Limit Of Power Conversion Efficiency Research Articles

Preferentially coordinating tin ions to suppress composition segregation for high-performance tin-lead mixed perovskite solar cells

Tin-lead mixed perovskites (TLPs) with a tunable and ideal bandgap exhibit great potential in approaching the Shockley–Queisser limit of power conversion efficiency (PCE). However, two critical issues are necessary to be addressed, including the oxidation of Sn2+ and negligible composition and phase segregation. The latter derives from the unbalanced crystallization rate between Sn- and Pb-based perovskites. Here, we report a strategy to address the above critical issues by introducing 3,4-Dihydroxybenzylamine hydrobromide (DHBABr) in the TLP precursor solution. DHBABr was revealed to promote the crystallization of FAPbI3 perovskite by suppressing the formation of crystalline DMSO-FA-Pb-I intermediates and retard the crystallization rate of FASnI3 by preferentially forming a steady amorphous DHBA-FA-Sn-I intermediate. This, therefore, balances the crystallization rate between Sn- and Pb-based perovskites. As a result, the spatial distribution of Sn/Pb ratio is much more uniform across the whole TLP film, which benefits the upscaling of the manufacturing process. Relying on this doping strategy accompanied by the surface passivation with DHBABr, which reduces the defect density of TLP, inhibits the oxidation of Sn2+, and optimizes the band alignment of the device, we have achieved a PCE of 22.44 % with Voc of 0.853 V and FF of 80.0 %, along with an enhanced long-term stability of T80 = 476 h under continuously light illumination in the champion device.

Carrier transport layer engineering of Cs2TiI2Br4 halide double perovskite solar cell via SCAPS 1D: Approaching the Shockley-Queisser limit

All-inorganic Cs2TiIxBr(6-x)-based perovskite solar cells (PSCs) are recently attracting a lot of attention for their tunable bandgaps, earth abundance, non-toxicity, and ultra-stability. Among the Cs2TiIxBr(6-x) family of materials, Cs2TiI2Br4 with a bandgap of ∼1.38 eV has the potential to be an excellent single junction solar cell material with a theoretically higher Shockley-Queisser limit of power conversion efficiency (PCE). Its excellent optoelectronic properties make it a potential candidate for being the highest-performing PSC from the Cs2TiIxBr(6-x) family. In our study, a total of eight hole transport materials (P3HT, PTAA, Spiro-OMeTAD, PEDOT:Pss, CuSCN, CuI, NiO, and MoO3) and six electron transport materials (PCBM, TiO2, CdS, SnO2, ZnO, and IGZO) were investigated to select suitable charge transport materials. The defect densities of interface and absorber, different absorber layer thicknesses, several metal work functions, series-shunt resistance, and temperature were investigated to derive the conditions for optimum performance. After thorough investigation, we derived four novel devices with the combination of all the organic and inorganic charge transport materials to provide optimum performance. Among them, the combination of inorganic SnO2 and CuSCN as electron and hole transport layer respectively achieved the highest PCE of 23.41 %.

Interfacial Layer Materials with a Truxene Core for Dopant-Free NiOx-Based Inverted Perovskite Solar Cells.

Nickel oxide (NiOx) is commonly used as a holetransporting material (HTM) in p-i-n perovskite solar cells. However, the weak chemical interaction between the NiOx and CH3NH3PbI3 (MAPbI3) interface results in poor crystallinity, ineffective hole extraction, and enhanced carrier recombination, which are the leading causes for the limited stability and power conversion efficiency (PCE). Herein, two HTMs, TRUX-D1 (N2,N7,N12-tris(9,9-dimethyl-9H-fluoren-2-yl)-5,5,10,10,15,15-hexaheptyl-N2,N7,N12-tris(4-methoxyphenyl)-10,15-dihydro-5H-diindeno[1,2-a:1',2'-c]fluorene-2,7,12-triamine) and TRUX-D2 (5,5,10,10,15,15-hexaheptyl-N2,N7,N12-tris(4-methoxyphenyl)-N2,N7,N12-tris(10-methyl-10H-phenothiazin-3-yl)-10,15-dihydro-5H-diindeno[1,2-a:1',2'-c]fluorene-2,7,12-triamine), are designed with a rigid planar C3 symmetry truxene core integrated with electron-donating amino groups at peripheral positions. The TRUX-D molecules are employed as effective interfacial layer (IFL) materials between the NiOx and MAPbI3 interface. The incorporation of truxene-based IFLs improves the quality of perovskite crystallinity, minimizes nonradiative recombination, and accelerates charge extraction which has been confirmed by various characterization techniques. As a result, the TRUX-D1 exhibits a maximum PCE of up to 20.8% with an impressive long-term stability. The unencapsulated device retains 98% of their initial performance following 210days of aging in a glove box and 75.5% for the device after 80days under ambient air condition with humidity over 40% at 25°C.

