Dynamics and Time Correlation of Acoustic Emission, Electrical Noises and Quantum Yield Fluctuations in Optoelectronic Devices

2007 ◽  
Author(s):  
O. V. Lyashenko ◽  
V. P. Veleshchuk ◽  
O. I. Vlasenko ◽  
R. G. Chuprina
Keyword(s):  
Acoustic Emission ◽  
Quantum Yield ◽  
Optoelectronic Devices ◽  
Time Correlation

scholarly journals Nanostructured Inorganic Metal Halide Perovskites for Optoelectronic Applications

2021 ◽  
Author(s):  
◽  
Parth Vashishtha
Keyword(s):  
Quantum Dots ◽  
Quantum Yield ◽  
Synthesis Method ◽  
Visible Region ◽  
Optoelectronic Devices ◽  
Metal Halide ◽  
Colloidal Synthesis ◽  
Layered Perovskite ◽  
Perovskite Nanocrystals ◽  
Optoelectronic Applications

<p>Semiconductor quantumdots have proven to be promising materials for optoelectronic devices, such as light emitting devices (LEDs) and solar cells, due to their thin linewidth of emission, high photoluminescence quantum yield and high absorption coefficient. Over the last decade, perovskite crystals have gained significant attention due to their extraordinary optoelectronic properties. Therefore, perovskite nanocrystals combine the advantage of both crystalline perovskite and quantum dots. Here, we synthesised high quantum yield (50 - 80 %) monodispersed CsPbX₃ (X= Cl, Br, I) quantum dots, with tuneable emission spectra over the entire visible region, by a colloidal synthesis method. We have then successfully processed them to produce thin films as the emitting layer in an organic LED-type device architecture. Most importantly, we demonstrated field induced halide separation in mixed halide CsPb(Br/I)₃ NCs which is the reason color instability in these LEDs.  Perovskite nanocrystal LEDs were found to have low external quantum efficiency (EQE) due to their bulky ligands. As a result, Ruddlesden-Popper (RP) phase layered perovskite was investigated to increase the EQE over perovskite QD LEDs. As a result, we constructed RP perovskite phase CsPbX₃ LEDs with emission through the entire visible spectrum (460-700 nm). Colour tuning was achieved by taking advantage of both quantum confinement effect and halide mixing. The EQE of these LEDs outperformed the literature values in the blue and blue-green spectral regions, with relatively long life time.  We also invented a novel perovskite nanocrystals made from thalliumlead halide by replacing caesium with thallium. These materials are potential candidates for various optoelectronic applications. Size-, shape-, and composition- tuning in these nanocrystals were performed by varying the reaction conditions andmixing the halide composition. A weak confinementwas observed in these NCs. Additionally, we have shown the application of TlPbI₃ nanowires as photoconductors.  Collectively, this thesis includes the synthesis of various types of inorganic metal halide perovskite nanostructures followed by their implementation into working optoelectronic devices, specifically LEDs.</p>

The effect of 1D- and 2D-polymorphs on organic single-crystal optoelectronic devices: lasers and field effect transistors

2018 ◽  
Vol 6 (30) ◽  
pp. 7994-8002 ◽  
Author(s):  
Qing Liao ◽  
Zhen Wang ◽  
Qinggang Gao ◽  
Zhaoyi Zhang ◽  
Jiahuan Ren ◽  
...  
Keyword(s):  
Quantum Yield ◽  
Single Crystal ◽  
Field Effect ◽  
Carrier Mobility ◽  
Field Effect Transistors ◽  
Optoelectronic Devices ◽  
Laser Threshold ◽  
Photoluminescence Quantum Yield ◽  
Organic Single Crystal ◽  
Higher Carrier Mobility

The 2D-microdisk polymorphs of TPDSB exhibit a higher photoluminescence quantum yield (Φ), a lower laser threshold and a higher carrier mobility than 1D-microwire polymorphs.

