Research Jesús Alejandro De Sousa Rodríguez

Abstract

Triplet states are among the most promising systems for implementation as quantum sensors. NV centers have already been exploited for ultrasensitive detection of small magnetic fields, electrical currents, temperatures and even biomarkers. In the search of new systems for quantum sensing, single-wall carbon nanotubes (SWCNTs) emerge as a promising platform due to the possibility of tuning their strongly-bound excitonic states via internal and external functionalization. Recently, I demonstrated using optically detected magnetic resonance (ODMR) that controlled sp3-functionalization of their wall, to generate sp3 defects with a persistent organic free radical, leads to a clear exchange interaction between the unpaired electron of the radical and the triplet excitons in the defects, permitting to tune the intersystem crossing. Very recently, I demonstrated that such sp3 defects can even exhibit ODMR signals at room temperature and under ambient conditions, with signals depending strongly on temperature, pointing at different exciton dynamics. This now opens new opportunities for quantum sensing. Within this project, I will focus on the miniaturization of our current ODMR spectrometer, to enable a portable ODMR on a chip setup aiming for applications in thermometry, magnetometry, and in-situ (bio)sensing.

Researcher(s)

• Promoter: De Sousa Rodríguez Jesús Alejandro

Research team(s)

• Theory and Spectroscopy of Molecules and Materials (TSM²)

Project type(s)

• Research Project

Abstract

This project is a fundamental research project funded by the MSCA-PF programm. In this project, we will focus on single-walled carbon nanotubes (SWCNTs) and functionalise them exohedrally and endohedrally to create new functionalities for enhanced emission. SWCNTs possess uniquely diverse optoelectronic properties that depend critically on their exact diameter and chiral structure. Their quasi one-dimensional structure, high carrier mobility, photochemical and mechanical stability, combined with extremely narrow and tunable emission in the near-infrared (NIR), make them interesting candidates as active material in NIR organic light-emitting diodes (OLEDs) or light-emitting transistors (LETs). The integration of SWCNTs in OLEDs and LETs has so far been limited by their typically low intrinsic emission quantum efficiency. Enhancing the SWCNTs emission efficiency, therefore, requires an in-depth understanding of the complex exciton photophysics, in particular, that of the multiple dark excitons. In this project we will focus on the role of the triplet excitons in SWCNTs, through combining optical spectroscopy with the spin-selective magnetic resonance technique, namely optically-detected magnetic resonance (ODMR). Finally, as a proof-of-principle, these functionalized SWCNTs will be integrated in LETs and OLEDs and in operando characterization through, amongst others, electrically-detected magnetic resonance (EDMR) will be performed to determine the role of the spin-dependent electron-hole recombination processes in the devices, opening new avenues to highly emissive NIR-OLEDs/LETs, essential for a wide range of biomedical and biosensing applications.

Researcher(s)

• Promoter: Cambré Sofie
• Fellow: De Sousa Rodríguez Jesús Alejandro

Research team(s)

• Nanostructured and organic optical and electronic materials (NANOrOPT)
• Theory and Spectroscopy of Molecules and Materials (TSM²)

Project type(s)

• Research Project