Optical Thin Film and Photovoltaic (PV) Related Technologies, Volume II

A special issue of Coatings (ISSN 2079-6412). This special issue belongs to the section "Surface Engineering for Energy Harvesting, Conversion, and Storage".

Deadline for manuscript submissions: 10 July 2024 | Viewed by 8996

Special Issue Editor


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Guest Editor
School of Intelligent Mechatronics Engineering, Sejong University, Gwangjin-gu, Seoul 05006, Republic of Korea
Interests: photovoltaics; energy conversion; magnetic nanoparticles; material synthesis (hydrothermal/solvothermal, solid state reaction); thin film growth; transparent conducting oxides (TCOs); thin-film transistor (TFT); vacuum deposition via sputtering; ferroelectrics; electromagnetism simulation
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Special Issue Information

Dear Colleagues,

As interest in the problem of global warming has grown, many groups have begun to search extensively for renewable sources such as solar, wind power, hydroelectric energy, and biomass devices which can provide energy without harm to humans or the Earth. Among them, solar energy-based photovoltaic (PV) devices are considered the most likely candidates for a clean energy solution which avoids the emission of carbon dioxide resulting from the burning of fossil fuels. Since the photovoltaic effect was first reported by E. Becquerel in 1839, the phenomenon has been exploited for the conversion of solar energy directly into clean, reliable, scalable, and affordable energy such as electricity. Photovoltaic (PV) devices represented by solar cells and conventional solar cells have been widely used as both negative (N) and positive (P) types of semiconductor material. Between the two different materials, a particular substrate absorbs light and emits electrons, or photons, that can move freely.

Meanwhile, the choice of structure (manufacturing structure, layers, and surface design, etc.) and materials (substrate, absorbance, and metal electrode) is a very important factor for the high performance of solar cells.

Moreover, flexible PV devices with foldable properties have been emerging on the new renewable energy market. Flexible PV devices can also be wearable and can be produced through low-cost and simple processes while achieving high performance. Flexible PV devices require technology that focuses on the substrate, materials, driving circuits, etc.

This Special Issue will deal with state-of-the-art technologies and the latest research advances in the photovoltaic (PV) field and energy-related research, including:

  • organic and inorganic photovoltaics;
  • solar cells with silicon and beyond;
  • flexible photovoltaics;
  • photovoltaic technology and related technologies;
  • energy conversion technology;
  • film coating technology in vacuum and non-vacuum.

We look forward to receiving your contribution.

Prof. Dr. Sangmo Kim
Guest Editor

Manuscript Submission Information

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Keywords

  • thin film growth
  • solar cell
  • flexible energy conversion
  • coating technology
  • photovoltaic (PV)-related technologies

Published Papers (10 papers)

