Quality Of Films Research Articles

Natural Chelating Agent-Treated Electron Transfer Layer for Friendly Environmental and Efficient Perovskite Solar Cells.

In perovskite solar cells (PSCs), the electron transfer layer (ETL) characteristics have significant effects on the photoelectric conversion efficiency (PCE) of the devices. Herein, a natural chelating agent polymer polyaspartic acid (PASP) is doped into the SnO2 precursor solution attributed to a strong interaction between PASP molecules and SnO2, which strengthens the interface contact and passivates the vacancy oxygen trap of the obtained SnO2 ETL, thus promoting the transfer of electrons. In addition, PASP can also regulate the growth of perovskite crystals, leading to an improved crystal quality of the perovskite films. Meanwhile, there is an excellent chelate anchoring of PASP to uncoordinated Pb2+, facilitating the reduction of trap defects at the interface, improving the stability of device, and suppressing the leakage of toxic Pb. Finally, the photovoltaic performance of the optimized device was greatly improved, and the PCE was increased from 21.22 to 23.49%, with outstanding environmental stability. This work provides an inexpensive and efficient treatment strategy that improves the performance and stability of friendly environmental PSCs.

Improving FAPbBr3 Perovskite Crystal Quality via Additive Engineering for High Voltage Solar Cell over 1.5 V.

Lead bromide-based perovskites are promising materials as the top cells of tandem solar cells and for application in various fields requiring high voltages owing to their wide band gaps and excellent environmental resistances. However, several factors, such as the formation of bulk and surface defects, impede the performances of corresponding devices, thereby limiting the efficiencies of these devices as single-junction devices. To reduce the number of defect sites, urea is added to the formamidinium lead bromide (FAPbBr3) perovskite material to increase its grain size. Nevertheless, urea undesirably reacts with lead(II) bromide (PbBr2) in the perovskite structure, creating unfavorable impurities in the device. To solve this problem, herein, in addition to urea, we introduced formamidinium chloride (FACl) into FAPbBr3. Owing to the synergistic effect of urea and FACl, the FAPbBr3 film quality effectively improved due to suppression of the generation of impurities and stabilization of film crystallinity. Consequently, the FAPbBr3 single-junction solar cell constructed using FACl and urea as additives demonstrated a power conversion efficiency of 9.6% and an open-circuit voltage of 1.516 V with negligible hysteresis. This study provides new insights into the use of additive engineering for overcoming the energy losses caused by defects in perovskite films.

Effects of pulse time offset between Cr and Zr dual cathodes in closed-magnetic-field unipolar high-power impulse magnetron sputtering

Two cathode (target) materials, Cr and Zr, were paired in a closed-field magnetron dual-cathode configuration and used in unipolar high-power impulse magnetron sputtering (HiPIMS). Two pulse widths (pulse-on durations) and various pulse-time offsets between the negative-voltage pulses of the Cr and Zr targets were investigated by setting the synchronization delay between the HiPIMS power supplies of the two targets at two different Ar pressures. Several trends were observed by analyzing the waveforms of the target discharge current, target discharge voltage, and substrate current. The closed-magnetic-field dual-cathode configuration significantly enhanced the HiPIMS discharge efficiency of the Zr target at all pressures; however, the enhancement for the Cr target was considerably lower. The ion fluxes toward the substrate were influenced by two competing mechanisms. The charged species generated from the previous pulse on one target could be attracted by the subsequent pulse of the adjacent target as a preionized medium to enhance the HiPIMS discharge. However, the fraction of the previously emitted ion flux toward the substrate could be reduced. When a shorter pulse width of 70 μs was applied, the ion flux that reached the substrate was mainly affected by the pulse power of the Zr target, and delaying the pulses of the Cr target with a relatively lower ion yield can achieve a higher ion flux toward the substrate. Increasing the pulse width significantly increased ion fluxes emitted from both the Cr and Zr targets, increasing the total ion flux toward the substrate. The study indicates that for the Cr and Zr dual cathode pair, a pulse time offset of one pulse width plus more than approximately 200 μs would be the most efficient way to obtain the highest ion fluxes toward the substrate and achieve a better film quality.

Natural Antioxidant Vitamin C Improves Photovoltaic Performance of Tin-Lead Mixed Perovskite Solar Cells.

