Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 27 for “"non-radiative recombination"”.
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GaN sensorių optinio ir elektrinio atsako charakteristikų tyrimas /
… defects. Therefore, carrier lifetime ascribed to radiative and non-radiative recombination has been examined by combining time-resolved luminescence and microwave probed photo-conductivity transient techniques, respectively. The charge collection efficiency (CCE) has been examined by surface and …
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Advancing inorganic perovskite solar cells for application in tandem architectures
… the internal field and therefore increasing non-radiative recombination. Even though the ion densities were similar, this decrease in PCE was lower in DMAI-CsPbI3 perovskite solar cells as compared to CsPbI2Br perovskite solar cells. This suggests that the more effective interface passivation …
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Fabrication and Characterization of Electrically Injected Photonic Crystal Light Emitters
… the optical mode to the gain medium and reduces non-radiative recombination at the semiconductor air interfaces formed by the photonic crystal air holes. The use of a submicron diameter oxide aperture enables optical and electrical confinement. The design parameters of the photonic crystal …
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Structure, electronic levels, and ionic interactions of 1 nanometer silicon particles
… dependent density functional theory, which show radiative traps accessible via direct excitation at the band edge of the ground state geometry. The self-trapped excitons proposed by Lannoo et al. [1, 2] are found to be unstable for the Si29H24 structure, with the outer-well leading to …
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Comparative study of dilute nitride and bismide sub-junctions for tandem solar cells
… with dark currents that are dominated by non-radiative recombination mechanisms.
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Numerical Simulation and Experimental Investigation of Quantum Dash Lasers at Elevated Temperatures: Design and Operation of Monolithic InAs/InP Quantum Dash Ridge Laser Diodes Operating in the C-Band
… accounts for a significant portion of the non-radiative recombination occurring in these devices and is a major driver in the roll-off observed for higher current densities and temperatures. The model is then used to test a variety of design considerations that would offer potential …
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Charge Carrier Relaxation in Halide Perovskite Semiconductors for Optoelectronic Applications
… small band offset arising from a Rashba effect. Recombination and device performance of perovskites are thus better described within a direct bandgap model. We finally study carrier recombination in perovskites and the impact of photon recycling. We show that, for an internal photoluminescence …
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Spectroscopic Studies of Charge Dynamics in Non-Fullerene Organic Solar Cells
… has been made recently by the development of non-fullerene electron acceptor materials. They benefit from good tunablity of energy levels as well as greater thermal and photochemical stability, and remarkable power conversion efficiencies of up to 16.5 % have been achieved. Furthermore, they …
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Microstructured Halide Perovskites for Energy Applications
… in extremely thin layers to prevent charge recombination within the bulk, and careful attention to surface quality, where structural defects often form traps. A key strategy to mitigate these issues is passivation, a process that involves applying layers or chemical treatments to reduce …
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Towards High-Performance Multi-Junction Perovskite Solar Cells: Fabrication, Interlayer Design, and Characterisation
… to improve optical transparency, reduce non-radiative recombination losses, and enhance operational stability. I demonstrate its successful integration into a range of device architectures, including all- perovskite tandem solar cells, triple-junction perovskite solar cells, and …
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Understanding Photoluminescence Quantum Yield In Cesium Lead Tribromide Nanocrystals
… resulting in carrier relaxation through non-radiative recombination mechanisms. This dissertation focuses on understanding the formation of electronic traps within CsPbBr3 NCs and designing effective strategies to mitigate their impact and occurrence. Chapter 2 introduces two precise PLQY …
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Halide Perovskites for Photovoltaics and Light-Emitting Diodes
… layer material and the dominant bimolecular recombination process observed in nanosecond-scale transient PL measurements. Two typical interfacial engineering methods to improve the quality of halide perovskite and device performance are then presented. Optimised NiOx is adopted to improve the …
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STUDY OF WURTZITE AND ZINCBLENDE GAN BASED GREEN LED HETEROSTRUCTURE
… the carriers away from defects, suppressing non-radiative recombination rate and this is hence a possible mechanism for improvement of the IQE of LED devices. Conventional wz-GaN based LEDs are limited in IQE by a strong in-build electric field when a large amount of indium is used to achieve …
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Enhancing quantum-dot luminescence in visible and infrared light emitting devices
… of the PbS core by the CdS shell against a non-radiative recombination pathway caused by a neighboring conductive layer within the device architecture.
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Microscopy study of extreme lattice mismatched heteroepitaxy using interfacial misfit arrays
… to active regions of devices, thus leads to non-radiative recombination and damages device performance. The majority of the work done in this field has been focused on the interfacial misfit (IMF) array based growth mode between GaAs and GaSb, and AlSb on Si substrate. Since the formation of …
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Understanding and Controlling the Optoelectronic Properties of Cs2AgBiBr6 Double Perovskite
… that grain boundaries are the dominant non-radiative recombination sites. I also demonstrate through field-effect transistor and temperature-dependent transient current measurements that grain boundaries act as the main channels for ion transport. Interestingly, I find a positive …
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Light-Matter Interactions in High-Efficiency Photovoltaics, Light-Emitting Devices, and Strongly Coupled Microcavities
… as a function of material properties such as non-radiative recombination and the probability of photon escape. We determine that a perovskite active layer material with non-radiative rates k₁< 1x10⁴ s⁻¹ can result in practical PCE improvements of up to 1.8% due to photon recycling alone, and …
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Einfluss der Lumineszenzmechanismen und der elektrischen Kontakte auf die Effizienz von InGaN Leuchtdioden
In dieser Arbeit wurden die beiden wichtigsten Komponenten von (AlGaIn)N-basierenden Leuchtdioden untersucht, die einen wesentlichen Einfluss auf die externe Leistungseffizienz der Leuchtdioden haben: die elektrischen und optischen Eigenschaften des p-Kontakts sowie die Lumineszenzeffizienz der als …
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Energetics and Dynamics in Quantum Confined Semiconductor Nanostructures
… promotes coupling to other pathways that sponsor non-radiative recombination even more efficiently than QDs. In all samples, exciting with high energies severely diminishes PL QYs as these energies generate highly excited charge-carriers that can access solvent/environmental pathways.</p>
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Generalized detailed balance theory of solar cells
… silicon, the focus was on the investigation of recombination and light trapping with spectrally and spatially resolved EL. First the relation between EL and quantum efficiency is verified experimentally before the application for the extraction of diffusion lengths and back side reflectances is …
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