•Ammonium sulfide (NH4)2S is introduced to the SnO2 precursor solution for passivating the SnO2 surface defects by terminating the Sn dangling bonds at the surface.•The linkage of Sn–S–Pb anchors the ...perovskite crystals at the perovskite/SnO2 interface, which increases the electron extraction efficiency and the stability of PSC.•The power conversion efficiency (PCE) of the PSC is greatly promoted from 18.67% to 20.03%, compared with the reference one.
Tin oxide (SnO2) is widely adopted as an electron transport layer (ETL) in perovskite solar cells (PSCs). However, the oxygen vacancies of the SnO2 not only are the trap states of the nonradiative recombination of photogenerated carriers, but also build the potential barrier of carrier transport. To solve this issue, ammonium sulfide (NH4)2S is introduced to the SnO2 precursor for passivating the surface defects by terminating the Sn dangling bonds (S–Sn bonds). After reducing the surface traps, the electron mobility and conductivity of SnO2 film are enhanced significantly while the carrier recombination is decreased. Additionally, the energy level of S-SnO2 is also slightly modified. Therefore, this sulfide-passivated mothed remarkably improves the electron collection efficiency of the ETL. Furthermore, the linkage of Sn–S–Pb anchors the perovskite crystals at the perovskite/SnO2 interface, which increases the electron extraction efficiency and the stability of PSC. Based on this S-SnO2 ETL, the power conversion efficiency of the PSC is greatly promoted from 18.67% to 20.03%, compared with the reference one. In this study, it is proven that the surface defect passivation of SnO2 is an efficient and simple method to improve the photovoltaic performance, as a promising ETL for high-efficiency device.
An organic-inorganic perovskite formamidinium tin iodide (HC(NH2)2SnI3– FASnI3) is used as light absorbing layer in photovoltaics due to its lead-free nature, wider bandgap of 1.41 eV and better ...temperature stability than CH3NH3SnI3. In the present investigations, SCAPS simulation with comparison to the experimental as well as simulation data for FASnI3-based solar cell device is accomplished for high power conversion efficiency with proper optimization. The variation in the device design key parameters such as absorber, hole transport layer and electron transport layer thickness including defect density, doping concentration in absorber, carriers capture cross sections and interfacial defects are examined with their impact on device performance. The preliminary structure of device is based on the reported experimental and simulation work with the efficiency of 1.75% and 1.66%, respectively. After the SCAPS simulation with the optimization of basic parameters in this work, the final optimized performance parameters of the solar cell device are found to be enhanced with short-circuit current density (Jsc) of 31.20 mA/cm2, open-circuit voltage (Voc) of 1.81 V, fill factor (%FF) of 33.72% and power conversion efficiency (%PCE) of 19.08%.
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•Physics behind the performance parameters in (HC(NH2)2SnI3– FASnI3) PSC device.•Comparison FASnI3-based PSC performance with reported experimental and SCAPS simulation results.•Study the effect on the device with the variation of basic parameters of cell.•Final optimized parameters achieved: Jsc-31.20 mA/cm2, Voc-1.81 V, FF-33.72% and PCE-19.08%.
Summary
A lead‐free, completely inorganic, and nontoxic Cs2TiBr6‐based double perovskite solar cell (PSC) was simulated via SCAPS 1‐D. La‐doped BaSnO3 (LBSO) was applied as the electron transport ...layer (ETL) unprecedentedly in the simulation study of PSCs, while CuSbS2 was utilized as the hole transport layer (HTL). wxAMPS was used to validate the results of SCAPS simulations. Moreover, the first‐principle density function theory (DFT) calculations were performed for validating the 1.6 eV bandgap of the Cs2TiBr6 absorber. To enhance the device performance, we analyzed and optimized various parameters of the PSC using SCAPS. The optimum thickness, defect density, and bandgap of the absorber were 1000 nm, 1013 cm−3, and 1.4 eV, respectively. Furthermore, the optimum thickness, hole mobility, and electron affinity of the HTL were 400 nm, 102 cm2V−1 s−1, and 4.1 eV, respectively. However, the ETL thickness had a negligible effect on the device's efficiency. The optimized values of doping density for the absorber layer, HTL, and ETL were 1015, 1020, and 1021 cm−3, respectively. Herein, the effect of different HTLs was analyzed by matching up the built‐in voltage (Vbi) in respect of the open‐circuit voltage (VOC). It was found that the Vbi was directly proportional to the VOC, and CuSbS2 was the champion in terms of efficiency for the PSC. The optimum work function of metal contact and temperature of the PSC were 5.9 eV and 300 K, respectively. After the final optimization, the device achieved an exhilarating PCE of 29.13%.
