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The sufficient material selection of electron transport layer (ETL) enormously promises exceptional conversion efficiency from perovskite (PVT) solar cells (PSCs), which in turn give rise to their rapid establishment in world-wide photovoltaic (PV) market. Among the tactics exerted on ETLs, and thus, intensifies the adequacy of associated PSCs, the methodology of doping stands productive. Therefore, this research validates the implementation of such effectual ETLs on widely approved methyl ammonium lead triiodide (MAPbI 3)–based PSCs. The work brings together two versions of zinc oxide (ZnO) ETLs: one in its pristine form, and the other is aluminum (Al) co-doped with silver (Ag) represented as Ag-AZO. The investigation launches the PV capabilities of Ag-AZO ETL against its undoped correspondent. Accordingly, the earlier part of the investigation centers on the experimental assessment of ZnO and Ag-AZO nanoparticles (NPs) affirming their material and morphological aspects. Later, the research deals with the involvement of both NPs as ETLs signifying the PV potential of MAPbI 3 –based PSCs through comprehensive numerical analysis. The judgements of investigation declare that MAPbI 3 –based PSC with Ag-AZO ETL yields a desirable power conversion efficiency (PCE) of 27.26 % against 25.98 % from the control cell. The investigation will definitely enlighten the development of forthcoming efficient PSCs incorporated with appropriate multiple metals co-doped ETLs. • Ag and Al co-doped ZnO (Ag-AZO) nanoparticles were synthesized using solution process. • The potential of Ag-AZO electron transport layers of perovskite solar cells was validated through numerical analysis. • By applying an Ag-AZO layer, an exceptional efficiency of 27.26 % was accomplished. [ABSTRACT FROM AUTHOR]

The electron transport layer (ETL) is essential for electron collection from the absorbing layer to the conductive electrode in solar cell devices, such as perovskite solar cells. Zinc oxide (ZnO) is regarded as a promising ETL material thanks to its wide bandgap and high electron mobility. In this study, multiple-layer ZnO thin films were elaborated using inkjet printing and investigated using X-ray diffraction, Fourier transform infrared spectroscopy, spectrophotometry, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and electrical measurements. All samples show a characteristic infrared vibration of Zn–O bonding and a hexagonal wurtzite crystalline phase. Moreover, the deposited films exhibit preferential growth directions, with a highly textured ZnO film along the (100) orientation after 8-layer inkjet printing. The ZnO films also show a direct bandgap with a stable energy of 3.25 ± 0.02 eV and strong visible light transmittance, with a moderate decrease as the number of inkjet-printed layers increases. The variations in film electrical resistivity result from competing structural and electron scattering mechanisms and present the lowest value of about 9 × 103 Ω cm for the 8-layer ZnO film. Our work underlines the successful elaboration of ZnO thin films by inkjet printing and sets the stage for further studies about other inkjet-printed materials of interest for solar cell technology. • Zinc oxide films are elaborated at room temperature by multiple-layer inkjet printing. • Multilayer films show a ZnO wurtzite phase and crystallographically textured growth. • ZnO films exhibit high visible light transmittance and a stable and direct bandgap. • Phase changes and electron scattering modes affect electrical resistivity of films. • Inkjet-printed ZnO is promising for electron transport in perovskite solar cells. [ABSTRACT FROM AUTHOR]

Aiming to enhance the properties of gallium doped zinc oxide (GZO) for considering it as a promising electron transport layer (ETL) in perovskite solar cells (PSCs), GZO thin films were sputtered using radio frequency (RF) magnetron sputtering under different Ar gas flow from 2 sccm to 5 sccm. Then the variations of morphological, structural, optical and electrical properties of the GZO thin films were studied thoroughly. The sputtered GZO films showed polycrystallinity having a hexagonal wurtzite-type crystal structure with a preferred crystal orientation in the direction of (0 0 2). In terms of morphological analysis, EDX confirmed the presence of Ga and FESEM analysis revealed that the thickness and grain size of deposited films gradually increase with the increment of Ar flow. Further, the film deposited at 3 sccm showed the lowest electrical resistivity of 1.09 × 10−02 Ω-cm and achieved the highest carrier concentration of 1.586 × 1019 cm−3. All the GZO films showed optical transmittances between ∼80 % and ∼90 %. Finally, the simulation study validated the use of sputtered GZO as ETL in PSCs. This study provides a significant path for the researchers to optimize the RF-sputtered GZO films by varying the Ar gas flow rate for confirming their use as promising ETL in PSCs. • Effect of Ar gas flow on the RF sputtered GZO film properties. • Lower Ar flow produces films with higher optical transmittance. • Energy bandgap reduces with the increment of Ar gas flow rate. • Higher Ar gas flow produces films with higher grain size and thickness. • RF sputtered GZO as ETL in pesrovskite solar cells through SCAPS-1D. [ABSTRACT FROM AUTHOR]

