Colloidal semiconductor quantum shells for solution-processed laser applications

Laser diodes based on solution-processed semiconductor quantum dots (QDs) present an economical and color-tunable alternative to traditional epitaxial lasers. However, their efficiency is significantly limited by non-radiative Auger recombination, a process that increases lasing thresholds and diminishes device longevity through excessive heat generation. Recent advancements indicate that these limitations can be mitigated by employing spherical quantum wells, or quantum shells (QSs), in place of conventional QDs. The unique QS geometry is designed to suppress multi-exciton Auger decay through exciton-exciton repulsion, thereby extending multi-exciton lifetimes and enhancing their radiative recombination efficiency. In this review, we examine optoelectronic characteristics of QSs and discuss their integration into photonic laser cavities. We further present experimental data demonstrating QS performance in femtosecond, quasi-continuous-wave (quasi-CW), and two-photon upconverted laser configurations, underscoring QS capability to achieve efficient lasing with reduced thresholds and lower energy losses.