The oxidation of Sn2+ can occur even after the completion of the perovskite crystallization in a low oxygen environment. Concerning this, the natural antioxidant vitamin C (VC) is introduced to the surface of Sn-Pb mixed perovskite using a postprocessing method to achieve the purpose of inhibiting Sn2+ oxidation and enhancing perovskite solar cells performance. The results indicate that the VC could effectively inhibit Sn2+ oxidation and heal the vacancy defects of the annealed perovskite film. Meanwhile, the introduction of VC significantly improves the morphology and crystalline quality of the perovskite films. After optimization, the highest power conversion efficiency of the VC-treated Sn-Pb mixed device increased to 20.44%. Moreover, the VC-treated unencapsulated device shows excellent long-term stability, retaining 75.3% of its initial efficiency after 800 h of aging in a N2 atmosphere, which is much higher than the 20.1% of the control device.

Homogenizing The Low-Dimensional Phases for Stable 2D-3D Tin Perovskite Solar Cells.

2D-3D tin-based perovskites are considered as promising candidates for achieving efficient lead-free perovskite solar cells (PSCs). However, the existence of multiple low-dimensional phases formed during the film preparation hinders the efficient transport of charge carriers. In addition, the non-homogeneous distribution of low-dimensional phases leads to lattice distortion and increases the defect density, which are undesirable for the stability of tin-based PSCs. Here, mixed spacer cations [diethylamine (DEA+) and phenethylamine (PEA+)] are introduced into tin perovskite films to modulate the distribution of the 2D phases. It is found that compared to the film with only PEA+, the combination of DEA+ and PEA+ favors the formation of homogeneous low-dimensional perovskite phases with three octahedral monolayers (n=3), especially near the bottom interface between perovskite and hole transport layer. The homogenization of 2D phases help improve the film quality with reduced lattice distortion and released strain. With these merits, the tin PSC shows significantly improved stability with 94% of its initial efficiency retained after storing in a nitrogen atmosphere for over 4600h, and over 80% efficiency maintained after continuous illumination for 400h.

The growth evolution of SnSe-doped SnTe alloy by in-situ selenization substitution method

In the era of increasing environmental pollution and energy crisis, the development of thermoelectric materials to achieve the reuse of waste heat energy is of great significance. SnTe, as an environmentally friendly thermoelectric material, its high electronic-thermal conductivity and coupled high electrical conductivity originated from intrinsic high carrier hole concentration leads to the unsatisfactory thermoelectric properties. With a lot of research going on to optimize thermoelectric performance by decoupling the thermo-electrical contradiction, the entropy engineering strategy, which can independently modulate lattice thermal conductivity is proved to be feasible by increasing the internal configurational entropy through doping. However, due to the uncontrollable growth microscopic process and the perturbation of film quality, the desired precise phase doping remains a challenge. In this work, we report an instantiation of the entropy increase of SnSe-doped SnTe alloy thin films prepared by two-step magnetron sputtering and selenization method. The microstructure and physical properties of thin films were investigated for replaying and controlling the growth evolution of in-situ selenization substitution. When the reaction temperature and duration were adjusted to 300℃ and 30 mins respectively, the desired pure phase doping was obtained. This work provides a new method of doping modification of SnTe materials, and the product as a new functional material expands the thermoelectric material library. In particular, it has positive reference significance for the development of synthesis controllability and structure establishment of complex polycrystalline materials.

Monoammonium Modified Dion-Jacobson Quasi-2D Perovskite for High Efficiency Pure-Blue Light Emitting Diodes.

Quasi-2D perovskites exhibit impressive optoelectronic properties and hold significant promise for future light-emitting devices. However, the efficiency of perovskite light-emitting diodes (PeLEDs) is seriously limited by defect-induced nonradiative recombination and imbalanced charge injection. Here, the defect states are passivated and charge injection balance is effectively improved by introducing the additive cyclohexanemethylammonium (CHMA) to bromide-based Dion-Jacobson (D-J) structure quasi-2D perovskite emission layer. CHMA participates in the crystallization of perovskite, leading to high quality film composed of compact and well-contacted grains with enhanced hole transportation and less defects. As a result, the corresponding PeLEDs exhibit stable pure blue emission at 466nm with a maximum external quantum efficiency (EQE) of 9.22%. According to current knowledge, this represents the highest EQE reported for pure-blue PeLEDs based on quasi-2D bromide perovskite thin films. These findings underscore the potential of quasi-2D perovskites for advanced light-emitting devices and pave the way for further advancements in PeLEDs.