Novelty Statement
LBSO was used as the ETL for the very first time in the simulation study of PSCs, while CuSbS2 was utilized as the HTL.
DFT calculations were performed to understand the electronic behavior of Cs2TiBr6 absorber and validation of the SCAPS simulation results was accomplished via wxAMPS.
Different parameters of the absorber layer, ETL, and HTL were optimized using SCAPS and a PCE of 29.13% was achieved after the final optimization of the device.
We simulated a fully inorganic, lead‐free, and non‐toxic FTO/LBSO/Cs2TiBr6/CuSbS2/Au heterostructure via SCAPS‐1D. We analyzed and optimized the effect of variation in thickness, defect density, doping density, and bandgap of absorber, thickness and doping density of ETL, thickness, doping density, electron affinity, and hole mobility of HTL along with the operating temperature and metal work function of the PSC. Furthermore, we validated the simulation results utilizing wxAMPS and performed DFT calculations to validate the 1.6 eV bandgap of the Cs2TiBr6 absorber.
An electron transporting layer (ETL) plays an important role in extracting electrons from a perovskite layer and blocking recombination between electrons in the fluorine-doped tin oxide (FTO) and ...holes in the perovskite layers, especially in planar perovskite solar cells. Dense TiO2 ETLs prepared by a solution-processed spin-coating method (S-TiO2) are mainly used in devices due to their ease of fabrication. Herein, we found that fatal morphological defects at the S-TiO2 interface due to a rough FTO surface, including an irregular film thickness, discontinuous areas, and poor physical contact between the S-TiO2 and the FTO layers, were inevitable and lowered the charge transport properties through the planar perovskite solar cells. The effects of the morphological defects were mitigated in this work using a TiO2 ETL produced from sputtering and anodization. This method produced a well-defined nanostructured TiO2 ETL with an excellent transmittance, single-crystalline properties, a uniform film thickness, a large effective area, and defect-free physical contact with a rough substrate that provided outstanding electron extraction and hole blocking in a planar perovskite solar cell. In planar perovskite devices, anodized TiO2 ETL (A-TiO2) increased the power conversion efficiency by 22% (from 12.5 to 15.2%), and the stabilized maximum power output efficiency increased by 44% (from 8.9 to 12.8%) compared with S-TiO2. This work highlights the importance of the ETL geometry for maximizing device performance and provides insights into achieving ideal ETL morphologies that remedy the drawbacks observed in conventional spin-coated ETLs.
The conduction band energy, conductivity, mobility, and electronic trap states of electron transport layer (ETL) are very important to the efficiency and stability of a planar perovskite solar cell ...(PSC). However, as the most widely used ETL, TiO2 often needs to be prepared under high temperature and has unfavorable electrical properties such as low conductivity and high electronic trap states. Modifications such as elemental doping are effective methods for improving the electrical properties of TiO2 and the performance of PSCs. In this study, Nb-doped TiO2 films are prepared by a facile one-port chemical bath process at low temperature (70 °C) and applied as a high quality ETL for planar PSCs. Compared with pure TiO2, the Nb-doped TiO2 is more efficient for photogenerated electron injection and extraction, showing higher conductivity, higher mobility, and lower trap-state density. A PSC with 1% Nb-doped TiO2 yielded a power conversion efficiency of more than 19%, with about 90% of its initial efficiency remaining after storing for 1200 h in air or annealing at 80 °C for 20 h in a glovebox.
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•Tungsten-doped TiO2 ETL successfully deposited on FTO substrates through low-temperature solution processed.•Tungsten dopant reduces trap-state density and enhances the ...conductivity.•Cs0.05(MA0.17FA0.83)0.95Pb(I0.83Br0.17)3 PSC has improved by 28.1% via tungsten-doped TiO2.
In this work, W-doped TiO2, was successfully fabricated, as electron transport layer (ETL) in perovskite solar cells (PSCs) via low-temperature solution-processed method, whose outstanding performances were verified. The experimental results reveal that, W6+ was doped into the TiO2 lattice successfully. The improved ETL exhibit significantly improved on conductivity, transport and extraction of photo-generated carriers and less trap-state density as compared with the pristine TiO2 films. Meanwhile, strengthening the velocity of carrier and collection of sufficient charge can efficiently increase short-circuit current (JSC) which favor an improved fill factor (FF) and a higher power conversion efficiency (PCE). Our optimized cation–anion-mixed PSC based on W-doped TiO2 has achieved an efficiency of 18.85%. This improved PCE is almost 28.1% higher than that of the pure TiO2. This study provides a promising approach to design metal-doped TiO2 for fabricating high-performance perovskite solar cells.