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Research

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14 pages, 8667 KiB  
Article
Improvement of X-ray Photoelectric Conversion Performance of MAPbI3 Perovskite Crystals by Ionic Liquid Treatment
by Xueqiong Su, Ruimin Wang, Huimin Yu, Jin Wang, Ruixiang Chen, He Ma and Li Wang
Coatings 2024, 14(5), 633; https://doi.org/10.3390/coatings14050633 - 16 May 2024
Viewed by 133
Abstract
Although perovskite has great potential in optoelectronic devices, the simultaneous satisfaction of material stability and high performance is still an issue that needs to be solved. Most perovskite optoelectronic devices use quantum dot spin coating or the gas-phase growth of perovskite thin films [...] Read more.
Although perovskite has great potential in optoelectronic devices, the simultaneous satisfaction of material stability and high performance is still an issue that needs to be solved. Most perovskite optoelectronic devices use quantum dot spin coating or the gas-phase growth of perovskite thin films as the photoelectric conversion layer. Due to stability limitations, these materials often experience a significant decrease in photoelectric conversion efficiency when encountering liquid reagents. The self-assembled growth of hybrid perovskite crystals determines superior lattice ordering and stability. There are three types of ionic liquids—[Emim]BF4, EMIMNTF2, and HMITFSI—that can effectively enhance the X-ray photoelectric conversion performance of hybrid perovskite crystal CH3NH3PbI3 (MAPbI3), and the enhancement in the photocurrent leads to an improvement in the sensitivity of X-ray detectors. We soak the perovskite crystals in an ionic liquid and perform two treatment methods: electrification and dilution with ETOH solution. It is interesting to find that MAPbI3 perovskite single crystal materials choose the same optimized ionic liquid species in X-ray detection and photovoltaic power generation applications, and the effect is quite the opposite. Compared with untreated MAPbI3 crystals, the average photocurrent density of Electrify-HMITFSI MAPbI3 increased by 826.85% under X-ray excitation and the sensitivity of X-ray detectors made from these treated MAPbI3 crystals significantly increased by 72.6%, but the intensity of the PL spectrum decreased to 90% of the untreated intensity. Full article
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12 pages, 2915 KiB  
Article
Light-Field Optimization of Deep-Ultraviolet LED Modules for Efficient Microbial Inactivation
by Jiaxin Huang, Qingna Wang, Xiaofang Ye, Wenxiang Li, Keyang Cheng, Shanzhi Qu, Wenyu Kang, Jun Yin and Junyong Kang
Coatings 2024, 14(5), 568; https://doi.org/10.3390/coatings14050568 - 3 May 2024
Viewed by 526
Abstract
Public awareness of preventing pathogenic microorganisms has significantly increased. Among numerous microbial prevention methods, the deep-ultraviolet (DUV) disinfection technology has received wide attention by using the nitride-based light-emitting diode (LED). However, the light extraction efficiency of DUV LEDs and the utilization rate of [...] Read more.
Public awareness of preventing pathogenic microorganisms has significantly increased. Among numerous microbial prevention methods, the deep-ultraviolet (DUV) disinfection technology has received wide attention by using the nitride-based light-emitting diode (LED). However, the light extraction efficiency of DUV LEDs and the utilization rate of emitted DUV light are relatively low at the current stage. In this study, a light distribution design (referred to as the reflective system) was explored to enhance the utilization of emitted DUV from LEDs, leading to successful and efficient surface and air disinfection. Optical power measurements and microbial inactivation tests demonstrated an approximately 79% improvement in average radiation power density achieved by the reflective system when measured at a 5 cm distance from the irradiation surface. Moreover, a statistically significant enhancement in local surface disinfection was observed with low electric power consumption. The reflective system was integrated into an air purifier and underwent air disinfection testing, effectively disinfecting a 3 m3 space within ten minutes. Additionally, a fluorine resin film at the nanolevel was developed to protect the light module from oxidation, validated through a 1200 h accelerated aging test under humid conditions. This research offers valuable guidance for efficient and energy-saving DUV disinfection applications. Full article
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11 pages, 1958 KiB  
Article
Optimizing Sputter Deposition Conditions of Silver Thin Films Used in Low-Emissivity Coatings in an In-Line Deposition System
by Clàudia Campos, Natalia Herguedas and Enrique Carretero
Coatings 2023, 13(9), 1556; https://doi.org/10.3390/coatings13091556 - 6 Sep 2023
Cited by 1 | Viewed by 1058
Abstract
This research sought to determine the optimal conditions for depositing thin silver layers in the fabrication of low-emissivity coatings. The study utilized an in-line semi-industrial high-vacuum magnetron sputtering system with rectangular targets, closely resembling those used in industrial settings. Trilayer AZO/Ag/AZO structures were [...] Read more.
