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Significant progress has been made in the advancement of perovskite solar cells, but their commercialization remains hindered by their lead-based toxicity. Many non-toxic perovskite-based solar cells have demonstrated potential, such as Cs2AgBi0.75Sb0.25Br6, but their power conversion efficiency is inadequate. To address this issue, some researchers are focusing on emerging acceptor–donor–acceptor'–donor–acceptor (A-DA'D-A)-type non-fullerene acceptors (NFAs) for Cs2AgBi0.75Sb0.25Br6 to find effective electron transport layers for high-performance photovoltaic responses with low voltage drops. In this comparative study, four novel A-DA'D-A-type NFAs, BT-LIC, BT-BIC, BT-L4F, and BT-BO-L4F, were used as electron transport layers (ETLs) for the proposed devices, FTO/PEDOT:PSS/Cs2AgBi0.75Sb0.25Br6/ETL/Au. Comprehensive simulations were conducted to optimize the devices. The simulations showed that all optimized devices exhibit photovoltaic responses, with the BT-BIC device having the highest power conversion efficiency (13.2%) and the BT-LIC device having the lowest (6.8%). The BT-BIC as an ETL provides fewer interfacial traps and better band alignment, enabling greater open-circuit voltage for efficient photovoltaic responses. [ABSTRACT FROM AUTHOR]

A high-quality tin oxide electron transport layer (ETL) is a key common factor to achieve high-performance perovskite solar cells (PSCs). However, the conventional annealing technique to prepare high-quality ETLs by continuous heating under near-equilibrium conditions requires high temperatures and a long fabrication time. Alternatively, we present a non-equilibrium, photoexcitation-induced passivation technique that uses multiple ultrashort laser pulses. The ultrafast photoexcitation and following electron–electron and electron–phonon scattering processes induce ultrafast annealing to efficiently passivate surface and bulk defects, and improve the crystallinity of SnO2, resulting in suppressing the carrier recombination and facilitating the charge transport between the ETL and perovskite interface. By rapidly scanning the laser beam, the annealing time is reduced to several minutes, which is much more efficient compared with conventional thermal annealing. To demonstrate the university and scalability of this technique, typical antisolvent and antisolvent-free processed hybrid organic–inorganic metal halide PSCs have been fabricated and achieved the power conversion efficiency (PCE) of 24.14% and 22.75% respectively, and a 12-square-centimeter module antisolvent-free processed perovskite solar module achieves a PCE of 20.26%, with significantly enhanced performance both in PCE and stability. This study establishes a new approach towards the commercialization of efficient low-temperature manufacturing of PSCs. [ABSTRACT FROM AUTHOR]

The Copper (Cu)-based perovskite materials, (CH3NH3)2CuX4 or (MA)2CuX4 with [X = Cl4, Cl2I2, and Cl2Br2] are explored for use in perovskite solar cells (PSCs). The foremost objectives of this investigation are the optimization and finding the combination of Electron Transport Layer [ETL], Perovskite Absorber Layer (PAL) and the different organic and inorganic Hole Transport Layers [HTLs] for better device performance. The impact of other important functional parameters on the performance of PSCs are also studied. These parameters are, thicknesses of PAL, operating temperature (T), series resistance (RS), and radiative recombination rate under the illuminance of AM1.5. This SCAPS-1D simulation study deduced the optimized value of the thickness for (MA)2CuCl4, (MA)2CuCl2I2 and (MA)2CuCl2Br2 based absorber layer to be 400 nm, 500 nm and 600 nm, respectively at defect density (Nt) of 1 × 1013 cm−3 and 300 K operating temperature. The optimum value of operating temperature is 300 K for all PSCs but for C60/(MA)2CuCl4/Cu2O PSC, optimum value is 320 K at 400 nm of absorber layer. With considerations of all these optimum values, the highest power conversion efficiency of 28.31% has been obtained for the PCBM/(MA)2CuCl2Br2/CuI configuration at operating temperature of 300 K. Thus, the study reveals that PCBM as ETL, while CuI and Cu2O as HTLs are most suitable for the Cu-based PSC. Based upon the comparison with experimental results, our findings are indicative of the fact that traditional charge transport materials like TiO2 and spiro-OMeTAD may not be the best choices for new lead-free Cu-based PSCs. [ABSTRACT FROM AUTHOR]

Perovskite solar cells (PSCs), which are constructed using organic–inorganic combination resources, represent an upcoming technology that offers a competitor to silicon-based solar cells. Electron transport materials (ETMs), which are essential to PSCs, are attracting a lot of interest. In this section, we begin by discussing the development of the PSC framework, which would form the foundation for the requirements of the ETM. Because of their exceptional electronic characteristics and low manufacturing costs, perovskite solar cells (PSCs) have emerged as a promising proposal for future generations of thin-film solar energy. However, PSCs with a compact layer (CL) exhibit subpar long-term reliability and efficacy. The quality of the substrate beneath a layer of perovskite has a major impact on how quickly it grows. Therefore, there has been interest in substrate modification using electron transfer layers to create very stable and efficient PSCs. This paper examines the systemic alteration of electron transport layers (ETLs) based on electron transfer layers that are employed in PSCs. Also covered are the functions of ETLs in the creation of reliable and efficient PSCs. Achieving larger-sized particles, greater crystallization, and a more homogenous morphology within perovskite films, all of which are correlated with a more stable PSC performance, will be guided by this review when they are developed further. To increase PSCs’ sustainability and enable them to produce clean energy at levels previously unheard of, the difficulties and potential paths for future research with compact ETLs are also discussed.

At present, heavy-metal-free quantum dot light-emitting diodes (QLEDs) have shown great potential as a research hotspot in the field of optoelectronic devices. This article reviews the research on heavy-metal-free quantum dot (QD) materials and light-emitting diode (LED) devices. In the first section, we discussed the hazards of heavy-metal-containing quantum dots (QDs), such as environmental pollution and human health risks. Next, the main representatives of heavy-metal-free QDs were introduced, such as InP, ZnE (E=S, Se and Te), CuInS2, Ag2S, and so on. In the next section, we discussed the synthesis methods of heavy-metal-free QDs, including the hot injection (HI) method, the heat up (HU) method, the cation exchange (CE) method, the successful ionic layer adsorption and reaction (SILAR) method, and so on. Finally, important progress in the development of heavy-metal-free QLEDs was summarized in three aspects (QD emitter layer, hole transport layer, and electron transport layer).