First-principles investigation of photovoltaic material based on lanthanide metals

Searching for photovoltaic materials with high efficiency conforms to the goal for accessing low carbon and sustainable energy. This work explores the properties of RA3X3 compounds (R = La, Sm, Gd, Tb, Dy, Ho, Er; A = Cd, Zn; X = As, P) through a screening process, focusing on the huge potential of RCd3P3 series for further investigation in photovoltaic applications. Results show that RCd3P3 series with a direct or quasi-direct bandgap have an ultra-low exciton binding energy, which is favorable for separating electron and hole pairs. Moreover, these candidates possess high optical absorption in the visible light regions, and the power conversion efficiency limit of RCd3P3 series can be as high as 24.5 % at the thickness of 4 μm. These results could enrich the database of potential solar cells based on lanthanide materials.

Strategy for perovskite solar cells approaching to S–Q limited efficiency

Despite recent substantial improvements in the efficiency of perovskite solar cells, the record efficiency of single-junction perovskite solar cells still falls short of the theoretical limiting efficiency predicted by Shockley–Queisser due to the presence of various loss mechanisms. It is essential to determine the dominant loss factors limiting power conversion efficiency () to clarify the future technical strategy towards ultimate efficiency. In this paper, we numerically investigate the impact of various loss mechanisms on the performance of realistic record perovskite solar cells, and identify the most important factors limiting the of perovskite solar cells. The results demonstrate that Shockley–Read–Hall recombination and series resistance, as well as optical loss are the most important factors for future improvement in efficiency.

Performance improvement of perovskite/CIGS tandem solar cell using barium stannate charge transport layer and achieving PCE of 39 % numerically

The way to overperform the Shockley-Quisser limit of power conversion efficiency (PCE) for single junction solar cell is tandem device. In this work, a perovskite solar cell (PSC) and Copper Indium Gallium Selenide (CIGS) based solar cell (CSC) are individually optimized and implemented as PSC/CSC tandem (PSSC) device in SCAPS-1D. The perovskites which are highly stable and optically fit for PSSC, consists of triple or quadruple mixed cations, lead (Pb) and halides and the most popular perovskite of this kind is Cs0.15MA0.15 FA0.70Pb(I0.85Br0.15)3 which is used as absorber material in the PSC presented in this work. Another important aspect of PSC is selection of suitable material for charge transport layers. For the first time, a never explored before the oxide perovskite namely the barium stannate (BaSnO3) is used as electron transport layer (ETL) along with NiO as hole transport layer (HTL) in the reported PSC which provides impressive short circuit current density (JSC), open circuit voltage (VOC), fill-factor (FF) and PCE of 23.89 mAcm−2, 1.48 V, 88.92 %, 31.53 % respectively. Moreover, a comprehensive analysis of the PSC without HTL but with BaSnO3 as ETL is carried out and improved records are observed. Finally, the optimized PSSC which consists of HTL free PSC and CSC can deliver a PCE as high as 39 % which is the highest ever predicted value and is attributed to the well-matched energy band alignment of BaSnO3 with the absorber. This work can be a potential contributor to the high efficiency solar cell fabrication roadmap.

The application of chlorine substituted conjugated block copolymers in the single-component organic solar cells

The inferior short-circuit current density (JSC) of the conjugated block copolymers (CBCs) based single component organic solar cells (SCOSCs), compared with that of binary all-polymer systems, is the main reason for their limited power conversion efficiency (PCE). To improve the JSC of SCOSCs by enhancing the light-harvesting ability, we designed and synthesized three narrower bandgap acceptor monomers with different chlorine-substituted terminals, and incorporated them into the CBCs. As the position of chlorine substitution altered, the blend morphology, the device performance, and the physical mechanism changed accordingly. It is worth noting that the PB-b-PYCl-2-based SCOSCs exhibited a significantly improved JSC, accompanied by the best PCE of 13.42 %, and good thermal stability. This study illustrated the terminal chlorination strategy is a promising way to modify the device performance of the SCOSCs.

