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CENTER FOR EXCITONICS SEMINAR SERIES:
Harnessing Spin, Delocalization and Coherence in Molecular Semiconductors
November 4, 2014 at 4:30pm / 6-120
Akshay Rao
Optoelectronics Group, Cavendish Laboratory, University of Cambridge
[a_rao_01]
Abstract: For more than three decades the electronic properties of molecular
semiconductors have been described as 'limited by disorder'. Thus, attempts to
improve their performance have mainly focused on materials properties such as improving
crystallinity and charge mobility. But recent results suggest that some of the most
interesting and technologically relevant properties of these systems emerge from the
interplay of spin, delocalisalised electronic states, coherent charge motion and
vibrational coherence. In this talk I will discuss how these 'disordered'
materials can harness these phenomena to enable 100% efficient photon to electron
conversion in photovoltaics [1-3] and 200% efficient conversion of spin-singlet excitons
to spin-triplet excitons via singlet excitons fission. I will also discuss all optical
methods to couple singlet fission with conventional inorganic semiconductors [4], with an
aim of overcoming thermalisation losses in photovoltaics, and the unique spin properties
of helical molecular systems.
[1] Science, 335, 6074, 1340-1344, (2012), [2] Nature 500, 435-439 (2013), [3] Science,
343, 6170, 512-516, (2014), [4] Nature Materials, DOI: 10.1038/NMAT4093, (2014)
Bio: Akshay Rao is an Advanced Research Fellow and Group Leader at the Cavendish
Laboratory, University of Cambridge. His is interested in the electronic and optical
properties of molecular semiconductors, quantum dots and novel nanoscale structures. He
has worked extensively on organic photovoltaics as well as singlet exciton fission in
molecular semiconductors, using ultrafast spectroscopy to elucidate the how charge
delocalisation, spin and vibrational coherence underlie the physics of these systems.
Akshay received his undergraduate degree from St Stephen's College, University of
Delhi in 2006 and his MSc from the University of Sheffield in 2007. He received his PhD
from the University of Cambridge in 2011, with Prof. Sir Richard Friend. From 2011 to 2014
he held a Junior Research Fellowship. As of October 2014, he is setting up an independent
research group at the University of Cambridge.
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Please post and forward to your groups.
-------------------------------------------
CENTER FOR EXCITONICS SEMINAR SERIES:
Harnessing Spin, Delocalization and Coherence in Molecular Semiconductors
November 4, 2014 at 4:30pm / 6-120
Akshay Rao
Optoelectronics Group, Cavendish Laboratory, University of Cambridge
[a_rao_01]
Abstract: For more than three decades the electronic properties of molecular
semiconductors have been described as 'limited by disorder'. Thus, attempts to
improve their performance have mainly focused on materials properties such as improving
crystallinity and charge mobility. But recent results suggest that some of the most
interesting and technologically relevant properties of these systems emerge from the
interplay of spin, delocalisalised electronic states, coherent charge motion and
vibrational coherence. In this talk I will discuss how these 'disordered'
materials can harness these phenomena to enable 100% efficient photon to electron
conversion in photovoltaics [1-3] and 200% efficient conversion of spin-singlet excitons
to spin-triplet excitons via singlet excitons fission. I will also discuss all optical
methods to couple singlet fission with conventional inorganic semiconductors [4], with an
aim of overcoming thermalisation losses in photovoltaics, and the unique spin properties
of helical molecular systems.
[1] Science, 335, 6074, 1340-1344, (2012), [2] Nature 500, 435-439 (2013), [3] Science,
343, 6170, 512-516, (2014), [4] Nature Materials, DOI: 10.1038/NMAT4093, (2014)
Bio: Akshay Rao is an Advanced Research Fellow and Group Leader at the Cavendish
Laboratory, University of Cambridge. His is interested in the electronic and optical
properties of molecular semiconductors, quantum dots and novel nanoscale structures. He
has worked extensively on organic photovoltaics as well as singlet exciton fission in
molecular semiconductors, using ultrafast spectroscopy to elucidate the how charge
delocalisation, spin and vibrational coherence underlie the physics of these systems.
Akshay received his undergraduate degree from St Stephen's College, University of
Delhi in 2006 and his MSc from the University of Sheffield in 2007. He received his PhD
from the University of Cambridge in 2011, with Prof. Sir Richard Friend. From 2011 to 2014
he held a Junior Research Fellowship. As of October 2014, he is setting up an independent
research group at the University of Cambridge.