This work reports on the synthesis of polymeric PANI-rGO-WS 2 (PGW) nanocomposites were synthesized with varying concentrations of WS 2 via chemical oxidative polymerization. FESEM images elucidated that the surface morphology of PGW3 carried a structure comprising of PANI nanofibers embedded on the top of the overlapped rGO and WS 2 nanosheets. XRD and FTIR spectroscopy showed the molecular interaction among the constituents and affirmed the formation of PGW nanocomposite. UV–Vis. spectroscopy revealed the absorption of light in visible region with the for PGW3 nanocomposite. Photoluminescence spectroscopy showed light absorption in blue color region with excellent color purity. TGA showed the optimized PGW3 nanocomposite has inflated thermal stability. Current density for PGW3 nanocomposite was examined using J-V characteristic curve and found 96% higher than polyaniline. The increased conductivity and high electron-hole recombination rate attributed to the formation of enhanced charge transport network in PGW3 nanocomposite. These results evinced the optimized PGW3 nanocomposite as an ETL for OLED applications. • In-situ oxidative polymerization method is used to synthesize PANI-rGO-WS 2 nanocomposites with varying concentration of WS 2. • The band gap of optimized PGW3 nanocomposite is determined to be 1.95 eV with a crystallite size of 6.54 nm. • PGW3 nanocomposite showed blue emission at 483 nm range with 39% color purity. • The mobility of charge carriers was also calculated using hall effect measurement and found to be 2.707 m2V−1s−1 • The current density for the optimized PGW3 was evaluated ∼3.45 Acm−2 using J-V characteristic curve. [ABSTRACT FROM AUTHOR]

The need for an excellent electron transport layer (ETL) material is immensely significant for higher conversion efficiency of perovskite solar cells (PSCs). This work centers on the exceptional performance achieved by the Al-doped ZnO (AZO) ETL with reference to undoped ZnO (ZnO). Both doped and undoped ETL materials were synthesized and characterized to determine their structural, morphological, and optical behavior. In this work, solar cell performance of two similar CsPbIBr 2 -based PSCs with different ETLs namely FTO/ZnO/CsPbIBr 2 /NiO (Cell #1) and FTO/AZO/CsPbIBr 2 /NiO (Cell #2) are investigated through numerical simulation method. The obtained characteristics affirms that Cell #2 offers sufficient better performance parameters (J sc , V oc , FF, and η ) against Cell #1 with respect to variation in CsPbIBr 2 PVT, ETL and HTL thickness. The adverse effect on J-V characteristics caused by controllable introduction of defect density (N t) in PVT layer is negligible for Cell #2 compared to its ZnO counterpart. Further, the contribution of AZO ETL layer on cell's performance is evaluated in terms of variation in respective ETL and HTL thickness. The investigation reveals that Cell #2 offers a desirable η of 19.46% at electron capture cross section of 2 × 10−15 cm2 while Cell #1 delivers only 12.48%. • Highly conductive Al-doped zinc oxide (AZO) layer was synthesized using a solution process. • The performance of all-inorganic perovskite solar cells was determined using simulation. • By applying an AZO electron transport layer, over 19 % efficiency was achieved for perovskite solar cells. [ABSTRACT FROM AUTHOR]

