Journal Article crystallinity photostability 2D lead halide perovskites 2D perovskites CISS effect CsPbBr3 quantum dots LEDs LiNiO Rashba-like splittings Ruddlesden-Popper layered perovskites binding energies in exciton complexes chiral perovskites chiro-spintronics color tunability configuration interaction methods crystal orientation dangling octahedra edge states effective mass calculations electron-phonon interactions intermediate phases lead halide perovskites local symmetry optical excitation orientation perovskite solar cells polarons quantum correlations single quantum dot spectroscopy