Low‐Temperature TiO2 Electron Transporting Layer for Planar Hole Transport Material‐Free Carbon Electrode‐CsFA‐Based Perovskite Solar Cells

Carbon electrode‐based perovskite solar cells (C‐PSCs) without a hole transport material (HTM) are cost‐effective and exhibit impressive long‐term stability. The electron transporting layer (ETL) plays a crucial role in planar CsFA‐based HTM‐free C‐PSCs, serving as both an electron transporter and a hole barrier. Herein, the role of low‐TiO2 morphology and thickness on the performance of CsFA‐based HTM‐free C‐PSCs are addressed. Herein, the devices are fabricated with a simple structure fluorine‐doped tin oxide /TiO2 nanoparticles (TiO2 NPs)/Cs0.17FA0.83Pb(I0.83Br0.17)3/carbon, using low‐temperature processes (≤150 °C) under ambient air conditions. By optimizing TiO2 NP layer thickness via spin‐coating speed adjustments, the ETL's coverage and compactness are improved, enhancing the perovskite film's quality, crystallinity, and grain size. An optimal TiO2 ETL at 1500 rpm yields 10.80% efficiency and demonstrates exceptional stability, maintaining 80% efficiency over 120 days in an air environment without encapsulation. The enhancement in device performance is attributed to improved surface properties of the TiO2 NPs ETL, effectively reducing interfacial charge recombination. This straightforwardly supports the development of sustainable, commercial‐ready CsFA HTM‐free C‐PSCs.

Gas Molecule Assisted All-Inorganic Dual-Interface Passivation Strategy for High-Performance Perovskite Solar Cells.

The trap states at both the upper and bottom interfaces of perovskite layers significantly impact non-radiative carrier recombination. The widely used solvent-based passivation methods result in the disordered distribution of surface components, posing challenges for the commercial application of large-area perovskite solar cells (PSCs). To address this issue, a novel NH3 gas-assisted all-inorganic dual-interfaces passivation strategy is proposed. Through the gas treatment of the perovskite surface, NH3 molecules significantly enhanced the iodine vacancy formation energy (1.54eV) and bonded with uncoordinated Pb2+ to achieve non-destructive passivation. Meanwhile, the reduction of the film defect states is accompanied by a decrease in the work function, which promotes carrier transport between the interface. Further, a stable passivation layer is constructed to manage the bottom interfacial defects using inorganic potassium tripolyphosphate (PT), whose ─P═O group effectively mitigated the charged defects and lowered the carrier transport barriers and nucleation barriers of PVK, while the gradient distribution of K+ improved the crystalline quality of PVK film. Based on the dual-interface synergistic effect, the optimal MA-contained PSCs with an effective area of 0.1 cm2 achieved an efficiency of 24.51% and can maintain 90% of the initial value after aging (10-20% RH and 20°C) for 2000h.

Tin Gallium Oxide Epilayers on Different Substrates: Optical and Compositional Analysis

Electron beam techniques have been used to analyze the impact of substrate choice and growth parameters on the compositional and optical properties of tin gallium oxide [(SnxGa1−x)2O3] thin films grown by plasma‐assisted molecular beam epitaxy. Sn incorporation and film quality are found to be highly dependent on growth temperature and substrate material (silicon, sapphire, and bulk Ga2O3) with alloy concentrations varying up to an x value of 0.11. Room temperature cathodoluminescence spectra show the Sn alloying suppressing UV (3.3–3.0 eV), enhancing blue (2.8–2.4 eV), and generating green (2.4–2.0 eV) emission, indicative of the introduction of a high density of gallium vacancies (VGa) and subsequent VGa–Sn complexes. This behavior was further analyzed by mapping composition and luminescence across a cross section. Compared to Ga2O3, the spectral bands show a clear redshift due to bandgap reduction, confirmed by optical transmission measurements. The results show promise that the bandgap of gallium oxide can successfully be reduced through Sn alloying and used for bandgap engineering within UV optoelectronic devices.

Magnetic anisotropy and GGG substrate stray field in YIG films down to millikelvin temperatures

