Perovskite Silicon Tandem Solar Cells Research Articles

Machine Learning-Enabled Optical Architecture Design of Perovskite Solar Cells.

Perovskite solar cells, emerging as a cutting-edge solar energy technology, have demonstrated a power conversion efficiency (PCE) of >26%, which is below the theoretical limit of 33%. This study, employing a combination of neural network models and high-throughput simulation calculations, taking the single-junction FAPbI3 cell as an illustrative example, indicates that a pyramid structure, in comparison of a planar one, can increase the highest Jsc to 27.4 mA/cm2 and the PCE to 28.4%. Both Jsc and PCE surpass the currently reported experimental results. The optimized periodicity and tilt angle of the pyramid structure align with the textured structure of crystalline silicon solar cells. These results underscore the substantial development potential of neural network inverse design based on high-throughput calculations in the field of optoelectronic devices and provide theoretical guidance for the design of monolithic perovskite-silicon tandem solar cells.

Enhancing perovskite-silicon tandem solar cells through numerical optical and electric optimizations for light management.

We integrated optical and electrical numerical simulations to precisely investigate the effectiveness of using a pyramidal perovskite (Cs0.18FA0.82Pb(I,Br)3) nanostructured film as an example in perovskite-silicon tandem solar cells to reduce reflective losses and balance the current densities. Through our calculations, the PCE of tandem solar cells can be improved from 29.2% (the planar structures without texturing) to 36.1% in the best-performing textured tandem devices under the consistently calculated absorbed and EQE spectrum, where the predicted open-circuit voltage could reach over 2 V. These findings offer valuable theoretical insights for the advancement and optimization of perovskite-silicon tandem solar cells.

Scenario-based recycling strategies for perovskite-silicon tandem solar cells: a harmonized life cycle assessment study

Environmental performances of end-of-life strategies for perovskite–silicon tandem solar cells.

Toward efficient and industrially compatible fully textured perovskite silicon tandem solar cells: Controlled process parameters for reliable perovskite formation

AbstractCapitalizing on the existing silicon industry, fully textured perovskite‐silicon tandem solar cells have a great potential to penetrate the electricity market. While the use of textured silicon with large pyramid size (> 1 μm) enhances the power conversion efficiency (PCE), it also presents process complications. To achieve high performance, meticulous control of deposition parameters on textured silicon is required. This study provides a guideline for the use of the hybrid evaporation/spin‐coating route to form high‐quality perovskite absorbers. Using various characterization techniques, we highlight intrinsic differences between perovskite growth on flat versus textured substrates. Furthermore, we provide pathways to ensure a high perovskite phase purity, reveal mitigation strategies to avoid the formation of undesired dendritic perovskite structures, give guidelines to ensure photostability, and discuss the “misleading” effect of residual PbI2 on the perovskite photoluminescence response. A good understanding of the perovskite growth on textured silicon enables the fabrication of a tandem device with a PCE > 26% (without employing additives or surface treatments) and a good operational stability. The comprehensive guidelines in this study provide a better understanding of perovskite formation on textured silicon and can be transferred when upscaling the hybrid route perovskite deposition.

Nanostructured anti-reflection coating for absorption enhancement in perovskite silicon tandem solar cells

Perovskite-silicon tandem solar cells have captured the attention of the solar cell research community due to the advantages of perovskites, such as, an easy fabrication process using sol-gel methods and silicon bottom cells that can be fabricated using well-established fabrication techniques. The present study discusses the design, optimization, and numerical analysis related to the role of nanostructured anti-reflection coating design for perovskite (MAPbI3) silicon tandem solar cells. In the design, the top cell is taken as MAPbI3 and the bottom cell is C-silicon. The anti-reflection coating is designed with SiO2 nanoparticles embedded in ITO. These nanostructured top anti-reflection coating results are compared with its planar top cell counterpart. SiO2 nanoparticle diameter and interparticle separation are optimized to get maximum absorption in the top cell. Upon optimization, it was found that a design having SiO2 nanoparticles with a diameter of 60 nm and no interparticle separation showed the most reduction in reflection, which in turn led to an increase in absorption in the top cell. The proposed structure enhances current density by 8.3% over the planar cell. This top cell current is matched to the bottom silicon thickness. These findings were validated using Mie scattering and the Bruggmann effective medium approximation.

