• Current Photovoltaic Research
• /
• v.3 no.4
• /
• pp.116-120
• /
• 2015

A hybrid transparent conducting layer was applied for Si photodetector. To realize the hybrid transparent conducting layer, a 200 nm-thick ITO layer was deposited onto a Si substrate, following by a solution-processed AgNWs-coating on the ITO. The hybrid transparent conducting layer showed an excellent low electric resistance of $15.9{\Box}/{\Omega}$ with a high optical transparency of 86.89%. Due to these optical and electrical benefits, the hybrid transparent conductor-embedding Si diode provides an extremely high rectifying ratio of 3386. Under light-illumination, the hybrid transparent conductor device provides extremely high photoresponses for broad wavelengths. This implies that a functional design for hybrid transparent conductor is crucial for photoelectric devices and applications.

• Journal of Ocean Engineering and Technology
• /
• v.30 no.1
• /
• pp.57-67
• /
• 2016

As a new technical approach, an attempt was made to realize a photovoltaic system for an eco-environmental leisure ship by simultaneously actuating nine photovoltaic solar panels in association with the application of a sail-controlling system using wind energy. In this approach, the photovoltaic system consisted of a solar module, an inverter, a battery, and the relevant components, while the sail-controlling device was equipped with sail up/down and mast turning systems. The previously mentioned eco-environmental leisure ship utilizes a photovoltaic hybrid system that uses solar and wind energy as renewable energy sources. Furthermore, this research included a performance evaluation of the manufactured prototype, the acquisition of the purposed quantity values, and development of the purposed items. The significant items, including the sail up/down speed (seconds) and mast turning angle (degrees) were evaluated for a performance test. A wind direction sensitivity of 90% and maximum instant charging power of 900 W were also obtained in the process of the performance evaluation. In addition, the maximum sail time was also evaluated in order to acquire the optimum value. The performance evaluation showed that the prototype with a photovoltaic hybrid system was suitable for sailing an eco-environmental leisure ship using solar and wind energy.

• Advances in nano research
• /
• v.2 no.1
• /
• pp.23-56
• /
• 2014

The significant growth of the Si photovoltaic industry has been so far limited due to the high cost of the Si photovoltaic system. In this regard, the most expensive factors are the intrinsic cost of silicon material and the Si solar cell fabrication processes. Conventional Si solar cells have p-n junctions inside for an efficient extraction of light-generated charge carriers. However, the p-n junction is normally formed through very expensive processes requiring very high temperature (${\sim}1000^{\circ}C$). Therefore, several systems are currently under study to form heterojunctions at low temperatures. Among them, carbon nanotube (CNT)/Si hybrid solar cells are very promising, with power conversion efficiency up to 15%. In these cells, the p-type Si layer is replaced by a semitransparent CNT film deposited at room temperature on the n-doped Si wafer, thus giving rise to an overall reduction of the total Si thickness and to the fabrication of a device with cheaper methods at low temperatures. In particular, the CNT film coating the Si wafer acts as a conductive electrode for charge carrier collection and establishes a built-in voltage for separating photocarriers. Moreover, due to the CNT film optical semitransparency, most of the incoming light is absorbed in Si; thus the efficiency of the CNT/Si device is in principle comparable to that of a conventional Si one. In this paper an overview of several factors at the basis of this device operation and of the suggested improvements to its architecture is given. In addition, still open physical/technological issues are also addressed.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.23 no.11
• /
• pp.84-93
• /
• 2009

In this paper, we propose to study the possibility of using a photovoltaic system combined with a high speed micro-turbine. This hybrid system can work as stand-alone system or grid connected system as it will be a part of a micro-grid. Initially, we propose Matlab/Simulink dynamic models of photovoltaic, micro turbine systems and supercapacitor. Then, we carry out a simulation comparison of the two systems, this is, with supercapacitor and without supercapacitor bank. We show that supercapacitor bank as short-term storage device was necessary to reduce the fast fluctuation of power in the case of sensitive loads. It is verified the simulation results of Matlab/Simulink based hybrid power system represent the effectiveness of the suggested hybrid power system.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2010.02a
• /
• pp.97-97
• /
• 2010

We demonstrate the hybrid polymer-quantum dot based multi-functional device (Organic bistable devices, Light-emitting diode, and Photovoltaic cell) with a single active-layer structure consisting of CdSe/ZnS semiconductor quantum-dots (QDs) dispersed in a poly N-vinylcarbazole (PVK) and 1,3,5-tirs- (N-phenylbenzimidazol-2-yl) benzene (TPBi) fabricated on indium-tin-oxide (ITO)/glass substrate by using a simple spin coating technique. The multi-functionality of the device as Organic bistable device (OBD), Light Emitting Diode (LED), and Photovoltaic cell can be successfully achieved by adding an electron transport layer (ETL) TPBi to OBD for attaining the functions of LED and Photovoltaic cell in which the lowest unoccupied molecular orbital (LUMO) level of TPBi is positioned at the energy level between the conduction band of CdSe/ZnS and LiF/Al electrode (band-gap engineering). Through transmission electron microscopy (TEM) study, the active layer of the device has a p-i-n structure of a consolidated core-shell structure in which semiconductor QDs are uniformly and isotropically adsorbed on the surface of a p-type polymer core and the n-type small molecular organic materials surround the semiconductor QDs.