Quantum magnonics investigates the quantum-mechanical properties of magnons, such as quantum coherence or entanglement for solid-state quantum information technologies at the nanoscale. The most promising material for quantum magnonics is the ferrimagnetic yttrium iron garnet (YIG), which hosts magnons with the longest lifetimes. YIG films of the highest quality are grown on a paramagnetic gadolinium gallium garnet (GGG) substrate. The literature has reported that ferromagnetic resonance (FMR) frequencies of YIG/GGG decrease at temperatures below 50 K despite the increase in YIG magnetization. We investigated a 97 nm-thick YIG film grown on 500 μm-thick GGG substrate through a series of experiments conducted at temperatures as low as 30 mK, and using both analytical and numerical methods. Our findings suggest that the primary factor contributing to the FMR frequency shift is the stray magnetic field created by the partially magnetized GGG substrate. This stray field is antiparallel to the applied external field and is highly inhomogeneous, reaching up to 40 mT in the center of the sample. At temperatures below 500 mK, the GGG field exhibits a saturation that cannot be described by the standard Brillouin function for a paramagnet. Including the calculated GGG field in the analysis of the FMR frequency versus temperature dependence allowed the determination of the cubic and uniaxial anisotropies. We find that the total crystallographic anisotropy increases more than three times with the decrease in temperature down to 2 K. Our findings enable accurate predictions of the YIG/GGG magnetic systems behavior at low and ultralow millikelvin temperatures, crucial for developing quantum magnonic devices.

Influence of Post-Annealing Treatment on Some Physical Properties of Cerium Oxide Thin Films Prepared by the Sol–Gel Method

In this study, thin films of Cerium Oxide CeO2 were fabricated using the sol–gel technique and deposited onto a glass substrate. The annealing process was carried out at various temperatures ranging from 200 to 600 °C to investigate the structural, morphological, and optical properties of the films and their interrelations. X-ray diffraction (XRD) patterns revealed the crystalline nature of the prepared films, with film quality exhibiting enhancement with increasing annealing temperature. The average crystallite size, dislocation density, microstrain, and lattice constant were determined from XRD patterns. Higher annealing temperatures were found to increase the crystallite size values from 4.71 to 15.33 nm and decrease the dislocation density and microstrain of the unit cell. Scanning electron microscope (SEM) images illustrated the uniformity of the films, presenting a spheroid shape. Optical properties such as transmittance, absorbance, reflectance, the direct band gap, extinction coefficients, the refractive index, and optical conductivity were assessed using optical measurements. The direct optical band gap of the CeO2 film was observed to decrease from 3.99 to 3.75 eV with increasing film thickness. Using the Wemple and DiDomenico (WDD) single-oscillator model, dispersion energy parameters were calculated based on the refractive index. The nonlinear optical properties of the CeO2 thin films were evaluated using these dispersion energy parameters. The improvement of optical parameters holds significance in standardizing CeO2 thin films for various optoelectronic applications.

Innovative surface passivation of CZTSSe thin films: Ammonium sulfide treatment with plasma etching

For CZTS(e) solar cells, the passivation of interfacial defects is crucial for effectively reducing carrier recombination at the interface. This study examined the combined impact of plasma etching and surface sulfuration on the passivation of interface defects in CZTSSe thin films. The results indicated that plasma etching could improve the surface quality of the thin films and passivate surface defects. The (NH4)2S vapor had a significant sulfuration effect on the surface of the CZTSSe thin films post-etching. The surface defects of the CZTSSe film were passivated by the sulfur element entering the film by sulfuration. Moreover, the bandgap of the CZTSSe thin films was improved. The efficiency of the solar cell device increased by 1.72 % with a plasma etching duration of 5 min and (NH4)2S vaporization treatment of 15 min. This study proposes a novel approach that employs surface passivation techniques to enhance the efficiency of CZTSSe thin film solar cells.

Study of the effects of heating on the physical, optical, and electrical properties of NiO thin films synthesized using a low-cost sol-gel method

Developments in low-cost techniques for growing high-quality nickel oxide thin films (NiOTFs) are critical enablers for the fabrication of NiO-based devices, particularly solar cells, light-emitting diodes, lasers, and many other applications. In this study, it has been demonstrated that the optical, electrical, and structural characteristics of NiOTFs coated on glass substrate employing a low-cost solution method are strongly influenced by post-thermal annealing treatments in ambient air. A comprehensive study was carried out on the characteristics of the deposited NiOTFs. X-ray diffraction (XRD) measurements indicate the enhancement of the crystal quality of films after annealing. There is a noticeable change and improvement in coated NiOTFs with heat treatment at 300 and 600 ℃ due to clear shifts in density. During the heating temperature increment, the energy of the band gap was shifted from 3.63 to 3.44 eV, and the electrical resistance of the NiOTFs varied from 1020 to 700 Ω-cm. Furthermore, the results indicate that the low-cost sol-gel (SG) deposition technique has a greater potential for producing high-quality p-type NiOTFs with minimal defects for electronic device applications.

