Protocol for the synthesis of perovskite nanocrystal thin films via in situ crystallization method
Ontology highlight
ABSTRACT:
SUBMITTER: Noguera-Gomez J
PROVIDER: S-EPMC10560831 | biostudies-literature | 2023 Oct
REPOSITORIES: biostudies-literature
Similar Datasets
Project description:Metal halide perovskite solar cells (PSCs) have raised considerable scientific interest due to their high cost-efficiency potential for photovoltaic solar energy conversion. As PSCs already are meeting the efficiency requirements for renewable power generation, more attention is given to further technological barriers as environmental stability and reliability. However, the most major obstacle limiting commercialization of PSCs is the lack of a reliable and scalable process for thin film production. Here, a generic crystallization strategy that allows the controlled growth of highly qualitative perovskite films via a one-step blade coating is reported. Through rational ink formulation in combination with a facile vacuum-assisted precrystallization strategy, it is possible to produce dense and uniform perovskite films with high crystallinity on large areas. The universal application of the method is demonstrated at the hand of three typical perovskite compositions with different band gaps. P-i-n perovskite solar cells show fill factors up to 80%, underpinning the statement of the importance of controlling crystallization dynamics. The methodology provides important progress toward the realization of cost-effective large-area perovskite solar cells for practical applications.
| S-EPMC6724353 | biostudies-literature
Project description:The properties of layered inorganic semiconductors can be manipulated by the insertion of foreign molecular species via a process known as intercalation. In the present study, we investigate the phenomenon of organic moiety (R-NH3I) intercalation in layered metal-halide (PbI2)-based inorganic semiconductors, leading to the formation of inorganic-organic (IO) perovskites [(R-NH3)2PbI4]. During this intercalation strong resonant exciton optical transitions are created, enabling study of the dynamics of this process. Simultaneous in situ photoluminescence (PL) and transmission measurements are used to track the structural and exciton evolution. On the basis of the experimental observations, a model is proposed which explains the process of IO perovskite formation during intercalation of the organic moiety through the inorganic semiconductor layers. The interplay between precursor film thickness and organic solution concentration/solvent highlights the role of van der Waals interactions between the layers, as well as the need for maintaining stoichiometry during intercalation. Nucleation and growth occurring during intercalation matches a Johnson-Mehl-Avrami-Kolmogorov model, with results fitting both ideal and nonideal cases.
| S-EPMC4092025 | biostudies-other
Project description:Understanding and controlling the crystallization of organic-inorganic perovskite materials is important for their function in optoelectronic applications. This control is particularly delicate in scalable single-step thermal annealing methods. In this work, the crystallization mechanisms of flash infrared-annealed perovskite films, grown on substrates with lithographically patterned Au nucleation seeds, are investigated. The patterning enables the in situ observation to study the crystallization kinetics and the precise control of the perovskite nucleation and domain growth, while retaining the characteristic polycrystalline micromorphology with larger crystallites at the boundaries of the crystal domains, as shown by electron backscattering diffraction. Time-resolved photoluminescence measurements reveal longer charge carrier lifetimes in regions with large crystallites on the domain boundaries, relative to the domain interior. By increasing the nucleation site density, the proportion of larger crystallites is increased. This study shows that the combination of rapid thermal annealing with nucleation control is a promising approach to improve perovskite crystallinity and thereby ultimately the performance of optoelectronic devices.
| S-EPMC8437338 | biostudies-literature
Project description:ZnO-based ultraviolet (UV) photodetector can be easily fabricated by using sol-gel spin-coating method, however, the crystallization of amorphous state ZnO thin films is necessary to fabricate high performance UV photodetector. Thus, we devised a thermal dissipation annealing (TDA) method in which the heat transfer to the ZnO thin films can be synchronized with the heat release from the substrate. It was found that sol-gel spin-coated ZnO thin films can be crystallized through the mobility difference of ZnO molecules placed at the surface of ZnO thin films. Also, UV photodetector based on ZnO thin films annealed with the TDA method exhibited faster rise and decay time constant (τr = 35 ms and τd = 73 ms, respectively), a higher on/off current ratio, and reproducible photocurrent characteristics compared to that of the ZnO thin films annealed by using furnace and IR lamp. Therefore, these results indicated that the TDA method is a feasible alternative route for the fabrication of ZnO based high performance optoelectronic devices.
