Microcavity‐Enhanced High‐Radiance Infrared Lead Sulphide Colloidal Quantum Dot Light‐Emitting Diodes on Silicon

Shortwave infrared (SWIR) light‐emitting diodes (LEDs) are essential for next‐generation applications in machine vision, remote sensing, and communications; however, their performance in conventional bottom‐emission architectures is hampered by optical trapping in substrate modes and limited thermal dissipation on glass. In this work, we report high‐performance top‐emission quantum‐dot light‐emitting diodes (TQLEDs) based on colloidal lead sulphide (PbS) quantum dots that overcome these limitations. Critical to this architecture is the development of a high‐performance transparent conductive electrode optimized for the SWIR region. Integrating these electrodes into a low‐Q microcavity led to the modification of the far‐field radiation pattern, manifested by enhanced forward‐directed light emission and narrowed emission linewidth. Furthermore, the use of high‐thermal‐conductivity silicon as the carrier substrate enabled the devices to sustain significantly higher current densities compared to glass‐based counterparts. The synergy between resonant optical engineering and superior thermal management enabled a record‐high radiance exceeding 100 W sr ⁻¹  m ⁻² . Finally, we demonstrate the practical utility of these high‐flux emitters through the demonstration of active SWIR imaging of a see‐through undoped silicon wafer illuminated solely by active quantum‐dot LEDs (QLEDs). This work establishes top‐emission architectures on silicon as a viable pathway for integrated, high‐power infrared QLEDs.