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Lead halide hybrid solar cells have demonstrated exceptional performance in recent years, but concerns over their toxicity and instability have spurred the development of perovskite-based cells without lead. This work explores a lead-free perovskite material consisting of cesium tin-germanium triiodide solid solution perovskite (CsSn0.5Ge0.5I3) is utilized to fabricate solar cells with varying thicknesses and donor densities of the absorber layer. The results imply that enhancing the thickness of the layer boosts the power conversion efficiency (PCE) by facilitating better photon absorption. However, this increase in thickness also causes a reduction in both the open-circuit voltage (VOC) and fill factor (FF). In other words, while thickening the layer improves PCE through increased photon absorption, it also negatively impacts other key performance metrics, such as VOC and FF. Conversely, the effect of donor density (Nd) on the cell's performance is less significant than the CsSn0.5Ge0.5I3 layer's thickness. This study sheds light on the critical role of thickness and donor density in optimizing the performance of CsSn0.5Ge0.5I3-based solar cells. The performance of c-Si and CIGS-based single junction bottom cells under standalone conditions is also analyzed using JV and EQE curves. The C-Si-based single junction solar cell exhibited greater efficiency (21.28%) in converting photons of different wavelengths into electrons compared to the CIGS-based solar cell (16.26%). Lastly, for increasing the PCE of the single-junction solar cells the study moves towards multi-junction solar cells. In this context, two highly efficient TSCs (LFPVK/c-Si and LFPVK/CIGS) are designed and analyzed using the current matching technique, which involves the series connection of the top and bottom cells with increased PV parameters (LFPVK/c-Si-JSC: 21.44 mA/cm2, VOC: 1.45 V, FF: 82.17%, PCE: 25.54% and LFPVK/CIGS-JSC: 21.83 mA/cm2, VOC: 1.33 V, FF: 73.34%, PCE: 21.45%). [ABSTRACT FROM AUTHOR]

Numerous researchers have dedicated efforts toward enhancing the efficiency of solar cells, particularly through the utilization of multi-junction or tandem solar cell configurations. However, a common approach employed by many researchers involves the use of the standard absorption formula (SAF) to determine the transmitted spectrum from the top cell to illuminate the bottom cells. The SAF method relies on conventional absorption calculations, neglecting reflection, refraction, and parasitic absorption losses. In this study, the transfer matrix (TRM) method, which accounts for reflection and refraction losses and an interference effect, is reported for the accurate calculation of a filtered spectrum. A comparative analysis between the SAF and TRM approaches reveal that the TRM technique provides a more accurate representation of the transmitted spectrum, particularly when considering reflection, refraction, and parasitic absorption losses. The primary aim of this research is to precisely predict the efficiency of tandem configurations by integrating multiple low-bandgap semiconductor bottom cells (BCs) with a top cell (TC) based on high-bandgap perovskite (PVK). Furthermore, the optimization of current matching is achieved by adjusting the thicknesses of the top absorber layer (TAL) and bottom absorber layer (BAL) based on the obtained filtered spectra. Tandem devices optimized using the TRM approach exhibit superior performance, achieving efficiencies of 28.72% (PVK/c-Si), 27.88% (PVK/CIGS), and 29.99% (PVK/PVK). This comparative investigation underscores the importance of considering reflection and refraction losses in tandem solar cell design and highlights the effectiveness of the TRM technique in enhancing device performance. [ABSTRACT FROM AUTHOR]

Double-junction tandem solar cells (TSCs), featuring a wide-bandgap top cell (TC) and narrow-bandgap bottom cell (BC), outperform single-junction photovoltaics, demanding meticulous subcell selection and optimization. Lead-free double perovskites offer sustainable photovoltaic solutions and are less toxic with enhanced stability, versatile compositions, and favorable optoelectronic characteristics. This study investigates the design and performance of a lead-free all-double-perovskite tandem solar cell (DPTSC), utilizing Cs 2 AgBiBr 6 (CABB) with a bandgap of 2.05 eV and Cs 4 CuSb 2 Cl 12 (CCSC) with a bandgap 1.6 eV as absorbers in the TC and BC, respectively. The TC and BC were individually simulated and calibrated against experimental data, forming the basis for tandem device design and optimization. Series and shunt resistance, along with temperature effects on their performance, were examined. Meticulous adjustment of absorber thicknesses achieved optimal current matching between subcells. This fine-tuning closely matches TC current under AM 1.5G spectrum with BC current under a filtered spectrum. At optimal current matching (absorber thickness: 0.365 µm for the TC and 1.4 µm for BC), the DPTSC exhibits impressive power conversion efficiency (PCE) of 28.08% (with V oc = 2.47 V, J sc = 12.78 mA / cm 2 , FF = 88.95%). The external quantum efficiency (EQE), Mott–Schottky and carrier generation/recombination profiles under current matching conditions have also been acquired to provide comprehensive device design insights. The designed TSC shows improved stability against temperature variations. These findings highlight the potential for lead-free and stable double perovskites to serve as subcell absorbers, enabling highly efficient, commercially viable, nontoxic, and eco-friendly tandem photovoltaic technologies. This work contributes valuable insights for advancing TSC technology, supported by comparisons with existing simulated and experimental data. [ABSTRACT FROM AUTHOR]

