Short-circuit and open-circuit faults monitoring of IGBTs in solid-state-transformers using collector-emitter voltage

We report an inexpensive method using solvent-swollen poly(methyl methacrylate) as a sacrificial template for mesoporous titanium oxide thin films with tunable meso/nano morphology. The conversion efficiency reaches 4.2% despite using a solid-state electrolyte, which circumvents the longevity issues of liquid electrolytes. The cells show a large short-circuit photocurrent density of 7.98 mA, open-circuit voltage of 0.78 V, and maximum conversion efficiency of 4.2% under air-mass 1.5 global illumination. At higher titania precursor ratios, nanodisk particles are formed that increase light scattering and double the efficiency over our previous reports. The tunability of the semiconductor morphology and all solid-state nature of the cells makes the method a viable alternative to existing solar cell technology.

Download Full-text

Molecular Weight Effects of Biscarbazole-Based Hole Transport Polymers on the Performance of Solid-State Dye-Sensitized Solar Cells

Nanomaterials ◽

10.3390/nano10122516 ◽

2020 ◽

Vol 10 (12) ◽

pp. 2516

Author(s):

Minseon Kong ◽

Kyeong Seok Kim ◽

Nguyen Van Nga ◽

Yeonju Lee ◽

Yu Seong Jeon ◽

...

Keyword(s):

Molecular Weight ◽

Solar Cells ◽

Solid State ◽

Short Circuit ◽

Dye Sensitized Solar Cells ◽

Open Circuit ◽

Hole Transport ◽

Dye Sensitized ◽

Liquid Electrolytes ◽

Sensitized Solar Cells

The leakage and volatilization of liquid electrolytes limit the commercialization of dye-sensitized solar cells (DSCs). As solid-state (ss) hole-transporting materials, free from leakage and volatilization, biscarbazole-based polymers with different molecular weights (PBCzA-H (21,200 g/mol) and PBCzA-L (2450 g/mol)) were applied in combination with additives to produce ssDSCs. An ssDSC with PBCzA-H showed a better short-circuit current (Jsc), open-circuit voltage (Voc), and fill factor (FF) than a device with PBCzA-L, resulting in 38% higher conversion efficiency. Compared to the PBCzA-L, the PBCzA-H with a higher molecular weight showed faster hole mobility and larger conductivity, leading to elevations in Jsc via rapid hole transport, Voc via rapid hole extraction, and FF via lowered series and elevated shunt resistances. Thus, it is believed that PBCzA-H is a useful candidate for replacing liquid electrolytes.

Download Full-text

Extremely Thin Absorber Layers in Solid State Solar Cells

MRS Proceedings ◽

10.1557/proc-822-s7.5 ◽

2004 ◽

Vol 822 ◽

Author(s):

A. Bellaidi ◽

K. Ernst ◽

R. Könenkamp

Keyword(s):

Solid State ◽

Electrical Properties ◽

Open Circuit Voltage ◽

Short Circuit ◽

Short Circuit Current ◽

Open Circuit ◽

Optical And Electrical Properties ◽

Transfer Rates ◽

Ideal Tool ◽

Extremely Thin Absorber

AbstractWe report on recent progress in fabricating an inorganic solid state solar cell based on a nano-structured substrate with an extremely thin absorber, the so-called eta-cell. The cell uses HgCdTe as an absorber layer and TiO2 as a substrate. By adjusting the Hg/Cd ratio the conduction band edges in these two materials can be brought into alignment. This tuning provides an ideal tool to optimize the optical and electrical properties of the cell. In qualitative agreement with earlier work we find a band offset of 0.25 eV to give maximum transfer rates across the interface. The optimized cell has a short circuit current of 15 mA/cm2 and an open-circuit voltage of 0.6 V. We discuss the optical and electrical properties of the cell, and outline ideas to further improve the performance.