A potential technology for converting clean and renewable energy is perovskite solar cells (PSCs). The electron transport layer (ETL), one of the vital parts of PSCs, is essential for improving device stability and efficiency. The relevance of indium sulfide (In2S3) as a superior material for ETL in PSCs is explored in this article. We analyzed the operation of PSCs and emphasized the value of ETLs in enabling effective charge extraction and minimizing recombination losses. In2S3 is a favorable nanomaterial for ETL applications due to its advantageous bandgap, excellent electron mobility, and chemical stability. Furthermore, the perovskite layer is shielded by In2S3's passivation properties, which also increase the stability of the device. A summary of recent developments in In2S3-based ETL research, including material engineering and deposition methods improvements, has been provided. The main view for the future is the possibility of improved In2S3 property optimization and interface engineering to improve PSC performance. Collaboration between scientists working on solar energy, devices, and materials will probably lead to new discoveries and test the limits of In2S3-based ETLs. Novel hybrid architectures and tandem arrangements provide exciting opportunities for better charge extraction with existing electron transport materials. The current investigation of In2S3-based ETLs in PSCs offers significant promise to revolutionize the solar energy sector, opening the path for sustainable and effective photovoltaic technology. However, stability, toxicity, and large-scale production issues must be addressed.

Perovskite solar cells show great potential application prospects in the field of solar cells due to their promising properties. However, most perovskite solar cells that exhibit excellent photovoltaic performance typically require a carrier transport layer that necessitates a high-temperature annealing process. This greatly restricts the scalability and compatibility of perovskite solar cells in flexible electronics. In this paper, SnO2 nanoparticles with high crystallinity, good dispersibility and uniform particle size distribution are first prepared using a solvothermal method and dispersed in n-butanol solution. SnO2 electron transport layers are then prepared by a low-temperature spin coating method, and the photovoltaic characteristics of perovskite solar cells prepared with different SnO2 nanoparticles/n-butanol concentrations are studied. Results indicate that the rigid perovskite solar cell achieves the highest power conversion efficiency of 15.61% when the concentration of SnO2 nanoparticles/n-butanol is 15 mg mL−1. Finally, our strategy is successfully applying on flexible perovskite solar cells with a highest PCE of 14.75%. Our paper offers a new possibility for large-scale preparation and application of perovskite solar cells in flexible electronics in the future.

Perovskite solar cells are an attractive technology for renewable energy production. However, stability issues with the electron transport layer (ETL), particularly the colloidal tin oxide (SnO2) solution, can impact cell efficiency. In this study, a novel acidization treatment is introduced to reactivate long‐time stored SnO2 solutions, which previously led to low‐efficiency perovskite solar cells. The acidization treatment results in enhanced conductivity of the SnO2 layer, improved perovskite film quality, and ultimately increased efficiency. These findings show that a 1‐month stored SnO2 solution treated with acetic acid produces a device with a photoelectric conversion efficiency (PCE) of 20.9%, compared to 13.5% efficiency without treatment. With the addition of PEAI, the champion efficiency of the acetic acid‐treated device is 22.3%. This study provides a simple and effective engineering approach to fabricating high‐performance and stable ETLs for perovskite solar cells. [ABSTRACT FROM AUTHOR]

Zinc oxide (ZnO) electron transport layer (ETL) has been employed in inverted OSCs for highly efficient and stable devices. In this study, a Sn-doped ZnO layer was produced and employed in inverted OSCs based on the extensively used polymer, poly-3-hexylthiophene (P3HT). The performance of the reference device was enhanced from 1.01 to 3.45% by doping the ZnO layer with 3% Sn. The increased charge production, exciton dissociation, and better morphology, which led in an improved active layer/ETL interface, are the primaryleads to for the more than twofold PCE enhancement. Furthermore, after 3% Sn doping, the Voc of the reference device increased from 0.44 to 0.61 V due to a shift in the conduction band, which promotes charge transfer and minimizes energy loss in the device. The ETL's conductivity was increased by 7%, resulting in a considerable increase in photocurrent from 5.66 to 10.69 mA/cm2. As a result, Sn doping may be a promising low-cost technique to improve inverted OSC performance. [ABSTRACT FROM AUTHOR]

Environment friendly third-generation solar cells sensitized by dyes, quantum dots, and perovskites are seen as promising energy alternatives. Among the various strategies, employing one-dimensional nanostructures that exemplify the smallest dimension for efficient carrier transport rate from the active layer to electron transport layer (ETL) in photovoltaic devices is attempted in this work. We herein report the synthesis of well-aligned 1-D TiO2 nanocones as ETL for photovoltaic thin films by varying the precursor concentration (0.03 M, 0.04 M, 0.05 M) to track the evolution of growth. The hydrothermal approach is exploited to grow oriented rutile TiO2 nanocones on fluorine doped tin oxide (FTO) under neutral conditions. The examination of phase, crystallinity, morphology, and opto-electronic properties of the well-structured nanocone arrays is characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), ultra violet diffuse reflectance spectroscopy (UV-DRS), Brunnauer–Emmett–Teller (BET) surface area analysis, and field-dependent dark and photoconductivity analysis. The XRD pattern confirms the formation of the tetragonal rutile phase. SEM micrographs and UV-DRS spectroscopy reveals that the length of the nanocones and the energy gap is found to be maximum for 0.04 M concentration with a well-defined excitation band at 316 nm. Significantly, a strong light-trapping effect that decreases the incident light reflections and correspondingly increases the light absorption is unveiled through photoconductive studies for the TiO2 nanocones at 0.04 M having a surface area of 81.767 m2/g. The investigation essentially suggests that the as-prepared one-dimensional nanostructures would serve as efficient photoanodes in environment safe third-generation solar cells. [ABSTRACT FROM AUTHOR]

