Halogen perovskites represent a family of semiconductors with optical and transport properties that can be widely modified through element substitutions or crystal structure distortions. They are processable in solution and find application in solar cells, LEDs, lasers and detectors. Despite the high efficiency of 3D perovskites, 2D halide perovskites are more stable, durable, and chemically versatile. These materials, characterized by a two-dimensional crystal structure, are composed of thin layers of perovskite separated by organic cations and specifically the single crystal atomic configuration confers several advantageous properties and characteristics. Indeed, in 2D single crystals the absence of grain boundaries enhances electronic properties, such as charge transport.
Achieving the right crystal thickness is crucial for device performance too, preventing carrier loss, and ensuring effective light absorption to unlock the full potential of carrier transport. This can be attained by a successful space-confined method, which allows to control the thickness during perovskite preparation. The last one is crucial for 2D and quasi-2D perovskites, since it is essential for perovskites in solar cells to align their crystallography orientation with the carrier collection direction into the device, to permit the conduction. Indeed, 2D perovskites have to deal with their preferential orientation growth, which is typically parallel to the substrate with which they are in touch, insulating the carriers into the layers and causing transport carrier problems into the device. To avoid this problem, the task is to modify the orientation growth from parallel to vertical to the substrate.

In this contribution my work related to space-confined and orientation-growth techniques will be explained, in which the details of the processes and results obtained will be explored. Specifically, by confining the growth within specific spaces introducing modifications to confinement surfaces, it was possible to dictate the size and shape of the resulting single crystal. Moreover, to change the crystallography orientation, we worked with the addition of additives and using functionalized cations as spacers, in order to favor the vertical layer disposition. The samples obtained have been analyzed by different instruments, such as AFM, confocal microscope, XRD and others, investigating their thickness, morphology and orientation.