• Proceedings of the Korean Vacuum Society Conference
• /
• 2010.08a
• /
• pp.311-312
• /
• 2010

The fabricated photovoltaic cells based on PIN heterojunctions, in this study, have a structure of ITO/poly(3, 4-ethylenedioxythiophene)-poly(styrenesulfonate)(PEDOT:PSS)/donor/donor:C60(10nm)/C60(35nm)/2, 9-dimethyl-4, 7-diphenyl-1, 10-phenanthroline(8nm)/Al(100nm). The thicknesses of an active layer(donor:C60), an electron transport layer(C60), and hole/exciton blocking layer(BCP) were fixed in the organic photovoltaic cells. We investigated the performance characteristics of the PIN organic photovoltaic cells with copper phthalocyanine(CuPc), tetracene and pentacene as a hole transport layer. Discussion on the photovoltaic cells with CuPc, tetracene and pentacene as a hole transport layer is focussed on the dependency of the power conversion efficiency on the deposition rate and thickness of hole transport layer. The device performance characteristics are elucidated from open-circuit-voltage(Voc), short-circuit-current(Jsc), fill factor(FF), and power conversion efficiency($\eta$). As the deposition rate of donor is reduced, the power conversion efficiency is enhanced by increased short-circuit-current(Jsc). The CuPc-based PIN photovoltaic cell has the limited dependency of power conversion efficiency on the thickness of hole transport layer because of relatively short exciton diffusion length. The photovoltaic cell using tetracene as a hole transport layer, which has relatively long diffusion length, has low efficiency. The maximum power conversion efficiencies of CuPc, tetracene, and pentacene-based photovoltaic cells with optimized deposition rate and thickness of hole transport layer have been achieved to 1.63%, 1.33% and 2.15%, respectively. The photovoltaic cell using pentacene as a hole transport layer showed the highest efficiency because of dramatically enhanced Jsc due to long diffusion length and strong thickness dependence.

• Journal of the Korean Solar Energy Society
• /
• v.38 no.3
• /
• pp.21-28
• /
• 2018

The objects of PV (Photovoltaic) monitoring system is to reduce the loss of system and operation and maintenance costs. In case of PV plants with configured of centralized inverter type, only 1 PV module might be caused a large loss in the PV plant. For this reason, the monitoring technology of PV module-level that find out the location of the fault module and reduce the system losses is interested. In this paper, a fault diagnosis algorithm are proposed using thermal and electrical characteristics of PV modules under failure. In addition, the monitoring system applied with proposed algorithm was constructed. The wireless sensor using LoRa chip was designed to be able to connect with IoT device in the future. The characteristics of PV module by shading is not failure but it is treated as a temporary failure. In the monitoring system, it is possible to diagnose whether or not failure of bypass diode inside the junction box. The fault diagnosis algorithm are developed on considering a situation such as communication error of wireless sensor and empirical performance evaluation are currently conducting.

• Journal of the Korean Institute of Telematics and Electronics
• /
• v.15 no.1
• /
• pp.5-11
• /
• 1978

Si-ZnSe n-n heterojunction was made by growing ZnSe thin film on the Si single crystal (111) surface with Bash evaporating method in vacuum. This heterojunction was found to be a useful device for frequency meter in the visible wave-length from the measuring of the photovoltaic effect of the heterojunction.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.24 no.5
• /
• pp.351-354
• /
• 2011

This paper was carried about thermal analysis for high efficiency point contact solar cell. Therefore, we carried about 2-D device and process simulator according to design and process parameters. As a result of simulations, power transfer efficiency have decreased more increasing temperature. Especially, power transfer efficiency of room temperature have been showed 25%. The other hand, power transfer efficiency of 350 K kalvin temperature have been showed 20%. Therefore, we will considered design with thermal dissipation of device.

• Current Photovoltaic Research
• /
• v.2 no.4
• /
• pp.157-167
• /
• 2014

Colloidal quantum dot (CQD) solar cells have attracted great attention due to their cost-effectiveness and solution-processability, as well as their size-dependent optical and electrical properties. The power conversion efficiency of CQD solar cells has rapidly increased up to ~8.6%, which corresponds to the 3 - 4 fold improvement during the last 3 - 4 years. Up to now, there have been many pioneering results in CQD solar cells. Here, we review the recent progress of CQD solar cells including CQD synthesis strategy and device structure engineering.