Co-evaporated oriented DMA1-xCsxPbI3 perovskite films for photovoltaics

Thermally evaporated cesium lead triiodide (CsPbI3) is a frontier research direction for perovskite-silicon tandem solar cells because of the matching bandgap and good conformality with textured silicon. However, the random orientation and small grains for the co-evaporated CsPbI3 thin films fabricated at low temperature, resulting in harmful defects and non-radiative recombination. Here, dimethylammonium iodide (DMAI) is introduced into the co-evaporation system at a substrate temperature of 50 °C to prepare preferentially oriented DMA0.06Cs0.94PbI3 film with less defects and enhanced humidity stability. The bandgap also can be reduced from 1.76 eV (γ-CsPbI3) to 1.73 eV. The p-i-n photovoltaic device based on this film achieves an efficiency of 16.10% with suppressed non-radiative recombination, rivaling with the thermally evaporated wide-bandgap CsPbI3 solar cells prepared at a high temperature (∼ 350 °C). This in-situ evaporated alloying strategy can pave the way for the crystallization and defect control during perovskite co-evaporation.

Analysis of nanostructured anti reflection coating for various perovskite layer thicknesses in perovskite silicon tandem solar cells

The anti-reflection coating (ARC) plays an important role in the design of every kind of solar cell. The suitable optimization of the ARC layer can make a lot of difference in the final output of the cell, by reducing the reflections at the surface. In this regard, the present paper highlights and analyses numerically the effect of nanostructured ARC for different top perovskite layer thicknesses in perovskite-silicon tandem solar cells. In the present case, the nanostructures for ARC are considered to be made up of SiO2 nanoparticles (NP) embedded in ITO. To evaluate the effect of nanostructure for this proposed cell, the nanostructured tandem cell is compared with its planar ARC-based reference cell. The top perovskite active thickness is varied from 100 nm to 800 nm. It has been found that the effect of nanostructured ARC is more pronounced for thinner perovskite layer-based cells than for thicker layers. To reduce reflections at the front surface, the SiO2 NP diameter and inter-particle spacing are optimized. With the nanostructured ARC at the top, the cell achieved the current density rise of 11.3% as compared to the reference cell for a 100 nm thick perovskite-based tandem cell design. As both the sub-cells are in series in tandem design, the top cell current is matched to the bottom silicon layer current by optimizing the bottom cell too. The proposed ARC design has the added advantage that it can simply be done with sol–gel processes.

Versatile implied open‐circuit voltage imaging method and its application in monolithic tandem solar cells

AbstractAs the efficiency of perovskite silicon tandem solar cells is increasing, the upscaling for industrial production is coming into focus. Spatially resolved, quantitative, fast, and reliable contactless measurement techniques are demanded for quality assurance and to pinpoint the cause of performance losses in perovskite silicon tandem solar cells. In this publication, we present a measurement method based on spectrally integrated photoluminescence (PL) imaging to extract subcell‐selective implied open‐circuit ( ) images from monolithic perovskite silicon tandem solar cells. We validate the approach using spectrally resolved absolute PL measurements based on an integrating sphere for the perovskite top cell and PL‐calibrated carrier lifetime images for the silicon bottom cell. Additionally, measurements of solar cells with low contact losses are used to validate the new measurement technique. We find a good agreement of the images with the validating measurements with a maximum deviation of well below 1% compared to the validation measurements.

Perovskite/silicon tandem solar cells-compositions for improved stability and power conversion efficiency.

Perovskite/Silicon Tandem Solar Cells (PSTSCs) represent an emerging opportunity to compete with industry-standard single junction crystalline silicon (c-Si) solar cells. The maximum power conversion efficiency (PCE) of single junction cells is set by the Shockley-Queisser (SQ) limit (33.7%). However, tandem cells can expand this value to ~ 45% by utilising two stacked solar cells to harvest the solar spectrum more efficiently. 33.9% PCE has already been achieved with PSTSCs. This perspective analyses recent advances in PSTSC technology, with an emphasis on optimal perovskite composition, the problem and mitigation of light-induced halide phase segregation, self-assembled hole transporting monolayers and additives that can improve and stabilise the perovskite. Top-performing compositions show three cationic components (Cs+, FA+, Pb2+) and three anionic (I-, Br-, Cl-) with a bandgap between 1.55 and 1.77eV and a theoretical maximum of 1.73eV (717nm). Anionic additives such as (Br3)- and SCN- reduce trap states and segregation. 2D-perovskite grain boundary interfaces are created with cationic alkylammonium additives such as methyl-phenethylammonium (MPEA) and result in improved performance. 2-, 3- or 4-terminal devices with a (partly) textured silicon heterojunction (SHJ) bottom cell are ideal. An ultra-thin interfacial recombination layer (~ 5nm) of indium tin oxide (ITO) or indium zinc oxide (IZO) containing a carbazole-based hole transporting self-assembled monolayer (Me-4PACz) is used for optimal 2-terminal tandem devices.

