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Recently, SnO2-based perovskite solar cells (PSCs) have become more promising than traditional-material-based PSCs because of their simple low-temperature solution approach and low cost; meanwhile, the high-temperature process of mesoporous TiO2-based PSCs still offers a higher power conversion efficiency (PCE). In planar-based PSCs, nonradiative recombination of electron-hole pairs at the SnO2/perovskite interface leads to a loss of potential and a reduced PCE. Here, the SnO2-SDBS electron transport layer (ETL) is employed in PSCs to depress the defects of the SnO2 layer and the grain boundaries of the perovskite film. The surfactant SDBS was used as a wetting agent for SnO2 nanoparticles, to improve dispersibility. In addition, the benzene sulfonic acid group of SDBS attached to the SnO2-SDBS film can control the process of perovskite crystallization, producing a vertically aligned growth and large-grain perovskite layer. Finally, the open-circuit voltage was improved from 1.038 to 1.077 V and the PCE increased from 18.01% to 19.25% in the devices using the SnO2-SDBS ETL. The incorporation of SnO2-SDBS as an ETL paves the way to further performance enhancements of SnO2-based planar PSCs.

Flexible and self-powered photodetectors (PDs) have become one of the most popular topics, attracting researchers in the field of optoelectronic applications. In this study, for the first time, we demonstrate partial discharge detection in a practical environment with a prepared flexible device. Poly(vinylidene fluoride) (PVDF) is utilized as a highly transparent material in the UVC region, to create a flexible substrate with the antihumidity property. A detector that uses a mixed-halide perovskite (FAPbI3)1-x(MAPbBr3)x as the photoactive material is constructed in a vertical structure on the as-prepared hydrophobic PVDF substrate. The fabricated device exhibits good performance with a fast response speed (trise = 82 ms, tfall = 64 ms) and a high detectivity of 7.21 × 1010 Jones at zero bias under 254 nm UV illumination, along with superior mechanical flexibility at various bending angles. Additionally, the air-exposure stability and reproducibility of the as-prepared device exhibit almost the original performance after 6 weeks of storage. For practical applications, we demonstrate a facile and sensitive detection for UVC leakage from a germicidal lamp and simulated a partial discharge system using our PD without energy consumption. These results indicate that this new approach may be useful and convenient for the detection of the partial discharge as well as for several practical applications.

Deep-ultraviolet (UV) sensing has attracted significant interest because of its wide range of applications. A mixed-cation halide perovskite-based photodetector prepared by mixing CH3NH3PbX3 (X = I, Br, and Cl) and HC(NH2)PbX3 (X = I, Br, and Cl) exhibits high stability and excellent light absorption. In this study, perovskite was prepared by mixing CH3NH3+ (FA+) and HC(NH2)2+ (MA+) cations using I−, Br−, and Cl− halide anions. The bandgaps of the prepared perovskites increased to 1.48, 2.25, and 2.90 eV with I-, Br-, and Cl-, respectively, and the light absorption spectra shifted to shorter wavelengths. An increase in the redshift of the light absorption led to an increase in the photocurrent. The FAPbCl3-MAPbCl3-based photodetector showed a high responsivity of 5.64 mA/W, a detectivity of 4.03 × 1011, and an external quantum efficiency of 27.3%. The results suggested that the FAPbCl3-MAPbCl3 perovskite is suitable for deep-UV light sensing and is an excellent candidate for the fabrication of a sensitive photodetector.

Perovskite solar cells (PSCs) have attracted considerable attention as accessible solar cells due to its ease of fabrication, high energy-conversion efficiency, and low manufacturing costs. This st...

Organic material-based solar cell devices such as perovskite solar cells (PSCs) have attracted attention as renewable energy resources with low production cost, lightweight, wearable device applications, and large-area processability. To enhance device performance, many research groups have attempted to develop new materials and structures. Metal electrode materials play an important role in solar energy conversion in PSCs, owing to the ohmic contact and contact resistance between metal negative electrodes and photoactive layers. Until recently, conventional metal sources such as Ag, Au, or Cu have been used as electrodes. In this study, PSCs were employed in various metal negative electrodes using a thermal evaporator. The authors investigated the effect of metal negative electrodes on PSCs.