Electron transfer layer (ETL) is vital importance for obtaining high performance perovskite solar cells (PSC). This can be achieved by producing tin oxide (SnO2) ETL, which is produced at high temperature, has appropriate energy band alignment, high optical transmittance and high carrier mobility. ETL produced at low temperature generally has low crystallization, poor electron mobility, and abundant defects at grain boundaries. This prevents efficient load transport, creates recombination and causes serious energy losses. In this paper, 1-ethyl-3-methylimidazolium tetrafluoroborate (EMIMBF4) ionic liquid (IL) was added into SnO2 ETL in different concentrations to improve these negative properties caused by the production of SnO2 ETL at low temperature, using spin-coater technique at low temperature (100 °C) was prepared. Optical properties of EMIMBF4 IL doped SnO2 ETL and perovskite films were investigated using UV-vis-NIR spectrometry and photoluminescence spectrophotometer (PL) measurement. The surface morphology of the produced films was investigated by field emission scanning electron microscopy (FE-SEM) and atomic force microscopy (AFM). The crystal structure analysis of the films was carried out by X-ray diffraction (XRD). The hydrophilic/hydrophobic behavior of the surfaces was evaluated using contact angle measurement. It has been observed that EMIMBF4 doped SnO2 ETL films have fewer surface defects by passivation of surface defects compared to pure SnO2 ETL film and they crystallize at a relatively low and economical temperature (100°C). It has been determined that 0.5% EMIMBF4 doped films give better optical and structural results than other doped and pure ETL films, albeit low. [ABSTRACT FROM AUTHOR]

Perovskite Solar Cells (PSCs) have managed to significantly capture attention by achieving efficiency values of 25.6% in a remarkably short period of around ten years. Each layer within the device plays a crucial role in the overall device efficiency when it comes to PSC production. PC61BM, a derivative of fullerene, is one of the most commonly used electrontransport layers (ETLs) in inverted-type PSCs. In this study, the improvement of the ETL was aimed by incorporating C60 into PC61BM, and the effects of the doped ETL on MAPbI3-based inverted-type PSCs were investigated. For inverted type PSCs which are fabricated under high humidity (40-60%) and room conditions (~25 °C), the power conversion efficiencies (PCEs) have boosted from 11.54% (for undoped PC61BM) to 13.40% (for C60-doped PC61BM). To comprehend the sources of improvement in the fabricated devices, a series of characterizations were carried out, including Current Density-Voltage (J-V), Hysteresis Factor (HF), Scanning Electron Microscope (SEM), and Atomic Force Microscope (AFM) measurements. [ABSTRACT FROM AUTHOR]

All-inorganic cesium tin-germanium tri-iodide (CsSnGeI3) emerges as a potential light harvesting material for lead-free perovskite solar cells. The exploration of CsSnGeI3 has not yet been perceived owing to the conceivable challenges of imperfections in device fabrication, unoptimized alignment of the charge transport layers, and inappropriate device configuration. In this manuscript, we have elucidated the influence of BaSnO3 as an electron transport layer on the performance of Pb-free, all-inorganic cesium tin-germanium tri-iodide (CsSn0.5Ge0.5I3)-based perovskite solar cell using SCAPS-1D software. In our initial simulated results, the presented device achieves the best efficiency of 22.09% with JSC = 24.41 mAcm−2, VOC = 1.0655 V, and FF = 84.92%. Subsequently, we have analyzed the impact of thickness and defect density on the recombination rate of charge carriers in the Sn-Ge amalgamated perovskite absorber layer, diffusion length, and other performance parameters. From these results, we have optimized the suitable value of thickness (900 nm) and defect density (Nt ≈ 1×1011 cm−3) of Sn-Ge combination perovskite layer for efficient PVSCs devices. Furthermore, we have optimized the thickness, electron affinity, and carrier concentration of charge transport layers, and their optimized values have been obtained for the design of efficient device. Using the optimized values, proposed device yields the high performance in terms of best power conversion efficiency of 28.21% with JSC = 27.18 mAcm−2, VOC = 1.2427 V, and FF = 83.50%, without any hysteresis loss. Thus, this extensive simulation approach paves a formative research route for the practical fabrication of efficient Pb-free CsSnGeI3 perovskite-based solar cells. [ABSTRACT FROM AUTHOR]

Pristine fullerene C60 is an excellent electron transport material for state‐of‐the‐art inverted structure perovskite solar cells (PSCs), but its low solubility leaves thermal evaporation as the only method for depositing it into a high‐quality electron transport layer (ETL). To address this problem, we herein introduce a highly soluble bowl‐shaped additive, corannulene, to assist in C60‐assembly into a smooth and compact film through the favorable bowl‐ball interaction. Our results show that not only corannulene can dramatically enhance the film formability of C60, it also plays a critical role in forming C60‐corannulene (CC) supramolecular species and in boosting intermolecular electron transport dynamics in the ETL. This strategy has allowed CC devices to deliver high power conversion efficiencies up to 21.69 %, which is the highest value among the PSCs based on the solution‐processed‐C60 (SP‐C60) ETL. Moreover, the stability of the CC device is far superior to that of the C60‐only device because corannulene can retard and curb the spontaneous aggregation of C60. This work establishes the bowl‐assisted ball assembly strategy for developing low‐cost and efficient SP‐C60 ETLs with high promise for fully‐SP PSCs. [ABSTRACT FROM AUTHOR]

In recent years, perovskite solar cells (PSCs) have gained major attention as potentially useful photovoltaic technology due to their ever-increasing power-conversion efficiency (PCE). The efficiency of PSCs depends strongly on the type of materials selected as the electron transport layer (ETL). TiO2 is the most widely used electron transport material for the n-i-p structure of PSCs. Nevertheless, ZnO is a promising candidate owing to its high transparency, suitable energy band structure, and high electron mobility. In this investigation, hybrid mesoporous TiO2/ZnO ETL was fabricated for a perovskite solar cell composed of FTO-coated glass/compact TiO2/mesoporous ETL/FAPbI3/2D perovskite/Spiro-OMeTAD/Au. The influence of ZnO nanostructures with different percentage weight contents on the photovoltaic performance was investigated. It was found that the addition of ZnO had no significant effect on the surface topography, structure, and optical properties of the hybrid mesoporous electron-transport layer but strongly affected the electrical properties of PSCs. The best efficiency rate of 18.24% has been obtained for PSCs with 2 wt.% ZnO. [ABSTRACT FROM AUTHOR]