This research sought to determine the optimal conditions for depositing thin silver layers in the fabrication of low-emissivity coatings. The study utilized an in-line semi-industrial high-vacuum magnetron sputtering system with rectangular targets, closely resembling those used in industrial settings. Trilayer AZO/Ag/AZO structures were deposited to enhance the wetting properties of the silver, and to protect it from the atmosphere. The effects of the power and argon flow on the sample properties were analyzed, along with variations in the silver thickness. The results demonstrate that a lower power (200 W) and higher argon flows (1000 sccm) lead to a higher transmittance and a lower sheet resistance, resulting in a reduced emissivity (up to 0.015 for 24 nm of silver). The identified optimal conditions offer valuable recommendations for producing more efficient and optically superior coatings. This study also reveals the importance of the silver thickness to the properties of the coatings, in accordance with previous research findings. These findings provide insights for improving the performance of low-emissivity coatings in various applications. Full article
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17 pages, 5443 KiB  
Article
Design and Analysis of Active Speed-Limit Mechanism for Large-Scale Spatial Solar Array
by Shuli Yang, Limin Shao, Lin Li, Mutian Li and Yunshuai Chen
Coatings 2023, 13(8), 1351; https://doi.org/10.3390/coatings13081351 - 1 Aug 2023
Viewed by 1114
Abstract
The multidimensional deployment of large-scale spatial solar arrays has been the basis for high-power advanced spacecraft and a symbol of the leaps forward in aerospace technology. Activated and passive drives have often been used in combination to implement the driving mechanism of large-scale [...] Read more.
The multidimensional deployment of large-scale spatial solar arrays has been the basis for high-power advanced spacecraft and a symbol of the leaps forward in aerospace technology. Activated and passive drives have often been used in combination to implement the driving mechanism of large-scale solar arrays, which can reduce the impact of the deployment and locking process. For the first time, a novel active speed-limit mechanism was introduced into the two-dimensional secondary deployable drive system of a large-scale spatial solar array, achieving a balance between large deployable driving torque and small locking impact load. A highly integrated and lightweight drive system has been designed, integrating motor drive, gear drive, and adaptive torque limiting device to achieve adaptive control of the deployment torque of the solar array. A dynamic simulation system for the entire process of a large-scale spatial solar array based on the Kane method and ADAMS model has been established. A two-dimensional secondary deployable motion control law for a large-scale solar array using an active speed-limit mechanism has been established, and the dynamic characteristic parameters of the active speed-limit driving mechanism have been determined, such as driving torque, driving mode, and driving speed. The results can be used to guide the design of the deployable driving mechanism for large-scale spatial solar arrays. Full article
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16 pages, 6169 KiB  
Article
Research on the Application of Domestic High-Modulus Carbon Fiber/Epoxy Composites to Solar Panels for Solar Arrays
by Shuli Yang, Limin Shao, Jingya Ma, Shouzhi Ren and Yunshuai Chen
Coatings 2023, 13(7), 1259; https://doi.org/10.3390/coatings13071259 - 18 Jul 2023
Cited by 5 | Viewed by 987
Abstract
Based on the new high-modulus carbon fiber CCM40J-6k, which is the critical raw material of a solar panel, the molding process of a mesh face sheet combined with epoxy resin, the overall mechanical performance of a mesh face sheet combined with aluminum honeycomb, [...] Read more.
Based on the new high-modulus carbon fiber CCM40J-6k, which is the critical raw material of a solar panel, the molding process of a mesh face sheet combined with epoxy resin, the overall mechanical performance of a mesh face sheet combined with aluminum honeycomb, the compatibility with polyimide insulation film + solar cell circuit, and the space environment adaptability must pass a test verification and assessment as the premise for large-scale orbit applications. Therefore, based on the traditional carbon fiber M40JB-6k as a reference, a systematic verification project was conducted to apply the CCM40J-6k carbon fiber composite at the process, component, and assembly levels. Six aspects of testing and verifying items were conducted, including mechanical properties under room temperature and thermal shock conditions, bonding force of mesh nodes, comparison of the adaptability of domestic and imported carbon fiber substrates to high–low temperature alternation, the ability of domestic carbon fiber substrates to adapt to the thermal environment after laying solar cell circuits, and in-orbit lifespan of solar panels. Based on the verification results, the mechanical properties of the substrate are the same as those of the imported M40JB-6k, and the actual molding process for M40JB-6k can be utilized. Sample pieces of the substrates can withstand the thermal shock and thermal cycling tests. The bending stiffness of the sample pieces before and after the tests is 3.5%~9.6% higher, and the bending strength is 4.2%~7.2% lower. The tensile strength of mesh nodes made of domestic carbon fiber is 18.9% higher than that of mesh nodes made of imported carbon fiber. The CCM40J-6k substrate is similar to triple-junction GaAs solar cells. The change rates of the open-circuit voltage and the short-circuit current of solar panels based on domestic carbon fiber after fatigue thermal cycling with 2070 cycles are 0.55% and 0.24%, respectively. The above results indicate that the comprehensive performance of the domestic carbon fiber CCM40J-6k meets the requirements and can be applied to solar panels for solar arrays. Full article