Loss Analysis of Fully‐Textured Perovskite Silicon Tandem Solar Cells: Characterization Methods and Simulation toward the Practical Efficiency Potential

Optimally enhancing the performance of perovskite silicon tandem solar cells comes with accurate identification of loss origins in the device in combination with optoelectrical device simulations assessing the respective efficiency gains to prioritize optimization pathways. Herein, various characterization methods, namely, spectrally resolved photoluminescence (PL), transient‐PL, PL‐based implied open‐circuit voltage (iVOC) imaging, spectrometric characterization, and Suns‐VOC measurements are combined to quantify current density–voltage (jV) photovoltaic metric losses of a fully‐textured perovskite silicon tandem solar cell (26.7% efficiency). The extracted device characteristic parameters are then used as a reference for the comprehensive optoelectrical Sentaurus simulation model which precisely reproduces the experimentally obtained optical and electrical solar cell characteristics, considering mobile ion dynamics. Subsequently, starting from the current device design, the authors alleviate one step at a time the loss constraints and show the impact of each loss channel on the efficiency, identifying the three major ones to be at the: 1) perovskite/C60 interface (−4.6%abs) , 2) the series resistance (−2.9%abs), and 3) light management (−2.1%abs), which limit the VOC, fill factor, and jSC of the device, respectively. Furthermore, it is demonstrated that a practical efficiency potential of 39.5% can be regarded as a practical limit for the presented tandem device architecture.

Molecular engineering of hole-selective layer for high band gap perovskites for highly efficient and stable perovskite-silicon tandem solar cells

Molecular engineering of hole-selective layer for high band gap perovskites for highly efficient and stable perovskite-silicon tandem solar cells

Overcoming Two Key Challenges in Monolithic Perovskite‐Silicon Tandem Solar Cell Development: Wide Bandgap and Textured Substrate—A Comprehensive Review

Abstract33.7% of power conversion efficiency (PCE) in monolithic perovskite‐silicon tandem solar cells (PSTSCs) is an eye‐catcher. Still, the issues emerging from their two main requirements, wide band gap (WBG) perovskites and textured substrates, trigger phase segregation, voltage deficit, perovskite strain, high recombination rates, shunt paths, etc. In addition, the ill‐defined relations of most of these issues to the WBG perovskites and silicon texture originating from the conflicting research outcomes have become severe impediments to developing PSTSCs. From this perspective, an overview of the recently developed monolithic PSTSCs discussing the major hurdles in their up‐scaling, stabilities, and commercialization is presented.

Low-temperature metallization & interconnection for silicon heterojunction and perovskite silicon tandem solar cells

In this work, we present results on various low-temperature approaches for the metallization and interconnection of high-efficiency solar cells as silicon heterojunction (SHJ) or perovskite silicon tandems. By using fine line screen printing for the cell metallization and Ag-free or -reduced interconnection technologies, we demonstrate the potential of these approaches both for SHJ and perovskite silicon tandem cells. Furthermore, low-temperature (LT, ∼200 °C) or ultra-low-temperature (ULT, ∼150 °C) processes are utilized for metallization and interconnection to treat these temperature-sensitive solar cells with a reduced energy consumption. We compare LT soldering of SHJ cells with Pb-free alloys to state-of-the-art soldering processes and interconnection with electrically conductive adhesives (ECAs). For successful module integration of perovskite silicon tandem solar cells, these findings provide the basis to build full-size tandem modules with different interconnection technologies.

Understanding Contact Nonuniformities at Interfaces in Perovskite Silicon Tandem Solar Cells Using Luminescence Imaging, Lock‐In Thermography, and 2D/3D Simulations

The top cell of a perovskite silicon tandem solar cell requires several material layers on each side of the perovskite absorber to efficiently extract electrons and holes, respectively. These layers must meet multiple requirements simultaneously, namely, low interface recombination, good charge carrier selectivity, low contact resistivity, and high optical transparency. Due to the complex architecture, characterization techniques are required in material and process optimization to identify loss mechanisms. Spatial resolution of the characterization is gaining importance along with the upscaling of the perovskite technology. Herein, electro‐ and photoluminescence (EL and PL) imaging is combined with illuminated lock‐in thermography (ILIT) for a comprehensive electro‐optical characterization of both subcells in perovskite silicon tandem devices with state‐of‐the‐art cell architecture. Thereby, the combination of the presented characterization methods together with numerical simulation models enables to carry out holistic investigations of device limitations. The strength of this approach is showcased by one particularly remarkable feature that is observed in the investigated tandem device, showing a low PL but high EL signal at local spots. Together with multidimensional optoelectrical device simulations, the measurements are explained and the root cause of this feature to originate from the perovskite/C60 interface is suggested.

