Data for Stable photoluminescence enhancement in monolayer molybdenum disulfide by superacid treatment

Despite its favorable PL character, the emission efficiency from as-grown 1L MoS2 is often poor, with the PL quantum yield (PLQY) reported to be as low as <1%. Treatment with superacid bis(trifluoromethanesulfonyl)amide (TFSA) has been widely reported to enhance the 1L MoS2 PL intensity by up to 2 orders of magnitude, capable of achieving near-unity PLQY (≥95%).

However, the long-term stability of the elevated 1L MoS2 PL emission under ambient conditions, which is a critical factor in the performance of practical optoelectronic devices, is not well-understood. In this work, we study the evolution of the PL character of TFSA-treated 1L MoS2 over 120 days of ambient storage. We reveal that the initial TFSA treatment leads to the formation of a nanoscale superacidic layer on the 1L MoS2 surface, yielding an order-of-magnitude increase in PL intensity, coupled with a blueshift and narrowing of the PL emission.