| S-EPMC7801514 | biostudies-literature
Project description:Amphiphilic block copolymer (a-BCP) micelles offer morphological diversity and dimensional tunability, making them suitable for the fabrication of perovskite nanocrystals. However, precise control over the nucleation and growth of perovskite nanocrystals using a-BCP colloidal templates remains underexplored. This study investigates the effects of toluene, methanol, and polystyrene-block-poly(2-vinylpyridine) (PS-b-P2VP) on the formation of cesium lead bromide (CsPbBr3) nanocrystals. The process involves four stages: (i) PS-b-P2VP micellization, (ii) PbBr2 complexation, (iii) coordination interaction with P2VP, and (iv) burst nucleation of CsPbBr3 nanocrystals. Toluene, a good solvent for PS but a nonsolvent for P2VP, PbBr2, and CsBr, facilitates the formation of PS-b-P2VP spherical micelles. Adding PbBr2 to these micelles in toluene results in multiple emulsion, dispersing PbBr2 microstructures (microemulsion) and forming [PbBr3]- complexes encapsulated by the micelles (nanoemulsion). Prolonged stirring enhances this nanoemulsion. CsBr, insoluble in toluene, must be dissolved in methanol before being mixed with micelle-encapsulated complexes, promoting quick crystal nucleation. However, excess methanol weakens micellization, leading to the formation of fused micelles and irregular nanocrystals. At a high methanol content, [PbBr4]2- complexes also form, driving CsPbBr3 to CsPb2Br5 transformation via Ostwald ripening, resulting in large CsPb2Br5 microcrystals that precipitate due to gravitational forces overcoming Brownian motion, destabilizing their dispersion in the solution.
| S-EPMC11565575 | biostudies-literature
Project description:Understanding the crystallization process for chemical solution deposition (CSD) processed thin films is key in designing the fabrication strategy for obtaining high-quality devices. Here, an in situ sample environment is presented for studying the crystallization of CSD processed thin films under typical processing parameters using near-grazing-incidence synchrotron X-ray diffraction. Typically, the pyrolysis is performed in a rapid thermal processing (RTP) unit, where high heating rates, high temperatures and atmosphere control are the main control parameters. The presented in situ setup can reach heating rates of 20°C s-1 and sample surface temperatures of 1000°C, comparable with commercial RTP units. Three examples for lead-free ferroelectric thin films are presented to show the potential of the new experimental set-up: high temperature, for crystallization of highly textured Sr0.4Ba0.6Nb2O6 on a SrTiO3 (001) substrate, high heating rate, revealing polycrystalline BaTiO3, and atmosphere control with 25% CO2, for crystallization of BaTiO3. The signal is sufficient to study a single deposited layer (≥10 nm for the crystallized film) which then defines the interface between the substrate and thin film for the following layers. A protocol for processing the data is developed to account for a thermal shift of the entire setup, including the sample, to allow extraction of maximum information from the refinement, e.g. texture. The simplicity of the sample environment allows for the future development of even more advanced measurements during thin-film processing under non-ambient conditions.
| S-EPMC7467347 | biostudies-literature
Project description:Porous tin dioxide is an important low-cost semiconductor applied in electronics, gas sensors, and biosensors. Here, we present a versatile template-assisted synthesis of nanostructured tin dioxide thin films using cellulose nanocrystals (CNCs). We demonstrate that the structural features of CNC-templated tin dioxide films strongly depend on the precursor composition. The precursor properties were studied by using low-temperature nuclear magnetic resonance spectroscopy of tin tetrachloride in solution. We demonstrate that it is possible to optimize the precursor conditions to obtain homogeneous precursor mixtures and therefore highly porous thin films with pore dimensions in the range of 10-20 nm (ABET = 46-64 m2 g-1, measured on powder). Finally, by exploiting the high surface area of the material, we developed a resistive gas sensor based on CNC-templated tin dioxide. The sensor shows high sensitivity to carbon monoxide (CO) in ppm concentrations and low cross-sensitivity to humidity. Most importantly, the sensing kinetics are remarkably fast; both the response to the analyte gas and the signal decay after gas exposure occur within a few seconds, faster than in standard SnO2-based CO sensors. This is attributed to the high gas accessibility of the very thin porous film.