The new generation of solar cell technology, perovskite solar cells (PSCs), are the most promising candidates to meet global energy demands. In the current study, we improved the efficiency of their cost-effective type, i.e., carbon-based PSCs, by employing an interface engineering on the tin dioxide (SnO 2) electron transport layer (ETL). A fluorine doped-zinc oxide material was used to treat the SnO 2 layer and prepare a better substrate for perovskite fabrication. The fabricated perovskite layer on the treated SnO 2 reveals better charge transfer, lower charge recombination, and lower leakage current. In addition, the fabricated perovskite layer on the modified ETL showed improved crystalline properties with passivated grain boundaries. As a result, a champion efficiency of 15.22% was recorded for the target carbon-based PSCs, referring to improved photovoltaic performance. Notably, the target devices showed a higher stability behavior against ambient air and kept 95% of their initial efficiency after 1658 h ageing time. • Developed an interface engineering technique utilizing fluorine-doped zinc oxide to enhance the efficiency of carbon-based perovskite solar cells (PSCs). • Achieved a champion efficiency of 15.22% for the PSCs, showcasing improved photovoltaic performance through better charge transfer, reduced recombination, and lower leakage current. • Demonstrated exceptional stability against ambient air, with the target devices maintaining 95% of their initial efficiency after 1658 h of aging time. [ABSTRACT FROM AUTHOR]

The research on the application of lead-free perovskite materials as an active layer in solar cells has been positively carried out for the last few years. Although the efficiency of lead-contained metal halide-based Perovskite has reached above 25%, but lead is a highly toxic substance that is hazardous to the environment, and this is one of the obstacles to their commercialization. In this article, a Sn-based Perovskite (CH 3 NH 3 SnI 3) solar cell with two distinct electron transport layers was simulated using GPVDM (General Purpose Photovoltaic Device Model) and fabricated with a simple sol-gel method. Along with the absorber layer, the charge transport materials also play an essential role in extracting electrical power. The comparison of ZnO and TiO 2 as electron collectors has been investigated and characterized, the hole-carrying layer has been eliminated for better findings. Remarkably, we achieve an efficiency of 7.33% and 6.75% in simulation and 6.90% and 5.81% from fabricated devices using ZnO and TiO 2 , respectively. • Tin-based perovskite materials have emerged as a replacement for their lead-based counterparts due to their desirable properties. • The choice of electron collectors (ZnO and TiO 2) with CH 3 NH 3 SnI 3 as absorber layers was fabricated and characterized. • The efficiencies of 7.33% (simulation) and 6.90% (fabrication) with ZnO and 6.75% (simulation) and 5.81% (fabrication) with TiO 2 as ETL are obtained. • ZnO seems to be a more efficient electron transporter than TiO 2 due to its high electron mobility and larger surface area. [ABSTRACT FROM AUTHOR]

The electron transport layer (ETL) is essential to improve device performance of organic solar cells (OSCs). Here, l -cystine, which is inexpensive and environmentally friendly, was successfully employed in OSCs of PTB7-Th:PC 71 BM as an ETL. The introduction of l -cystine can achieve an enormous enhancement in performance: Voc (open circuit voltage) from 0.74 to 0.79 V, Jsc (short-circuit current density) from 14.76 to 16.89 mA cm2, fill factor from 51.45% to 70.73%, and power conversion efficiencies from 5.62% to 9.44%, which is better than PFN (8.52%) as an ETL. The excellent PCE is attributed to the WF of Al was shifted from −4.23 to −3.87 eV by l -cysteine modified, thereby more effectively extracting and collecting carriers. This study demonstrates that the natural and non-toxic l -cystine is a strong competitor for ETL in high-efficiency OSCs. [Display omitted] • l -cystine have been successfully exploited as electron transport layer. • l -cystine can reduce the work function. • The device with l -cystine promotes J SC and PCE. [ABSTRACT FROM AUTHOR]

