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The performance of electronic and semiconductor devices is critically dependent on the distribution of guest molecules or atoms in a host matrix. One prominent example is that of organic light‐emitting diode (OLED) displays containing phosphorescent emitters, now ubiquitous in handheld devices and high‐end televisions. In such OLEDs the phosphorescent guest [normally an iridium(III)‐based complex] is typically blended into a host matrix, and charge injection and transport, exciton formation and decay, and hence overall device performance are governed by the distribution of the emissive guest in the host. Here high‐angle annular dark‐field scanning transmission electron microscopy (HAADF‐STEM) is used with depth sectioning to reconstruct the 3D distribution of emissive iridium(III) complexes, fac‐tris(2‐phenylpyridine)iridium(III) [Ir(ppy)3], blended into the amorphous host material, tris(4‐carbazoyl‐9‐ylphenyl)amine (TCTA), by resolving the position of each single iridium(III) ion. It is found that most Ir(ppy)3 complexes are clustered with at least one other, even at low concentrations, and that for films of 20 wt.% Ir(ppy)3 essentially all the complexes are interconnected. The results validate the morphology of blend films created using molecular dynamics simulations which mimic the evaporation film‐forming process and are also consistent with the experimentally measured charge transport and photophysical properties. [ABSTRACT FROM AUTHOR]

The traditional electrochemical caustic soda recovery system uses the generated pH gradient across the ion exchange membrane for the regeneration of spent alkaline absorbent from CO2 capture. This electrochemical CO2 capture system releases the by-products H2 and O2 at the cathode and anode, respectively. Although effective for capturing CO2, the slow kinetics of the oxygen evolution reaction (OER) limit the energy efficiency of this technique. Hence, this study proposed and validated a hybrid electrochemical cell based on the H2-cycling from the cathode to the anode to eliminate the reliance on anodic oxygen generation. The results show that our lab-scale prototype enabled effective spent caustic soda recovery with an electron utilisation efficiency of 90%, and a relative carbonate/bicarbonate diffusional flux of approximately 40%. The system also enabled the regeneration of spent alkaline absorbent with a minimum electrochemical energy input of 0.19 kWh/kg CO2 at a CO2 recovery rate of 0.7 mol/m2/h, accounting for 30% lower energy demand than a control system without H2-recycling, making this technique a promising alternative to the conventional thermal regeneration technology. [ABSTRACT FROM AUTHOR]

A commercial pure titanium (cp‐Ti) powder was used to produce a photoelectrode substrate via 3D‐printing and a commercial titanium foil (Ti‐foil) was used as substrate for direct comparison. TiO2 nanotubes were prepared on both Ti substrates via electrochemical anodization. Characterisation of electrodes showed similar results in all aspects analysed: morphology, absorbance, crystallinity, and photo‐current response. The efficiency of photoelectrocatlytic treatment of methylene blue dye (MB) in water with a single‐chip UVA‐LED was identical. The cp‐Ti/TiO2 electrode achieved 93±4 % removal of MB after 210 min, when combined with a four‐chip UVA‐LED. The cp‐Ti photoelectrode was also tested for the first time for photoelectrocatalytic treatment of benzothiazole (BTH). The highest degradation of BTH (98±2 %, 120 min) was also achieved using the four‐chip UVA‐LED. This study supports further development of 3D‐printed electrodes, maximizing the potential for the creation of novel electrodes for use in PEC technologies for abatement of organic pollutants. [ABSTRACT FROM AUTHOR]

Inorganic semiconductors like silicon and germanium are the foundation of modern electronic devices. However, they have certain limitations, such as high production costs, limited flexibility, and heavy weight. Additionally, the depletion of natural resources required for inorganic semiconductor production raises concerns about sustainability. Therefore, the exploration and development of organic semiconductors offer a promising solution to overcome these challenges and pave the way for a new era of electronics. New applications for electronic and optoelectronic devices have been made possible by the recent emergence of organic semiconductors. Numerous innovative results on the performance of charge transport have been discovered with the growth of organic electronics. These discoveries have opened up new possibilities for the development of organic electronic devices, such as organic solar cells, organic light-emitting diodes, and organic field-effect transistors. The use of organic materials in these devices has the potential to revolutionise the electronics industry by providing low-cost, flexible, and lightweight alternatives to traditional inorganic materials. The understanding of charge carrier transport in organic semiconductors is crucial for the development of efficient organic electronic devices. This review offers a thorough overview of the charge carrier transport phenomenon in semiconductors with a focus on the underlying physical mechanisms and how it affects device performance. Additionally, the processes of carrier generation and recombination are given special attention. Furthermore, this review provides valuable insights into the fundamental principles that govern the behaviour of charge carriers in these materials, which can inform the design and optimisation of future devices. [ABSTRACT FROM AUTHOR]

