Use this URL to cite or link to this record in EThOS: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.707787
Title: Nanostructured materials for optoelectronic devices
Author: Li, Guangru
ISNI:       0000 0004 6057 0187
Awarding Body: University of Cambridge
Current Institution: University of Cambridge
Date of Award: 2016
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Abstract:
This thesis is about new ways to experimentally realise materials with desired nano-structures for solution-processable optoelectronic devices such as solar cells and light-emitting diodes (LEDs), and examine structure-performance relationships in these devices. Short exciton diffusion length limits the efficiency of most exciton-based solar cells. By introducing nano-structured architectures to solar cells, excitons can be separated more effectively, leading to an enhancement of the cell’s power conversion efficiency. We use diblock copolymer lithography combined with solvent-vapour-assisted imprinting to fabricate nano-structures with 20-80 nm feature sizes. We demonstrate nanostructured solar cell incorporating the high-performance polymer PBDTTT-CT. Furthermore, we demonstrated the patterning of singlet fission materials, including a TIPS-pentacene solar cell based on ZnO nanopillars. Recently perovskites have emerged as a promising semiconductor for optoelectronic applications. We demonstrate a perovskite light-emitting diode that employs perovskite nanoparticles embedded in a dielectric polymer matrix as the emissive layer. The emissive layer is spin-coated from perovskite precursor/polymer blend solution. The resultant polymer-perovskite composites effectively block shunt pathways within the LED, thus leading to an external quantum efficiency of 1.2%, one order of magnitude higher than previous reports. We demonstrate formations of stably emissive perovskite nanoparticles in an alumina nanoparticle matrix. These nanoparticles have much higher photoluminescence quantum efficiency (25%) than bulk perovskite and the emission is found to be stable over several months. Finally, we demonstrate a new vapour-phase crosslinking method to construct full-colour perovskite nanocrystal LEDs. With detailed structural and compositional analysis we are able to pinpoint the aluminium-based crosslinker that resides between the nanocrystals, which enables remarkably high EQE of 5.7% in CsPbI3 LEDs.
Supervisor: Not available Sponsor: Gates Cambridge Scholarship
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.707787  DOI:
Keywords: Materials ; Optoelectronics ; perovskite ; solar cells ; light-emitting diodes ; nanocrystals ; nanostructures ; semiconductors
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