8
1 Introduction
with a championing photovoltaic efficiency of 16.4% at the Southern University of
Science and Technology in Shenzhen, he summarised.
Towards flexible electrodes and tunable surfaces, E.-H. Yang from the Stevens
Institute of Technology, USA, explained how nanofabrication of 1D and 2D materials
by growth is achieved for graphene/carbon electronics and TMDC heterostructure
assembly. In addition, he discussed the implementation of tunable wetting and surface
interaction with polymers. His group’s studies thereby highlighted the potential for
manipulation and control of liquid droplets for various applications including oil
separation, water treatment and anti-bacterial surfaces.
Indeed, 2D-materials research delivered great promises for the domain of nanoelectronics, but the field of optics may also benefit strongly by the employment of
novel materials, e.g. when peculiar properties, such as the tunable nonlinear optical response from 2D materials, become appealing for applications. S. Wu from
the Fudan University in Shanghai summarised how atomically thin 2D materials,
including graphene and TMDCs, became a new playground for nonlinear optics.
Besides experimental studies, theoretical modeling of band structures and optical
transitions has remained indispensable for a better understanding of the optoelectronic properties of homo- and hetero-multilayers based on 2D materials. Representative investigations regarding interlayer excitons had been the subject of researchers
working together with T. Stroucken and S.W. Koch at the UMR. Using a fully
microscopic theory to investigate TMDC homo- and hetero-multilayer structures,
T. Stroucken explained that predictions regarding the (co)existence of intra- and
interlayer excitons for various multilayer configurations were successfully made.
Also, the role of the environment in the work with 2D semiconductors matters,
as theoretical and experimental works have shown. Both, the impact of the substrate
and environment on optical properties of 2D semiconductors were discussed by
the author himself (UMR), using 2D WSe 2 and heterostructures comprising WSe 2
and hexagonal-BN (hBN) as primary platform for micro-PL (μ-PL) investigations
among other spectroscopic studies. It is generally understood that an interplay of
different effects influences resonance energies, linewidths and lifetimes, and that
optical properties can be further tailored using photonic microstructures.
Naturally, when envisioning devices and structures based on 2D materials, the
study of ultrafast charge transfer in 2D semiconductors and heterostructures becomes
very important, as Q. Xiong from the Nanyang Technological University in Singapore highlighted. He explained that the significance of ultrafast charge transfer (on
the sub-ps scale) and plasmonic hot carrier injection (≈ ps scale) in 2D semiconductors or heterostructures will further increase. New photophysical properties, such
as correlated fluorescence blinking and charge-induced second harmonic generation, reportedly related to these effects, may render these materials appealing for
all-optical ultrafast control of nonlinear frequency conversion.
Furthermore, Z. Fang from the Peking University shed light on plasmonic hot
electrons that were used to dope 2D materials for the tuning of electro-optical properties with relevance to applications, characterising these ultrathin nanomaterial systems with the help of near-field scanning optical microscopy and dark-field optical
microscopy.
1 Introduction
with a championing photovoltaic efficiency of 16.4% at the Southern University of
Science and Technology in Shenzhen, he summarised.
Towards flexible electrodes and tunable surfaces, E.-H. Yang from the Stevens
Institute of Technology, USA, explained how nanofabrication of 1D and 2D materials
by growth is achieved for graphene/carbon electronics and TMDC heterostructure
assembly. In addition, he discussed the implementation of tunable wetting and surface
interaction with polymers. His group’s studies thereby highlighted the potential for
manipulation and control of liquid droplets for various applications including oil
separation, water treatment and anti-bacterial surfaces.
Indeed, 2D-materials research delivered great promises for the domain of nanoelectronics, but the field of optics may also benefit strongly by the employment of
novel materials, e.g. when peculiar properties, such as the tunable nonlinear optical response from 2D materials, become appealing for applications. S. Wu from
the Fudan University in Shanghai summarised how atomically thin 2D materials,
including graphene and TMDCs, became a new playground for nonlinear optics.
Besides experimental studies, theoretical modeling of band structures and optical
transitions has remained indispensable for a better understanding of the optoelectronic properties of homo- and hetero-multilayers based on 2D materials. Representative investigations regarding interlayer excitons had been the subject of researchers
working together with T. Stroucken and S.W. Koch at the UMR. Using a fully
microscopic theory to investigate TMDC homo- and hetero-multilayer structures,
T. Stroucken explained that predictions regarding the (co)existence of intra- and
interlayer excitons for various multilayer configurations were successfully made.
Also, the role of the environment in the work with 2D semiconductors matters,
as theoretical and experimental works have shown. Both, the impact of the substrate
and environment on optical properties of 2D semiconductors were discussed by
the author himself (UMR), using 2D WSe 2 and heterostructures comprising WSe 2
and hexagonal-BN (hBN) as primary platform for micro-PL (μ-PL) investigations
among other spectroscopic studies. It is generally understood that an interplay of
different effects influences resonance energies, linewidths and lifetimes, and that
optical properties can be further tailored using photonic microstructures.
Naturally, when envisioning devices and structures based on 2D materials, the
study of ultrafast charge transfer in 2D semiconductors and heterostructures becomes
very important, as Q. Xiong from the Nanyang Technological University in Singapore highlighted. He explained that the significance of ultrafast charge transfer (on
the sub-ps scale) and plasmonic hot carrier injection (≈ ps scale) in 2D semiconductors or heterostructures will further increase. New photophysical properties, such
as correlated fluorescence blinking and charge-induced second harmonic generation, reportedly related to these effects, may render these materials appealing for
all-optical ultrafast control of nonlinear frequency conversion.
Furthermore, Z. Fang from the Peking University shed light on plasmonic hot
electrons that were used to dope 2D materials for the tuning of electro-optical properties with relevance to applications, characterising these ultrathin nanomaterial systems with the help of near-field scanning optical microscopy and dark-field optical
microscopy.