Tandem solar cells owing to their layered structure in which each sub-cell utilizes a certain part of the solar spectrum with reduced thermal losses, are promising applicants to promote the power conversion efficiency beyond the Shockley–Queisser limit of single-junction solar cells. This study delves into the performance and optimization of 4-terminal organic/silicon tandem solar cells through numerical simulations using SCAPS-1D software. The tandem architecture combining organic, perovskite, and silicon materials, shows potential in enhancing light absorption across the solar spectrum with complementary absorption spectra. Through innovative material exploration, optimization techniques are explored to advance the performance boundaries of organic/silicon tandem solar cells. The study employs the Beer–Lambert law to assess the impact of varied physical parameters on tandem solar cell efficiency, aiming to propose optimal configurations. Results indicate a maximum efficiency of 25.86% with P3HT:PC70BM organic active layer (150 nm thickness) and 36.8% with Cs2AgBi0.75Sb0.25Br6 active layer (400 nm thickness) in the studied 4-terminal tandem structures. These findings offer valuable insights into the complex physics of these tandem solar cells, for developing high-performance and commercially practical photovoltaic devices. [ABSTRACT FROM AUTHOR]

The power conversion efficiency of all-inorganic Sb2S3-on-Si two-terminal (2-T) monolithically integrated and four-terminal (4-T) mechanically stacked tandem solar cells are investigated. A one-dimensional solar cell capacitance simulator (SCAPS-1D) has been used to simulate the stand-alone antimony trisulfide (Sb2S3) top sub-cell, silicon (Si) bottom sub-cell, 2-T monolithic, and 4-T mechanically stacked tandem solar cells. The stand-alone sub-cells are optimized by extensive studies, including interface defects density, bulk defects density, absorber layer thickness, and series resistance. The power conversion efficiency (PCE) of simulated stand-alone sub-cells is compared and verified with the existing literature. A current matching condition is established to characterize the 2-T monolithic Sb2S3-on-Si tandem cell. A filtered spectrum has been utilized for bottom sub-cell measurement in the tandem solar cells. The best-simulated PCE of Sb2S3-on-Si 2-T monolithic and 4-T tandem cells is 30.22% and 29.30%, respectively. The simulation results presented in this paper open an opportunity for the scientific community to consider Sb2S3 as a potential top sub-cell material in Sb2S3-on-Si tandem solar cells with high PCE. [ABSTRACT FROM AUTHOR]

Shockley Queisser's theory states that the efficiency of single-junction solar cells is restricted. This constraint can be avoided by employing a tandem (stacking multiple cells) setup. Furthermore, stacking layers such as Perovskite/silicon in tandem architecture might boost efficiency. In this research, SCAPD-1D was used to simulate a monolithic 2T Perovskite/silicon tandem solar cell. The tandem configuration is composed of a narrow bandgap (1.1 eV) crystalline silicon Heterojunction with an intrinsic thin layer (HIT) solar cell at the bottom and a wide bandgap (1.8 eV) lead-free Perovskite (Cs2AgBi0.75Sb0.25Br6) solar cell on top. The proposed tandem device is simulated as a standalone and integrated structure. The PCE of the calibrated standalone cell is 14.54% (top cell) and 21.66% (bottom cell), respectively. The calibrated cells are used to design an integrated tandem configuration. The current matching condition is accomplished at varied thicknesses of top and bottom absorber layers. A bottom cell's ideal current matching thickness is 230 µm, while a perovskite top cell is 550 nm. The overall conversion efficiency of the tandem device is 26%, with an FF of 79.18%. [ABSTRACT FROM AUTHOR]

