-VCH GmbH.)