High-quality Perovskite Single Crystals Research Articles

Perovskite Single Crystals by Vacuum Evaporation Crystallization.

Perovskite single crystals have attracted tremendous attention owing to their excellent optoelectronic properties and stability compared to typical multicrystal structures. However, the growth of high-quality perovskite single crystals (PSCs) generally relies on temperature gradients or the introduction of additives to promote crystal growth. In this study, a vacuum evaporation crystallization technique is developed that allows PSCs to be grown under extremely stable conditions at constant temperature and without requiring additives to promote crystal growth. The new method enables the growth of PSCs of unprecedented quality, that is, MAPbBr3 single crystals that exhibit an ultranarrow full width at half maximum of 0.00701°, which surpasses that of all previously reported values. In addition, the MAPbBr3 single crystals deliver exceptional optoelectronic performance, including a long carrier lifetime of 1006ns, an ultralow trap-state density of 3.67 × 109 cm-3, and an ultrahigh carrier mobility of 185.86 cm2 V-1 s-1. This method is applicable to various types of PSCs, including organic-inorganic hybrids, fully inorganic structures, and low-dimensional structures.

Study on the growth and radiation detection performance of high-efficiency perovskite single crystal

The growth and radiation detection performance of high efficiency perovskite single crystal is studied. First, high-quality perovskite single crystals were successfully prepared by optimizing the growth conditions. Secondly, the structure, optical and electrical properties are characterized in detail, and the single crystal is found to be excellent. Moreover, the application of perovskite single crystal in radiation detection was also studied, and the results showed its high sensitivity, low detection limit and rapid response. This paper provides theoretical basis and experimental support for the application of perovskite single crystal in the field of practical radiation detection.

Ionic liquid-assisted growth of high-quality methylammonium lead bromide single crystals for photodetection applications

The addition of a 1-butyl-3-methylimidazolium bromide (BMIB) ionic liquid to the MAPbBr3 precursor solution shows a significant influence on the crystal optoelectronic properties and photodetection performance.

Interfacial diffused reaction at two-phase solution induced crystallization for high-quality perovskite single crystals

A novel and universal two-phase solution method is developed to grow high-quality halide perovskite single crystals in this work. It can be expected that this method will help to advance the application of perovskite optoelectronic devices.

Synergistic crystallization regulation and defect passivation for growth of high-quality perovskite single crystals towards ultrasensitive X-ray detection

This report demonstrates a method of synergistic defect passivation and crystallization regulation, which can significantly improve crystal quality and promote X-ray detector performance.

Interface-Tension-Assisted Temperature-Gradient Crystallization of High-Quality MAPbBr3 Perovskite Single Crystals with Low Defect Densities.

Comprehensive understanding and precise manipulation of the crystallization process for organic-inorganic hybrid perovskite materials are crucial for advancing perovskite single-crystal optoelectronic technology. In this study, we theoretically and experimentally investigated the influence of interface tension on the synthesis of perovskite single crystals. On the basis of the understanding of the nucleation and growth mechanisms, we developed a polydimethylsiloxane-assisted temperature-gradient growth technique to prepare high-quality MAPbBr3 single crystals. Using this technique, we harvested some high-quality MAPbBr3 single crystals, with the narrowest reported full width at half-maximum (0.00806°) of X-ray diffraction rocking curve, the longest carrier lifetime of 1002 ns, and an ultralow trap-state density of 4.25 × 109 cm-3. Furthermore, the X-ray detector fabricated using our MAPbBr3 single crystal exhibited a high sensitivity of 7275 μC Gy1- cm2 and a low minimum detection limit of 0.67 μGy s-1. This paper presents a novel method to control the crystallization and growth processes of high-quality perovskite single crystals.

Development of continuous solution growth method for growth of large and high-quality perovskite single crystals

Large perovskite single crystals with high quality cannot be obtained by traditional batch-type solution growth techniques, impeding their use in commercial applications. We report on developing a continuous solution growth (CSG) method that enables the growth of large, high-quality perovskite single crystals such as methylammonium lead tribromide (MAPbBr3), as well as triple-cation mixed hybrid. A 40 × 40 × 2 mm3 MAPbBr3 single crystal grown by this method, has a high mobility-lifetime (µτ) product of 3.3 × 10−3 cm2·V−1 and a low trap density of 8.22 ± 0.02 × 108 cm−3. Photoconductors (Au-MAPbBr3-Au) with a low dark current density of 3.9nA·cm−2 at 0.83 V·mm−1 exhibit excellent photons detection of both UV–visible and X-ray photons. For UV–visible photons, the responsivity is about 1.5 A·W−1 and 1.3 A·W−1 to 405 nm and 532 nm photons, respectively; for X-ray sensitivity is up to 2.35 × 105 µC Gyair−1 cm−2 and the lowest detection limit is 15.7 nGyair·s−1. High-contrast X-ray images were obtained with a large (40 mm × 40 mm) pixelated detector with 800 µm × 800 µm pixels. These results demonstrate that the CSG technique can produce high-quality, large perovskite single crystals for commercial applications, including photodetection and ionization radiation detection.

