Colloidal FAPbBr₃ perovskite nanocrystals for light emission: what's going on?

Abstract

Semiconducting nanomaterials have been widely explored in diverse optoelectronic applications. Colloidal lead halide perovskite nanocrystals (NCs) have recently been an excellent addition to the field of nanomaterials, promising an enticing...

Transient Energy-Resolved Photoluminescence Study of Excitons and Free Carriers on FAPbBr3 and FAPbBr3/SnO2 Interfaces

“…However, the overlapping nature of absorbance and emission features and the relatively narrow PL global peak suggest otherwise. A more plausible explanation is that emissions relate to free carriers (higher energy PL peak) and bounded excitons (lower energy PL peak), as suggested recently for the methylammonium bromide perovskite (MAPbBr 3 ) . This establishes the exciton energy at about 60 meV (estimated from the exciton peak energy 2.343 eV minus the free-carrier emission energy ca.…”

“…A more plausible explanation is that emissions relate to free carriers (higher energy PL peak) and bounded excitons (lower energy PL peak), as suggested recently for the methylammonium bromide perovskite (MAPbBr 3 ). 31 This establishes the exciton energy at about 60 meV (estimated from the exciton peak energy 2.343 eV minus the free-carrier emission energy ca. 2.283 eV, 34 see Supporting Information Table S1), consistent with what was previously reported 35,36 and higher than its iodine perovskite counterpart.…”

“…Figure b shows the deconvolution considering two components that yielded an R 2 = 0.999. Since FAPbBr 3 is expected to be a pure orthorhombic phase, ,, one can exclude the possibility of the second peak being associated with the mixture of crystalline phases. This also supported the X-ray diffraction pattern presented in Figure S5, consistent with previously published diffractograms. , Another possibility for the doublet is that it relates to defect-related trap states .…”

Deciphering the Role of Water in Promoting the Optoelectronic Performance of Surface-Engineered Lead Halide Perovskite Nanocrystals

“…3D APbX 3 (where A is an organic or inorganic cation, and X is a halide) LHPs possess large absorption coefficients, long charge carrier diffusion lengths, and small exciton binding energies ( E b ), which are highly desirable for solar cell applications . In contrast, light-emitting diodes (LEDs) benefit from a high E b , which is not commonly observed in traditional 3D perovskites . Despite this limitation, significant progress in photoluminescence (PL) efficiency has been achieved, owing to the high defect tolerance, color purity, and a wide range of color tunability of 3D perovskites .…”

“…In contrast, light-emitting diodes (LEDs) benefit from a high E b , which is not commonly observed in traditional 3D perovskites . Despite this limitation, significant progress in photoluminescence (PL) efficiency has been achieved, owing to the high defect tolerance, color purity, and a wide range of color tunability of 3D perovskites . However, 3D LHP-based devices lack long-term stability, restricting their commercialization.…”