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9 pages, 5005 KiB  
Article
Optoelectronic Properties of Ferroelectric Composites of Bi3.25La0.75Ti3O12 (BLT) and Co-Doped BLT Thin Films Modified by FeCo-Doped BLT
by Rui Tang, Rui He, Sangmo Kim and Chung Wung Bark
Coatings 2023, 13(7), 1223; https://doi.org/10.3390/coatings13071223 - 8 Jul 2023
Viewed by 797
Abstract
Driven by the growing demand for renewable and clean energy, the photovoltaic effect of various solar cells and materials was investigated for the conversion of light energy into electricity. We modified the Bi3.25La0.75Ti3O12 (BLT) and Co-doped [...] Read more.
Driven by the growing demand for renewable and clean energy, the photovoltaic effect of various solar cells and materials was investigated for the conversion of light energy into electricity. We modified the Bi3.25La0.75Ti3O12 (BLT) and Co-doped BLT (Co–BLT) composites with Fe and Co-doped BLT (FeCo–BLT) films to narrow the bandgap and increase visible light absorption, thereby improving the efficiency of the photovoltaic reaction. In this study, BLT and Co–BLT thin films were fabricated by off-axis sputtering and then modified with FeCo–BLT thin films to produce dual-ferroelectric, thin-film composite materials that improved the photovoltaic power generation performance. Photoelectric test results showed that the modified double-ferroelectric, thin-film composites had superior optoelectronic properties. The current density was significantly enhanced by modifying the BLT films with doped Fe and Co. Therefore, this modification improved the efficiency of ferroelectric thin-film photovoltaic reactions. Full article
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10 pages, 4936 KiB  
Article
Effect of the Working Pressure and Oxygen Gas Flow Rate on the Fabrication of Single-Phase Ag2O Thin Films
by Jiyoon Choi, Jiha Seong, Sangbin Park, Hyungmin Kim, Sangmo Kim, Kyung Hwan Kim and Jeongsoo Hong
Coatings 2023, 13(6), 1061; https://doi.org/10.3390/coatings13061061 - 7 Jun 2023
Viewed by 1163
Abstract
Ag2O thin films have been applied in various devices, such as photodetectors, photocatalysts, and gas sensors, because of their excellent thermal stability, strong electrical properties, and stable structures. However, because various phases of silver oxide exist, the fabrication of single-phase Ag [...] Read more.
Ag2O thin films have been applied in various devices, such as photodetectors, photocatalysts, and gas sensors, because of their excellent thermal stability, strong electrical properties, and stable structures. However, because various phases of silver oxide exist, the fabrication of single-phase Ag2O thin films using a general deposition system is difficult. In this study, Ag2O thin films were deposited on glass substrates at different working pressures and O2 gas flow rates using a facing-target sputtering (FTS) system. After optimizing the working pressure and O2 gas flow rate, the Ag2O thin films were post-annealed at different temperatures ranging from 100 to 400 °C to improve their crystallographic properties. The X-ray diffraction patterns of the as-fabricated Ag2O thin films indicated the presence of a single phase of Ag2O, and the ultraviolet–visible (UV–vis) spectral analysis indicated transmittance of 65% in the visible light region. The optimum working pressure and O2 gas flow rate were determined to be 4 mTorr and 3.4 sccm, respectively. Finally, the effect of the post-annealing temperature on the thin film was investigated; the Ag2O peak had high intensity at 300 °C, suggesting this as the optimum post-annealing temperature. Full article
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13 pages, 2190 KiB  
Article
In-Situ Piezoelectric Effect for Augmenting Performance of Self-Powered ZnO-Based Photodetector
by Thi My Huyen Nguyen and Chung Wung Bark
Coatings 2023, 13(5), 921; https://doi.org/10.3390/coatings13050921 - 14 May 2023
Cited by 4 | Viewed by 1167
Abstract
In this study, an in-situ piezoelectric effect is integrated into a photoactive region to develop a self-powered ultraviolet photodetector based on a p-n junction of ZnO@Polyvinylidene fluoride (PVDF) and poly [9,9-dioctylfluorene-co-N-[4-(3-methylpropyl)]-diphenylamine] (TFB). A ZnO@β-PVDF nanocomposite is fabricated using PVDF with the β-phase as [...] Read more.
In this study, an in-situ piezoelectric effect is integrated into a photoactive region to develop a self-powered ultraviolet photodetector based on a p-n junction of ZnO@Polyvinylidene fluoride (PVDF) and poly [9,9-dioctylfluorene-co-N-[4-(3-methylpropyl)]-diphenylamine] (TFB). A ZnO@β-PVDF nanocomposite is fabricated using PVDF with the β-phase as the polymer matrix and ZnO nanoparticles as fillers. The strong piezoelectricity of β-PVDF can facilitate the separation and transport of photogenerated electrons in the depletion area and considerably reduce the dark current when the device is polarized with an external bias, resulting in an improvement in the on/off ratio and detectivity. Under 365-nm UV illumination, the as-fabricated device exhibits a high detectivity of 4.99 × 1011 Jones, an excellent on/off ratio (up to 2.75 × 104), and a fast response speed of 46/53 ms (rise/fall times). The device functions stably over approximately 1000 continuous on/off cycles and exhibits extremely long-lasting photostability when exposed to UV light. The findings demonstrate a promising strategy for enhancing the performance of photodetectors for industrial applications. Full article
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Review