THE RELATIONSHIP BETWEEN RISKS OF OBSTRUCTIVE SLEEP APNEA AND DRY EYE DISEASE

Introduction: Dry Eye Disease (DED) may lead to decreased visual function, chronic tissue changes, eyelid, conjunctival, and corneal abnormality. The prevalence of DED in Asia ranges from 21.6%–37.6%. Several studies pointed out the relationship between DED and Obstructive Sleep Apnea (OSA). In patients with OSA, oxidative stress, hypoxia, and ocular surface inflammation increase, leading to a decrease in the functions of meibomian glands, goblet cells, corneal sensitivity, and tear production as a response to the stimulations from the lacrimal glands. The loss of conjunctival goblet cells and meibomian glands are implications of damage to the tear film quality, which results in DED. Method: This is a population-based cross-sectional study. Data were obtained from the database of Biomarker Smarthealth Research in Mendalanwangi, Sidorahayu, and Cepokomulyo Villages, which are located in Malang Regency, having risks of OSA (based on the STOP-BANG questionnaire), above ≥40 years old, and DED Examination with Tear Break-Up Time (TBUT), MGD (Meibominan Gland Dysfunction), Tear Meniscus (TM) involving a total of 518 respondents. The available data were then processed according to the variables and went through DED examinations. This study employed the purposive sampling method. Result: In this study, moderate risk of OSA suggests a significant influence on the occurrence of DED with an odds ratio (OR) 1.66 (p<0.05). In addition, moderate risk of OSA predisposes ADDE (Aqueous Deficiency Dry Eye)-type and Mix-type DED with OR 2.85 and 1.23 (p<0.05). High risk of OSA correlates with the occurrence of ADDE-type DED with OR 2.37 (p<0.05). The age group >60 years old shows a correlation with Mix-type DED with OR 2.09 (p<0.05). Women have a higher predisposition to ADDE-type with OR 2.58 (p<0.05). Conclusion: Moderate risk of OSA influences the occurrence of DED, both ADDE-type and Mix type; whereas high risk of OSA only correlates with ADDE-type. Older age plays a role in the occurrence of Mix-type DED and women have a higher tendency to present with ADDE- type.

Defect Passivation and Crystallization Regulation for Efficient and Stable Formamidinium Lead Iodide Solar Cells with Multifunctional Amidino Additive.

Amidino-based additives show great potential in high-performance perovskite solar cells (PSCs). However, the role of different functional groups in amidino-based additives have not been well elucidated. Herein, two multifunctional amidino additives 4-amidinobenzoic acid hydrochloride (ABAc) and 4-amidinobenzamide hydrochloride (ABAm) are employed to improve the film quality of formamidinium lead iodide (FAPbI3) perovskites. Compared with ABAc, the amide group imparts ABAm with larger dipole moment and thus stronger interactions with the perovskite components, i.e., the hydrogen bonds between N…H and I- anion and coordination bonds between C = O and Pb2+ cation. It strengthens the passivation effect of iodine vacancy defect and slows down the crystallization process of α-FAPbI3, resulting in the significantly reduced non-radiative recombination, long carrier lifetime of 1.7 µs, uniformly large crystalline grains, and enhances hydrophobicity. Profiting from the improved film quality, the ABAm-treated PSC achieves a high efficiency of 24.60%, and maintains 93% of the initial efficiency after storage in ambient environment for 1200 hours. This work provides new insights for rational design of multifunctional additives regarding of defect passivation and crystallization control toward highly efficient and stable PSCs.

In Situ Dynamic Spectroscopic Ellipsometry Characterization of Cu-Ligated Mercaptoalkanoic Acid "Molecular" Ruler Multilayers.

Hybrid strategies that combine conventional top-down lithography with bottom-up molecular assembly are of interest for a range of applications including nanolithography and sensors. Interest in these strategies stems from the ability to create complex architectures over large areas with molecular-scale control and precision. The molecular-ruler process typifies this approach where the sequential layer-by-layer assembly of mercaptoalkanoic acid molecules and metal ions are combined with conventional top-down lithography to create precise, registered nanogaps. However, the quality of the metal-ligated mercaptoalkanoic acid multilayer is a critical characteristic in generating reproducible and robust nanoscale structures via the molecular-ruler process. Therefore, we explore the assembly of alkanethiolate monolayers, mercaptohexadecanoic acid (MHDA) monolayers, and Cu-ligated MHDA multilayers on Au{111} substrates using atomic force microscopy and in situ dynamic spectroscopic ellipsometry. The chemical film thicknesses in situ dynamic spectroscopic ellipsometry agree with previous ex situ surface analytical methods. Moreover, in situ dynamic spectroscopic ellipsometry provides insight into the assembly process without interrupting the assembly process and potentially altering the characteristics of the resulting chemical film. By following the real-time dynamics of each deposition step, the assembly of the Cu-ligated MHDA multilayers can be optimized to minimize deposition time while having minimal impact to the quality of the chemical film.

