Solution-processed PbS quantum dot infrared laser with room-temperature tuneable emission in the optical telecommunications window.

Solution processed semiconductor lasers have achieved much success across the nanomaterial research community, including in organic semiconductors1,2, perovskites3,4 and colloidal semiconductor nanocrystals5,6. The ease of integration with other photonic components, and the potential for upscaling using emerging large area fabrication technologies, such as roll-to-roll7, make these lasers attractive as low-cost photonic light sources that can find use in a variety of applications: integrated photonic circuitry8,9, telecommunications10,11, chemo-/bio-sensing12,13, security14, and lab-on-chip experiments15. However, for fiber-optic or free-space optical (FPO) communications and eye-safe LIDAR applications, room temperature solution-processed lasers have remained elusive. Here we report the first solution processed laser, comprising PbS colloidal quantum dots (CQDs) integrated on a distributed feedback (DFB) cavitiy, with tuneable lasing wavelength from 1.55 μm - 1.65 μm. These lasers operate at room temperature and exhibit linewidths as low as ~0.9 meV.