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16 pages, 3793 KiB  
Review
Review on the Solar-Driven Photocathodic Protection of Metals in the Marine Environment
by Mingbo Yang, Ruizhe Jiang, Jinke Zhu, Xuan Zhang, Guidong Li, Weitao Li, Fubin Ma, Xueqing Jiang and Hong Li
Coatings 2024, 14(3), 276; https://doi.org/10.3390/coatings14030276 - 25 Feb 2024
Viewed by 776
Abstract
Photocathodic protection (PCP) technology has gained wide attention in the field of corrosion due to its green, environmentally friendly, and sustainable characteristics, and has become a protection technology with broad development prospects in the future marine environment. By investigating recent research results, the [...] Read more.
Photocathodic protection (PCP) technology has gained wide attention in the field of corrosion due to its green, environmentally friendly, and sustainable characteristics, and has become a protection technology with broad development prospects in the future marine environment. By investigating recent research results, the mainstream photoanode materials are TiO2, BiVO4, g-C3N4, ZnO, In2O3, SrTiO3 and other materials. Among them, TiO2 is an ideal photoanode material for PCP because of its efficient photochemical corrosion resistance, remarkable reaction stability, and excellent photoelectric properties. However, TiO2 itself has more drawbacks, such as limited utilization of visible light and low photogenerated electron-hole separation efficiency. These defects limit the wide application of TiO2 in PCP. Through modification methods, the reaction efficiency can be substantially improved and the availability of TiO2 can be increased. This paper lists the research progress of modifying TiO2 materials using metal and non-metal doping modification, semiconductor compounding technology, and energy storage materials for application in PCP, and introduces several new types of photoanode materials. This paper suggests new ideas for the design of more efficient photoanodes. Full article
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16 pages, 4495 KiB  
Review
On Numerical Modelling and an Experimental Approach to Heterojunction Tandem Solar Cells Based on Si and Cu2O/ZnO—Results and Perspectives
by Laurentiu Fara, Irinela Chilibon, Ileana Cristina Vasiliu, Dan Craciunescu, Alexandru Diaconu and Silvian Fara
Coatings 2024, 14(3), 244; https://doi.org/10.3390/coatings14030244 - 20 Feb 2024
Viewed by 785
Abstract
A comparative analysis of three advanced architectures for tandem solar cells (SCs) is discussed, respectively: metal oxide, thin film, and perovskite. Plasmonic solar cells could further increase solar cell efficiency. Using this development, an innovative PV technology (an SHTSC based on metal oxides) [...] Read more.
A comparative analysis of three advanced architectures for tandem solar cells (SCs) is discussed, respectively: metal oxide, thin film, and perovskite. Plasmonic solar cells could further increase solar cell efficiency. Using this development, an innovative PV technology (an SHTSC based on metal oxides) represented by a four-terminal Cu2O/c-Si tandem heterojunction solar cell is investigated. The experimental and numerical modelling study defines the main aim of this paper. The experimental approach to SHTSCs is analysed: (1) a Cu2O layer is deposited using a magnetron sputtering system; (2) the morphological and optical characterization of Cu2O thin films is studied. The electrical modelling of silicon heterojunction tandem solar cells (SHTSCs) is discussed based on five simulation tools for the optimized performance evaluation of solar devices. The main novelty of this paper is represented by the following results: (1) the analysis suggests that the incorporation of a buffer layer can improve the performance of a tandem heterojunction solar cell; (2) the effect of interface defects on the electrical characteristics of the AZO/Cu2O heterojunction is discussed; (3) the stability of SHTSCs based on metal oxides is studied to highlight the degradation rate in order to define a reliable solar device. Perspectives on SHTSCs based on metal oxides, as well as Si perovskite tandem solar cells with metal oxides as carrier-selective contacts, are commented on. Full article
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