Photo-induced defects in MAPbBr3 single crystals

Single crystals of hybrid organic–inorganic halide perovskite have exhibited significantly good stability and a low trap density, leading to advantageous applications in optoelectronics. Even with recent development of high-quality perovskite single crystals, a defect analysis should be addressed to improve device performance in addition to understand the interaction between photo-generated carriers and defects. In this paper, we present a photo-induced defect characterization of CH3NH3PbBr3 (MAPbBr3) perovskite single crystals using an interpretation of photo-current and photo-capacitance measurement. The bulk and the interfacial defect densities of MAPbBr3 crystals with a gold electrode are examined by the characterization of photo-capacitive response under three different wavelengths of light. The transient photo-response of the single crystals reveals the occurrence of carrier trapping and a recombination process. The photo-response under the various light conditions provides a possible origin of defects in MAPbBr3 single crystals. Our comprehensive optoelectronic analysis provides the establishment of the link between the carrier transport and device performance depending on the illuminations. The fundamental understanding of photo-induced defects in perovskites can be helpful to realize the origin of electrical loss and develop highly efficient optoelectronic devices.

Inch-sized high-quality perovskite single crystals by suppressing phase segregation for light-powered integrated circuits.

The triple-cation mixed-halide perovskite (FA x MA y Cs1-x-y )Pb(IzBr1-z )3 (FAMACs) is the best composition for thin-film solar cells. Unfortunately, there is no effective method to prepare large single crystals (SCs) for more advanced applications. Here, we report an effective additive strategy to grow 2-inch-sized high-quality FAMACs SCs. It is found that the judiciously selected reductant [formic acid (FAH)] effectively minimizes iodide oxidation and cation deprotonation responsible for phase segregation. Consequently, the FAMACs SC shows more than fivefold enhancement in carrier lifetimes, high charge mobility, long carrier diffusion distance, as well as superior uniformity and long-term stability, making it possible for us to design high-performance self-powered integrated circuit photodetector. The device exhibits large responsivity, high photoconductive gain, excellent detectivity, and fast response speed; all values are among the highest reported to date for planar-type single-crystalline perovskite photodetectors. Furthermore, an integrated imaging system is fabricated on the basis of 12 × 12 pixelated matrixes of the single-crystal photodetectors.

Electronic-Grade High-Quality Perovskite Single Crystals by a Steady Self-Supply Solution Growth for High-Performance X-ray Detectors.

High-quality perovskite single crystals with large size are highly desirable for the fundamental research and high energy detection application. Here, a simple and convenient solution method, featuring continuous-mass transport process (CMTP) by a steady self-supply way, is shown to keep the growth of semiconductor single crystals continuously stable at a constant growth rate until an expected crystal size is achieved. A significantly reduced full width at half-maximum (36 arcsec) of the (400) plane from the X-ray rocking curve indicates a low angular dislocation of 6.8 × 106 cm-2 and hence a higher crystalline quality for the CH3 NH3 PbI3 (MAPbI3 ) single crystals grown by CMTP as compared to the conventional inverse temperature crystallization (ITC) method. Furthermore, the CMTP-based single crystals have lower trap density, reduced by nearly 200% to 4.5 × 109 cm-3 , higher mobility increased by 187% to 150.2 cm2 V-1 s-1 , and higher mobility-lifetime product increased by around 450% to 1.6 × 10-3 cm2 V-1 , as compared with the ITC-grown reference sample. The high performance of the CMTP-based MAPbI3 X-ray detector is comparable to that of a traditional high-quality CdZnTe device, indicating the CMTP method as being a cost-efficient strategy for high-quality electronic-grade semiconductor single crystals.

Growth of metal halide perovskite materials

Perovskite materials, especially metal halide perovskites, exhibit excellent properties, such as large optical coefficients, high carrier mobilities, long carrier lifetimes, tunable resistivities, large X-ray attenuation coefficients, and simple processing techniques. In recent decades, perovskites have attracted significant attention in the photoelectric field due to their versatile utility in solar cells, light-emitting diodes, photodetectors, X/γ-ray detectors, and lasing. However, the wide applicability of perovskites highly depends on the quality of perovskite crystals and films. Thus far, several perovskite growth technologies and methods have emerged. Therefore, this review classified and summarized the main methods that have been employed to achieve perovskite growth in recent years, including the solution temperature-lowering (STL) method, inverse temperature crystallization (ITC), anti-solvent vapor-assisted crystallization (AVC), spin coating, and chemical vapor deposition (CVD). Through analysis and summary, it has been determined that the STL, ITC, and AVC methods are mainly used to grow high-quality perovskite single crystals. While the spin-coating method has a significant advantage in the preparation of perovskite films, the CVD method is propitious in the fabrication of a variety of morphologies of micro/nano perovskite materials. We hope that this review can be a comprehensive reference for scientific researchers to prepare perovskite-related materials.

