Suppressed Concentration Quenching Brightens Short‐Wave Infrared Emitters

Abstract The brightness of doped luminescent materials is usually limited by the ubiquitous concentration quenching phenomenon resulting in an intractable tradeoff between internal quantum efficiency and excitation efficiency. Here, an intrinsic suppression of concentration quenching in sensitized luminescent systems, by exploiting the competitive relationship between light emitters and quenchers in trapping excitation energies from sensitizers, is reported. Although Cr³⁺ sensitizers and trivalent lanthanide (Ln³⁺, Ln = Yb, Nd, and Er) emitters themselves are highly susceptible to concentration quenching, the unprecedentedly high‐brightness luminescence of Cr³⁺–Ln³⁺ systems is demonstrated in the short‐wave infrared (SWIR) range employing high concentrations of Cr³⁺, whereby a record photoelectric efficiency of 23% is achieved for SWIR phosphor‐converted light‐emitting diodes, which is about twice as high as those previously reported. The results underscore the beneficial role of emitters in terminating excitation energies, opening up a new dimension for developing efficient sensitized luminescent materials.