Stoichiometry Control in Dual-Band Emitting Yb³⁺-Doped CsPbCl_xBr_3–x Perovskite Nanocrystals

Abstract

Perovskite nanocrystals (NCs) are currently one of the most efficient optical materials in the visible spectral range. Much attention is paid to extending their efficiency to the near-infrared (NIR) spectral region, which will significantly benefit their applications in optoelectronics, photonics, and biomedicine. To further promote this effort, we developed a novel synthetic approach to dual-band emitting Yb3+-doped perovskite NCs, whose stoichiometry and hence the position of the visible photoluminescence can be tuned independently of the Yb3+-precursor. The intensity of the NIR emission from Yb3+ ions shows a notable nonlinear dependence on the excitation power. To describe the corresponding redistribution of the photoluminescence intensities between the emissive channels, we developed a theoretical description of the relaxation dynamics in the doped NCs, including both the energy transfer and quantum cutting processes. Finally, we showed that the dual-band photoluminescence in the doped NCs can be excited via two-photon absorption. Our findings thus pave the way for new nanomaterials that can be operated entirely in the NIR spectral range.

Anion-assisted Yb3+and Mn2+doping of 0D and 2D lead halide perovskite nanostructures

“…Typically, dopant-related emission in Yb 3+ :CsPbCl 3 NCs has a decay time at a millisecond timescale. 19,24,45 To deeply investigate this unusual behavior, we treated pristine CsPbCl 3 NCs with YbCl 3 and compare their optical properties with Yb 3+ :CsPbCl 3 NCs obtained by the direct colloidal synthesis. The optical and morphological Importantly, the absorption onset of the Yb 3+ -doped NCs is blue-shifted compared to pristine CsPbCl 3 NCs, which is attributed to the lattice contraction induced by the insertion of smaller-sized cations.…”

“…[20][21][22] Recently, several synthetic strategies have been developed to produce Yb 3+ -doped LHP NCs. 19,20,23,24 All of them require a high temperature (up to 240-260 1C 19,23,[25][26][27][28][29] ) of a chemical reaction that limits the morphology control. But for rare cases, 30 the controlling the morphology of Yb 3+ -doped LHP nanocrystals is impossible to obtain 1D or 2D nanostructures.…”

B‐Site Doping of Metal Halide Perovskite Nanoplatelets Influences Their Optical Properties

“…[97][98][99] Yb 3+ -doped perovskite nanocrystals have been also proposed as a unique perovskite system that may operate fully in the NIR spectral region using two-photon excitation of perovskite matrix followed by energy transfer to Yb 3+ dopants. [100] Moreover, Yb 3+ may be used to stabilize 𝛼-phase of CsPbI 3 nanocrystals. Shi et al performed Yb 3+ doping CsPbI 3 perovskite nanocrystals to obtain higher PL QY and better thermal stability; solar cells built with those Yb 3+ doped CsPbI 3 nanocrystals delivered higher power conversion efficiency and improved stability.…”

“…Mechanisms of sensitization of the emissive dopants in perovskite hosts are still under debate, and despite much work has been done to study them in Mn 2+ and Yb 3+ -doped perovskite nanocrystals, [18,19,21,100,105,[128][129][130][131][132] the generalized models describing dependencies of optical properties of such doped perovskite nanostructures on bandgap, dopant level, temperature, and excitation are in demand. In particular, the concentration dependencies of the optical parameters of doped NPls require further clarification, as they are essential for development of optimized emitters for different applications.…”

“…[ 97–99 ] Yb 3+ ‐doped perovskite nanocrystals have been also proposed as a unique perovskite system that may operate fully in the NIR spectral region using two‐photon excitation of perovskite matrix followed by energy transfer to Yb 3+ dopants. [ 100 ] Moreover, Yb 3+ may be used to stabilize α ‐phase of CsPbI 3 nanocrystals. Shi et al.…”