Barium di-silicide (BaSi2) material has attracted noteworthy interest in photovoltaics, thanks to its stability, abundant nature, and excellent production feasibility. In this current work, a two-terminal (2T) monolithic all-BaSi2 tandem solar cell is proposed and explored through extensive TCAD simulation. A BaSi2 bottom sub-cell with a bandgap of 1.3 eV, and a Ba(CxSi1−x)2 top sub-cell with a tunable bandgap are employed in the design. It was found that a bandgap of 1.8 eV, which corresponds to x = 0.78, is the optimum choice to obtain the maximum initial power conversion efficiency (η) of 30%. Then, the tandem performance is optimized by investigating the impact of doping and the thickness of both absorber layers. Further, the current matching point is monitored whilst altering the thickness of the top cell resulting in η = 32.83%%, and a short-circuit current density (Jsc) of 16.47 mA/cm2. Additionally, we have explored the influence of the defect density in the absorbers, and the work function of contacts on the performance parameters. All TCAD simulations are accomplished using the Silvaco Atlas package under AM1.5G illumination. [ABSTRACT FROM AUTHOR]

Optical design, photon management, and energy conversion efficiency are investigated through numerical simulation of perovskite/silicon tandem solar cell using the single-diode model. A strong near-infrared reflectance of roughly 60% is present in the perovskite-based top cell. ZnO and Si3N4 anti-reflection coating layers are placed on the surface of the perovskite layer and silicon sub-cell of the tandem solar cell respectively for photon management and minimizing the near-infrared reflectance loss. ZnO will act as an electron transport layer as well as an anti-reflection coating layer. The ZnO layer will minimize the near-infrared reflectance loss by the top cell in the device structure and allow the maximum transmittance of near-infrared photon energy to the silicon sub-cell. Intermediate anti-reflection Si3N4 layer assists in the maximum localization of the transmitted near-infrared photon energy in the silicon sub-cell. The efficiency of over 32% is achieved by optimizing the parameters of different materials such as perovskite, silicon, and anti-reflection coating layer in the tandem solar cell. The innovative idea of using electron transport material ZnO as an anti-reflection coating layer in the perovskite-based top cell can minimize the reflection loss by nearly 20%. The combination of ZnO and Si3N4 anti-reflection coating layers improved the conversion efficiency of the tandem cell by 1%. This result paves the way to realize highly efficient tandem solar cells through photon management. [ABSTRACT FROM AUTHOR]

Monolithic hybrid halide perovskite/crystalline silicon (c-Si) tandem solar cells have demonstrated their great potential to surpass the theoretical efficiency limit of single-junction devices. However, the stability of perovskite sub-cells is inferior to that of the c-Si solar cells that have been commercialized, casting serious doubt about the lifetime of the entire device. During device operation, light and heat are inevitable, which requires special attention. Herein, we review the current understandings of the intrinsic stability of perovskite/c-Si tandems upon light and/or heat aging. First, we summarize the recent understandings regarding light facilitated ion migration, materials decomposition, and phase segregation. In addition, the reverse bias effect on the stability of tandem modules caused by uneven illumination is discussed. Second, this review also summarizes the thermal-induced degradation and mismatch issue, which underlines the system design of perovskite/c-Si tandems. Third, recent strategies to improve the intrinsic stability of perovskite/c-Si tandems under light and/or heat are reviewed, such as composition engineering, crystallinity enhancement, interface modification, material optimization, and device structure modification. At last, we present several potential research directions that have been overlooked, and hope those are helpful for future research on perovskite based tandem solar cells. [ABSTRACT FROM AUTHOR]