Room-temperature liquid diffused separation induced crystallization for high-quality perovskite single crystals

Large single crystals serve as an ideal platform for investigating intrinsic material properties and optoelectronic applications. Here we develop a method, namely, room-temperature liquid diffused separation induced crystallization that uses silicone oil to separate the solvent from the perovskite precursors, to grow high-quality perovskite single crystals. The growth kinetics of perovskite single crystals using this method is elucidated, and their structural and optoelectronic properties are carefully characterized. The resultant perovskite single crystals, taking CH3NH3PbBr3 as an example, exhibit approximately 1 µs lifetime, a low trap density of 4.4 × 109 cm−3, and high yield of 92%, which are appealing for visible light or X-ray detection. We hope our findings will be of great significance for the continued advancement of high-quality perovskite single crystals, through a better understanding of growth mechanisms and their deployment in various optoelectronics. The diffused separation induced crystallization strategy presents a major step forward for advancing the field on perovskite single crystals.

High-Performance Planar-Type Ultraviolet Photodetector Based on High-Quality CH3NH3PbCl3 Perovskite Single Crystals.

A hybrid perovskite MAPbCl3 (MA = CH3NH3+) single crystal is considered to be one of the most viable candidates for the development of photodetectors because of its outstanding optoelectronic properties. However, the relatively lower crystalline quality of the reported MAPbCl3 single crystals fabricated by the traditional one-step inverse temperature crystallization results in momentous degradation in the performance of their photodetectors. Here, we present a novel two-step temperature process to fabricate high-quality MAPbCl3 single crystals, namely, lower temperature nucleation and higher temperature crystallization. These MAPbCl3 single crystals present low defect density (∼7.9 × 109 cm-3) commensurate with the best-quality crystals of hybrid organic-inorganic lead halide perovskites reported so far. Moreover, a high-performance ultraviolet photodetector was demonstrated on MAPbCl3 single crystals. At 30 V, the peak responsivity at 415 nm of the photodetector is as high as 3.73 A W-1 (light intensity = 1 mW cm-2), ∼2-3 orders of magnitude higher than that of the previously reported MAPbCl3 photodetectors. Meanwhile, the device has an ultrafast response speed with a rise time of 130 ns, which is one of the shortest values of MAPbX3-based photodetectors. Our findings open a new way to obtain high-quality perovskite single crystals and their high-performance photodetectors.

Low-temperature-gradient crystallization for multi-inch high-quality perovskite single crystals for record performance photodetectors

With their excellent optoelectronic properties, the practical application of single-crystalline organolead halide perovskite materials is now limited by the lack of a method to prepare high-quality perovskite single crystals in large dimension. Herein, we report our development of a low-temperature-gradient crystallization (LTGC) method for high-quality CH 3 NH 3 PbBr 3 (MAPbBr 3 ) perovskite single crystals with lateral dimension as large as two inches. The theoretical analysis suggests that a small temperature gradient should be used to restrain the growth condition, particularly the solution concentration, within the optimal single-crystal-growth (OSCG) zone. The solubility curve as a function of temperature reveals a sharp turning point at ∼60 °C, across which the first-order solubility derivative (dC/dT) shows very different behaviors: below this temperature, the dC/dT changes dramatically as the temperature increases, while above this temperature, the dC/dT enters a plateau where further temperature change has little effect on the derivative, meaning that one can attain both a substantial crystal growth rate and crystallization yield below this temperature. Utilizing this discovery, a MAPbBr 3 single crystal as large as 47 × 41 × 14 mm is obtained with high quality via the LTGC method. The single crystal exhibits the best optoelectronic quality among all MAPbBr 3 materials reported in the literature, including the best trap state density, mobility, carrier lifetime, and diffusion length. These superior optoelectronic properties are further transferred into a high-performance planar photodetector. The device exhibits high operational stability, high external quantum efficiency (13,453%), excellent detectivity as high as 8 × 10 13 Jones, and a fast response speed as quick as 15.8 μs. To our knowledge, both the detectivity and the response speed are the best among all MAPbBr 3 devices reported to date. The unique synthesis method and excellent crystalline quality of the perovskite single crystals make them promising candidates for the next generation of optoelectronic devices.