Photoluminescence Saturation in Quantum-Cutting Yb³⁺-Doped CsPb(Cl_1–xBr_x)₃ Perovskite Nanocrystals: Implications for Solar Downconversion

Abstract

Yb 3+ -doped halide perovskites have recently emerged as extraordinarily promising materials for solar spectral downconversion applications because of their extremely high photoluminescence quantum yields of nearly 200%, attributable to a highly efficient picosecond quantum-cutting process. One of the major roadblocks to widespread application of these materials is their photoluminescence saturation under modest photoexcitation fluences. In this study, we examine the excitation-fluence dependence of Yb 3+ -doped CsPb(Cl 1−x Br x ) 3 nanocrystal photoluminescence to develop a quantitative understanding of this saturation. Facile saturation is observed across a multitude of halide and Yb 3+ compositions, with specific trends that provide insight into the microscopic mechanism behind this saturation. We show that the data can be simulated well by a kinetic model that introduces a specific new Auger-type cross-relaxation process involving nonradiative energy transfer from photoexcited nanocrystals to Yb 3+ ions that are already in their luminescent 2 F 5/2 excited state from a previous photoexcitation event. This cross relaxation occurs with a subnanosecond rate constant, allowing it to compete with picosecond quantum cutting when excited-state Yb 3+ is accumulated. These results point to specific strategies for ameliorating photoluminescence saturation in this class of materials, one of which is demonstrated experimentally. The proposed strategies provide guidance for future materials development and application efforts involving these materials.

Mn2+/Yb3+ Codoped CsPbCl3 Perovskite Nanocrystals with Triple‐Wavelength Emission for Luminescent Solar Concentrators

“…demonstrated including main group elements (e.g., Al, Ca, Sr, Bi), [7][8][9][10] transition metals (e.g., Mn, Ni, Cd), [11][12][13][14][15][16][17][18][19][20][21][22][23][24][25] and rare earth elements (e.g., Yb, Ce, Pr). [26][27][28][29][30][31][32][33][34][35][36][37] Among all the dopant-induced properties, the emergence of new emission bands due to the introduction of additional radiative relaxation channels of excitons has been intriguing and promising in particular. [2] To this extent, doping Mn 2+ ions into host semiconductor crystals has historically been one of the most-studied model systems due to the possible introduction of a dopant emission channel through the d-d transition of Mn 2+ ion centers.…”

Doping Lanthanide Ions in Colloidal Semiconductor Nanocrystals for Brighter Photoluminescence

“…Although the use of quantum cutting perovskite-based LnSNCs holds great potential in photovoltaics, as a critical article by Erickson et al pointed out, intrinsic limitations are imposed by the photoluminescence saturation that is achieved under high solar irradiance. 298 In the same articles, strategies to overcome this limitation via a rational design of the material and engineering of the photovoltaic devices are also laid out.…”

Intermarriage of Halide Perovskites and Metal‐Organic Framework Crystals

“…Furthermore, long‐term stable PL was achieved after embedding into a polymer matrix (Figure a,b) . This approach opens opportunities for other lanthanide MOF composites, such as PL upconversion (Er 3+ ) and quantum cutting effects (for Yb 3+ ) …”