High‐Speed Deposition of Large‐Area Narrow‐Bandgap Perovskite Films for All‐Perovskite Tandem Solar Mini‐Modules

AbstractDeveloping all‐perovskite tandem solar cells is an effective approach to extend the limit of power conversion efficiency. However, fast preparation of large‐area and high‐quality narrow‐bandgap Sn‐based perovskite films still remains a major challenge in fabricating all‐perovskite tandem modules. Here high‐crystalline and compact narrow‐bandgap perovskite films with an area over 100 cm2 are well prepared by combining compositional, solvent and additive engineering. The use of 2‐methoxyethanol as a solvent enables the fast deposition of narrow‐bandgap perovskite films. Adding proper amounts of dimethyl sulfoxide and surfactant L‐α‐phosphatidylcholine into the narrow‐bandgap perovskite precursor effectively enhances the crystallinity and coverage of the resulting perovskite films, respectively. Based on these studies, narrow‐bandgap perovskite and all‐perovskite tandem mini‐modules with an aperture area of 10.4 cm2 are constructed and exhibit high efficiencies of 13.2% and 16.4%, respectively. This study provides an option for fast deposition of high‐quality narrow‐bandgap perovskite films, which is beneficial for the scalable production of all‐perovskite tandem solar modules.

Synergistic Effect of Size-Tailored Structural Engineering and Postinterface Modification for Highly Efficient and Stable Dye-Sensitized Solar Cells.

Despite significant progress in device performance, dye-sensitized solar cells (DSSCs) continue to fall short of their theoretical potential. Moreover, research in recent years needs to pay more attention to improving the device fabrication process. To achieve the theoretical efficiency limit, it is crucial to optimize the interface between the dye and TiO2 nanoparticles in the entire device stack. Our study indicates that optimizing the structure or size of the coadsorbents and implementing a monolayer adsorption process can be an effective strategy to reduce charge recombination and enhance light-harvesting properties. Our research aims to develop a surface-coating adsorbent plan that controls the TiO2 nanoparticle interface to achieve the radiative limit of power conversion efficiency (PCE). Specifically, we utilized 2-thiophenecarboxylic acid (THCA) or chenodeoxycholic acid (CDCA) as postinterfacial surface-coating adsorbents. Our results demonstrate that this approach effectively achieves the desired PCE limit. Combined with the coadsorbent structure engineering and interface optimization, the device increased the packing area on the TiO2 nanoparticles' surface, reaching an improved PCE of over 13.17% under simulated sunlight (1.5G), which is the highest efficiency of a porphyrin single dye-based DSSC. In particular, this practical approach was also applied to a large-area DSSC with an area of 3 cm2, yielding a remarkable PCE of 9.04%. Furthermore, when applied to a polymer gel electrolyte, this novel approach recorded the highest PCE of 11.16% with a long-term operational stability of up to 1000 h for the quasi-solid-state DSSCs. Our research findings provide a promising avenue for achieving high-performance DSSCs with ease of access and demonstrate practical applications as alternatives to conventional power sources.

Regulating molecular stacking to construct a superior interfacial contact for highly efficient and stable perovskite solar cells

The non-radiative charge carrier recombination loss at the surface and interface of the perovskite layers in perovskite solar cells (PSCs) is the main cause of their limited power conversion efficiency (PCE). Here we propose an efficient strategy to minimize the non-radiative recombination by introducing symmetric molecules with regular arrangement at the interface between the perovskite layer and hole transport layer (HTL). One end of the symmetric molecule gets in a close contact with the terminal groups of the molecules in the HTL, while the other end promotes connection with the perovskite, resulting in an enhanced interfacial electrical contact and a better valence band energy-level alignment for efficient hole extraction. In contrast, introducing similar but asymmetrical molecules forms a dimer structure and mismatched energy levels at the interface region, which is detrimental to the carrier transport. The best-performing planar PSC with the symmetric molecular modification exhibited an increase in the PCE from 21.05% to 24.02% with a substantially enhanced fill factor of 84.0%, which can be ascribed to the synergistic effects of surface defect passivation and reduction in the interfacial energy barrier. Furthermore, the corresponding unencapsulated PSC retained 80% of the original PCE after 4,000 h of aging in dry air.