Performance improvement mechanisms of perovskite solar cells by modification of NiO hole-selective contacts with self-assembled-monolayers

This study investigates effects of the modification of NiOx hole-selective contacts (HSCs) with self-assembled monolayers (SAMs), [2-(9H-carbazol-9-yl) ethyl]phosphonic acid (2PACz), on the characteristics of perovskite solar cells, used for perovskite–silicon tandem cells. After the NiOx layers were fabricated by RF sputtering, the 2PACz modification was performed by the spin-coating of a 2PACz solution and subsequent annealing at 100 °C for 10 min. The 2PACz-modified NiOx layer improved the solar cells' open-circuit voltage and short-circuit current density. Photoelectron yield spectroscopy measurements imply that the 2PACz monolayers increase the work function of the NiOx HSCs, thereby enhancing field-effect passivation at the perovskite–HSC interface. Density functional theory calculations and electron spin resonance measurements indicate that an increase in the work function results from a vacuum level shift due to the electric dipole moment of 2PACz molecules and formation of space-charge region at the NiOx–2PACz interface. The performance improvement is explained as a result of enhanced field-effect passivation caused by the vacuum level shift and thus the increase in the work function. These findings, which clarify SAM modification effects of HSCs on solar-cells’ performance, can contribute to the development of highly efficient and reliable perovskite–silicon tandem solar cells.

Interface engineering for high-performance, triple-halide perovskite-silicon tandem solar cells.

Improved stability and efficiency of two-terminal monolithic perovskite-silicon tandem solar cells will require reductions in recombination losses. By combining a triple-halide perovskite (1.68 electron volt bandgap) with a piperazinium iodide interfacial modification, we improved the band alignment, reduced nonradiative recombination losses, and enhanced charge extraction at the electron-selective contact. Solar cells showed open-circuit voltages of up to 1.28 volts in p-i-n single junctions and 2.00 volts in perovskite-silicon tandem solar cells. The tandem cells achieve certified power conversion efficiencies of up to 32.5%.

Insights into Perovskite Film Formation Using the Hybrid Evaporation/Spin-Coating Route: An In Situ XRD Study

The hybrid evaporation/spin-coating route has been widely used for fabrication of highly efficient fully textured perovskite silicon tandem solar cells and is a promising route for upscaling. Nevertheless, fundamental aspects of the fabrication process such as the kinetics of perovskite crystallization and the influence of the environmental conditions remain uncertain. In this work, we investigate the individual stages of tandem-relevant 1.66 eV bandgap perovskite formation and map the structural evolution from the precursor to the perovskite phase until the degradation phase. We find that the kinetics of these transitions can be tuned by varying the humidity or the temperature during the annealing treatment. Specifically, increasing the relative humidity up to 50% elevates the reaction rate and results in improved perovskite quality. This is directly reflected in the solar cell power conversion efficiency with a 3%abs increment on average. While high annealing temperatures are found to promote large grain size growth and enhanced crystallinity, we observe that above 150 °C the remnant PbI2 precursor compromises film quality. Furthermore, the perovskite formation kinetics is fitted using the Johnson–Mehl–Avrami–Kolmogorov model. The Avrami constant is found in the range 0.66–0.87, indicating a diffusion-controlled one-dimensional growth process with an associated activation energy of 54.49 kJ/mol. Using in situ XRD, this work gives insights on key process parameters to ensure reproducible synthesis of high-quality perovskite films.

Minimizing electro-optical losses of ITO layers for monolithic perovskite silicon tandem solar cells

Minimizing electro-optical losses of ITO layers for monolithic perovskite silicon tandem solar cells

Optimization of Efficient Perovskite-Si Hybrid Tandem Solar Cells

Perovskite-silicon tandem solar cells have attracted much attention to photovoltaic community because of their high efficiency via easy fabrication methods and availability of precursor material abundant in nature. The properties of both perovskite and silicon meet ideal solar cell standards such as high light absorption potential, long carrier diffusion length and fast charge separation process. Semi-transparent solar cell with widely tunable band gap of perovskite material is compatible with silicon solar cell for tandem structures. A perovskite-silicon tandem solar cell four terminal configuration optimization was performed through numerical simulation. The optimized four terminal perovskite-silicon tandem solar cell performances was investigated by varying the thickness of top and bottom solar cell absorber layers, defect density of the absorber layer, and temperature. Perovskite-silicon tandem solar cell showed better photovoltaic performance under constant illumination condition. A high performance mechanically attached four terminal (4-T) perovskite-silicon tandem solar cell has total power conversion efficiency (PCE) of 34.88% by optimized parameters through simulation. It has shown 37% efficiency with matched current of 23.71mA/cm2. These numerical simulation results are provided the parameter values for further experimental assignment.

A Review on Stability Challenges and Probable Solution of Perovskite–Silicon Tandem Solar Cells

A Review on Stability Challenges and Probable Solution of Perovskite–Silicon Tandem Solar Cells