Energy and Charge Transport in Emergent and Defective Semiconductors
The nature of energy and charge transport in semiconducting materials depends on the structure such a material possesses. We study both hybrid organic-inorganic and fully organic semiconducting materials to better understand how their static and dynamical structures impact energy and charge transport in these emerging materials.
Defective Hybrid Organic-Inorgnic Quantum Nanomaterials
While researchers have uncovered how the pristine structure of hybrid organic-inorganic (HOIP) perovskite and perovskite-like materials affects charge and exciton transport, there remains a gap in our understanding of how defective regions in these materials impact their electronic structure. We have developed chemical methods to introduce specific point defects in metal halide perosvkite-like quantum wells deterministically and spectroscopically characterize the electronic states arising from these defects. As shown in the figure at left, specific concentrations of the molecular constituents of HOIP quantum wells controls the shape, energy, and intensity of light emitted below the exciton gap of these materials. We have extended these chemical and characterization methods to both Pb containing and Pb-free derivatives. We intend to use coherent vibrational spectroscopic tools to assess how these light emission spectra couple to defect sites and leverage these properties for single photon emitters.
Representative publications:
1) 'Defect-Induced Narrowband Light Emission from a 2D Hybrid Lead Iodide Perovskite', Adedayo M. Sanni, Sydney N. Lavan, Zhen-Fei Liu, and Aaron S. Rury, The Journal of Physical Chemistry C, 2021, 125, 28004–28012
2) 'Kinetic Molecular Cationic Control of Defect-Induced Broadband Light Emission in 2D Hybrid Lead Iodide Perovskites.' Adedayo M. Sanni, and Aaron S. Rury, The Journal of Physical Chemistry Letters, 2021, 12, pp 101-110
3) 'Anharmonic Molecular Vibrational Probes of Dynamical Organic-Inorganic Interactions in 2D Hybrid Lead Iodide Perovskites' Adedayo M. Sanni, Sydney N. Lavan, and Aaron S. Rury, The Journal of Physical Chemistry C, 2020, 124, pp 13942-13955
4) 'Probing the Fabry-Perot Modes of Self-Assembled Excitonic Microcrystals with Subgap Light Emission', Adedayo M. Sanni, Shofikur Shohag, and Aaron S. Rury, The Journal of Physical Chemistry C, 2019, 123, pp 23103-23112
5) 'Room Temperature Broadband Light Emission From Hybrid Lead Iodide Perovskite-Like Quantum Wells: THz Spectroscopic Investigation of Metastable Defects', Adedayo M. Sanni, Sydney N. Lavan, Aleksandr Avramenko, Federico Rabuffetti, Leopoldo Suescun, and Aaron S. Rury, The Journal of Physical Chemistry Letters, 2019, 10, pp 1653-1662
Charge Transport in Organic Semiconductors
In organic semiconductors, charge transport depends on the coordinated motion of the molecules' nuclei, as shown at the left. Despite this importance, it is still not clear what set of molecular vibrations play the most significant role in mediating the motion of charge and energy.
In the context of these organic materials, our group seeks to uncover intra- and intermolecular vibrations whose motion is key to effective charge and energy transport in these emergent materials. To do so, we coherently perturb their structure using ultrafast pulses of light and then measure changes in the properties of interest, including band gap energy, mid-gap absorption, and anharmonic coupling. Using this ultra-broadband approach to semiconductor characterization, we aim to determine the design principles of next generation materials for electronic and opto-electronic application from the molecular level up.
Representative publications:
1) 'Defects Cause Subgap Luminescence from a Crystalline Tetracene Derivative', R. Eric McAnally, Jon A. Bender, Laura Estergreen, Ralf Haiges, Stephen E. Bradforth, Jahan M. Dawlaty, Sean T. Roberts, and Aaron S. Rury, The Journal of Physical Chemistry Letters, 2017, 8, pp 5993–6001