Establishing a blocking layer between the interfaces of the photoanode is an effective approach to improve the performance of dye-sensitized solar cells (DSSCs). In this work, HfO2 blocking layers are deposited via atomic layer deposition (ALD) onto tin-doped indium oxide (ITO) and TiO2. In both cases, addition of the blocking layer increases cell efficiencies to greater than 7%. The improved performance for a HfO2 layer inserted between the ITO/TiO2 interface is associated with an energy barrier that reduces electron recombination. HfO2 blocking layers between the TiO2/dye interface show more complex behavior and are more sensitive to the number of ALD cycles. For thin blocking layers on TiO2, the improved device performance is attributed to the passivation of surface states in TiO2. A distinct transition in dark current and electron lifetime are observed after 4 ALD cycles. These changes to performance indicate thick HfO2 layers on TiO2 formed an energy barrier that significantly hinders cell performance.
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http://dx.doi.org/10.1021/am505742y | DOI Listing |
Sensors (Basel)
December 2024
Department of P & M, PIR Mehr Ali Shah Arid Agriculture University, Rawalpindi 46000, Pakistan.
The vast interconnection of resource-constrained devices and the immense amount of data exchange in the Internet of Things (IoT) environment resulted in the resurgence of various security threats. This resource-constrained environment of IoT makes data security a very challenging task. Recent trends in integrating lightweight cryptographic algorithms have significantly improved data security in the IoT without affecting performance.
View Article and Find Full Text PDFMicromachines (Basel)
December 2024
School of Microelectronics, Northwestern Polytechnical University, Xi'an 710129, China.
Serious electron leakage and poor hole injection efficiency are still challenges for deep ultraviolet AlGaN-based light-emitting diodes with a traditional structure in achieving high performance. Currently, the majority of research works concentrate on optimizing the structures of the electron blocking layer (EBL) and last quantum barrier (LQB) separately, rather than considering them as an integrated structure. Therefore, in this study, an Al-content-varied AlGaN composite last quantum barrier (CLQB) layer is proposed to replace the traditional EBL and LQB layers.
View Article and Find Full Text PDFMaterials (Basel)
December 2024
Collaborative Innovation Center for Advanced Organic Chemical Materials Co-Constructed by the Province and Ministry, Ministry of Educational Key Laboratory for the Synthesis and Application of Organic Functional Molecules, College of Chemistry and Chemical Engineering, Hubei University, Wuhan 430062, China.
High-nickel ternary LiNiCoMnO (NCM622) is a promising cathode material for lithium-ion batteries due to its high discharge-specific capacity and energy density. However, problems of NCM622 materials, such as unstable surface structure, lithium-nickel co-segregation, and intergranular cracking, led to a decrease in the cycling performance of the material and an inability to fully utilize high specific capacity. Surface coating was the primary approach to address these problems.
View Article and Find Full Text PDFMaterials (Basel)
December 2024
Centre of Polymer and Carbon Materials, Polish Academy of Sciences, 34 M. Curie-Skłodowska Str., 41-819 Zabrze, Poland.
Phenothiazine-based photosensitizers bear the intrinsic potential to substitute various expensive organometallic dyes owing to the strong electron-donating nature of the former. If coupled with a strong acceptor unit and the length of N-alkyl chain is appropriately chosen, they can easily produce high efficiency levels in dye-sensitized solar cells. Here, three novel D-A dyes containing 1H-tetrazole-5-acrylic acid as an acceptor were synthesized by varying the N-alkyl chain length at its phenothiazine core and were exploited in dye-sensitized solar cells.
View Article and Find Full Text PDFCancer immunotherapy using engineered cytotoxic effector cells has demonstrated significant potential. The limited spatial complexity of existing models, however, poses a challenge to mechanistic studies attempting to approve existing approaches of effector cell-mediated cytotoxicity within a three-dimensional, solid tumor-like environment. To gain additional experimental control, we developed an approach for constructing three-dimensional (3D) culture models using smart polymers that form temperature responsive hydrogels.
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