Titanium dioxide (TiO 2) and holmium (1.2 mol% Ho3+) doped TiO 2 nanoparticles were synthesized via sol-gel method using polyvinylpyrrolidone (PVP) co-polymer as a pore forming agent. The nanoparticles were dispersed in a solvent and drop-cast on a glass substrate to make films. The films were then calcined at 550 °C for 4 h in a pre-heated muffle furnace. Methylammonium lead iodide (MAPbI 3) was incorporated with TiO 2 and TiO 2 :Ho3+ nanoparticles. Therefore, the samples TiO 2 , TiO 2 :Ho3+, TiO 2 :MAPbI 3 and TiO 2 :Ho3+:MAPbI 3 were obtained and their properties as an electron transporting and photon absorption layers, respectively, were evaluated for possible application in perovskite solar cells. XRD results revealed a rutile phase which was found to be consistent with the RAMAN analysis. FESEM showed spherical nanoparticles with irregular pore size for TiO 2 and TiO 2 :Ho3+ samples, whereas MAPbI 3 nanocrystals seemed to have filled-up the pores in TiO 2 :MAPbI 3 and TiO 2 :Ho3+:MAPbI 3 samples. UV–Vis results showed an expected UV absorption of TiO 2 with the absorption band at ∼366 nm and upon doping with 1.2 mol% of Ho3+ ions, an improved absorption and a shift towards the visible region was observed. Small absorption bands at ∼453, 541 and 645 nm were detected, which are resulting from the Ho3+ transitions. When MAPbI 3 was incorporated with TiO 2 :Ho3+, absorption in the visible range remained improved with the bands at ∼541 and 645 becoming intense. TiO 2 :MAPbI 3 sample showed a further absorption improvement with a red-shift of the absorption band. The band gap energy was estimated and found to be ∼3.00, 2.35, 2.32 and 2.34 eV for TiO 2 , TiO 2 :Ho3+, TiO 2 :MAPbI 3 and TiO 2 :Ho3+:MAPbI 3 , respectively. The red-shift and the reduction of the bandgap values is a good indication that these materials will absorb as much photons in the visible and near-infrared regions. The current-voltage (I–V) analysis revealed that the sample TiO 2 :MAPbI 3 have higher current flow, implying lower resistance in the material. The PL results indicated low electron-hole recombination as the intensity was considerably decreased upon doping with Ho3+ and incorporating MAPbI 3. • Sol-gel synthesis of Ho3+ doped TiO 2 nanoparticles and incorporation with MAPbI 3. • XRD showed that all samples are highly crystalline. • FESEM showed spherical nanoparticles with irregular pore size. • Improved photon absorption and a shift to the visible and near-infrared regions was observed. • Higher current flow, implying lower resistance in the materials was demonstrated. [ABSTRACT FROM AUTHOR]

Interfacial engineering plays a key role in the performance enhancement of organic solar cells (OSCs), which has a significant impact on the charge collection and transport in the devices. Herein, the conventional devices based on PTB7-Th:PC 71 BM were prepared by introducing a non-conjugated small molecule tetrasodium iminodisuccinate (IDS) as an electron transport layer (ETL). It is shown that IDS as ETL improves the charge transfer and collection and simultaneously inhibits the charge recombination in the devices. Consequently, the optimal power conversion efficiency (PCE) of the device with IDS as ETL reaches up to 9.45%, with an open circuit voltage (V OC) of 0.80 V, a short circuit current density (J SC) of 16.88 mA cm−2 and a fill factor (FF) of 70.01%. This work provides a new approach to optimize the PCEs of the OSCs. [Display omitted] • A non-conjugated small molecule tetrasodium iminodisuccinate (IDS) have been successfully exploited in OSCs as ETL. • IDS modifies the active layer to exhibit a smoother interfacial morphology, which promotes the charge transport. • The device with IDS achieves the PCE of 9.45%, which is 57.23% efficiency improvement compared to the device without ETL. [ABSTRACT FROM AUTHOR]