Inorganic-organic metal halide perovskite light harvester-based perovskite solar cells (PSCs) with widely tunable bandgap have achieved rapid growth in power conversion efficiency, which exceeds 25% now. It is deliberated that if a semitransparent solar cell made of wider bandgap materials was placed on top of a narrow bandgap materials-based solar cell such as a silicon solar cell, with proper optical and electrical arrangements, the resultant tandem device consisting of two subcells could more effectively utilize the solar spectrum than a single junction solar cell. In a perovskite/silicon tandem solar cell (PSTSC), a semitransparent PSC with a wider bandgap is placed on top of a narrow bandgap silicon solar cell. The PSC efficiently harvests the higher energy photons in the ultraviolet and visible regions of the solar spectrum while the silicon solar cell can convert the photons of the infrared region to power. The PSTSC is proposed as a potential candidate to overcome the Shockley-Queisser limit of single-junction silicon solar cells. Though the theoretical limit of a PSTSC is calculated as ∼42%, its actual efficiency achieved until now is less than 30%. Therefore, a great scope of research exists in improving the efficiency of PSTSCs. Current issues of stability and upscaling of the device in PSCs are also a matter of concern for PSTSCs. A tandem device consists of multiple parts, and different configurations can be applied, thus tuning the architecture of the device. Altering various parts may result in significant changes in the efficiency of the device. In this review, competing architectures of otherwise comparable devices are compared in terms of photovoltaic properties. Thus, future directions to improve the efficiency of the device based on architecture design are proposed herein. In particular, the influence of the polarity of PSCs and the surface morphology of silicon solar cells (both front and rear) on determining the properties of the PSTSC are discussed. [ABSTRACT FROM AUTHOR]

The work presented in this paper is part of the current context of research aimed at improving the performance of tandem DJ solar cells and understanding basic materials science based on III–V materials which has become a major field of studies in photovoltaics. This research's main objective is to highlight the impact of band gap energy of materials used, in forming a quantum well structure (quantum confinement) as well as the correct choice of the tunnel junction (materials, thickness) on improving the electrical conversion efficiency and achieving optimum power of InGaP/GaAs DJ solar cell. In this regard, modeling a solar cell is the powerful tool that will allow us to link the characteristics of this cell with the properties of the material and the manufacturing technology to improve cell performance. To carry out our objectives, a numerical study presented by a numerical model of a GaInP/GaAs tandem cell built in Silvaco software showing the criteria of choosing the best junction tunnel (materials, thickness, doping..) which contribute to higher efficiency of DJ solar cell as well as to limit the various losses and therefore achieve a good compromise between cost and structure. This numerical model emphasizes the use of the III–V compound material of GaAs, ternary Ga1 –xInxP, (AlxGa1 –xAs and quaternary (AlxGa1–x)1 –yInyP), aiming at the potential of the band gap energy of these materials used on absorbing more photon energy from the optical source and then converting the optical energy on more electrical energy. The simulation results presented have enabled us to better understand the contours of the performance of tandem solar cells (single, dual junction) and to understand the need for their optimizations. These by the exploitation of the electrical and optical characteristics J–V, P–V which induced us to extract the photovoltaic parameters (Jsc, Voc, Pmax, FF, η) of tandem cells. Furhermore, the efficiency of carrier confinement is shown in quantum well active layer. [ABSTRACT FROM AUTHOR]

In this study, we discuss a simulation model for a tandem device with MAPbSnI3 as a bottom subcell having bandgap of 1.2 eV and MACsPb(I0.6Br0.4) as a top subcell having bandgap of 1.8 eV. These perovskite material-based top and bottom cells are first examined under standalone condition. Simulation result shows the efficiency of standalone MAPbSnI3 and MACsPb(I0.6Br0.4) devices to be 15.34% and 12.74% respectively. These results are consistent with previously reported experimental findings. We have also analyzed the effect of defect density, perovskite thickness and contact work function on overall efficiency of the solar cell. It has been found that defect density in the perovskite layer should be smaller than 1013 cm−3 and the optimal work function for the front contact of the perovskite solar cell was found to be 5.44 eV, while for the back contact it is 4.22 eV for optimal performance of the solar cell. The matching of tandem stacks is investigated in terms of the equal short-circuit currents of subcells. This condition is met at perovskite thicknesses of 400 nm and 150 nm for MAPbSnI3 and MACsPb(I0.6Br0.4), respectively. Finally, to evaluate tandem solar cell performance, the top cell was operated under the standard AM 1.5 spectrum retaining perovskite thickness at 400 nm, while the bottom cell efficiency was calculated in a filtered spectrum. Improved efficiency of 20% is obtained for the MACsPb(I0.6Br0.4)/MAPbSnI3 tandem solar cell. The analysis and findings reported in this work give a potential route for tandem solar cell design. [ABSTRACT FROM AUTHOR]

