Abstract
Cesium lead halide has been extensively studied as efficient materials for optoelectronic device applications. Beyond Cs(Ⅰ), the exploration of other inorganic A-site monovalent cations remains limited, though Rb(Ⅰ) stands out as a potential alternative whose role in colloidal nanocrystals is largely unexplored. Here, Rb (Ⅰ) is employed as an effective A-site cation in forming monoclinic-phase RbPb_2Cl_5, where Pb (Ⅱ) heptahedrally coordinated. A template-mediated cation exchange strategy is employed where 0D Rb_4CdCl_6 used as host nanocrystals. Upon introduction of Pb (Ⅱ), fast Cd to Pb ion exchange triggers and 2D RbPb_2Cl_5 in rhombic prism, hexagonal prism or hexagonal platelet-shaped nanocrystals are formed depending on the reaction conditions. Further to explore the optoelectronic properties, photo response measurements are carried out which exhibit significant pyro-photocurrent response from these nanocrystals even under ultra-low-intensity light illumination (7 nW cm~(-2)) across ultraviolet (UV) to near-infrared (NIR) spectral range. Despite its centrosymmetric structure, RbPb_2Cl_5 generates pyro-photocurrent due to surface halide deficiencies, supported by DFT which shows surface polarization of |△P| = 0.173 C ~(-2). These findings highlight the pivotal role of Rb (Ⅰ) in stabilizing these nanostructures and open a new avenue for their application in advanced optoelectronic devices.
NETL
NSTL
Wiley