Organic photodetectors with bulk heterojunctions were constructed with a structure of ITO/ZnO/P3HT:PC 61 BM/MoO 3 /Al. The effect of the thickness of the ZnO layer on the properties of the device were investigated by fabricating photodetectors with different ZnO layer thicknesses: 20, 40, 50, 60, and 80 nm. The 40 nm-thick ZnO electron transport layer provided the device with a low dark current density (1.7 × 10−9 A/cm2), high specific detectivity (2.7 × 1013 Jones), wide linear dynamic range (78.9 dB), and fast response speed (τ r / τ f = 0.61/0.75 μs). The results show that an optimal thickness of the ZnO electron transport layer can effectively block hole injection into the active layer, which is a promising strategy to improve the performance of organic photodetectors. • Change defect concentration by simple spin coating. • Low dark current density with 1.7 × 10−9 A/c m2. • High specific detectivity 2.7 × 1013 Jones. • Detect a wide light intensity range with 78.9 dB. • Fast response speed with τ r / τ f = 0.61/0.75 μs. [ABSTRACT FROM AUTHOR]

During the past decade in the perovskite solar cells (PSCs) field, mesoporous titanium oxide (mp-TiO 2) has been widely used as electron transport layers (ETLs) to promote the electron extraction process and also as a scaffold for the perovskite layer (PSK) to gain better PSC performance. Usually, the interface between the mp-TiO 2 layer and PSK needs a modification process to boost the performance of mp-TiO 2 -based PSCs. Here, lithium chloride (LiCl) was used to modify the ETL/PSK interface. Results showed that a simple interface engineering based on LiCl could improve the morphology and crystalline properties of the PSK film, and motivate charge transport processes at the ETL/PSK interface and within PSK due to lower grain boundaries in PSK. Overall, ETL interface engineering with a 0.03 M LiCl solution leads to an efficiency of 11.24% for PSCs, higher than that of 7.42% for control devices. In addition, the modified PSCs compared to control PSCs were more stable in an environment with a humidity of 25%. The improved stability is caused by reduced GBs and a suppressed lead iodide (PbI 2) surplus in the modified PSK. • The photovoltaic properties of PSCs increased by interfacial engineering method. • The recombination processes are suppressed in modified PSCs. • The modified layer drastically passivates grain boundaries in the perovskite layer. • The stability of PSCs increase by employing the interfacial engineering method. [ABSTRACT FROM AUTHOR]

Organic-inorganic solar cells (PSCs) are considered emergent photovoltaics (PV) technology. For better performance and stability of the PSCs, the selection of the electron transport layer (ETL) is vital. In this study, Cd doped ZnO (CZO) nanoparticles (NPs) are synthesized using the solution process. The optical properties of the CZO NPs were determined experimentally. With Cd doping, the optical bandgap was reduced and the lowest bandgap was obtained for 2% Cd doping. With further increase of Cd doping concentrations, the bandgap was slightly increased. However, the highest values of refractive index were obtained for Cd doping of 1%. The optical parameters were used to simulate the n-i-p (FTO/ETL/MAPbI 3 /HTL/Au)-structured PSCs using gpvdm solar simulator. The simulated parameters viz. short circuit current density (J sc), open circuit voltage (V oc), fill factor (FF), and power conversion efficiency (η) of the CZOs-based PSCs were compared with the parameters obtained for ZnO ETL. An efficiency of 26.07% was achieved for PSC with 1% Cd-doped ZnO, which is 9.72% higher than the efficiency of ZnO-based PSC (η ∼ 23.76%). These experimental results proved an opportunity to improve the performance of the PSCs via Cd doping. • The optical simulation was carried out to predict the influence of Cd doping in ZnO on performance perovskite solar cells. • The short circuit current density was enhanced by 9.5% via Cd doping. • The best efficiency of 23.76% was achieved for Cd doping of 1%, which was 9.72% higher than the undoped ZnO. [ABSTRACT FROM AUTHOR]

