Highly Anisotropic Organometal Halide Perovskite Nanowalls Grown by Glancing‐Angle Deposition

Polarizers are ubiquitous components in current optoelectronic devices as displays or photographic cameras. Yet, control over light polarization is an unsolved challenge, since the main drawback of the existing display technologies is the significant optical losses. In such a context, organometal halide perovskites (OMHP) can play a decisive role given their flexible synthesis with tunable optical properties such as bandgap and photoluminescence, and excellent light emission with a low non‐radiative recombination rate. Therefore, along with their outstanding electrical properties have elevated hybrid perovskites as the material of choice in photovoltaics and optoelectronics. Among the different OMHP nanostructures, nanowires and nanorods have lately arisen as key players in the control of light polarization for lighting or detector applications. Herein, the fabrication of highly aligned and anisotropic methylammonium lead iodide perovskite nanowalls by glancing‐angle deposition, which is compatible with most substrates, is presented. Their high alignment degree provides the samples with anisotropic optical properties such as light absorption and photoluminescence. Furthermore, their implementation in photovoltaic devices provides them with a polarization‐sensitive response. This facile vacuum‐based approach embodies a milestone in the development of last‐generation polarization‐sensitive perovskite‐based optoelectronic devices such as lighting appliances or self‐powered photodetectors. A novel vacuum‐based approach, compatible with most substrates, for the fabrication of aligned organometal halide perovskite vertical nanowalls by glancing‐angle deposition, is presented. Their alignment provides the samples with strong anisotropic properties, such as photoluminescence. Furthermore, their implementation in photovoltaic devices provides them with a polarization‐sensitive response, a milestone for the development of self‐powered photodetectors.