Organic–inorganic hybrid photodiodes have garnered research interest to achieve high-performance optoelectronic devices with longer lifetime. In the present study, a fluorescent 1,8-naphthalimide (NI) derivative BHSHNI was synthesized through bromination of 3-hydroxy naphthalic anhydride and subsequent imidation reaction with salicyloyl hydrazide. The IR, NMR and mass spectrometry studies confirmed the molecular structure of the NI derivative. Intramolecular charge transfer was confirmed using theoretical and fluorescence emission studies. Thermal investigations suggested good stability of BHSHNI and cyclic voltammetry indicated an electrochemical band gap of 1.10 eV. Surface uniformity and pit-free morphology was observed in SEM and AFM images of thin films formed by BHSHNI. The organic (PEDOT:PSS) and hybrid (organic–inorganic) p–n type diodes were successfully constructed using BHSHNI. The hybrid diode exhibited better features with ideality factors of 9.3 and 15.2 in dark and visible light, respectively, with a dielectric constant of 7.65 at 30 kHz. The calculated responsivity of the hybrid diode was found to be 66.26 μ A / W . The device incorporating BHSHNI as functional material with NiO can be further explored for photodiode applications. [ABSTRACT FROM AUTHOR]

In just a few years, the worldwide scientific community has worked diligently to increase the photovoltaic conversion efficiency of perovskite solar cells from 3.8% to 25.7%. Due to its low stability and poor scalability, it still lags in commercial performance concerning the crystalline silicon solar cell. Most of the high-efficiency perovskite solar cells (PSC) reported in the literature are on a 0.01 cm2 area, and the efficiency of PSC decreases with an increase in area. The maximum said stability to date is 10,000 h which is relatively low compared to crystalline silicon technology. This work discussed the causes of instability, degradation mechanism, scalable fabrication methods, and high-stability perovskite solar cell. It emphasised the need for setting up testing protocols for universal stability testing of perovskite solar cell technology. The study found that trap states in the absorber layer, hole transport layer (HTL), and electron transport layer (ETL) are the reason for lower stability. The lower dimension perovskite solar cell shows better stability compared to its 3D counterparts.

Abstract Tin oxide (SnO2) nano-crystalline thin films were deposited on silicon and glass substrates at room temperature by sputtering at a constant power of 30 W and different working pressure of 10, 7, and 5 mTorr. Surface morphology, electrical and optical properties of the films were investigated to optimise the deposition condition of the films as electron transport layer (ETL) for high-power conversion efficiency perovskite solar cells. The films were characterized by scanning electron microscopy (SEM), UV–Vis–NIR Spectrophotometer, and Four-point probe. SnO2 films obtained at working pressure of 10 mTorr exhibited uniform surface morphology with high light transmittance (90%) and conductivity (4 S/m). These sputtered SnO2 films appeared to have shown promising properties as ETL for PSC, and further investigation is justified to establish the optimal fabrication parameters and resulting energy conversion efficiency.

Perovskite solar cells could strongly compete with the silicon solar cells in the market soon as illustrated in recent studies. In this work, promising and stable metal-free perovskite solar cells (PSCs) has been successfully fabricated using an inorganic SnO2/Quantum dot SnO2 (QD-SnO2) double layer as an efficient electron transport layer via a low-temperature solution process. The fully-air fabricated PSCs in the form of FTO/SnO2/QD-SnO2/CH3NH3PbI3/Carbon were tested at different annealed QD-SnO2 between 300 and 500 °C. The as-prepared QD-SnO2 and the fabricated devices are characterized by various techniques, including XRD, XPS, HR-TEM, FE-SEM, UV–vis–NIR spectroscopy, PL, and solar simulator. The prepared QD-SnO2 at 300 °C has shown well-ordered nanoparticles of 5.6 nm in diameter with superior carrier density (1.5 × 1015 cm−3) and highest carrier mobility (64.1 cm2·V-1·s−1), accelerating the carriers separation process within the cell. The best devices demonstrated a maximum power conversion efficiency (PCE) of 11.7%, VOC 0.81 V, JSC 19.5 mA·cm−2, and FF 74%. The presence of an interfacial layer of QD-SnO2 over the blocking SnO2 upsurges the band gaps alignment and accelerates the carriers extraction rate affecting the performance of the fabricated perovskite devices. Moreover, the optimized fabricated devices revealed a shelf stability-life of four months in humid air (40%–50%) with >83% of its initial PCE. This simple synthetic approach can develop the opportunities to transfer the cell from the lab to the market, which will be compatible with large-scale production.

Magnetron sputtering technology benefits from an easy process parameter adjustment strategy, good experimental reproducibility, and high-quality film formation; thus, it is widely used in thin-film electronic devices. In the present work, the thickness and morphology of the TiO2 electron transport layer were controlled by magnetron sputtering time, and based on this technology, planar heterojunction perovskite solar cells were prepared. The results showed that with an increase in the sputtering time, the surface roughness of the TiO2 film decreased, and the electrical homogeneity and square resistance of the film increased. Especially, the film transmittance showed a maximum value of 82.29% at 45 min of deposition, and the so prepared perovskite solar cells exhibited the highest photoelectric conversion efficiency of up to 12.42%.

Abstract Perovskite solar cells are an attractive technology for renewable energy production. However, stability issues with the electron transport layer (ETL), particularly the colloidal tin oxide (SnO2) solution, can impact cell efficiency. In this study, a novel acidization treatment is introduced to reactivate long‐time stored SnO2 solutions, which previously led to low‐efficiency perovskite solar cells. The acidization treatment results in enhanced conductivity of the SnO2 layer, improved perovskite film quality, and ultimately increased efficiency. These findings show that a 1‐month stored SnO2 solution treated with acetic acid produces a device with a photoelectric conversion efficiency (PCE) of 20.9%, compared to 13.5% efficiency without treatment. With the addition of PEAI, the champion efficiency of the acetic acid‐treated device is 22.3%. This study provides a simple and effective engineering approach to fabricating high‐performance and stable ETLs for perovskite solar cells.

