Nano-engineered solution processed solid-state semiconductor lasers
Abstract
This thesis describes various methods for patterning the electronic and physical
structure of conjugated polymers, ranging from molecular to sub-wavelength
scales. This was done to improve the operation, fabrication and application of
conjugated polymer distributed feedback lasers and additionally new gain
materials were explored to overcome to some of the limitations.
Organic lasers are currently limited to pulsed operation and unable to
achieve continuous wave operation. The effects of triplet states preventing
continuous wave operation is explored here, and a triplet management
scheme based on selectively quenching guest molecules was used to structure
the excited states. Using excited state spectroscopy this scheme was optimised
and then utilised to extend the conjugated polymer lifetime by a factor of ~3.
CH₃NH₃PbI₃ perovskite waveguides were also fabricated and then
nanostructured using nanoimprinted substrates to make one of the first
perovskite distributed feedback lasers. Perovskite semiconductors share many of
the same properties as organic semiconductors with the potential not to suffer
from triplet-state interactions.
The physical engineering of conjugated polymers was also explored with
the development of a new solvent based nanoimprinting method for the nano-structuring of polymer films. This processed allowed for the imprinting of sub-wavelength scale gratings directly into conjugated polymers. The structured
polymer films were subsequently explored as data transmitters as well as
distributed feedback lasers. Lastly, the engineering moved to the molecular
scale. Using cocaine molecules, a specially synthesised molecularly imprinted
polymer used to develop the first “laser turn-on” detection system, combing
both physical and electronic structuring themes of the thesis.
Type
Thesis, PhD Doctor of Philosophy
Rights
Embargo Date: 2018-09-26
Embargo Reason: Thesis restricted in accordance with University regulations. Print and electronic copy restricted until 26th September 2018
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