Enhancing the Performance of Fa‐Based Printable Mesoscopic Perovskite Solar Cells via the Polymer Additive

AbstractThe low cost and scalability advantages of printable mesoscopic perovskite solar cells (p‐MPSCs) are impaired by the issue of limited power conversion efficiency (PCE). Herein, the PCE of p‐MPSCs is improved by introducing the polymer additive polyacrylonitrile (PAN) into the formamidinium (FA)‐based perovskite for crystallization and defect modulation. PAN forms hydrogen bond and coordination bond with halide perovskite through its C≡N group. Such interactions improve the crystallization and filling of FA‐based perovskite in the mesoscopic scaffold and bring a long carrier lifetime by passivating defects. The synergy improves the PCE of p‐MPSCs from 16.80% to 18.33%. Meanwhile, the hydrophobic nature of PAN enhances the device's resistance against moisture. This work demonstrates that the polymer additive is a promising choice for breaking the PCE limit of p‐MPSCs.

Design of an eco-friendly perovskite Au/NiO/FASnI3/ZnO0.25S0.75/FTO, device structure for solar cell applications using SCAPS-1D

Formamidinium Tin Iodide (FASnI3) based perovskite solar cells (PSC) have captured the interest of scientific community because of wide bandgap and good thermal stability, but limited power conversion efficiency (PCE) restricts their extensive adaptation. Here, we present the design of a FASnI3 active layer-based PSC with Nickel oxide (NiO) as Hole Transport Layer (HTL) & Zinc Oxy-Sulphide (ZnO0.25S0.75) as the Electron Transport Layer (ETL). The proposed Au/NiO/FASnI3/ZnO0.25S0.75/FTO, device structure is investigated using SCAPS-1D solar cell capacitance simulator. The performance parameters of proposed solar cells device structure are investigated with variations in active layer (FASnI3) thickness, defect density & doping concentration; and variations of NiO HTL & ZnO0.25S0.75 ETL thickness, electron affinity & doping concentration to obtain higher performance. Moreover, the influence of series & shunt resistance, and temperature on the performance parameters of proposed solar cell device structure is inspected. The proposed Au/NiO/FASnI3/ZnO0.25S0.75/FTO, device structure revealed excellent solar cell performance parameters such as low short-circuit current density (Jsc) of ∼28.35 mA/cm2, high Fill Factor (FF) of ∼89.64%, reasonable open-circuit voltage (Voc) of ∼1.2419 V, & admirable PCE of ∼31.57%, suitable for lead-free and eco-friendly solar cell device applications.

Solution-processed polymer bilayer heterostructures as hole-transport layers for high-performance opaque and semitransparent organic solar cells

Interfacial layer materials such as hole-transport layers (HTLs) are critical to realizing high-performance organic solar cells (OSCs). However, most OSCs are relying on a prominent HTL material of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) with the hygroscopic and acidic feature, which induces poor device stability and limited power conversion efficiencies (PCEs). Here, a novel type of HTLs is developed by combining intrinsically stable poly(triarylamine) (PTAA) with modified PEDOT:PSS for efficient opaque and semitransparent OSCs with good stability. Using diluted solution processing, isopropanol-diluted PEDOT:PSS (ID-PEDOT:PSS) is deposited onto hydrophobic PTAA to improve interfacial compatibility, thereby forming a fitted polymer bilayer heterostructure HTL of PTAA/ID-PEDOT:PSS with high film quality and good transparency. For applications in OSCs with a nonfullerene acceptor (M36), the resulting opaque devices deliver an improved PCE of 14.45%, much higher than 5.72% and 13.21% for the pure PTAA and PEDOT:PSS HTLs-based devices, respectively. The stability of the PTAA/ID-PEDOT:PSS-based OSCs is improved simultaneously, where a normalized PCE for the device after storage over three months retains above 80%, much better than those of devices with other two HTLs. This novel HTL is further used to achieve efficient and stable semitransparent M36-based devices for the first time, exhibiting an outstanding PCE of 12.34% at a high average visible transmittance of 25.56%. Our findings provide an excellent semiconducting interlayer candidate to develop promising opaque and semitransparent OSCs.

