11.12.2019 Exciton Photophysics in Low Dimensional Nanomaterials

             Low dimensional materials such as single-walled carbon nanotubes (SWCNTs) and semiconducting transition metal dichalcogenides (TMDs) have recently gained tremendous interest as a nanomaterial for next generation optoelectronics and quantum photonic devices. However, the photophysics of excitons in SWCNTs is not yet fully understood and is largely affected by detrimental extrinsic effects, which give rise to strongly reduced device performance.

The first part of my talk presents novel ways and techniques to completely remove detrimental spectral diffusion and blinking in the emission of surfactant dispersed SWCNTs on millisecond time scales and also demonstrates pronounced single photon emission in combination with 50-fold enhanced emission efficiency. The demonstrated single photon emission is promising for applications in quantum cryptography, while the achieved stable long term emission is important for optoelectronic devices. I will also discuss a new regime of intrinsic exciton photophysics in air-suspended ultra-clean SWCNTs that is characterized by ultra-narrow exciton linewidth and prolonged emission times up to 18 ns. These lifetimes are two orders of magnitude better than prior measurements and in agreement with values predicted by theorists a decade ago.

The second part of my talk will focus on our recent and ongoing studies related to the photophysics of emitters in 2D materials including TMDs and hexagonal boron nitride.