Nanoimprinted Halide Perovskite Nanowires with Directly-Written Gratings

Perovskite nanowires demonstrate low-threshold lasing owing to the huge optical gain of their material and their self-resonance behavior. However, their lasing properties still can be optimized and improved because light outcoupling through their subwavelength facets is not optimal for many applications. Here we demonstrate a versatile method for improvement of the lasing properties of a single perovskite CsPbBr3 nanowire by defining an additional grating on its surface. Such direct patterning is carried out by high-throughput nanoimprinting method, which does not damage the material or worsen its material properties as it might happen after applying conventional lithographical approaches. Such direct imprinting of gratings on the CsPbBr3 nanowires provides us with the ability to modify their eigen- modes, improve directivity of their outcoupled stimulated emission and narrow their lasing spectral lines, while keeping their lasing threshold almost unchanged. Concurrently, the number of their modes are reduced (by half) and the quality factor of their remaining lasing modes is increased (by about 2-folds). These findings indicate that direct writing of nanopatterns on halide perovskite nanowires via nanoimprint lithography holds great promise for imparting additional structural functions to these nanowires while leaving their material unharmed.