Utilizing machine learning algorithm in predicting the power conversion efficiency limit of a monolithically perovskites/silicon tandem structure

Tandem structures have been introduced to the photovoltaics (PV) market to boost power conversion efficiency (PCE). Single-junction cells’ PCE, either in a homojunction or heterojunction format, are clipped to a theoretical limit associated with the absorbing material bandgap. Scaling up the single-junction cells to a multi-junction tandem structure penetrates such limits. One of the promising tandem structures is the perovskite over silicon topology. Si junction is utilized as a counter bare cell with perovskites layer above, under applying the bandgap engineering aspects. Herein, we adopt BaTiO 3 /CsPbCl 3 /MAPbBr 3 /CH 3 NH 3 PbI 3 /c-Si tandem structure to be investigated. In tandem PVs, various input parameters can be tuned to maximize PCE, leading to a massive increase in the input combinations. Such a vast dataset directly reflects the computational requirements needed to simulate the wide range of combinations and the computational time. In this study, we seed our random-forest machine learning model with the 3×10 6 points’ dataset with our optoelectronic numerical model in SCAPS. The machine learning could estimate the maximum PCE limit of the proposed tandem structure at around 37.8%, which is more than double the bare Si-cell reported by 18%.

Boosting radiation of stacked halide layer for perovskite solar cells with efficiency over 25%

<h2>Summary</h2> Although halide perovskite solar cells (PSCs) have shown tremendous progress in device performance, state-of-the-art PSCs are still far below the theoretical efficiency. To further reach the theoretical limit, it is essentially required to maximize radiative recombination in the full device stack. Here, we report that boosting radiation in the full device stack is an effective way for reaching the radiative limit of power conversion efficiency (PCE) by demonstrating the correlation between external photoluminescence quantum efficiency (PLQE) of the full device stack and PCE of the devices. We found that controlling the bottom charge transporting layer (CTL)/perovskite interface is a main factor to boost radiation in the full device stack. The device combined with the interface and bulk engineering exhibited an improved external PLQE of 15.57%, resulting in an improved PCE of over 25% (certified 25.06%) and almost 95% achievement rate of the radiative limit open-circuit voltage (<i>V</i>_oc).

Stable chemical enhancement of passivating nanolayer structures grown by atomic layer deposition on silicon.

Incorporation of carrier-selective passivating contacts is on the critical path for approaching the theoretical power conversion efficiency limit in silicon solar cells. We have used plasma-enhanced atomic layer deposition (ALD) to create ultra-thin films at the single nanometre-scale which can be subsequently chemically enhanced to have properties suitable for high-performance contacts. Negatively charged 1 nm thick HfO2 films exhibit very promising passivation properties - exceeding those of SiO2 and Al2O3 at an equivalent thickness - providing a surface recombination velocity (SRV) of 19 cm s-1 on n-type silicon. Applying an Al2O3 capping layer to form Si/HfO2/Al2O3 stacks gives additional passivation, resulting in an SRV of 3.5 cm s-1. Passivation quality can be further improved via simple immersion in hydrofluoric acid, which results in SRVs < 2 cm s-1 that are stable over time (tested for ∼50 days). Based on corona charging analysis, Kelvin probe measurements and X-ray photoelectron spectroscopy, the chemically induced enhancement is consistent with changes at the dielectric surface and not the Si/dielectric interface, with fluorination of the Al2O3 and underlying HfO2 films occurring after just 5 s HF immersion. Our results show that passivation is enhanced when the oxides are fluorinated. The Al2O3 top layer of the stack can be thinned down by etching, offering a new route for fabrication of ultra-thin highly passivating HfO2-containing nanoscale thin films.

Nano-optical designs for high-efficiency monolithic perovskite–silicon tandem solar cells

Perovskite–silicon tandem solar cells offer the possibility of overcoming the power conversion efficiency limit of conventional silicon solar cells. Various textured tandem devices have been presented aiming at improved optical performance, but optimizing film growth on surface-textured wafers remains challenging. Here we present perovskite–silicon tandem solar cells with periodic nanotextures that offer various advantages without compromising the material quality of solution-processed perovskite layers. We show a reduction in reflection losses in comparison to planar tandems, with the new devices being less sensitive to deviations from optimum layer thicknesses. The nanotextures also enable a greatly increased fabrication yield from 50% to 95%. Moreover, the open-circuit voltage is improved by 15 mV due to the enhanced optoelectronic properties of the perovskite top cell. Our optically advanced rear reflector with a dielectric buffer layer results in reduced parasitic absorption at near-infrared wavelengths. As a result, we demonstrate a certified power conversion efficiency of 29.80%.