| S-EPMC7116275 | biostudies-literature
Project description:The synthesis method of transparent and flexible ZnO thin films is currently considered the most important factor for the fabrication of next generation wearable devices. To fabricate transparent and flexible devices by using sol-gel spin-coated ZnO thin films, an annealing step is necessary; however, annealing processes at high temperatures decompose polymer substrates due to their low melting temperature. It was found that sol-gel spin-coated ZnO thin films can be crystallized through the mobility difference of ZnO molecules placed at the surface of ZnO thin films. Especially, ZnO thin films can be annealed at high temperature (above 500 °C) by using a thermal dissipation annealing (TDA) method without the deformation of the polymer substrate. A transparent and flexible ultraviolet photodetector based on ZnO thin films annealed with the TDA method exhibited fast rise and decay time constants, a high on/off current ratio, and reproducible photocurrent characteristics. Thus, these results indicated that the TDA method is a feasible alternative route for the fabrication of next generation wearable devices.
| S-EPMC8693368 | biostudies-literature
Project description:The phenomenon of current-voltage hysteresis observed in perovskite-based optoelectronic devices is a critical issue that complicates the accurate assessment of device parameters, thereby impacting performance and applicability. Despite extensive research efforts aimed at deciphering the origins of hysteresis, its underlying causes remain a subject of considerable debate. By employing nanoscale investigations to elucidate the relationship between hysteresis and morphological characteristics, this study offers a detailed exploration of photocurrent-voltage hysteresis at the nanoscale within perovskite optoelectronic devices. Through the meticulous analysis of localized I-V curve arrays, our research identifies two principal hysteresis descriptors, uncovering a predominantly inverted hysteresis pattern in 87% of the locations examined. This pattern is primarily attributed to the energetic barrier encountered at the interface between the probe and the perovskite material. Our findings underscore the pronounced heterogeneity and grain-dependent variability inherent in hysteresis behavior, evidenced by an average Hysteresis Index value of 0.24. The investigation suggests that the localized hysteresis phenomena cannot be exclusively attributed to either photocharge collection processes or organic cation migration at grain boundaries. Instead, it appears significantly influenced by localized surface trap states, which play a pivotal role in modulating electron and hole current dynamics. By identifying the key factors contributing to hysteresis, such as localized surface trap states and their influence on electron and hole current dynamics, our findings pave the way for targeted strategies to mitigate these effects. This includes the development of novel materials and device architectures designed to minimize energy barriers and enhance charge carrier mobility, thereby improving device performance and longevity. This breakthrough in understanding the microscale mechanisms of hysteresis underscores the critical importance of surface/interface defect trap passivation in mitigating hysteretic effects, offering new pathways for enhancing the performance of perovskite solar cells.
| S-EPMC10948732 | biostudies-literature
Project description:Combinatorial synthesis via a continuous composition spread is an excellent route to develop thin-film libraries as it is both time- and cost-efficient. Creating libraries of functional, multicomponent, complex oxide films requires excellent control over the synthesis parameters combined with high-throughput analytical feedback. A reliable, high-throughput, in-situ characterization analysis method is required to meet the crucial need to rapidly screen materials libraries. Here, we report on the combination of two in-situ techniques-(a) Reflection high-energy electron diffraction (RHEED) for heteroepitaxial characterization and a newly developed compositional analysis technique, low-angle x-ray spectroscopy (LAXS), to map the chemical composition profile of combinatorial heteroepitaxial complex oxide films deposited using a continuous composition spread method via pulsed laser deposition. This is accomplished using a unique state-of-the-art combinatorial growth system with a fully synchronized four-axis mechanical substrate stage without shadow masks, alternating acquisition of chemical compositional data using LAXS at various different positions on the [Formula: see text] 41 mm [Formula: see text] 41 mm range and sequential deposition of multilayers of SrTiO[Formula: see text] and [Formula: see text] on a 2-inch (50.8 mm) [Formula: see text] wafer in a single growth run. Rutherford backscattering spectrometry (RBS) is used to calibrate and validate the compositions determined by LAXS. This study shows the feasibility of combinatorial synthesis of heteroepitaxial, functional complex oxide films at wafer-scale via two essential in-situ characterization tools-RHEED for structural analysis or heteroepitaxy and LAXS for compositional characterization. This is a powerful technique for development of new films with optimized heteroepitaxy and composition.
| S-EPMC8901668 | biostudies-literature