SnO2 film is one of the most widely used electron transport layers (ETL) in perovskite solar cells (PSCs). However, the inherent surface defect states in SnO2 film and mismatch of the energy level alignment with perovskite limit the photovoltaic performance of PSCs. It is of great interesting to modify SnO2 ETL with additive, aiming to decrease the surface defect states and obtain well aligned energy level with perovskite. In this paper, anhydrous copper chloride (CuCl2) was employed to modify the SnO2 ETL. It is found that the adding of a small amount of CuCl2 into the SnO2 ETL can improve the proportion of Sn4+ in SnO2, passivate oxygen vacancies at the surface of SnO2 nanocrystals, improve the hydrophobicity and conductivity of ETL, and obtain a good energy level alignment with perovskite. As a result, both the photoelectric conversion efficiency (PCE) and stability of the PSCs based on SnO2 ETLs modified with CuCl2 (SnO2-CuCl2) is improved in comparison with that of the PSCs on pristine SnO2 ETLs. The optimal PSC based on SnO2-CuCl2 ETL exhibits a much higher PCE of 20.31% as compared to the control device (18.15%). The unencapsulated PSCs with CuCl2 modification maintain 89.3% of their initial PCE after exposing for 16 d under ambient conditions with a relative humidity of 35%. Cu(NO3)2 was also employed to modify the SnO2 ETL and achieved a similar effect as that of CuCl2, indicating that the cation Cu2+ plays the main role in SnO2 ETL modification. [ABSTRACT FROM AUTHOR]

Chemical bath deposition (CBD) is a widely used approach to deposit the tin oxide (SnO2) electron transport layer (ETL) in the perovskite solar cell (PSC). However, the defect states in the CBD‐resulted SnO2 ETLs limit the electron extraction/transport from the perovskite to the ETL and lead to poor PSC performance. Herein, ethylenediaminetetraacetic acid dipotassium (EDTA‐2K) is used as an additive in the CBD precursor of the SnO2 ETL, which results in the chelation of Sn2+ and EDTA during the hydrolysis process. This strategy decreases the concentration of free Sn2+ in the precursor for hydrolysis and slows down the CBD process, thus attributes to the decreased surface defect states as well as the enhanced conductivity of the ETL. As a result, the EDTA‐2K additive makes the CBD SnO2 ETL with efficient electron extraction and transporting capability. The champion device achieves a power conversion efficiency (PCE) of 21.87%, which is significantly higher than that of the pristine CBD SnO2‐based device (20.25%). In addition, the device with an active area of 1.21 cm2 achieves a high PCE of 19.23%. This strategy makes the CBD SnO2 an excellent ETL candidate for the development of low‐cost and large‐scale PSCs. [ABSTRACT FROM AUTHOR]

Tin oxide (SnO2) semiconductor is recognized as a highly promising material for the electron transport layer (ETL) in perovskite solar cells (PSC) due to their wide band gap energy and high electron mobility. This material has been considered as the potential alternative material for substituting the conventional titanium dioxide (TiO2). In the form of nanostructure material, it is expected that SnO2 as the ETL in PSC device can be significantly improved owing to its high surface area leading to more intensive photon absorption. In this present study, SnO2 nanoparticles were synthesized via the hydrothermal method with temperature variations ranging from 120 °C to 160 °C for 16 hours. The as-synthesized samples were characterized using X-ray diffraction (XRD), scanning electron microscope (SEM), and an ultraviolet-visible (UV-Vis) spectrophotometer. The SnO2 nanoparticles were then integrated into the PSC device as the ETL, and the performance testing was conducted using a semiconductor parameter analyzer to obtain the I-V curve. On the basis of investigation results, it has been found that the temperature used during the hydrothermal process plays a crucial role in determining the crystallinity, morphology, and band gap energy of the SnO2 nanoparticles. The results of the PSC performance test indicate that SnO2 nanoparticles synthesized at a hydrothermal temperature of 150 °C demonstrated the highest power conversion efficiency (PCE) of 3.89 %. This outcome confirms the viability of SnO2 nanoparticles produced through the hydrothermal method. [ABSTRACT FROM AUTHOR]

Quantum dot light-emitting diodes (QLEDs) are considered as the ideal candidate for next-generation displays, solid-state lighting, and optical communication applications. Although the efficiency of QLEDs has been significantly improved to the level comparable to that of organic light-emitting diodes in recent years, simultaneously achieving high efficiency and high brightness still remains challenging for QLEDs. In this work, we report a facile and effective electron-transport-layer interface control strategy of incorporating 3-aminopropyl triethoxysilane (APTES) into a ZnO nanocrystal-solution to enhance charge injection balance and suppress interfacial exciton quenching via in-situ formation of ZnO/organic silica (hereinafter referred to as ZnO/SiO 2) quasi core/shell nanoparticles in the solution, enabling red QLEDs to exhibit a maximum luminance intensity of 261,700 cd m−2, a peak external quantum efficiency (EQE) of 19.0%, and low efficiency roll-off at high luminance (an EQE up to 16.8% remained at a brightness of 200, 000 cd m−2). Our results demonstrate that substituting quasi core/shell-structured ZnO/SiO 2 nanoparticles for traditional ZnO nanocrystals as electron transport materials is a simple and effective means of fabricating QLEDs with both high efficiency and high luminance, which is expected to facilitate the development of QLED technology toward practical applications in lighting, displays and optical communication. [ABSTRACT FROM AUTHOR]

The electron‐transport layer (ETL) of n–i–p‐structured perovskite solar cells (PSCs) plays vital important roles determining their photovoltaic performance. It is known that the ETL lying underneath can affect the crystallization process of the upper perovskite layer. Furthermore, the buried interface between ETL and perovskite is usually the place where severe non‐radiative recombination happens. Herein, MXene (Ti3C2)‐modified TiO2 (TiO2:MXene) is demonstrated as an excellent ETL for high‐performance PSCs. The FAPbI3‐based and MAPbI3‐based cells with TiO2:MXene achieved a power conversion efficiency (PCE) of up to 24.63% and 20.1%, respectively. Importantly, the target cell shows superior stability and device consistency. The target devices keep ≈98% of their initial PCE after 7 weeks stored in an ambient environment with 40%–60% relative humidity at 25 °C, whereas the PCE of the reference cell declined to ≈90% of its initial value under the same test conditions. It is found that the perovskite film on TiO2:MXene ETL has excellent crystallinity and structural uniformity. For the first time, grazing‐incidence small‐angle X‐ray scattering technique is employed to probe the structural information of complete PSC devices on a large scale, providing new possibilities of characterizing large‐size PSC modules. [ABSTRACT FROM AUTHOR]