• Proceedings of the KIEE Conference
• /
• 2006.07a
• /
• pp.18-19
• /
• 2006

The recent interest in distributed generation (DG) due to the opening of the electricity market and the need for alternatives to conventional fossil fuel-based electricity generation has created renewed interest in grid-connected photovoltaic(PV) systems. Many studies are being performed at the power system level to examine the impacts of grid-connected PV systems and several models for PV arrays have been proposed in the literature. However, the complexity of these models and difficulties of implementing them in various software programs can be deterrents to their use. This paper proposes a robust and flexible PV device model suitable for dynamic and transient studies where the PV array's non-linear DC characteristics are important. The model's implementation in software is straightforward and it can even be constructed using standard software library components, as demonstrated using PSCAD/EMTDC.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.25 no.4
• /
• pp.270-275
• /
• 2012

Power MOSFET(metal oxide silicon field effect transistor) operate voltage-driven devices, design to control the large power switching device for power supply, converter, motor control, etc. But on-resistance characteristics depending on the increasing breakdown voltage spikes is a problem. So 600 V planar power MOSFET compare to 1/3 low on-resistance characteristics of super junction MOSFET structure. In this paper design to 600 V planar MOSFET and super junction MOSFET, then improvement of comparative analysis breakdown voltage and resistance characteristics. As a result, super junction MOSFET improve on about 40% on-state voltage drop performance than planar MOSFET.

• Current Photovoltaic Research
• /
• v.5 no.4
• /
• pp.145-149
• /
• 2017

Transition metal dichalcogenides (TMDs) have attracted much attention because of their excellent optical and electrical properties, which are the applications of next generation photoelectric devices. In this study, $MoS_2$, which is a representative material of TMDs, was formed by magnetic sputtering method and surface changes and optical characteristics were changed with thickness variation. In addition, by implementing the photodetector of $MoS_2/p-Si$ structure, it was confirmed that the change of the electrical properties rather than the change of the optical properties according to the thickness change of $MoS_2$ affects the photoresponse ratio of the photodetector. This result can be used to fabricate effective photoelectric devices using $MoS_2$.

• Proceedings of the Materials Research Society of Korea Conference
• /
• 2009.05a
• /
• pp.11.1-11.1
• /
• 2009

Bulk-heterojunction type organic photovoltaic cells have been remarkably improved due to the development of efficient donors and post treatment process. However, most of researchers have studied on the OPVs using spin-coating method during the past decade. To commercialize the OPVs, much cheaper printing process should be developed such as inkjet, screen, gravure, and so on. In this study, we have focused on the development of printing technology using Inkjet and Aerosol-Jet printing, which can offer reliable device performance. Finally, 4.5% power conversion efficiency can be achieved under AM 1.5 1sun light illumination, which is the highest value in printed OPVs. We reveal that substantial improvement can be realized by highly efficient bulk heterojunction after printing. Also, we can confirm these two printing methods are promising fabrication methods for large area OPVs. Also, flexible and large area (18 cm2) printed OPVs have been fabricated and device performance will be discussed in detail.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2010.08a
• /
• pp.313-313
• /
• 2010

The performance of polymer photovoltaic cells based on blends of poly(3-hexylyhiophene) (P3HT) and phenyl-C61-butyric acid methyl ester (PCBM) is strongly influenced by blend composition and thickness. Polymer photovoltaic cells based on bulk-heterojunction have been fabricated with a structure of ITO/poly(3, 4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS)-pentacene/poly (3-hexylthiophene) (P3HT):phenyl-C61-butyric acid methyl ester (PCBM)/Al. We have prepared PEDOT:PSS by dissolving pentacene in N-methylpyrrolidine (NMP) and mixing with PEDOT:PSS. Pentacene was added a maximum concentration of approximately 5.5mg to the PEDOT:PSS solution and sonicated for 10 min. Active layer (P3HT:PCBM) (1:1) was strongly influenced by PEDOT:PSS-pentacene. We have investigated the performance of photovoltaic device with different concentration of P3HT:PCBM (1:1) 2.0wt%, 2.2wt%, 2.4wt% and 2.6wt%, respectively. The photocurrent and power conversion efficiency (PCE) showed a maximum between 2.0wt% and 2.2wt% concentration of P3HT:PCBM. This implied that both morphology and electron transport properties of the layer influenced the performance of the present photovoltaic cells. As the concentration of P3HT:PCBM blends as an active layer was increased, the power conversion efficiency was decreased. P3HT:PCBM layer and PEDOT:PSS-pentacene layer were characterized by work function, UV-visible absorption, atomic force microscopy (AFM), X-ray diffraction (XRD) and scanning electron microscope (SEM).