Improving the efficiency of solar cells based on CsSn0.5Ge0.5I3 perovskite by using ZnO nanorods

Subject of study. Environmentally friendly tin and germanium-based halide perovskite materials are promising candidates attracting more attention as lead-free halide perovskite solar cells. However, the limited power conversion efficiency of these perovskites is an important issue in the solar cells field. Therefore, in the present study, a different lead-free perovskite was used to reach higher power conversion efficiency. Devices with an indium tin oxide/electron transport layer/perovskite/hole transport layer/Ag structure but different absorber layers were simulated. Simulation was done using the Solar Cell Capacitance Simulator (SCAPS-1D) to investigate the photovoltaic performance of solar cells with CsGeI3 and CsSnI3 perovskites as the absorber layer. Method. Simulation was done by using the SCAPS software, which is a one-dimensional solar cell simulation platform developed at the Department of Electronics and Information Systems of the University of Gent, Belgium. Main results. The effect of the absorber layer thickness was investigated, and a maximum power conversion efficiency of 10.51% was obtained for 1000 nm thick CsGeI3, while the maximum value of 12.83% was obtained for 400 nm thick CsGeI3. Then, to further increase the efficiency, devices with an alternative lead-free CsSn0.5Ge0.5I3 perovskite including a planar ZnO layer and ZnO nanorod arrays as electron transport layers was used in the simulation, and the thickness of the absorber layer was optimized for both devices. For the maximum power conversion efficiency of the devices, the values of 17.56% and 22.61% were achieved for devices with a ZnO layer and ZnO nanorods, respectively. It is noted that the simulation results of this study could provide a perspective towards fabricating an environmentally friendly perovskite-based solar cell. Practical significance. The main significance of the present work is obtaining a significant power conversion efficiency of 22.61% for a device based on environmentally friendly perovskite. Similar work was done in 2021 by M. Azadinia et al. [Mater. Today Energy20, 100647 (2021)10.1016/j.mtener.2021.100647], in which a comparable power conversion efficiency of 26.9% was reported for a device with CsSn1−xGexI3 perovskite.

Light-induced trap emptying revealed by intensity-dependent quantum efficiency of organic solar cells

Revisiting the intensity-dependent quantum efficiency (IDQE) technique in the context of non-fullerene acceptors, we find that at forward-bias conditions, the response exhibits what seems to be anomalous behavior that is not consistent with light excitation induced trap filling. Analysis based on the Shockley–Read–Hall model leads to the conclusion that the contacts cause the traps to be completely full in the dark. The role of the light excitation is to half-empty the traps, and thus, the “anomalous” behavior is created. By fitting the IDQE at several bias levels, we find that the trapping is consistent with multiphonon capture by a state close to the middle of the gap. As trap-assisted recombination is a significant loss mechanism, it is essential to fully monitor it for indoor applications as well as to cross the single junction 20% power conversion efficiency limit.

Path toward the Performance Upgrade of Lead-Free Perovskite Solar Cells Using Cu2ZnSn1–xGexS4 as a Hole Transport Layer: A Theoretical Simulation Approach

Recently, formamidinium tin iodide (CH(NH2)2SnI3, FASnI3) perovskite has emerged as a promising candidate for lead-free perovskite solar cells. However, a limited power conversion efficiency (PCE) was achieved when the conventional TiO2 and Spiro-OMeTAD were selected as the electron transport layer and hole transport layer (ETL/HTL), respectively. By employing numerical modeling of the FTO/TiO2/FASnI3/Spiro-OMeTAD/Au heterostructure, we noticed that the conduction-band offset (ΔEC) between TiO2/perovskite and valence-band offset (ΔEV) between perovskite/Spiro-OMeTAD layers are suboptimal, resulting in limited PCE. To overcome this shortcoming, we replace WO3 and inorganic Cu2ZnSn1–xGexS4 (CZTGS) as the ETL and HTL, respectively, which dramatically improves the PCE by creating a suitable ΔEC and ΔEV. This behavior has been investigated by the simulation using impedance spectroscopy, revealing that the high VOC and PCE are attributed to the relatively large recombination resistance (Rrec) at the CZTGS/perovskite interface. Further enhancement in PCE has been attained by replacing the MoOx:Au composite for the Au back contact. Considering the paramount importance of electronic levels of the active layer in device physics, we further optimize the band gap and electron affinity of the FASnI3 layer and study the corresponding changes in solar cell parameters. The combined effect of material simulation on the modified device exhibited an inspiring PCE of 17.1% and VOC of 0.75 V, which are mainly attributed to the correct energy level alignment at different heterojunctions and suitable work function of the alternative back contact.