Zinc oxide (ZnO) grown on indium tin oxide (ITO) glass substrates were decorated with bismuth sulfide (Bi 2 S 3) nanorods by thermal decomposition of bismuth ethylxanthate precursor method. Different thicknesses of ZnO/Bi 2 S 3 bilayer films were prepared by controlling the spin speed of bismuth xanthate precursors (5000, 6000 and 7000 rpm, respectively) and applied as the electron transport layer (ETL) in organic solar cells (OSCs) with the structure of ITO/ZnO/Bi 2 S 3 /PM6:Y6/MoO 3 /Ag. The effects of different thickness of ZnO/Bi 2 S 3 as ETLs on device performance and stability were investigated in detail. Firstly, the device based on ZnO/Bi 2 S 3 6000 rpm as ETL confirmed excellent performance with the power conversion efficiency (PCE) of 12.50%, which was improved by 28.60% of the reference device without Bi 2 S 3 nanorods coated. XRD and SEM results showed that Bi 2 S 3 nanorods covered the ZnO surface well. Electrical conductivity and the current density-voltage (J-V) curve results under dark conditions showed that when Bi 2 S 3 nanorods were added between the active layer and ZnO, the interfacial conductivity can be effectively increased and improved the interfacial carrier transport efficiency. Secondly, the stability results of the ZnO/Bi 2 S 3 6000 rpm device demonstrated that the PCE of ZnO/Bi 2 S 3 6000 rpm device was maintained about 91.54%, while that of pure ZnO as ETL was maintained about 75.26% of the original value after 33 h in air. This means that the ZnO/Bi 2 S 3 prepared by thermal decomposition of the bismuth xanthate precursor on ZnO is a promising electron transport material in OSCs. • ZnO/Bi 2 S 3 films were applied as the electron transport layer in solar cells. •Bi 2 S 3 layer was fabricated by thermal decomposition of bismuth ethylxanthate. •The efficiency and stability of devices were improved using ZnO/Bi 2 S 3 films. [ABSTRACT FROM AUTHOR]

Hybrid perovskite solar cells (PSCs) have introduced as a good revolution photovoltaic to meet the green world energy demands. The crystallinity improvement of PSCs is a practical approach to improve the efficacy of PSCs. Double cation formamidinium (FA)/methylammonium (MA) PSCs were fabricated by using a simple sequential deposition process. The mesoporous titanium dioxide (TiO 2) layers with 200 nm thickness were used as the electron transport layer (ETL). It was observed that with changing the FA/MA precursor temperature could achieve more desirable perovskite films for photovoltaic applications. Our measurements show that with pre-heating of FA/MA solution at 55 °C the defects on the perovskite layer are well passivated. Besides, the perovskite with better crystallinity and smooth morphology, and the defect-free surface was achieved. It is delightful that perovskite with 55 °C reveals stronger photon absorption and better charge collection. Using the pre-heating approach, a redshift in edge absorption of the perovskite films was observed, indicating a better light-harvesting phenomenon in the corresponding perovskite films. Through optimization of the pre-heating temperature of FA/MA solution, a champion PCE of 13.77% was yielded for PSCs higher than of 10.05% one for pre-heating. Also, modified mixed cation devices revealed higher stability behavior in atmospheric conditions than the reference devices. Image 1 • The optoelectrical properties of mixed cation perovskite are modified using different FA/MA solution temperature. • This modification results in enhancing of the average device power conversion efficiency reaching to 13.7%. • The enhancement in performance originates from improved perovskite film formation and more efficient charge extraction. [ABSTRACT FROM AUTHOR]

Two perovskite solar cells one with leaves and needles like TiO 2 (LNT) and other with meso-porous TiO 2 as electron transfer layer (ETL) were fabricated. The perovskite solar cell structure FTO/Compact-TiO 2 /LNT/CH 3 NH 3 PbBr 3 /Spiro-OMeTAD/Ag with leaves and needles like TiO 2 electron collector, exhibit high efficiency up to 9% being supported by high open-circuit voltage and fill factor up to 0.8 V and 0.89, respectively. The second perovskite solar cell structure FTO/Compact-TiO 2 /Meso-porous TiO 2 /CH 3 NH 3 PbBr 3 /Spiro-OMeTAD/Ag with meso-porous TiO 2 electron collector, efficiency is 6.2% with open-circuit voltage and fill factor up to 0.77 V and 0.71 respectively. As compared to meso-porous TiO 2 electron collector layer, leaves and needles like TiO 2 has better electron band alignment with compact TiO 2 as hole blocking layer and hence, results in higher efficiency. Image 1 • A novel architecture of Perosvkite solar cell has been proposed. • A new leaves and needles like structure of TiO 2 has been grown using simple technique. • Application of leaves and needles like structures of TiO 2 has been demonstrated as an electron transport layer. • Power conversion efficiency of 9% for the proposed solar cell has been achieved. [ABSTRACT FROM AUTHOR]