The perovskite solar cell is capable of energy conversion in a wide range of wavelengths, from 300 nm to 800 nm, which includes the entire visible region and portions of the ultraviolet and infrared regions. To increase light transmittance of perovskite solar cells and reduce manufacturing cost of perovskite solar cells, soda-lime glass and transparent conducting oxides, such as indium tin oxide and fluorine-doped tin oxide are mainly used as substrates and light-transmitting electrodes, respectively. However, it is evident from the transmittance of soda-lime glass and transparent conductive oxides measured via UV-Vis spectrometry that they absorb all light near and below 310 nm. In this study, a transparent Mn-doped ZnGa2O4 film was fabricated on the incident surface of perovskite solar cells to obtain additional light energy by down-converting 300 nm UV light to 510 nm visible light. We confirmed the improvement of power efficiency by applying a ZnGa2O4:Mn down-conversion layer to perovskite solar cells.

The effective use of a europium metal-organic framework (Eu-MOF) as a photoabsorber material has been reported. Using the advantages of Eu-MOFs including simple preparation, wide bandgap structure, and stability in the environment, a self-powered and high UVC-selectivity detector based on Eu-MOF nanoparticles was prepared with a simple device geometry. The as-fabricated photodetector was highly sensitive to 254 nm UV illumination without an external power supply. Accordingly, it exhibited a high UVC-to-UVA rejection ratio (

Over the past decades, ferroelectric photovoltaic (FE-PV) systems, which use a homogenous ferroelectric material as a light-absorbing layer, have been studied using ferroelectric oxides. The PV activity of materials can be enhanced by adjusting the bandgap of materials, and it would have a large effect on the ferroelectric complex oxides. This phenomenon in epitaxial thin films of ferroelectric complex oxide, Bi3.25La0.75Ti3O12 (BLT), Fe- and Co-doped films were observed. Compared with undoped BLT, Co-(BLCT) doping and Fe and Co combined (BLFCT) doping resulted in the gradual reduction in the bandgap and efficient visible light absorption. The reduction in the bandgap to 11.4% and 18.1% smaller than the experimentally measured Eg of the bismuth titanate-based film using a simple Fe- and Co-doping method was performed, while maintaining ferroelectricity by analyzing the BLCT and BLFCT films based on polarization loops, and the temperature range of the out-of-plane lattice parameters and the photocurrent density of the BLFCT film was 32.2 times higher than that of the BLT film, which was caused by the decrease in the bandgap. This simple doping technique can be used to tune additional wide-bandgap complex oxides so that they can be used in photovoltaic energy conversion or optoelectronic devices.

In this study, high-quality SrMnO3 (001) film was grown on a SrTiO3(001) substrate using a 4 N purity target by 90° off-axis RF magnetron sputtering. In this study, the influence of the plasma center and surrounding positions on the growth of the SrMnO3 film was investigated under different sputtering temperatures and working pressure conditions. The results revealed that the SrMnO3 film exhibited the best crystallinity at the sputtering center under a high working pressure (135 mTorr), high substrate temperature (750 °C), and Ar to O ratio of 1:1. After investigating the relationship between the growth rate and the working pressure through the Alpha step, the film was grown at a lower sputtering rate of 2 nm/min. X-ray diffraction confirmed that the SrMnO3 film was epitaxially grown on the SrTiO3 substrate with an orientation relationship of SrMnO3(001)//SrTiO3(001). The growth state of SrMnO3 on the crystal SrTiO3 substrate was investigated by scanning electron microscopy (SEM); the results revealed that the surface was smooth and compact. In addition, the atomic force microscopy results were consistent with the SEM result; the results revealed that the surface of the film was atomically flat, and the atomic level flatness was 0.906 nm. Furthermore, the contact angle measurement results revealed that the film and substrate surface energy were almost similar and exhibited similar adhesion and internal stress. In addition, energy-dispersive X-ray spectroscopy analysis revealed that the atomic composition ratio in the high-temperature sputtered SrMnO3 film was consistent with the stoichiometric ratio of SrMnO3. The scope and results of this study will lay a foundation on the further research of the performance of SrMnO3 film.

