Organic–inorganic perovskite solar cells have attracted much attention as high performance and low-cost photovoltaic devices. Because it consists of p-type hole transport layer, perovskite layer, and ...n-type electron transport layer similar to a p–i–n structure, it works effectively even under low-illuminance conditions, such as indoor lighting. In this work, we focused on the characteristics of perovskite solar cells under low-illuminance conditions, and a detailed investigation was carried out. The open-circuit voltage yielded at around 70% of AM1.5 at 0.1 mW/cm2 illuminance, which is similar to that under indoor lighting. From impedance spectroscopy, it was suggested that the planar-type structure solar cell provided better resistance characteristics than that of the mesostructured cell for indoor applications. Comparing the characteristics of these types of solar cells, planar-type solar cells show higher voltage than mesostructured cells under low-illuminance conditions. These results have shown important implications for various applications of perovskite solar cells.
Perovskite solar cells (PSCs) have achieved certified power conversion efficiency (PCE) over 25%. Though their high PCE can be achieved by optimizing absorber layer and device interfaces, the ...intrinsic instability of perovskite materials is still a key issue to be resolved. Mixed‐halide perovskites using multiple halogen constituents have been proved to improve robustness; however, the anion at the X site in the ABX3 formula is not limited to halogens. Other negative monovalent ions with similar properties to halogens, such as pseudo‐halogens, have the opportunity to form perovskites with ABX3 stoichiometry. Recently, thiocyanates and formates have been utilized to synthesize stable perovskite materials. This review presents the evolution of pseudo‐halide perovskite solar cells in the past few years. The intrinsic properties, their effects on crystal structure, and bandgap engineering of the pseudo‐halide perovskites are summarized. Various thiocyanate compounds applied in the fabrication of perovskite solar cells are discussed. The fabrication process, film formation mechanism, and crystallinity of pseudo‐halide perovskites are elucidated to understand their effects on the photovoltaic performance and device stability. Other applications of pseudo‐halide perovskites are summarized in the final section. Lastly, this review concludes with suggestions and outlooks for further research directions.
Monovalent pseudo‐halide anions share similar properties to halide anions. This review presents the evolution of pseudo‐halide perovskite solar cells in the past few years. The role of pseudo‐halides and their position and occupation in perovskite crystal, its impact on perovskite film quality, solar cell stability and photovoltaic performance, and pseudo‐halide optoelectronic devices beyond solar cells are compared comprehensively.
•NiOx films' optoelectronic properties were significantly controlled by thickness and annealing.•As-prepared films changed preferential plane from 200 to 111 after annealing.•Microstrain and ...dislocation density increased in annealed films due to poor crystallinity.•As-prepared (20 nm) and annealed (60 nm) films showed the highest mobility of 10.12 and 4.47 cm2/V-s, respectively.
The fabrication of highly efficient nickel oxide (NiOx) thin film for optoelectronic devices is a challenging task because optoelectronic properties are considerably influenced by deposition technique and film thickness. The effect of thickness on the film properties of electron beam–physical vapour-deposited NiOx thin film has been investigated in this work. The influence of post-annealing treatment on the optoelectronic properties of the film was compared with that of the as-deposited one. Optical transparency gradually decreased upon the successive increment in thickness of the as-deposited and annealed films. The surface roughness of as-deposited films increased linearly with the increase in film thickness, but this behaviour was altered in post-annealed films. Spherical grains with high packing density were observed on the as-deposited films, but the grain size was altered substantially on the post-annealed films. The annealed films presented a higher work function than their corresponding as-deposited films. This work presents important insights into the design of photovoltaic devices with an effective deposition process, including a high material utilisation. Moreover, an attempt of fabricating inverted perovskite solar cell on as-deposited and annealing NiOx film as hole transporting material exhibited power conversion efficiency of 11.98% and 12.28%, individually. It was noticed that the high temperature annealing on NiOx film had a very little impact on the comparative photovoltaic performance of aforementioned PSC devices.
The rapid emergency of data science, information technology, and artificial intelligence (AI) relies on massive data processing with high computing efficiency and low power consumption. However, the ...current von‐Neumann architecture system requires high‐energy budget to process data computing and storage between central computing unit and memory. To overcome this problem, neuromorphic computing system which mimics the operation of human brain has been proposed to perform computing in an energy‐efficient manner. Recently, organic–inorganic halide perovskite compounds have been demonstrated as promising components for neuromorphic devices owing to their strong light absorption, solution processability, and unique properties such as ion migration, carrier trapping effects and phase transition. In this review paper, we report recent advances of neuromorphic devices which employed organic–inorganic halide perovskite compounds by analyzing their fundamental operating mechanisms, device architectures, applications and future prospective.
Neuromorphic devices have been attracted much attention as next generation computing system to process the large amount of data. This review paper reports on neuromorphic devices based on organic–inorganic halide perovskite compounds including fundamental operating mechanisms, device architectures, applications, and future prospective.