The performance of a perovskite solar cell (PSC) is improved with a graphene electron transport layer (ETL) using Silvaco simulation software. Factors affecting solar cell performance such as absorber layer thickness, carrier mobility, doping concentration and carrier transport layer thickness have been studied. Higher carrier mobility, and fabrication cost are the most important factors toward the increment of the PSC utilization. Graphene is used here as an ETL due to its high carrier mobility, high optical transparency and good optical, mechanical and electrical properties at a low cost. The simulation is based on glass/ITO/Graphene/CH 3 NH 3 PbI 3 /Spiro-OMeTAD/Au structure which yields to photovoltaic (PV) parameters of V oc = 1.094 V, J sc = 21.24 mA/cm2, FF = 90.185%, and power conversion efficiency of 20.95%. Moreover, the optimum thicknesses of 600 nm and 21 nm are determined for the perovskite absorber and ETL, respectively. • Graphene is employed as the ETL in PSC structure. • An optimum structure is obtained considering thickness and doping concentration variations. • The maximum PCE of 20.95% is achieved. [ABSTRACT FROM AUTHOR]

An organic-inorganic perovskite formamidinium tin iodide (HC(NH 2) 2 SnI 3 – FASnI 3) 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 CH 3 NH 3 SnI 3. In the present investigations, SCAPS simulation with comparison to the experimental as well as simulation data for FASnI 3 -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 (J sc) of 31.20 mA/cm2, open-circuit voltage (V oc) of 1.81 V, fill factor (%FF) of 33.72% and power conversion efficiency (%PCE) of 19.08%. Image 1 • Physics behind the performance parameters in (HC(NH 2) 2 SnI 3 – FASnI 3) PSC device. • Comparison FASnI 3 -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: J sc -31.20 mA/cm2, V oc -1.81 V, FF-33.72% and PCE-19.08%. [ABSTRACT FROM AUTHOR]

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 (CH 3 NH 3 Pb(I 1-x Br x) 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/TiO 2 /CH 3 NH 3 Pb(I 1-x Br x) 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. [ABSTRACT FROM AUTHOR]

The structure and the physical dimension of the electron transport layer (ETL) in perovskite solar cell (PSC) determine the carrier transport characteristics to the electrode and then the overall performance of the device. ETL with ultimately thin and single-crystalline should facilitate enhanced photogenerated carrier transport to the electrode, inducing a highly dynamic charge transfer at the interface of ETL and perovskite absorber layer. Here, we demonstrated that a planar few atoms (5 monolayer or 5L) thick MoS 2 nanosheets synthesized directly onto the ITO substrate allows a facile interfacial charge transfer and transport as judged from the open circuit voltage (V oc) value, steady-state photoluminescence and external quantum efficiency (EQE) analysis results. We found that the nanosheets crystallinity properties determines the photoelectrical process in the PSC device. The champion device in this study can produce a power conversion efficiency (PCE) as high as 3.36% with a short-circuit current density (J sc), open circuit voltage (V oc) and fill-factor (FF) of as high as 16.24 mA cm−2, 0.56 V and 0.370, respectively. The champion device also exhibited a reasonable high stability properties that shows it can retain more than 90% of its initial PCE when operated under irradiation of 1 sun at maximum power-point. Due to the single crystallinity and the large area properties, the MoS 2 nanosheets prepared using the present method may find extended application as high-performance ETL of perovskite solar cells. Ultra-thin MoS 2 nanosheets demonstrates promising performance as electron transport layer in perovskite solar cells. Image 1 • Simple approach for the synthesis of large-scale atoms thick MoS 2 nanosheets on ITO substrate is presented. • Performance of ultra-thin MoS 2 nanosheets as electron transport layer of perovskite solar cells is demonstrated. • Perovskite solar cells performance increases as the thickness of the MoS 2 nanosheets decreases. [ABSTRACT FROM AUTHOR]