Perovskite solar cells (PSCs) based on SnO2 electron transport layers have attracted extensive research due to their compelling photovoltaic performance. Herein, we presented an in situ passivation of SnO2 with low‐cost hydroxyacid potassium synergist during deposition to optimize the interface carrier extraction and transport for high power conversion efficiency (PCE) and stabilities of PSCs. The orbital overlap of the carboxyl oxygen with the Sn atom alongwith the homogenous nano‐particle deposition effectively suppresses the interfacial defects and releases the internal residual strains in the perovskite. Accordingly, a PCE of 24.91 % with a fill factor (FF) up to 0.852 is obtained for in situ passivated devices, which is one of the highest values for SnO2‐based PSCs. Moreover, the unencapsulated device maintained 80 % of its initial PCE at 80 °C over 600 h, 100 % PCE at ambient conditions for 1300 h, and 98 % after one week maximum power point tracking (MPPT) under continuous AM1.5G illumination. [ABSTRACT FROM AUTHOR]

Tin dioxide (SnO2) has recently been recognized as an excellent electron transport layer (ETL) for perovskite solar cells (PSCs) due to its advantageous properties, such as its high electron mobility, suitable energy band alignment, simple low-temperature process, and good chemical stability. In this work, nitrogen-doped graphene quantum dots (N-GQDs) were prepared using a hydrothermal method and then used to fabricate N-GQD:SnO2 nanocomposite ultrathin films. N-GQD:SnO2 nanocomposite ultrathin films were investigated and applied as electron transport layers in planar PSCs. The presence of N-GQDs with an average size of 6.2 nm in the nanocomposite improved its morphology and reduced surface defects. The excitation–emission contour map indicated that the N-GQDs exhibited a remarkably enhanced light-harvesting capability due to the possibility of absorbing UV light and producing emissions in the visible range. The quenching of photoluminescence spectra showed that the N-GQDs in nanocomposite ultrathin films improved electron extraction and reduced charge recombination. As a result, the power conversion efficiency (PCE) of our planar PSCs fabricated with the optimized N-GQD:SnO2 nanocomposite electron transport layer was improved by 20.4% over pristine SnO2-based devices. [ABSTRACT FROM AUTHOR]

Sputter-deposited polycrystalline BaSi2 films capped with a 5 nm thick a-SiC layer showed high photoresponsivity. This means that the a-SiC layer functions as a capping layer to prevent surface oxidation of BaSi2. Based on the measured absorption edge, the electron affinity of the a-SiC layer, and the work function of the TiN layer, the a-SiC is considered to act as an electron transport layer (ETL) for the BaSi2 light absorber layer/a-SiC interlayer/TiN contact structure in a BaSi2 solar cell. Using a 10 nm thick p+-BaSi2 layer as a hole transport layer, we investigated the effect of the BaSi2/a-SiC layered structure on the device performance of a BaSi2-pn homojunction solar cell by a one-dimensional device simulator (AFORS-HET v2.5). The a-SiC ETL effectively separates photogenerated carriers and allows transport of electrons while blocking holes to achieve an efficiency of 22% for a 500 nm thick BaSi2 light absorber layer. [ABSTRACT FROM AUTHOR]

All-inorganic CsPbI3–xBrx perovskite solar cells (PSCs) are advantageous in terms of high thermal stability, while its efficiency lags behind those of organic-inorganic hybrid perovskite counterparts. Defect passivations have been extensively applied for enhancing efficiency of all-inorganic PSCs, which are mainly based on univocal defect passivation of perovskite layer. Herein, we incorporated a bis-dimethylamino-functionalized fullerene derivative (abbreviated as PCBDMAM) as an interlayer between ZnO electron transport layer (ETL) and all-inorganic CsPbI2.25Br0.75 perovskite layer, accomplishing synchronous defect passivations of both layers and consequently dramatic enhancements of efficiency and thermal stability of PSC devices. Upon spin-coating PCBDMAM onto ZnO ETL, the surface defects of ZnO especially oxygen vacancies can be effectively passivated due to the formation of Zn−N ionic bonds. In addition, PCBDMAM incorporation affords effective passivation of PbI and IPb antisite defects within the atop perovskite layer as well via coordination bonding with Pb2+. As a result, the regular-structure planar CsPbI2.25Br0.75 PSC device delivers a champion power conversion efficiency (PCE) of 17.04%, which surpasses that of the control device (15.44%). Moreover, the PCBDMAM-incorporated PSC device maintains ~ 80% of its initial PCE after 600 h heating at 85 °C hot plate in N2 atmosphere, whereas PCE of the control device degrades rapidly to ~ 62% after 460 h heating under identical conditions. Hence, PCBDMAM incorporation benefited dramatic improvement of the thermal stability of PSC device.

To enhance the overall performance of perovskite solar cells, the quality of the electron transport layer (ETL) held significant importance. Zinc oxide (ZnO) emerged as highly promising due to its exceptional optical and electrical characteristics. This study included the incorporation of lanthanum (La III) into the ZnO lattice to improve its optoelectronic properties. All the produced thin films were crystallized at low annealing temperatures. Through careful analysis, it was observed that the inclusion of doping with 4% La (III) resulted in increased crystallinity, leading to low surface roughness. Additionally, this doping strategy facilitated enhanced mobility of charge carriers and conductivity.

The power conversion efficiency (PCE) of thin-film solar cells (TFSCs) has drastically increased in the last few years. In this regard, perovskite solar cells (PSCs) come on the top thanks to their bandgap tunability, lower fabrication cost, and high absorption coefficient. In this work, a comprehensive simulation study is presented in which methylammonium-free PSCs are analyzed and designed. Also, the design of the presented solar cell structure is based on using a hole transport layer (HTL)-free. So, the design is carried out in such a way as to prevent the instability and cost issues associated with the organic materials, usually incorporated in HTLs, as well as methylammonium (MA) which limits the device operation stability. Next, the conduction band offset between the perovskite as an absorber and the electron transport layer (ETL) is controlled to provide a spike-like band offset that is more desirable by selecting appropriate materials serving as ETLs. The work function of the back contact is also investigated, and it is found that using Carbon, which has a lower cost than gold, is beneficial to get high efficiency. An enhanced performance has been achieved by combining the different steps of the design. This is reflected in the PCE which performs 25.35% instead of the initial calibrated cell which shows a PCE of 20.7%. The PCE could further be boosted to 27.8% if reduced absorber and interface defects are included. The calibration and simulation of the presented PSCs were done by utilizing SCAPS one-dimensional simulator, based on practical material parameters, at AM1.5 illumination.