In recent years, the optical behavior of complex oxides are being increasingly used in light-harvesting applications. Perovskites are promising candidates for photovoltaic, photocatalytic, and optoelectric applications because of tunable band gaps and other unique properties such as fer-roelectricity To study the optical behavior of ferromagnetic-ferroelectric oxides, SrMnO3 (SMO3) targets intended for use in magnetron sputtering were prepared using SrCO3 (99.99%) and Mn2O3 (99.99%) powders by a two-step solid reaction method. Experiments were performed at various temperatures to determine the optimum calcination temperature of the SMO3 powder (1000 °C) and optimum sintering temperature of the prepared target (1300 °C), in an effort to optimize the preparation process of the target at the laboratory scale and reduce the cost of the target by more than 20-fold. Samples of the ground powder were calcined at 800, 1000, 1200, and 1300 °C for 10 h, and the resultant targets were pressed into 1 -in molds after grinding and subsequently sintered at the same temperatures at which the corresponding powders were calcined, i.e., at 800, 1000, 1200, and 1300 °Cfor 48 h. The microcrystalline state of the powders was observed by scanning electron microscopy. The prepared targets were analyzed by X-ray diffraction, and the results were compared with the powder diffraction file card of hexagonal SMO3 to determine the optimum calcination temperature and sintering temperature of the powder formulation. Finally, the Vickers hardness values of the targets were measured, and the optimum target preparation process was determined.

Perovskite solar cells have been attracting extensive attention because of their superior photovoltaic performances and lower costs as compared to those of prevailing photovoltaic technologies. There are four main interfaces in perovskite solar cells: flourine-doped tin oxide/electron transport layer, electron transport layer/perovskite layer, perovskite layer/hole transport layer, and hole transport layer/metal electrode. Among them, the interface between the perovskite layer (general formula RPbX3) and electron transport layer significantly affects the power conversion efficiency. In this study, a layer of TiO2, which is the most popular metal oxides used for perovskite solar cells applications, was deposited as the electron transport layer. To enhance the perovskite solar cells performance, surface treatment was performed with TiCl4 (80 mM). To investigate the effect of TiCl4 treatment, ultraviolet-visible spectroscopy was performed on the perovskite film. Atomic force microscopy, X-ray diffraction, scanning electron microscopy and performance of perovskite solar cells have been also evaluated in this paper. The results indicated that the TiCl4 treatment significantly improved the perovskite solar cells performance.

Organic/inorganic metal halide formamidinium lead iodide (FAPbI3) perovskites exhibit excellent optical properties, a suitable band gap, a wide light-absorption range, and superior electron-hole mobility. However, it is difficult to fabricate high-quality α-phase FAPbI3 film due to the relatively easy formation of the more stable δ-FAPbI3 (hexagonal structure). To overcome this, in this study, formamidinium lead bromide (FAPbBr3) was used to induce the synthesis of stable α-phase FAPbI3. The resulting light-absorbing layer was composed of (FAPbI3)0.95 (FAPbBr3)0.05, but δ-phase FAPbI3 could be still observed. To suppress the formation of δ-phase FAPbI3 , methylammonium chloride (MACl) was added to the (FAPbI3)0.95 (FAPbBr3)0.05 precursor solution. At an optimal MACl content of 40 mol%, perovskites with improved crystallinity and large crystallite size could be fabricated, resulting in a perovskite solar-cell efficiency of 18.204%.

Ferroelectric random-access memory (FeRAM) is non-volatile, facilitates data storage via ferroelectricity, and it has attracted research attention as potential data storage means in high-performance computing applications. However, retention and fatigue problems have hampered its commercialization. Recently, the atomically controllable HfO2 FeRAM with high-density-storage capability has been developed. Although HfO2 is compatible with silicon-based fabrication technologies, its experimental realization is yet to be investigated. Thus, in this study, we have synthesized ZrO2-doped HfO2 (also referred to as Hf0.5Zr0.5O2 or HZO) with enhanced operating characteristics via a solid-state reaction and optimized ball-milling process. The HZO ceramic targets are sintered at different temperatures between 1000 °C and 1600 °C, and the influence of the sintering temperature on the HZO target properties is investigated. As observed, the HZO target sintered at 1600 °C optimum for film growth.

