ABSTRACT Wavelength‐tunable nanolasers, critical for manipulating light‐matter interactions, are typically achieved by electrical, mechanical, or thermal approaches. Here, we demonstrate a chemical strategy for tunable nanolasing via refractive index (RI) modulation in 2D Ti 3 C 2 T x MXene nanoparticle (NP) lattices. The Ti 3 C 2 T x colloidal solution is coated into a film and then patterned into NP lattices by nanoimprint and dry etching. Employing these lattices as the distributed feedback (DFB) cavities and dye solutions as the gain medium, we realize room‐temperature dual‐mode lasing emission at 443 and 452 nm, which correspond to the upper and lower band edges, respectively. Furthermore, the intercalation and deintercalation through solution immersion and thermal annealing are developed to effectively modify the surface terminations and interlayer environment of Ti 3 C 2 T x and shift the RI of cavities. This leads to variations in the resonant wavelength and a 5 nm reversible tuning of the lasing emission. Our work presents a new chemical perspective for applying 2D materials to tunable nanolasers and is promising for applications such as imaging, chem/bio‐sensing, and optical display.
Zheng et al. (2026) studied this question.