Tin oxide (SnO2) nano-crystalline thin films were deposited on silicon and glass substrates at room temperature by sputtering at a constant power of 30 W and different working pressure of 10, 7, and 5 mTorr. Surface morphology, electrical and optical properties of the films were investigated to optimise the deposition condition of the films as electron transport layer (ETL) for high-power conversion efficiency perovskite solar cells. The films were characterized by scanning electron microscopy (SEM), UV–Vis–NIR Spectrophotometer, and Four-point probe. SnO2 films obtained at working pressure of 10 mTorr exhibited uniform surface morphology with high light transmittance (90%) and conductivity (4 S/m). These sputtered SnO2 films appeared to have shown promising properties as ETL for PSC, and further investigation is justified to establish the optimal fabrication parameters and resulting energy conversion efficiency. [ABSTRACT FROM AUTHOR]

Compositional engineering is considered one of the recent interesting techniques used in the field of perovskite solar cells (PSCs). In this method, more than one material was used in a specific cation in the perovskite structure. This work aims to simulate the cesium-containing triple-cation perovskite (TCP) via the SCAPS-1D simulation program with a device structure of ITO/SnO2/TCP/Spiro-OMeTAD/Au. First, we studied the effect of interface defects on the PCSs with respect to experimental results and found that when no interface defects occur, the power conversion efficiency (PCE) reaches a value of 22.16% which is higher than the reported PCE, implying that the fabricated cell suffers from the interface defects as a main effect on cell degradation. Incorporating interface defects into the simulation results in a very good match between the experimental and simulated data with a PCE of 17.92%. Further, to provide possible routes to enhance the performance of the solar cell under investigation, impacts of absorber layer thickness, conduction band offset (CBO), surface recombination velocity, and light intensity were explored. In addition, hole transport layer (HTL)-free design was investigated to alleviate the instability issues associated to the organic HTL, leading to a PCE of 18.28%, for a surface velocity of 104 cm/s, which is interestingly higher than the initial cell. The provided study reveals the critical role of interface defects and other key design factors and suggests potential solutions to alleviate the subsequent degradation mechanisms, thereby enhancing the overall cell performance. [ABSTRACT FROM AUTHOR]

Among the factors that lead to the reduction of the efficiency of perovskite solar cells (PSCs) the difficulty involved in realizing a high‐quality film and the efficient charge transfer that takes place at the interface between electron‐transport layer (ETL) and perovskite is worth mentioning. Here, a strategy for planar‐type devices by natural bio‐functional interfaces that uses a buried electron‐transport layer made of cobalamin complexed tin oxide (SnO2@B12) is demonstrated. Having systematically investigated the effects of SnO2@B12 interfacial layer in perovskite solar cells, it can be concluded that cobalamin can chemically link the SnO2 layer and the perovskite layer, resulting in improved perovskite film quality and interfacial defect passivation. Utilizing SnO2@B12 improves the efficiency of planar‐type PSCs by 20.60 %. Furthermore, after 250 h of exposure to an ambient atmosphere, unsealed PSCs containing SnO2@B12 degrade by 10 %. This research provides a viable method for developing bio‐functional molecules that will increase the effectiveness and durability of planar‐perovskite solar cells. [ABSTRACT FROM AUTHOR]

The power conversion efficiency (PCE) of perovskite solar cells (PSCs) has seen effective performance upgrades, showing remarkable academic research and commercial application value. Compared with commercial silicon cells, the PCE gap is narrowing. However, the stability, cost, and large-scale production are still far behind. For scale-up preparing high-efficiency and stable PSCs, there is a variety of related research from each functional layer of perovskite solar cells. This review systematically summarizes the recent research on the functional layers, including the electron transport layer, perovskite layer, hole transport layer, and electrode. The common ETL materials, such as TiO2, SnO2, and ZnO, need doping and a bi-layer ETL to promote their property. Large-scale and low-cost production of perovskite layers with excellent performance and stability has always been the focus. The expensive and instability problems of Spiro-OMeTAD and electrode materials remain to be solved. The main problems and future development direction of them are also discussed. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Inverted perovskite solar cells (PSCs) have attracted increasing attention in recent years owing to their low‐temperature fabrication proces s. However, they suffer from a limited number of electron transport materials available with [6,6]‐phenyl C61 butyric acid methyl ester (PCBM) to be the most widely studied based on its appropriate energy levels and high electron mobility. The low relative permittivity and aggregation tendency upon illumination of PCBM, however, compromises the solar cell efficiency whereas its modest hydrophobicity negatively impacts on the device stability. Alternative electron transport materials with desired properties and appropriate degree of hydrophobicity are thus desirable for further developments in inverted PSCs. Herein, we synthesize a triethyleneglycol C60 mono‐adduct derivative (termed as EPF03) and test it as a novel electron transport material to replace PCBM in inverted PSCs based on a quadruple cation (RbCsMAFA) perovskite. We also compare this derivative with two novel fullerenes decorated with two (EPF01) or one dodecyl (EPF02) long side chains. The latter two fail to perform efficiently in inverted PSCs whereas the former enabled a power conversion efficiency of 18.43%, which represents a 9% improvement compared to the reference device using PCBM (17.21%). The enhanced performance mainly stems from improved electron extraction and reduced recombination enabled by the insertion of the large relative permittivity amongst other properties of EPF03. Furthermore, our results indicate that triethylene glycol side chains can also passivate perovskite trap states, suppress ion migration and enhance photostability and long‐term stability of EPF03 based perovskite solar cells. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Inverted perovskite solar cells (PSCs) have attracted increasing attention in recent years owing to their low‐temperature fabrication proces s. However, they suffer from a limited number of electron transport materials available with [6,6]‐phenyl C61 butyric acid methyl ester (PCBM) to be the most widely studied based on its appropriate energy levels and high electron mobility. The low relative permittivity and aggregation tendency upon illumination of PCBM, however, compromises the solar cell efficiency whereas its modest hydrophobicity negatively impacts on the device stability. Alternative electron transport materials with desired properties and appropriate degree of hydrophobicity are thus desirable for further developments in inverted PSCs. Herein, we synthesize a triethyleneglycol C60 mono‐adduct derivative (termed as EPF03) and test it as a novel electron transport material to replace PCBM in inverted PSCs based on a quadruple cation (RbCsMAFA) perovskite. We also compare this derivative with two novel fullerenes decorated with two (EPF01) or one dodecyl (EPF02) long side chains. The latter two fail to perform efficiently in inverted PSCs whereas the former enabled a power conversion efficiency of 18.43%, which represents a 9% improvement compared to the reference device using PCBM (17.21%). The enhanced performance mainly stems from improved electron extraction and reduced recombination enabled by the insertion of the large relative permittivity amongst other properties of EPF03. Furthermore, our results indicate that triethylene glycol side chains can also passivate perovskite trap states, suppress ion migration and enhance photostability and long‐term stability of EPF03 based perovskite solar cells. [ABSTRACT FROM AUTHOR]