Boosting Solar Water Splitting Performance of Cu3BiS3‐Based Photocathode via Ag Doping Strategy

AbstractA photovoltaic wittichenite semiconductor of Cu3BiS3, due to its optimal bandgap, high light absorption coefficient, and various advantages of low cost and environmental‐friendliness, has been considered a competitive candidate for solar absorber materials of photocathode for photoelectrochemical water splitting. However, the presence of various deleterious defects in the Cu3BiS3 lattice and its high conduction band minimum are detrimental factors that restrict further enhancements in the conversion efficiency of Cu3BiS3‐based photocathode. Herein, a one‐step solution‐based Ag element doping strategy is proposed to improve the crystalline quality of Cu3BiS3 films, which includes enlarging the grain size and reducing the intergranular gaps. Additionally, the Ag‐doped Cu3BiS3 layer can form a more favorable band alignment with the buffer layer. Ultimately, the fabricated composite Cu3BiS3‐based photocathode doped with 3% Ag delivers a remarkable photocurrent density of 13.6 mA cm−2 under 0 VRHE, an applied bias photon‐to‐current efficiency of 2.85%, and long‐term stability exceeding 12 h. Furthermore, with the assistance of a BiVO4 photoanode, the tandem cell also achieves an unbiased solar‐to‐hydrogen efficiency of 2.64%, with no significant decline observed within 20 h.

Enhancing the Efficiency and Stability of Inverted Formamidinium-Cesium Lead-Triiodide Perovskite Solar Cells through Lewis Base Pretreatment of Buried Interfaces.

Mixed components of formamidinium(FA) and cesium (Cs)-based perovskite solar cells are the most hopeful for commercialization owing to their excellent operational and phase stabilities, especially for devices with inverted structure. The nonradiative recombination of carriers can be effectively suppressed through interface optimization, therefore, the performance of devices can be improved. Notably, the buried interface emerges as critical aspects such as charge transport, charge recombination kinetics, and morphology of perovskite films. This study focuses on a straightforward yet effective approach to overcome buried interface challenges between organic polymers (poly(-triarylamine) (PTAA) and FACs-based perovskite films. The PTAA substrate is pretreated with a Lewis base known as 2-butynoic acid (BA) with a C═O functional group. First, it can be an interfacial buffering layer, harmonizing stress mismatch between the perovskite and PTAA layers, consequently optimizing crystallization and improving perovskite film quality. Second, Pb2+ defect can be passivated at the buried interface of the perovskite film through binding with the C═O group of the BA molecule. This dual-function strategy leads to a substantial enhancement in both photoelectric conversion efficiency (PCE) and stability of devices. Finally, the PCE of the device-modified buried interface with BA reaches an impressive 23.33%. Furthermore, unencapsulated devices with BA treatment maintain approximately 94% of their initial efficiency after aging at maximum power point tracking for 1000 h.

A Revisit of Crystallization in Tin Halide Perovskite Thin Films: From Nucleation, Intermediate to Crystal Growth

AbstractPerovskite solar cells (PSCs) are exuding unique charm in the third generation of thin film solar cell technology with high power conversion efficiency (PCE) and low production cost. Recently, the lead‐free tin halide perovskite solar cells (TPSCs) have drawn significant research interests due to the advantages of low toxicity, near‐ideal bandgap and high carrier mobility. However, the rapid crystallization and easy oxidation limits the film quality and final performance of the solar cells. Therefore, the deposition of high‐quality tin halide perovskite films is key to the advance of TPSCs. In this review, the classical theory of solution nucleation and crystal growth is reviewed and correlated to the practical deposition of tin perovskite film. The physicochemical properties of tin perovskite with those of lead counterpart and the differences in the crystallization process is carefully compared. On this basis, recent regulation strategies are systematically summarized in terms of the nucleation management, intermediate phase engineering and crystal growth regulation. In addition, the preparation of mixed tin‐lead (Sn‐Pb) PSCs toward high performance is also discussed, as well as the limiting factors for device performance and stability. Finally, the future challenges and prospects of the crystallization regulation are discussed toward more efficient and stable TPSCs.