Controlling phase transitions in correlated materials yields emergent functional properties, providing new aspects to future electronics and a fundamental understanding of condensed matter systems. With vanadium dioxide (VO

In this letter, we report on the simple process of preparing perovskite oxide SrMnO3 and the studying of the size effect on electrochemical properties for high-performance supercapacitor electrode. The high-crystalline micro-sized and nano-sized perovskite oxide SrMnO3 particles were successfully synthesized by a simple solid-state reaction, followed by a simple size reduction using high-energy ball milling. The electrochemical properties of the SrMnO3 had intriguing results on both sizes of particle, especially when comparing between before and after cycles. After a size reduction, the specific capacitance of the particles increased approximately twofold. Interestingly, the micro-sized SrMnO3 gained ∼500% its initial specific capacitance after 3000 successive cycles due to electrochemical nano-feature activation and oxygen-vacancy production, while the specific capacitance for the nano-sized SrMnO3 remained almost unchanged. Our work suggested a cost-effective and simple technique for high-performance perovskite-based supercapacitor electrodes by achieving the desired performance.

In this study, a self-powered lead-halide perovskite-based deep-ultraviolet (UV) photodetector was prepared using a solution process. A heterojunction of mixed (FAPbI3)0.97(MAPbBr3)0.03 perovskite was utilized as the photo-absorber layer, and spiro-OMeTAD was utilized as the hole injection layer in a vertical structure. The device exhibited an outstanding on/off photocurrent ratio of more than 103, a good responsivity of 52.68 mA W−1, and a high detectivity of 4.65 × 1011 Jones under 254 nm UV illumination without an external bias. Moreover, the detector demonstrated superior stability while retaining a quick response speed after three weeks of storage in ambient air without encapsulation. Thus, the present study has developed a promising photodetector for several applications in the deep-UV region.

As the BO6 octahedral structure in perovskite oxide is strongly linked with electronic behavior, it is actively studied for various fields such as metal–insulator transition, superconductivity, and...

The ferroelectric material chosen for a solar cell has to absorb as much of the solar spectrum as possible, therefore a low band gap is desirable, but it is rarely known for phase transition temperature on the bandgap engineered ferroelectric materials. The phase transition temperature of a ferroelectric material can be determined by monitoring its dielectric constant with increasing temperature, as the dielectric constant changes abruptly at the phase transition temperature. Here, we inform the measurement of the phase transition temperature of the ferroelectric complex oxide Bi3.25La0.75Ti3O12 as well as cobalt and iron doped Bi3.25La0.75Ti3O12 bulk ceramics for photovoltaic cells based on dielectric monitoring with changing temperature. We synthesized lanthanum-modified bismuth-titanate-based ceramics with various doping concentrations transition metal to Ti. X-ray diffraction analysis revealed that all the compounds crystallized in an orthorhombic structure. Their morphologies and size distributions were observed using scanning electron microscopy. From the ultraviolet-visible spectroscopy absorption spectra of the synthesized powder, bandgaps were checked. An inductance-capacitance-resistance meter was used to obtain the relationship between dielectric responses and the temperature of the targets in a tube furnace. We observed that the dielectric constant increases gradually with increasing temperature, until the transition temperature and subsequently decreases, and we were able to determine the phase transition temperatures of the tested materials. Furthermore, the results revealed that all the doped bismuth titanates keep their phase transition temperatures, which were sufficiently high, to maintain their ferroelectric properties above room temperature.

Perovskite solar cells (PSCs) represent the third generation of solar cells that comprise a semiconductor electrode, a counter electrode, and an electrolyte. Perovskite solar cells (PSCs) have been comprehensively researched and led to an impressive improvement in a short period of time as cheaper alternatives to silicon solar cells due to their high energy-conversion efficiency and low production cost. Tin oxide (SnO2) has attracted attention as a promising candidate for electron transport material of perovskite solar cells, because it can be easily processed by low annealing temperature and solution processing method. However, in the fabrication of SnO2 electron transfer layer (ETL) via the conventional solution method, it is greatly difficult to increase the size of the substrate by the solution treatment method or to commercialize it. In this work, we report the photovoltaic characteristics of SnO2 based electron transport layer for perovskite solar cells (PSCs) fabricated by the thermal-evaporation processing method. The deposited SnO2 layer with the thermal evaporator is known to be not crystallographically stable. To solve this problem, we performed the annealing process at relatively low temperature (below 200 °C). As a result, we could confirm the optimum annealing temperature and we could demonstrate PSCs with thermally deposited SnO2 as the compact electron transport layer through a low-temperature annealing process. It would contribute to new opportunities in commercialization and development of perovskite solar cells.

