High Q‐Factor and Low Threshold Continuous‐Wave Near‐Infrared Lasing with Quasi‐2D Perovskites

Abstract

Quasi‐2D perovskites have shown great potential in achieving solution‐processed electrically pumped laser diodes due to their multiple‐quantum‐well structure, which induces a carrier cascade process that can significantly enhance population inversion. However, continuous‐wave (CW) optically pumped lasing has yet to be achieved with near‐infrared (NIR) quasi‐2D perovskites due to the challenges in obtaining high‐quality quasi‐2D films with suitable phase distribution and morphology. This study regulates the crystallization of a NIR quasi‐2D perovskite ((NMA)2FAn−1PbnI3n+1) using an 18‐crown‐6 additive, resulting in a compact and smooth film with a largely improved carrier cascade efficiency. The amplified spontaneous emission threshold of the film is reduced from 47.2 to 35.9 µJ cm−2. Furthermore, by combining the film with a high‐quality distributed feedback grating, this study successfully realizes a CW NIR laser of 809 nm at 110 K, with a high Q‐factor of 4794 and a low threshold of 911.6 W cm−2. These findings provide an important foundation for achieving electrically pumped laser diodes based on the unique quasi‐2D perovskites.

Tin-Halide Perovskites for Near-Infrared Light-Emitting Diodes

“…Therefore, most of the efforts, today, in manipulating the Sn 4+ defect mainly include two strategies: (1) control the oxidation reaction process (from Sn 2+ to Sn 4+ process) 36,38,39 and (2) induce a reduction reaction by introducing reductants (from Sn 4+ to Sn 2+ process). 40 The unsaturated Sn dangling bonds are susceptible to the adsorption of a variety of nucleophilic molecules, triggering the oxidation process.…”

“…Sn 4+ defects are formed due to oxidation of Sn 2+ during the growth process of THP films . A redox reaction is dominated by the source materials on both sides of the reaction and the redox potential (RP) governing the redox process: Sn 2 + + oxidant ↔ RP Sn 4 + + oxidant 2 − Therefore, most of the efforts, today, in manipulating the Sn 4+ defect mainly include two strategies: (1) control the oxidation reaction process (from Sn 2+ to Sn 4+ process) ,, and (2) induce a reduction reaction by introducing reductants (from Sn 4+ to Sn 2+ process) . The unsaturated Sn dangling bonds are susceptible to the adsorption of a variety of nucleophilic molecules, triggering the oxidation process .…”

Long-term air-stable amplified spontaneous emission in quasi-2D perovskite films through ligand engineering

“…13,14 The natural quantum well structure permits the effective energy funneling from small- n to large- n domains, thus facilitating the population inversion and lowering the threshold of stimulated emission significantly. 15–17 In recent years, several groups have reported low threshold pulsed pumped lasing, 18–20 and even continuous wave optical pumped lasing 6,8,21 based on quasi-2D perovskite films. Thanks to hydrophobic long-chain ligands, quasi-2D perovskites exhibit better stability in ambient atmosphere.…”