Growth of Hybrid Perovskite Crystals from CH3NH3PbI3–xClx Solutions Subjected to Constant Solvent Evaporation Rates

Abstract

In this work, we subjected hybrid lead-mixed halide perovskite (CH3NH3PbI3–xClx) precursor inks to different solvent evaporation rates in order to facilitate the nucleation and growth of perovskite crystals. By controlling the temperature of perovskite solutions placed within open-air rings in precise volumes, we established control over the rate of solvent evaporation and, thus, over both the growth rate and the shape of perovskite crystals. Direct utilization of diluted lead-mixed halide perovskites solutions allowed us to control the nucleation and to favor the growth of only a low number of perovskite crystals. Such crystals exhibited a clear sixfold symmetry. While crystals formed at a lower range of temperatures (40–60 °C) exhibited a more compact dendritic shape, the crystals grown at a higher temperature range (80–110 °C) displayed a fractal dendritic morphology.

Generation of Hybrid Lead Halide CH3NH3PbI3-xClx Perovskite Crystals via Convective Self-Assembly

“…We start this section with Figure 2 where we compare thin films of hybrid lead halide CH 3 NH 3 PbI 3-x Cl x perovskites fabricated by spin coating and CSA at both high and low deposition speeds and at two different processing temperatures (i.e., 17 • C and 30 • C; these temperature values were chosen because we had not studied our perovskite system in this temperature range until now; studies performed on the same perovskite system in the 40-110 • C interval were recently published elsewhere [54]). Note here that the spin coating procedure was actually carried out at room temperature, but using perovskite solutions that were priorly kept at 17 • C and 30 • C (Figure 2a,d).…”

“…Hybrid lead halide I101 perovskite precursor ink was purchased from Ossila Ltd. (Sheffield, UK), and it was specially formulated for casting in the low-humidity (20% to 35%) air. This ink is suitable to be used in the fabrication of perovskite-based devices such as solar cells or LEDs [54,71]. The I101 perovskite ink was composed of a mixture of precursor materials such as methylammonium iodide (MAI) and lead chloride (PbCl 2 ) dissolved in dimethylformamide (DMF) in a 3:1 ratio [72] and could be coated onto a solid or flexible substrate [73].…”

“…For example, according to available theoretical calculations [52], a power conversion efficiency of over 30% is attainable by perovskite solar cells. Of course, this implies a better understanding of the internal phenomena taking place in such devices, especially with respect to the crystallization of the employed perovskite materials [53,54].…”

“…These methods include many different scalable deposition techniques employed to transform specific perovskite solutions into thin films [60], such as spin coating [61], spray coating [62], inkjet printing [63] and blade coating [64]. Here, we also include a simple yet practical method able to produce hybrid lead halide perovskite crystals of controlled morphology from precursor ink solutions of small volumes that were placed into open-air Teflon rings and heated to a desired temperature in order to crystallize at controlled solvent evaporation rates [54].…”

Optoelectronic Evolution in Halogen-Doped Organic–Inorganic Halide Perovskites: A First-Principles Analysis

“…It was discovered that CH 3 NH 3 PbI 3 can generate and transport more electrons compared to the other two structures [13]. As research has progressed, doping halogen elements has been verified as an effective strategy for modifying the physical properties of materials [14][15][16][17][18][19][20][21][22][23][24][25]. In 2019, Pramchu et al applied density functional theory to investigate the impact of Cl and Br doping on the surface of CH 3 NH 3 PbI 3 perovskites and their influence on structural stability.…”