• Current Photovoltaic Research
• /
• v.2 no.4
• /
• pp.152-156
• /
• 2014

We report hybrid solar cells fabricated with polymer/fullerene bulk heterojunction layers that contain inorganic nanocrystals synthesized by in-situ reaction in the presence of polymer chains. The inorganic (cadmium sulfide) nanocrystal ($CdS_{NC}$) was generated by the reaction of cadmium acetate and sulfur by varying the reaction time up to 30 min. The synthesized $CdS_{NC}$ showed a rectangular flake shape, while the size of $CdS_{NC}$ reached ca. 150 nm when the reaction time was 10 min. The performance of hybrid solar cells with $CdS_{NC}$ synthesized for 10 min was better than that of a control device, whereas poor performances were measured for other hybrid solar cells with $CdS_{NC}$ synthesized for more than 10 min.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2013.02a
• /
• pp.299-299
• /
• 2013

Indium Tin Oxide (ITO) has widely been used as a transparent conductive oxide (TCE) for photovoltaic devices. Lately, flexibility of ITO becomes an issue as demand of flexible device increases. Several scientists have tried to substitute ITO to different materials such as conductive polymer, graphene, CNT, and metal nanowire because of ITO brittleness. Among the substitute materials, PEDOT:PSS has mostly paid attention because PEDOT:PSS has excellent flexibility and good conductivity. The conductivity of PEDOT:PSS increases up to 1000 S/cm with additives such as DMSO, EG, sorbitol, and so on. In our research group, we introduce a conductive polymer PEDOT:PSS as a buffer layer to improve not only flexibility but also conductivity. As PEDOT:PSS layer forms beneath ITO thin film (20 nm), sheet resistance decreases from $230{\Omega}$/${\Box}$ to $85{\Omega}$/${\Box}$ and crack initiation decreases from 4.5 mm to 3.5 mm as well. We have fabricated organic photovoltaic device and power conversion efficiencies using conventional ITO electrode and ITO/PEDOT:PSS hybrid electrode. The photovoltaic property such as power conversion efficiency for ITO/PEDOT:PSS hybrid electrode is comparable to the value obtained using conventional ITO electrode on glass substrate.

• Journal of IKEEE
• /
• v.25 no.4
• /
• pp.716-720
• /
• 2021

In this study, we examine the availability of a cooling patch to enhance the output power of a hybrid energy device (HED) comprising a photovoltaic cell (PVC) and a thermoelectric generator (TEG). The cooling patch attached on the back of the TEG drops the temperature of the PVC via the TEG and makes a large thermal gradient across the TEG under irradiances in a range of 200 to 1000 W/m². The cooling patch is more effective for the output power of the HED as the irradiance increases, and it enhances the maximum output power of the HED to 42.1 mW at an irradiance of 1000 W/m². The increment in the maximum output power reaches 27% owing to the attachment of the cooling patch that does not consume any power.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.38 no.11
• /
• pp.907-914
• /
• 2014

The objective of this study was to increase the generating efficiency of concentrated photovoltaics (CPV) by using hybrid solar tracking. Further, the proposed system was demonstrated to have the ability to extract thermal energy from a concentrated photovoltaic system by using thermal absorbers containing heat pipe, which could then be used for a heating system or hot-water supply. The average electrical efficiency was 16 during the day, and the average thermal efficiency was 62. Therefore, this system demonstrated a total efficiency (electrical thermal) of 78. All the processes, i.e., tracking of the sun, calculation of the sun's position, reinstatement of the heating device toward the east for tracking on the next day, and system shutdown, were programmed using Simulink. A parametric analysis of the heat pipe, concentration ratio, and inlet velocity was also performed in terms of the operating temperature of the CPV and the outlet temperature. The simulation and experimental results for the thermal absorber were found to be in good agreement.

• Proceedings of the KIPE Conference
• /
• 2001.10a
• /
• pp.534-538
• /
• 2001

Energy storage devices with high energy density as well as high power density are expected to be developed from the point of view of compensation of fluctuating load and generated power by distributed generations such as wind turbines, photovoltaic cells and so on. SMES (Superconducting Magnetic Energy Storage) has higher power density than other energy storage methods, and secondary batteries have higher energy density than SMES. The hybrid energy storage device using SMES and secondary batteries is proposed as the energy storage method with higher power and energy density, the sharing method of power reference value for each storage device, simulation and experimental results are presented.