The solar technology, specifically the Perovskite based photovoltaics (PV) offers a substantial attribution in the recent times. Apart from the stability, flexibility as well as the higher ...efficiency, more focus is given to use a lead-free combined with the eco-friendly as well as the cheaper materials in PSC device fabrication. The non-volatile PVK, i.e., Cesium tin iodide (CsSnI3) can be a suitable material for fabricating the PSC device, this is not only a cost effective, but also offers eco-friendliness containing higher optoelectronic nature due to its smaller bandgap, i.e., 1.3 eV. The proper inclusion of Sn in perovskite also improves the stability of the device. In the current simulation work the CsSnI3 is utilized as an active layer whereas biosynthesized (BS) ZnO-NP as Electron Transport Layer (ETL) for cost effective production. Likewise, Spiro-OMeTAD is designed as the Hole Transport Layer (HTL) for superior holes collection. The comprehensive simulation is used for obtaining suitable CsSnI3 thickness, working temperature, and total defectivity, resistances impact, respectively. The currently simulated PSC deals with an exceptional power conversion efficiency (PCE) around 26.32%. The obtained results shown in the present investigation may demonstrates an exclusive approach for the development of the lead-free solar cells.
•A comprehensive study of Perovskite Solar Cell (PSC) are accomplished using SCAPS-1D simulating software.•Biosynthesized ETL of ZnO is utilized in the proposed PSC device to obtain maximum possible efficiency.•The optoelectronic properties for all the constituent PSC are investigated and studied.•The novel Biosynthesized ETL of ZnO offers excellent efficiency of 26.32%.•The present work can be valuable for futuristic device optimization of PSC.
Exploration of low-temperature solution-processed methodology for fabricating planar perovskite solar cells (PSCs) is meaningful for simplifying manufacturing, roll-to-roll industrial mass production ...on flexible substrates and designing perovskite tandem devices. However, some complicated, time consuming, or even high-cost methodologies such as atomic layer deposition, magnetron sputtering, and utilizing careful interface engineering are still needed for preparing efficient planar PSCs with TiO2 electron transport layers (ETLs) at low temperature. Here, we report a simple ligand-exchange strategy to overcome the problems. We use oleic acid (OA) molecules as surface ligands for synthesis well crystalline and monodisperse TiO2 nanocrystals. Subsequently, instead of high temperature decomposition, we find that the ligand-exchange strategy can also totally peel off these insulating ligands on the TiO2 nanocrystal surfaces and form high-quality TiO2 ETLs at low temperature. The OA-free TiO2 ETLs prepared at 150°C show high conductivity, fast electron extraction and transport speeds, low series resistance and high shunt resistance in the assembled PSCs, contributing to high performance devices with slight hysteresis and good reproducibility.
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•A novel and simple ligand-exchange strategy is introduced.•High quality TiO2 electron transport layers are fabricated at low temperature.•The best-performance device achieves a PCE of 19.07% with slight hysteresis.
Numerical simulations can provide the physical insights into the carrier transport mechanism in the solar cells, and the factors influencing their performance. In this paper, perovskite solar cell ...(PSC) based on the mixed perovskite (CH3NH3Pb(I1-xBrx)3 has been numerically simulated using the SCAPS simulator. A comparative analysis of different electron transport layers (ETLs) based on their conduction band offsets (CBO) has been performed, while Spiro-OMeTAD was used as a hole transport layer (HTL). Among the proposed ETLs, CdZnS performed better and demonstrated the power conversion efficiency (PCE) of 25.20%. Also, the PCE of the PSC has been optimized by adjusting the doping concentrations in the ETL, Spiro-OMeTAD layer, and the thickness of the perovskite light absorber layer. It was found that the doping concentration of 1021 cm−3 for the CdZnS based ETL and 1020 cm−3 for Spiro-OMeTAD are the optimum concentrations values for demonstrating enhanced efficiency. A 600 nm thick perovskite layer has found to be appropriate for the efficient PSC design. For the initial guessing and numerical model validation, the photovoltaic data of a very stable (over one year with PCE ~13%) n-i-p structured (ITO/TiO2/CH3NH3Pb(I1-xBrx)3/Spiro-OMeTAD/Au) PSCs was used. These numerically simulated results signify the optimum performance of the photovoltaic device that can be further implemented to develop the highly efficient PSCs.
•PSC based on the mixed perovskite has been numerically simulated using SCAPS simulator.•A comparative analysis of different ETLs based on their CBOs has been performed.•These numerically simulated results signify the optimum performance of the PSCs.
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