David Tiede1,Carlos Romero-Pérez1,Katherine Koch2,Maurico E. Calvo1,Juan F Galisteo-López1,Ajay Ram Srimath Kandada2,Hernán Miguez1
Institute of Materials Science of Seville1,Wake Forest University2
David Tiede1,Carlos Romero-Pérez1,Katherine Koch2,Maurico E. Calvo1,Juan F Galisteo-López1,Ajay Ram Srimath Kandada2,Hernán Miguez1
Institute of Materials Science of Seville1,Wake Forest University2
In the past years, halide perovskite-based devices are shifting towards low-dimensional functionalized structures and morphologies such as 2D, 2D/3D or perovskite nanocrystals (pNCs). For the latter, a common approach is to employ ligands, which ultimately determine the photophysical properties and in particular the interaction among individual NCs. As an alternative approach, mesoporous matrices can be employed to synthesize pNCs and have been established as a promising ligand free approach. [1,2] From a more fundamental perspective, this material system allows to study the interaction of excitations in pNCs with their neighbouring pNCs isolated from ligand or solvent induced effects characteristic of colloidal NCs. [3]<br/><br/>In this presentation, we employ FAPbBr<sub>3</sub> NCs of various sizes synthesized in porous matrices to determine the role of interparticle interaction on charge carrier recombination isolated from ligand and solvent induced effects. A broad photophysical characterization comprising time resolved absorption and emission spectroscopies as a function of temperature and fluence is employed to study the transition from isolated emitters to interconnected NCs array that preserves confinement effects while allowing for long range electronic transport. From a spectroscopic point of view, the effect of confinement is verified through thermalization dynamics. We demonstrate that interconnectivity determines charge carrier dynamics as it affects trap filling, radiative recombination and multiparticle interactions. We rationalize these findings by employing recombination and diffusion models for both the isolated and interconnected case and study the transition between these scenarios. Such transition regime is of great importance in terms of possible device performance, since the interplay of transport and (non) radiative recombination while maintaining confinement effects will determine its ultimate efficiency.<br/><br/><b>References</b><br/>[1] A. Rubino, L. Caliò, A. García-Bennett, M. Calvo, H. Míguez, Adv. Optical Mater.<br/>(2020), 8, 1901868<br/>[2] A. Rubino, L. Caliò, M. Calvo, H. Míguez, Solar RRL (2021), 5 (8), 2100204<br/>[3] A. Rubino et. al, J. Phys. Chem. Lett. (2021), 21, 1, 569-575