Virtual power plants (VPPs) are an effective platform for attracting private investment and customer engagement to speed up the integration of green renewable resources. In this paper, a robust bidding strategy to participate in both energy and ancillary service markets in the wholesale electricity market is proposed for a realistic VPP in Western Australia. The strategy is accurate and fast, so the VPP can bid in a very short time period. To engage customers in the demand management schemes of the VPP, the gamified approach is utilized to make the exercise enjoyable while not compromising their comfort levels. The modelling of revenue, expenses, and profit for the load-following ancillary service (LFAS) is provided, and the effective bidding strategy is developed. The simulation results show a significant improvement in the financial indicators of the VPP when participating in both the LFAS and energy markets. The payback period can be improved by 3 years to the payback period of 6 years and the internal rate of return (IRR) by 7.5% to the IRR of 18% by participating in both markets. The accuracy and speed of the proposed bidding strategy method is evident when compared with a mathematical method. [ABSTRACT FROM AUTHOR]

Red‐emitting organic light‐emitting diodes (OLEDs) are important for displays and lighting, with the latter benefiting from solution processable materials, which would enable low embedded energy, scalable fabrication. Herein, the effect of annealing and phase separation on the performance of solution‐processed OLEDs incorporating a light‐emitting layer composed of the exciplex host, m‐MTDATA:OXD‐7, and a red phosphorescent light‐emitting dendrimer, Ir(tDCpq)3, is described. Solution‐processed OLEDs containing an annealed emissive layer with a low dendrimer concentration (2 wt%) are found to have the best performance, which is higher than the device in which the light‐emitting layer is not annealed. The improvement in the performance of the annealed device is ascribed to improved charge mobility within the emissive layer caused by phase separation of the OXD‐7. The OLEDs containing annealed m‐MTDATA:OXD‐7:(2 wt%) Ir(tDCpq)3 have maximum current, power, and external quantum efficiencies of 17.9 cd A−1, 19.4 lm W−1, and 14.8 ± 0.6%, respectively. The fact that the maximum external quantum efficiency (EQE) of 14.8% is larger than that expected based on the photoluminescence quantum yield (PLQY) and the normal out‐coupling efficiency of 20% from a bottom‐emitting device is determined to arise from the different pathways of exciton formation under photoexcitation and charge injection. [ABSTRACT FROM AUTHOR]

The photophysical and charge transport properties of neat and blend films of fac-tris[2-phenylpyridinato-C2,N]iridium(III) [Ir(ppy)3]-cored light-emitting dendrimers and tris(4-carbazoyl-9-ylphenyl)amine (TCTA)-based hosts, with each combination having the same first generation dendrons were measured and compared. The first generation dendrons were composed of bis(fluorenyl)carbazolyl with n-propyl surface groups, or biphenyl with 2-ethylhexyloxy or t-butyl surface groups. Dendronisation of the emitter and host was found to decrease the energy transfer efficiency from the host to the guest relative to an evaporated Ir(ppy)3:TCTA blend film, with the blend composed of materials with biphenyl dendrons and t-butyl surface groups having the largest decrease. The hole mobilities of the solution processed neat and blend layers were found to be 1–2 orders of magnitude lower than those of the equivalent evaporated films. The blend film containing the host and dendrimer with first generation biphenyl dendrons and 2-ethylhexyloxy surface groups had the highest photoluminescence quantum yield (PLQY), comparable to evaporated Ir(ppy)3:TCTA-based films but the lowest hole mobility (≈10−8 cm2 V−1 s−1). In contrast, the blend with the dendrimers composed of the bis(fluorenyl)carbazolyl dendrons with n-propyl surface groups had a low PLQY but higher hole mobility. It was found for the combinations of these solution processable materials that the hole mobility of the blend film was the limiting factor in OLED performance. Devices containing an emissive layer of the materials with the bis(fluorenyl)carbazolyl dendrons with n-propyl surface groups (11 mole percent of the emitter) had a PLQY of 40.8% but the highest external quantum efficiency of 10.0 ± 0.4%, reaching a maximum luminance of almost 10 000 cd m−2. [ABSTRACT FROM AUTHOR]

Tris(4‐carbazoyl‐9‐ylphenyl)amine (TCTA) is a commonly used host material for organic light‐emitting diodes (OLEDs). TCTA has poor solubility and hence to improve solubility the authors have synthesized first‐ and second‐generation TCTA‐based dendrimers with n‐propyl surface groups. These dendrimeric TCTA hosts have improved solubility and similar photophysical properties to TCTA. The hole mobility of solution‐processed TCTA is found to be an order of magnitude less than films formed by evaporation and similar to that of the two dendronized TCTAs (mobilities in the order of 10−5 cm2 V−1 s−1). The hole mobility in the films is found to decrease when a green emissive first‐generation light‐emitting dendrimer is blended with the host materials due to charge trapping on the emissive guest. In the case of the second‐generation host, there is evidence of a degree of phase separation in the film. Organic light‐emitting diodes are fabricated at guest concentrations corresponding to the maximum observed photoluminescence quantum yield (PLQY) and lowest hole mobility. It is found that the external quantum efficiency (EQE) does not always scale with the PLQY, leading to devices that have EQEs higher than expected based on the PLQY and outcoupling of light from a bottom emitting device. [ABSTRACT FROM AUTHOR]