Fibrous nanomaterials have been widely employed toward the improvement of photovoltaic devices. Their light-trapping capabilities, owing to their unique structure, provide a direct pathway for ...carrier transport. This paper reports the improvement of perovskite solar cell (PSC) performance by a well-dispersed TiO2-coated gold nanowire (GNW) in a TiO2 cell layer. We used an artificially designed cage-shaped protein to synthesize a TiO2-coated GNW in aqueous solution under atmospheric pressure. The artificially cage-shaped protein with gold-binding peptides and titanium-compound-biomineralizing peptides can bind GNWs and selectively deposit a thin TiO2 layer on the gold surface. The TiO2-coated GNW incorporated in the photoelectrodes of PSCs increased the external quantum efficiency within the range of 350–750 nm and decreased the internal resistance by 12%. The efficient collection of photogenerated electrons by the nanowires boosted the power conversion efficiency by 33% compared to a typical mesoporous-TiO2-nanoparticle-only electrode.
Accurate estimation of annual output energy yield (Eout,annual$E_{\text{out,annual}}$) for perovskite/silicon (PSK/cSi) tandem solar cells is pivotal in assessing their suitability for ...building‐integrated photovoltaics (BIPV). This study pioneers five machine learning models of ensembles of trees, Gaussian process regressions, regression trees, support vector machines, and artificial neural networks (ANN) to predict output power density and compute Eout,annual$E_{\text{out,annual}}$ for 2T, 3T, and 4T PSK/cSi tandem configurations in Japan's outdoor conditions. Seven predictive inputs of visible‐light solar irradiance, near‐infrared‐light solar irradiance, incident solar spectrum angle, solar module temperature, perovskite thickness, perovskite bandgap, and terminal of tandem configuration (T) drive the machine learning models. These models optimize Eout,1‐month$E_{\text{out,1‐month}}$ predictions using k‐fold cross‐validation and Bayesian algorithms, showcasing superior precision in Eout,annual$E_{\text{out,annual}}$ prediction compared to prior models. The ANN model emerges as the best model, displaying the minimal error in predicting Eout,1 month$E_{\text{out,1} \textrm{ } \text{month}}$, used to estimate Eout,annual$E_{\text{out,annual}}$ across five Japanese locations (Gifu, Naganuma, Okinoerabu, Tosu, and Tsukuba). Results from these locations in blue‐rich solar spectrum zones identify the 4T PSK/cSi tandem configuration, featuring the most outstanding mean maximal Eout,annual$E_{\text{out,annual}}$ (93.63, 263.02, 153.59, and 91.75 kWh m−2 for the east, rooftop, south, and west directions), as the prime candidate for BIPV applications.
The article explores optimizing ensembles of trees, Gaussian process regressions, regression trees, support vector machines, and artificial neural networks using k‐fold cross‐validation. Significant improvements in output energy yield predictions are highlighted, particularly in 4‐terminal perovskite solar cell/crystalline‐silicon (4T PSK/cSi) configurations. The 4T PSK/cSi tandem setup excels in building‐integrated photovoltaics due to its superior performance under blue‐rich solar spectra.
Structure and crystal growth of nickel oxide thin films (10–300nm) prepared by low-temperature sputtering have been investigated by scanning electron microscopy (SEM), X-ray diffraction, and ...spectroscopic ellipsometry. Very thin films are compact and homogeneous and are made of almost randomly oriented crystals. A preferential growth direction is then observed following the (111), (220) and (311) planes to the detriment of the (222) and (200) planes, inducing a growth of the materials in columns perpendicularly to the substrate. An optical model able to account for this particular structure has been created from the spectroscopic ellipsometry measurements, and correlates well with the structure observed by SEM. Moreover, it enables an accurate estimation of the thickness without damage to the substrate.
•NiOx thin films (10–300nm) are deposited at low temperature.•Compact films (up to 20nm) can be used for thin film devices.•The growth follows preferential directions leading to columnar growth.•A simple model based on spectroscopic ellipsometry measurements is built.•This model represents well the particular structure of the films and the thickness.
Perovskite solar cells have attracted much attention as next-generation solar cells because of their high efficiency and low fabrication costs. Moreover, perovskite solar cells are a promising ...candidate for indoor energy harvesting. We investigated the effect of bandgap tuning on the characteristics of triple cation-based perovskite solar cells under fluorescent lamp illumination. According to the current density-voltage curves, perovskite solar cells with a wider bandgap than the conventional one exhibited improved open-circuit voltage without sacrificing short-circuit current density under fluorescent lamp illumination. Moreover, the wider bandgap perovskite films including a large amount of bromine in the composition did not show phase segregation, which can degrade the photovoltaic performance of perovskite solar cells, after fluorescent lamp illumination. Our results demonstrate the facile strategy to improve the performance of perovskite solar cells under ambient lighting and great potential of perovskite solar cells for indoor applications such as power sources for the internet of things.
Heavily Br-doped PSCs have a segregation-free effect in low-illuminance conditions, leading to the highest performances.
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