The ability to reverse or switch the polarization of a ferroelectric thin film through a mechanical force under an atomic force microscopy (AFM) tip offers the exciting possibility of a voltage-free control of ferroelectricity. One of the important metrics for characterizing such a switching process is the critical force Fc required to reverse a polarization. However, the experimentally measured values of Fc display a large uncertainty and vary significantly even for the same ferroelectric film. Here, using BaTiO3 thin films as a model system, we systematically evaluate Fc using a combination of AFM-based experiments and phase-field simulations. In particular, we study the influence of the AFM tip radius, misfit strain, and film thickness on Fc as well as the interplay between the flexoelectric and piezoelectric effects. This work provides a deeper understanding on the mechanism and control of mechanically induced ferroelectric switching and thus guidance for exploring potential ferroelectric-based nanodevices based on mechanical switching.

In the proposed method, we could complete the synthesis with only 3 h of thermal treatment, which is relatively fast in comparison to the previously reported procedure, without an expensive gascontrolled chamber system. The compound comprises Re2O3 and NiO3 powders that were mixed thoroughly in a stoichiometric ratio in a ball mill for 24 h and then dried in an oven at a 100 °C. The powder mixture was quickly calcined at various temperature for at least 3 h in an oxygen gas flow compared to conventional annealing method. After calcination at 1100 °C, the detected XRD peaks matched well with peaks of the standard ABO3 perovskite structure. Moreover, EDX and FT-IR spectral analysis results confirmed that the mixture had formed stoichiometry ReNiO3. All prepared samples comprised plate-like grains with a random orientation, and their average particle size was in the range of 1 to 3 μm calculated from FE-SEM images.

In this study, an in-situ piezoelectric effect is integrated into a photoactive region to develop a self-powered ultraviolet photodetector based on a p-n junction of ZnO@Polyvinylidene fluoride (PVDF) and poly [9,9-dioctylfluorene-co-N-[4-(3-methylpropyl)]-diphenylamine] (TFB). A ZnO@β-PVDF nanocomposite is fabricated using PVDF with the β-phase as the polymer matrix and ZnO nanoparticles as fillers. The strong piezoelectricity of β-PVDF can facilitate the separation and transport of photogenerated electrons in the depletion area and considerably reduce the dark current when the device is polarized with an external bias, resulting in an improvement in the on/off ratio and detectivity. Under 365-nm UV illumination, the as-fabricated device exhibits a high detectivity of 4.99 × 1011 Jones, an excellent on/off ratio (up to 2.75 × 104), and a fast response speed of 46/53 ms (rise/fall times). The device functions stably over approximately 1000 continuous on/off cycles and exhibits extremely long-lasting photostability when exposed to UV light. The findings demonstrate a promising strategy for enhancing the performance of photodetectors for industrial applications.

Understanding metal-to-insulator phase transitions in solids has been a keystone not only for discovering novel physical phenomena in condensed matter physics but also for achieving scientific breakthroughs in materials science. In this work, we demonstrate that the transport properties (i.e., resistivity and transition temperature) in the metal-to-insulator transitions of perovskite nickelates are tunable via the epitaxial heterojunctions of LaNiO3 and NdNiO3 thin films. A mismatch in the oxygen coordination environment and interfacial octahedral coupling at the oxide heterointerface allows us to realize an exotic phase that is unattainable in the parent compound. With oxygen vacancy formation for strain accommodation, the topmost LaNiO3 layer in LaNiO3/NdNiO3 bilayer thin films is structurally engineered and it electrically undergoes a metal-to-insulator transition that does not appear in metallic LaNiO3. Modification of the NdNiO3 template layer thickness provides an additional knob for tailoring the tilting angles of corner-connected NiO6 octahedra and the linked transport characteristics further. Our approaches can be harnessed to tune physical properties in complex oxides and to realize exotic physical phenomena through oxide thin-film heterostructuring.

