Quantum-Cutting Ytterbium-Doped CsPb(Cl_1–xBr_x)₃ Perovskite Thin Films with Photoluminescence Quantum Yields over 190%

Abstract

A two-step solution-deposition method for preparing ytterbium-doped (Yb3+) CsPb­(Cl1–x Br x )3 perovskite thin films is described. Yb3+-doped CsPb­(Cl1–x Br x )3 films are made that exhibit intense near-infrared photoluminescence with extremely high quantum yields reaching over 190%, stemming from efficient quantum cutting that generates two emitted near-infrared photons for each absorbed visible photon. The near-infrared Yb3+ f–f photoluminescence is largely independent of the anion content (x) in CsPb­(Cl1–x Br x )3 films with energy gaps above the quantum-cutting threshold of twice the Yb3+ f–f transition energy, but it decreases abruptly when the perovskite energy gap becomes too small to generate two Yb3+ excitations. Excitation power dependence measurements show facile saturation of the Yb3+ luminescence intensity, identifying a major challenge for future solar applications of these materials.

Size control over metal–organic framework porous nanocrystals

“…37,41,60 Nano-MOF particle sizes can be further reduced by adding Brønsted bases to enhance linker deprotonation (eqn (1)). 60 Irreversible ligand deprotonation may lead, however, to unchecked particle growth through rapid metal-ligand complexation, unless counterbalanced by excess surfacecapping ligands-illustrating the intricate kinetic balance of the four key underlying processes outlined in eqn (1)- (4).…”

“…Nanocrystals are distinguished from their bulk counterparts by the extreme size-dependence of their functional properties. For example, catalytic activities of metal nanoparticles, 1 nanocrystal plasmon resonance energies, 2,3 and quantum dot absorption and emission proles in photovoltaic, solar fuel, and luminescence technologies [4][5][6] reect underlying electronic structures sensitive to sub-nanometre size variations. Tailoring nanocrystals to a given application therefore relies on generating particles with precise diameter values and uniform size distributions.…”

Recent Progress in Metal Halide Perovskite Micro‐ and Nanolasers

“…Additionally, the exact underlying mechanisms for low PLQYs in these NCs has not been fully discovered, which significantly limit the rational design of perfect NCs and thus hamper their applications for violet‐emitting devices. Recently, doping impurities into perovskite host are considered as an efficient way to improve their PLQY and stabilities . Most excitingly, by doping with Ni ions or passivating with trivalent metal ions, the defects in CsPbCl 3 can be well eliminated .…”

Engineering 3D perovskites for photon interconversion applications

“…Organic-and inorganic-based lead halide perovskites have exhibited unprecedented success in optoelectronics [30][31][32][33] such as PVs, light emitting diodes (LEDs), and more recently in photon interconversion applications [19,23,[34][35][36][37]. Their successful application in optoelectronics is in large parts based on their rich photophysical properties such as long carrier lifetimes, high absorption cross sections, and compositional tunability of the bandgap.…”