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.
Results
Showing 1 to 20 of 37 for “"EQE"”.
-
Charakterisierung und Optimierung von (Al, Ga)N-basierten UV-Photodetektoren
… 300 nm with a high external quantum efficiency (EQE). First, experimental and simulated results were combined to give a detailed study of the performance of top- and bottom-illuminated Al0.5Ga0.5N/AlN MSM PD on planar c-sapphire templates. Of particular note here is the threshold and saturation …
-
Charge Carrier Balance in Lead Halide Perovskite Light Emitting Diodes
… related to the External Quantum Efficiency (EQE), and is thought to have additional effects on device endurance and stability. In this thesis I present a series of experiments and simulations to study the charge balance in Lead Halide Perovskite (LHP) emitter LEDs. These LHP LEDs, …
-
Enhancing quantum-dot luminescence in visible and infrared light emitting devices
… investigate how the external quantum efficiency (EQE) of colloidal quantum-dot light emitting devices (QD-LEDs) can be enhanced by addressing in situ QD photoluminescence (PL) quenching mechanisms occurring with and without applied bias. QD-LEDs promise efficient, high colour-quality solid-state …
-
Efficiency loss mechanisms in colloidal quantum-dot light-emitting diodes
… relatively low external quantum efficiencies (EQE). In this thesis, we study the efficiency loss mechanisms present in the latest generation of QD-LEDs. We start with understanding the origin of reduced efficiencies at high current density operation, known as the efficiency roll-off. Through …
-
The Role of Quantum Dot Size on the Performance of Intermediate Band Solar Cells
… Power Dependent PL, External Quantum Efficiency (EQE), Temperature Dependent Solar Power Conversion Efficiency, and Current-Voltage measurements. The efficiency measurements demonstrate the critical role of QD size on the performance of QD IBSCs. The EQE measurement indicates a change in the …
-
Electroluminescence characterization of organometallic perovskite solar cells
… electroluminescence quantum efficiency (LED-EQE) of appoximately 14%, with an energy conversion efficiency of 18%. Observation of the thermally activated reigme and high LED-EQE during a voltage sweep requires an unusually low sweep rate (<5mV / s), which is significantly slower than the …
-
Temperature Characterization of Colloidal Quantum Dot Light Emitting Diodes
… nature and origin of turn-on voltage, current, EQE, EQE roll-off, and hysteresis.
-
Plasmon supported defect absorption in amorphous silicon thin film solar cells and devices
… configuration an external quantum efficiency (EQE) signal is observed for photon energies below the bandgap of a-Si:H. States must be present that allow transitions for sub-bandgap energies. By a variation of the Ag NP position within the applied devices the role of interface states is …
-
Effects of Thickness, Morphology and Molecular Structure of Donor and Acceptor Layers in Thermally Interdiffused Polymer Photovoltaics
… in the external quantum efficiencies (EQE) as compared with bilayer devices. Auger spectroscopy, combined with argon-ion beam milling, serves to record the concentration depth profile and identify concentration gradients in the device through detection of the sulfur in the P3OT …
-
Excitonic spin engineering in optoelectronic devices
… in an all-organic solar cell. We measure an EQE as high as 109%, breaking the conventional limit of 100%. We utilize the magnetic field effect of fission to characterize and quantize the fission yield in these devices, demonstrating that an increase in absorption should lead to even higher …
-
Development of hybrid inorganic-organic light-emitting devices with metal oxide charge transport layers
… be addressed---the external quantum efficiency (EQE) needs to be improved and the biggest technical challenge is to increase the device operational lifetime. Balanced charge injection and transport is vital for improving the device efficiency which demands for selection of better charge injection …
-
Designing Planar Silicon Solar Cells for Singlet Fission Sensitization
… photocurrent and external quantum efficiency (EQE). Planar devices are simpler to fabricate than microwire devices and reproduce the planar geometry of optical test samples to connect studies of the interface to device performance. This thesis integrates modeling and experimental approaches to …
-
Numerische Simulationen von Dünnschichtsolarzellen aus amorphem und mikrokristallinem Silizium : Modellvalidierung und Einflüsse der Substrattopographie auf die elektrischen Solarzelleneigenschaften
… experimentellen Hell- und Dunkelkennlinien sowie EQE-Spektren validiert werden. Durch die Implementierung von Band-zu-Band-Tunnelprozessen in die Solarzellenmodellierung wird zudem gezeigt, dass einerseits die experimentell beobachteten Halbleitereigenschaften von transparenten leitfähigen Oxiden …
-
Halide Perovskites for Photovoltaics and Light-Emitting Diodes
… achieved in halide perovskite-based LEDs with EQE improved from below 1% to ~20% in less than 4 years. This remarkable progress can mainly be attributed to the optimisation of halide perovskite properties. This dissertation focuses on the correlation between optical and electrical properties of …
-
SYNTHESIS OF POLYMER STRUCTURES FOR INCREASING ENERGY CONVERSION IN SOLAR CELLS
… They are encapsulated on a solar cell and their EQE and J-V curves are measured. It carries out a gain of 4.3 % for the short circuit current; that means 68 % of the shading loss is recovered, and the cost is down by 5.6 % because of the saved area. However, the efficiency is enhanced in the …
-
Einfluss des Heterostrukturdesigns auf die Effizienz und die optische Polarisation von (In)AlGaN-basierten Leuchtdioden im ultravioletten Spektralbereich
… auf die externe Quanteneffizienz (EQE) von ultravioletten (UV) Leuchtdioden (LEDs) untersucht. Durch Simulationen der LED-Heterostruktur in Kombination mit Elektrolumineszenzmessungen an 320nm LEDs konnte eine gezielte Verbesserung der Heterostruktur und damit der internen …
-
CdTe solar cells: growth phenomena and device performance
… current (OBIC) and external quantum efficiency (EQE) system built as part of this work and having the capacity to measure EQE or OBIC maps with a resolution of 12.5pm. The system was used to evaluate the photovoltaic response of CdTe/CdS devices as a function of wavelength with the impact of the …
-
THREE DIMENSIONAL SOLAR CELLS ---- BASED ON OPTICAL CONFINEMENT GEOMETRIES
… higher absorption and corresponding Jsc, why the EQE spectrum is higher and broader comparing the planar cell, and even why OCGPV would be able to performance better at very high light intensity. Based the ideas from these models, 3 series of OCGPV devices are designed and also introduced in this …
-
Precise Characterization and Investigation of Laser Cooling in III-V Compound Semiconductors
… the key concepts of external quantum efficiency (EQE) and parasitic background absorption in a semiconductor laser cooler. The external quantum efficiency describes how well recombination radiation is removed from the cooling device and is precisely measured by All-optical Scanning Laser …
-
Surface and interface engineering in quantum dot and double-heterojunction nanorod light-emitting diodes
… many applications. External quantum efficiency (EQE) at luminance levels relevant for high-end displays and general lighting (~1,000 and ~5,000 cd/m2, respectively) is modest at best. Therefore, promoting charge balance is critical for improving the performance of QD-LEDs. The first approach …
Page 1 of 2