In this study, Co-doped TiO2 was prepared successfully using a solvothermal method with trimesic acid (H3BTC) as an organic framework to form the Co-doped Ti metal–organic framework (Co-doped Ti-MOF). By thermally decomposing the Co-doped Ti-MOF in air, the framework template was removed, and porous Co-doped TiO2 was obtained. The crystal structure of the material was analyzed using X-ray diffraction. The morphology was examined using scanning electron microscopy (SEM) and focused ion beam SEM. The large specific surface area was determined to be 135.95 m2 g–1 using Brunauer–Emmett–Teller theory. Fourier transform infrared spectroscopy verified the presence of Ti–O–Ti and Co–O vibrations in the as-prepared sample. Furthermore, the results of UV–vis spectroscopy showed that doping with Co remarkably improved the absorption ability of Ti-MOF toward the visible-light region with a band gap energy of 2.38 eV (λ = 502 nm). Steady-state photoluminescence and electrochemical impedance spectroscopy were conducted to illustrate the improvement of electron transfer in the doped material further. The optimum power conversion efficiency of solar cells using 1 wt % Co-doped TiO2 as an electron transport layer was found to be 15.75%, while that of solar cells using commercial dyesol TiO2 is only 14.42%.

Recently, single-crystal silicon solar cells have achieved efficiencies of 25%. However, their production is energy-demanding and relatively expensive. Therefore, photovoltaic cells based on organic- inorganic hybrid perovskites have attracted considerable attention owing to their high conversion efficiencies, simple preparation, and potentially low production costs. In this study, we investigated the effect of Fe3+ doped into a compact and mesoporous layer of TiO₂ on the efficiency of the resultant perovskite solar cell (PSC). The efficiencies achieved for PSCs with Fe3+/TiO₂ were higher than those for cells with pure TiO₂ nanoparticles. The samples were characterized by X-ray diffraction, scanning electron microscopy, ultraviolet-visible spectroscopy, and current-voltage measurements. The photoelectrode PSC exhibited a high light-to-electric-energy conversion efficiency under a simulated solar light irradiation of 100 mW/cm² (AM 1.5). Our results suggest that Fe3+ nanoparticles in the TiO₂ layer may contribute to the performance improvement of the PSC.

Although there is considerable interest in BiFeO3 owing to its versatile physical properties, which make it suitable for a wide range of applications, its high leakage current is a significant limi...

In this work, to explore the influence of phosphor additives on the conversion efficiency of perovskite solar cells (PSC), we introduce a Y₃Al5O12:Ce3+ (YAG:Ce3+) phosphor layer. The YAG:Ce3+ nanophosphor acts as a light down-converting material to absorb high energy photons and emit lower energy photons that match well with the absorption of the perovskite layer, yielding more excited photo-generated electron-hole pairs. Therefore, the incident solar light can be harvested more effectively. We used 8 mg/ml of TiO₂ mixed with YAG:Ce3+ in the PSCs and realized a light-to-electric energy conversion efficiency of 13.34%, a short circuit current density of 21.23 mA/cm², an open circuit voltage of 0.97 V, and a FF of 55.96%. Higher efficiencies were achieved for PSCs with phosphor-mixed TiO₂ than for cells with pure TiO₂ nanoparticles. The samples were characterized by XRD, SEM, UV-vis, PL, and IV-curves. Photoelectrode DSSC with light-to-electric energy conversion efficiency was achieved under a simulated solar light irradiation of 100 mW/cm² (AM 1.5).

Piezoelectric nanogenerators (PNGs) have been studied as renewable energy sources. PNGs consisting of organic piezoelectric materials such as poly(vinylidene fluoride) (PVDF) containing oxide complex powder have attracted much attention for their stretchable and high-performance energy conversion. In this study, we prepared a PNG combined with PVDF and lanthanum-modified bismuth titanate (Bi4−XLaXTi3O12, BLT) ceramics as representative ferroelectric materials. The inserted BLT powder was treated by high-speed ball milling and its particle size reduced to the nanoscale. We also investigated the effect of particle size on the energy-harvesting performance of PNG without polling. As a result, nano-sized powder has a much larger surface area than micro-sized powder and is uniformly distributed inside the PNG. Moreover, nano-sized powder-mixed PNG generated higher power energy (> 4 times) than the PNG inserted micro-sized powder.