Recently, thin-film solar cells have received much attention due to low production cost. However, such cells suffer from low efficiency due to which they cannot be used for practical applications. To cater this problem, we have numerically investigated thin-film tandem solar cells comprising of double active layers made of amorphous silicon (a-Si) and crystalline silicon (c-Si) of different energy bandgaps. The tandem cell is found to absorb large amount of solar photons compared to a single a-Si and c-Si solar cells. To further improve the absorption efficiency, we efficiently utilized the surface plasmon resonance (SPR) effect of plasmonic nanoparticles, which are deposited in the form of a square lattice in the top a-Si active layer. The absorption characteristics of the cell are enhanced and tuned by optimizing the material and size of the nanoparticles. Moreover, periodic disorders are incorporated, which allow mixing of plasmonic modes having different angular momenta, resulting in a super broadband light absorption from 300 to 1100 nm and yielding a short circuit current density of 33.917 mA/cm2 in the active layers. The proposed plasmonic tandem cell can be advantageous for most of the photovoltaic applications. [ABSTRACT FROM AUTHOR]

Perovskite being a wide bandgap material has shown profound impact as an active material for the use of top cell in the tandem solar cell. However, finding a suitable low-bandgap material for the bottom cell of the perovskite associated tandem solar cell has always been a concern for researchers. Over the last decade, several materials for designing of the bottom cell have been reported as a combination to perovskite for superior efficiency. In this paper, a novel perovskite/Mg2Si based monolithic tandem solar cell is reported through numerical simulations using AFROS-HET v2.5. The reported device shows 25% efficiency prior to optimization. However, the structure of the device has been optimized to obtain better results in terms of efficiency by varying active layer thickness and using different electron/hole transport materials. About 8% improvement in efficiency has been noticed by the selection of optimum design parameters. Further, to account for the temperature reliability of the proposed design, the device is simulated for a temperature range of 300 K–450 K. This study highlights a drop-in open-circuit voltage (VOC) by a factor of about 0.1 V with an increase in temperature by about 50 K. Results clearly establish that structural and temperature variations significantly affect overall device performance. Results have been suitably analyzed so as to set a roadmap for further research work in this direction and explore the best of the characteristics of this unique tandem solar cell structure. [ABSTRACT FROM AUTHOR]

This work shows the design of a high-efficiency solar cell in an indium-gallium-arsenide/–gallium-arsenide multiple quantum well (MQW) structure. The main concerns regarding the solar cell are its fabrication complexity, design complexity, and efficiency. Tandem solar cells are designed to absorb the maximum amount of solar energy. In a tandem structure, different positive-negative junctions are responsible for absorbing different portions of the solar spectrum. Besides this, the embedded MQW structure also helps to increase the efficiency of the solar cell. The maximum efficiency of the tandem solar cell in the different material structures is reported to be around 45%–46%. Proper matching of different material parameters such as the lattice-matched semiconductor and thickness of the tandem solar cell can increase the efficiency of the solar cell. This paper introduces a tandem solar cell having an efficiency of around 50%. This comparative study shows the improved performance of the proposed solar cell. A graphical user interface is also developed for solar cell simulation. [ABSTRACT FROM AUTHOR]

An analytical model is used to describe the electrical characteristics of a dual-junction tandem solar cell performing with a conversion efficiency of 32.56% under air mass 1.5 global (AM1.5G) spectrum. The tandem structure consists of a thin heterojunction top cell made of indium gallium phosphide (InGaP) on gallium arsenide (GaAs), mechanically stacked on a relatively thick germanium (Ge) substrate, which acts as bottom cell. In order to obtain the best performance of such a structure, we simulate for both the upper and lower sub-cell the current density–voltage, power density–voltage, and spectral response behaviors, taking into account the doping-dependent transport parameters and a wide range of minority carrier surface recombination velocities. For the proposed tandem cell, our calculations predict optimal photovoltaic parameters, namely the short-circuit current density (Jsc), open-circuit voltage (Voc), maximum power density (Pmax), and fill factor (FF) are Jsc = 28.25 mA/cm2, Voc = 1.24 V, Pmax = 31.64 mW/cm2, and FF = 89.95%, respectively. The present study could prove useful in supporting the design of high efficiency dual junction structures by investigating the role of different materials and physical parameters. [ABSTRACT FROM AUTHOR]

Small-molecule Π-systems bearing donor (D) and acceptor (A) groups constitute an interesting class of dyes because of their tunable strong absorption, which covers the visible and near-infrared range. The dipolarity associated with D–A structures directs antiparallel stacking arrangements in the solid state, thus reducing the dipolar disorder at the supramolecular level. Their straightforward synthesis and purification make them good candidates for photovoltaic application with power conversion efficiencies >6 %. This review summarizes the application of D–A dyes, and in particular merocyanines, in organic photovoltaics in recent years. [ABSTRACT FROM AUTHOR]