Corrosion Monitoring of the Active/Passive/Transpassive State of a High-Alloy CrMnNi Steel by Means of Acoustic Emissions

2016 ◽  
Vol 367 ◽  
pp. 42-51 ◽  
Author(s):  
Marcel Mandel ◽  
Wladimir Kietov ◽  
Lutz Krueger
Keyword(s):  
Acoustic Emission ◽  
Signal Intensity ◽  
Corrosion Behaviour ◽  
Bubble Formation ◽  
Acoustic Emissions ◽  
Time Correlation ◽  
Sulphuric Acid Solution ◽  
Passive State ◽  
Corrosion Monitoring ◽  
High Alloy

The corrosion behaviour of a high-alloy CrMnNi steel was investigated electrochemically in a 0.5 M sulphuric acid solution. The characteristic regions of the active, passive and transpassive state for the material were monitored by means of acoustic emissions. To this end, the steel was potentiostatically polarised and the acoustic emission signal was recorded on the specimen’s surface at a distance of 5 cm from the location of corrosion. Analysis of the acoustic emission signals revealed an increase in signal intensity due to hydrogen bubble formation when the material was cathodically polarised. Furthermore, for anodic polarisation, a continuous decline in the signal-time correlation occurred when the material was polarised in the active/passive state, whereas a sharp point of inflexion and drastic reduction in intensity was recognised when the material was polarised in the passive state. Moreover, a further increase in signal intensity was observed when the transpassive state was reached. The increase at transpassivity was related to the onset of oxygen bubble formation at the electrode.

scholarly journals Nanostructured Inorganic Metal Halide Perovskites for Optoelectronic Applications

2021 ◽  
Author(s):  
◽  
Parth Vashishtha
Keyword(s):  
Quantum Dots ◽  
Quantum Yield ◽  
Synthesis Method ◽  
Visible Region ◽  
Optoelectronic Devices ◽  
Metal Halide ◽  
Colloidal Synthesis ◽  
Layered Perovskite ◽  
Perovskite Nanocrystals ◽  
Optoelectronic Applications

<p>Semiconductor quantumdots have proven to be promising materials for optoelectronic devices, such as light emitting devices (LEDs) and solar cells, due to their thin linewidth of emission, high photoluminescence quantum yield and high absorption coefficient. Over the last decade, perovskite crystals have gained significant attention due to their extraordinary optoelectronic properties. Therefore, perovskite nanocrystals combine the advantage of both crystalline perovskite and quantum dots. Here, we synthesised high quantum yield (50 - 80 %) monodispersed CsPbX₃ (X= Cl, Br, I) quantum dots, with tuneable emission spectra over the entire visible region, by a colloidal synthesis method. We have then successfully processed them to produce thin films as the emitting layer in an organic LED-type device architecture. Most importantly, we demonstrated field induced halide separation in mixed halide CsPb(Br/I)₃ NCs which is the reason color instability in these LEDs.  Perovskite nanocrystal LEDs were found to have low external quantum efficiency (EQE) due to their bulky ligands. As a result, Ruddlesden-Popper (RP) phase layered perovskite was investigated to increase the EQE over perovskite QD LEDs. As a result, we constructed RP perovskite phase CsPbX₃ LEDs with emission through the entire visible spectrum (460-700 nm). Colour tuning was achieved by taking advantage of both quantum confinement effect and halide mixing. The EQE of these LEDs outperformed the literature values in the blue and blue-green spectral regions, with relatively long life time.  We also invented a novel perovskite nanocrystals made from thalliumlead halide by replacing caesium with thallium. These materials are potential candidates for various optoelectronic applications. Size-, shape-, and composition- tuning in these nanocrystals were performed by varying the reaction conditions andmixing the halide composition. A weak confinementwas observed in these NCs. Additionally, we have shown the application of TlPbI₃ nanowires as photoconductors.  Collectively, this thesis includes the synthesis of various types of inorganic metal halide perovskite nanostructures followed by their implementation into working optoelectronic devices, specifically LEDs.</p>

Highly fluorescent dual-emission red carbon dots and their applications in optoelectronic devices and water detection

2019 ◽  
Vol 43 (7) ◽  
pp. 3050-3058 ◽  
Author(s):  
Qingwen Guan ◽  
Rigu Su ◽  
Miaoran Zhang ◽  
Rui Zhang ◽  
Weijun Li ◽  
...  
Keyword(s):  
Quantum Yield ◽  
Carbon Dots ◽  
Optoelectronic Devices ◽  
Dual Emission ◽  
White Leds ◽  
Water Detection ◽  
Co Doped

Synthesis of dual-emission nitrogen and sulfur co-doped (N,S)-CDs with a quantum yield up to 29.7% and their applications in white LEDs and water detection.

Propagation of acoustic emission signals in metallic fuselage structure

2001 ◽  
Vol 148 (4) ◽  
pp. 169-177 ◽  
Author(s):  
R.P. Dalton ◽  
P. Cawley ◽  
M.J. Lowe
Keyword(s):  
Acoustic Emission
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