In recent years, the optical behavior of complex oxides are being increasingly used in light-harvesting applications. Perovskites are promising candidates for photovoltaic, photocatalytic, and optoelectric applications because of tunable band gaps and other unique properties such as fer-roelectricity To study the optical behavior of ferromagnetic-ferroelectric oxides, SrMnO₃ (SMO₃) targets intended for use in magnetron sputtering were prepared using SrCO₃ (99.99%) and Mn₂O₃ (99.99%) powders by a two-step solid reaction method. Experiments were performed at various temperatures to determine the optimum calcination temperature of the SMO₃ powder (1000 °C) and optimum sintering temperature of the prepared target (1300 °C), in an effort to optimize the preparation process of the target at the laboratory scale and reduce the cost of the target by more than 20-fold. Samples of the ground powder were calcined at 800, 1000, 1200, and 1300 °C for 10 h, and the resultant targets were pressed into 1 -in molds after grinding and subsequently sintered at the same temperatures at which the corresponding powders were calcined, i.e., at 800, 1000, 1200, and 1300 °Cfor 48 h. The microcrystalline state of the powders was observed by scanning electron microscopy. The prepared targets were analyzed by X-ray diffraction, and the results were compared with the powder diffraction file card of hexagonal SMO₃ to determine the optimum calcination temperature and sintering temperature of the powder formulation. Finally, the Vickers hardness values of the targets were measured, and the optimum target preparation process was determined.

Perovskite solar cells have been attracting extensive attention because of their superior photovoltaic performances and lower costs as compared to those of prevailing photovoltaic technologies. There are four main interfaces in perovskite solar cells: flourine-doped tin oxide/electron transport layer, electron transport layer/perovskite layer, perovskite layer/hole transport layer, and hole transport layer/metal electrode. Among them, the interface between the perovskite layer (general formula RPbX₃) and electron transport layer significantly affects the power conversion efficiency. In this study, a layer of TiO₂, which is the most popular metal oxides used for perovskite solar cells applications, was deposited as the electron transport layer. To enhance the perovskite solar cells performance, surface treatment was performed with TiCl₄ (80 mM). To investigate the effect of TiCl₄ treatment, ultraviolet-visible spectroscopy was performed on the perovskite film. Atomic force microscopy, X-ray diffraction, scanning electron microscopy and performance of perovskite solar cells have been also evaluated in this paper. The results indicated that the TiCl₄ treatment significantly improved the perovskite solar cells performance.

The electron transport layer (ETL) of organic–inorganic perovskite solar cells plays an important role in their power conversion efficiency (PCE). In this study, TiO2 hollow nanospheres with a diameter of 150 nm were prepared by a facile synthesis method. The synthesized TiO2 hollow nanospheres had a highly porous structure with a surface area of 85.23 m2g−1, which is significantly higher than commercial TiO2 (P25) (54.32 m2g−1), indicating that they can form an ideal mesoporous layer for Formamidinium iodide-based perovskite solar cells (PSCs). In addition, the nanospheres achieved a remarkable perovskite performance, and the average PCE increased from 12.87% to 14.27% with a short circuit current density of 22.36 mAcm−2, an open voltage of 0.95 V, and a fill factor of 0.65. The scanning electron microscopy images revealed that the enhanced PCE could be due to the improved carrier collection and transport properties of the nanosphere, which enabled efficient filtration of perovskite into the TiO2 mesoporous ETL. The TiO2 hollow nanospheres fabricated in this study show high potential as a high-quality ETL material for efficient (FAPbI3)0.97(MAPbBr3)0.03-based PSCs.

The electron transport layer (ETL) of organic–inorganic perovskite solar cells plays an important role in their power conversion efficiency (PCE). In this study, TiO2 hollow nanospheres with a diameter of 150 nm were prepared by a facile synthesis method. The synthesized TiO2 hollow nanospheres had a highly porous structure with a surface area of 85.23 m2 g−1, which is significantly higher than commercial TiO2 (P25) (54.32 m2 g−1), indicating that they can form an ideal mesoporous layer for Formamidinium iodide-based perovskite solar cells (PSCs). In addition, the nanospheres achieved a remarkable perovskite performance, and the average PCE increased from 12.87% to 14.27% with a short circuit current density of 22.36 mAcm−2, an open voltage of 0.95 V, and a fill factor of 0.65. The scanning electron microscopy images revealed that the enhanced PCE could be due to the improved carrier collection and transport properties of the nanosphere, which enabled efficient filtration of perovskite into the TiO2 mesoporous ETL. The TiO2 hollow nanospheres fabricated in this study show high potential as a high-quality ETL material for efficient (FAPbI3)0.97(MAPbBr3)0.03-based PSCs.