We hereby propose a non-expensive method for the deposition of pure and Al-doped hematite photoanodes in the configuration of thin films for the application of dye-sensitized solar cells (DSSC). The electrodes have been prepared from hematite nanoparticles that were obtained by thermal degradation of a chemical precursor. The particles have been used in the preparation of a paste, suitable for both screen printing and doctor blade deposition. The paste was then spread on fluorine-doped tin oxide (FTO) to obtain porous hematite electrodes. The electrodes have been sensitized using N3 and D5 dyes and were characterized through current/voltage curves under simulated sun light (1 sun, AM 1.5) with a Pt counter electrode. Al-doping of hematite showed interesting changes in the physical and electrochemical characteristics of sensitized photoanodes since we could notice the growth of AlFeO (hercynite) as a secondary crystal phase into the oxides obtained by firing the mixtures of two chemical precursors at different molar ratios. Pure and Al-doped hematite electrodes have been used in a complete n-type DSSCs. The kinetics of charge transfer through the interface dye/electrolyte was studied and compared to that of a typical p-type DSSC based on NiO photocathodes sensitized with erythrosine B. The results suggest a potential application of both FeO and FeO/AlFeO as photoanodes of a tandem DSSC. [ABSTRACT FROM AUTHOR]

We report results from Hall effect studies on AlGaAs ( x = 0.23-0.24) with bandgap energies of 1.76 ± 0.01 eV grown by liquid-phase epitaxy (LPE). Room-temperature Hall measurements on unintentionally doped AlGaAs revealed p-type background doping for concentrations in the range 3.7-5.2 × 10 cm. Sn, Te, Ge, and Zn-doped AlGaAs were also characterized to study the relationship between doping concentrations and the atomic fractions of the dopants in the melt. Temperature-dependent Hall measurements were performed to determine the activation energies of the four dopants. Deep donor levels (DX centers) were dominant for Sn-doped AlGaAs, but not for Te-doped AlGaAs. Comparison of the temperature-dependent Hall effect results for unintentionally and intentionally doped AlGaAs indicated that the impurity contributing to the p-type background doping had the same activation energy as Mg. We thus suggest a Te-doped emitter and an undoped or Ge-doped base to maximize the efficiency of AlGaAs ( x ∼ 0.23) solar cells grown by LPE. [ABSTRACT FROM AUTHOR]

The photovoltaic conversion efficiency for monolithic GaInP/GaInAs/Ge triple-junction cell with various bandgap combination (300 suns, AM1.5d) was theoretically calculated. An impressive improvement on conversion efficiency was observed for a bandgap combination of 1.708, 1.194, and 0.67 eV. A theoretical investigation was carried out on the effect of dislocation on the metamorphic structure's efficiency by regarding dislocation as minority-carrier recombination center. The results showed that only when dislocation density was less than 1.6×10 cm, can this metamorphic combination exhibit its efficiency advantage over the fully-matched combination. In addition, we also briefly evaluated the lattice misfit dependence of the dislocation density for a group of metamorphic triple-junction system, and used it as guidance for the choice of the proper cell structure. [ABSTRACT FROM AUTHOR]

This article reviews the new concepts and new trends of solar cell development. To increase the photoelectric conversion efficiency, reduce the cost, and for application in a much broader field, thin film solar cell, flexible solar cell, and tandem solar cell have become important subjects to be studied. As the representative of the solar cells of the third generation, the progress and challenges of dye sensitized solar cell was also reviewed. [ABSTRACT FROM AUTHOR]

Perovskite solar cells are used in silicon-based tandem solar cells due to their tunable band gap, high absorption coefficient and low preparation cost. However, the relatively large optical refractive index of bottom silicon, in comparison with that of top perovskite absorber layers, results in significant reflection losses in two-terminal devices. Therefore, light management is crucial to improve photocurrent absorption in the Si bottom cell. In this paper, nanoholes array filled with TiO2 is introduced into bottom cells design. By finite-difference time-domain methods, the absorption efficiency and photocurrent density in the range of 300–1100 nm has been analyzed, and the structural parameters have been also optimized. Our calculations show the photocurrent density which tends to be saturated with the increase in the height of the nanoholes. The absorption enhancement modes of photons at different wavelengths have been analyzed intuitively by the distribution of electric field. These results enable a viable and convenient route toward high efficiency design of perovskite/Si tandem solar cells. [ABSTRACT FROM AUTHOR]