Perovskite Solar Cells (PSC) are the fastest-growing generation of solar cells due to their high-power conversion efficiency (PCE) in a short period of time, simple synthesis process, high open-circuit voltage, and low cost. However, perovskite stability and the use of the toxic heavy metal of lead (Pb) are two significant challenges that still haunt the development of perovskite-based solar cells. This paper focuses on distinguishing and optimizing several key layers in the PSC structure; Electron Transport Layer (ETL), the absorber layer, and Hole Transport Layer (HTL) by conducting studies on the influence of various parameters towards the solar cell performance using SCAPs software device simulation. Moreover, distinct types of metal back contact also have been studied. In this simulation, it is found that each layer affects the performance of PSC and proves that the optimization of each layer effectively improves the performance of the PSC. Remarkable results of the optimized structure have achieved impressive PSC performance with J SC (29.516 mA / cm 2 ), V OC (1.3088 V), FF (73.26), and PCE (28.30%) by the parametric analysis. [ABSTRACT FROM AUTHOR]

Perovskite solar cells (PSCs) with CH3NH3PbX3 (MAPbX3, X = Br, I, Cl) as light-absorbing layer are used as a new generation of low-cost, high-efficiency photovoltaic devices. Compared with other types of photovoltaic devices, this type of cell has the advantages of abundant raw materials, simple process, etc., and its efficiency has risen rapidly from 3.8% to 25.7% in less than 15 years. It is almost comparable to commercial silicon solar cells and has become a new star in the field of energy applications. Normally, zinc oxide (ZnO) has been widely studied as the most important electron transport layer (ETL) of PSCs because of its advantages such as easy processed, high electron mobility, low manufacturing cost, and diverse morphology and structure. In this paper, ETL of ZnO nano film with different structures is taken as the research object, and its application in PSCs is summarized. The research progress of PSCs based on different morphology ZnO nano structures is introduced in detail, and the main problems faced by this type of solar cells are analyzed. In addition, the development trend of this device is proposed. [ABSTRACT FROM AUTHOR]

Abstract This paper elucidates the increased luminescence efficiency of CsPbBr2.1Cl0.9 sky-blue perovskite light-emitting diodes (PeLEDs) achieved through the interface modification of 3,4 ethylenedioxythiophene (PEDOT):polystyrene sulfonic acid (PSS)/quasi-two-dimensional (QTD) perovskite using CsCl and CsBr materials, respectively. QTD films were fabricated using ratios of CsPbBr2.1Cl0.9 doped with phenethylamine hydrobromide (PEABr) at 60%, 80%, and 100%. The solvent dimethyl sulfide (C2H6OS) was employed under the excitation of ambient and 365-nm laser lights. The PeLED structure was composed of Al/LiF/2,2',2"-(1,3,5-benzinetriyl)-tris(1-phenyl-1-H-benzimidazole) (TPBi)/CsPbBr2.1Cl0.9:PEABr/interface modification layer/PEDOT:PSS/ITO glass. The optimized results revealed that the luminance, current efficiency, and external quantum efficiency of the QTD CsPbBr2.1Cl0.9:80% PEABr PeLED with the CsCl interface modification additive was 892 cd/m2, 3.87 cd/A, and 5.56%, respectively.

Perovskite solar cells (PSCs) play a pivotal role in advancing renewable energy to achieve United Nation's Sustainable Development Goal 7 (SDG 7), which aims to ensure universal access to affordable, sustainable, reliable and modern energy services. Aiming to enhance the performance of PSCs by replacing the typically used electron transport layers (ETLs: TiO 2 , SnO 2 , ZnO etc.), we theoretically investigated the viability of tungsten oxide (WO X) as a promising ETL for PSCs. Moreover, the effect of altering the energy levels of WO X on cell performance has also been analyzed through simulation. Initially, 12 (twelve) PSC structures having the combination of different perovskite (PSK: CsPbBr 3 , CsPbI 3 , FAPbBr 3 , FAPbI 3) absorber layers with different organic hole transport layers (HTLs: Spiro-OMeTAD, P3HT, PEDOT:PSS) and a fixed ETL of WO X were optimized numerically for comparing their performance. As CsPbBr 3 -based PSCs showed the best performance, further simulations were performed by varying some WO X /CsPbBr 3 interface properties such as interface defect density, conduction band offset (CBO) between WO X and CsPbBr 3 , energy bandgap (E g) of WO X etc. Finally, the best-performed PSCs were found for the E g = 3.5 eV of WO X and the CBO of - 0.5 eV confirming the conduction band minimum (CBM) of WO X is lower than that of CsPbBr 3 by 0.5 eV. A properly chosen WO X layer enhanced the efficiency of CsPbBr 3 -based PSCs up to 14.65 %, 14.52 % and 16.09 %, aproaching the Shockley-Queisser (S-Q) limit (16.37% for CsPbBr 3 -based solar cell) from the initial values of 11.39 %, 11.27 %, and 12.49 %, respectively. This study ensures WO X is a promising ETL for which a proper PSC structure having a suitable PSK and an HTL can improve cell performance. Moreover, the importance of modifying energy levels of ETL material in enhancing the performance of PSCs is explored. As a result, this study opens a path for the researchers to develop WO X having suitable CBM and E g , so that it can be well-suited with a properly matched PSK material resulting in enhanced cell performance. • PSCs consisting of Cs and FA-based different perovskites and WO X as ETL are studied theoretically. • CsPbBr 3 -based PSCs having WO X as ETL exhibit the best performances. • WO X /CsPbBr 3 interface properties are varied to study their effect on cell performances. • The position of the conduction band minimum and energy band gap of WO X are optimized. • The identified optimum value conduction band offset at the WO X /CsPbBr 3 interface is −0.5 eV. [ABSTRACT FROM AUTHOR]