Download Full-text

Effect of In2S3 Buffer Layer in TiO2/In2S3/CuInS2 Structure

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.702.123 ◽

2013 ◽

Vol 702 ◽

pp. 123-127

Author(s):

Wei Jei Tzeng ◽

Mei Lun Wu ◽

Li Jiaun Lin ◽

Horng Yi Chang

Keyword(s):

Solid State ◽

Buffer Layer ◽

White Light ◽

Open Circuit Voltage ◽

Short Circuit ◽

Short Circuit Current ◽

Open Circuit ◽

Nanotube Arrays ◽

Thickness Increase ◽

Thin Structure

The anodized TiO2nanotube arrays (TNAs) have a benefit to provide large surfaces and straight electron transmitting routes to the electrode. However, it is difficult to fulfill with solid state electrolytes or photosensitive materials into the long TiO2nanotubes. The substrate of Ti/wave-like TiO2was prepared by peel-off the TNAs. The In2S3buffer layer between wave-like TiO2and CuInS2determines the photosensitivity of the Ti/wave-like TiO2/In2S3/CuInS2thin structure. The In2S3and CuInS2are well-crystallized at 300oC. The CuInS2phase forms in In2S3layer due to Cu diffusion independent on the slight loss of sulfur. The CuInS2direct deposition on Ti/wave-like TiO2substrate can not exhibit photosensitivity. When CuInS2deposited on In2S3to form Ti/wave-like TiO2/In2S3/CuInS2structure, the short-circuit current and the open-circuit voltage increase with the thickness increase of In2S3layer while illuminated by 50 mW/cm2white light.

Download Full-text

Development of fullerene derivatives with high LUMO level through changes in π-conjugated system shape

Pure and Applied Chemistry ◽

10.1351/pac-con-11-11-01 ◽

2012 ◽

Vol 84 (4) ◽

pp. 945-952 ◽

Cited By ~ 6

Author(s):

Yutaka Matsuo

Keyword(s):

Solid State ◽

Current Density ◽

Short Circuit ◽

Short Circuit Current ◽

Short Circuit Current Density ◽

Open Circuit ◽

Fullerene Derivative ◽

Supramolecular Organization ◽

High Electron ◽

Organic Thin Film

This article describes a concept for designing fullerene-based electron-accepting materials to obtain high open-circuit voltage (VOC) in organic thin-film photovoltaic devices without an accompanying decrease in short-circuit current density. The keys to this concept are (1) reducing the size of the fullerene π-conjugated system to realize high VOC and (2) shortening the inter-fullerene distance in the solid-state packing structure to achieve high short-circuit current density (JSC), which is made possible by well-designed supramolecular organization or a small organic addend. In this article, two representative examples are discussed. One is 1,4-bis(silylmethyl)[60]fullerene (SIMEF), which forms a columnar fullerene-core array for high electron mobility and undergoes thermal crystallization for good phase separation with the electron-donating material. The other is a 56π-electron fullerene derivative bearing a dihydromethano group, the smallest carbon addend, which does not disrupt fullerene–fullerene contact in the solid state.

Download Full-text

Solid state PbS Quantum dots /TiO2 Nanoparticles heterojunction solar cell

MRS Proceedings ◽

10.1557/opl.2012.723 ◽

2012 ◽

Vol 1390 ◽

Author(s):

Lioz Etgar ◽

Michael Grätzel

Keyword(s):

Quantum Dots ◽

Solar Cells ◽

Solid State ◽

Short Circuit ◽

Open Circuit ◽

Layer By Layer ◽

Heterojunction Solar Cells ◽

Layer Deposition ◽

Pbs Quantum Dots ◽

Open Circuit Photovoltage

ABSTRACTSolid state PbS Quantum Dots (QDs)/TiO2 Nanoparticles heterojunction solar cells were produced by depositing PbS QDs on a 500nm thick Mesoscopic TiO2 films using layer-by-layer deposition. The heterojunction solar cells show photovoltaic response from the visible to the near infra-red region. Importantly, the PbS QDs act here as photosensitizers and at the same time as hole conductors. The PbS QDs/TiO2 device produces a remarkable short circuit photocurrent (Jsc) of 16.3 mA/cm2, an open circuit photovoltage (Voc) of 0.54 V and a fill factor (FF) of 0.41, corresponding to a light to electric power conversion efficiency (η) of 4.04% under 0.9 sun intensity.

Download Full-text

Dye Sensitized Solar Cell Based on Polyethylene Glycol/4,4’-Diphenylmethane Diisocyanate Copolymer Quasi Solid State Electrolyte

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.625.140 ◽

2014 ◽

Vol 625 ◽

pp. 140-143

Author(s):

Liow Kai Sing ◽

Coswald Stephen Sipaut ◽

Rachel Fran Mansa ◽

Jedol Dayou

Keyword(s):

Polyethylene Glycol ◽

Solid State ◽

Open Circuit Voltage ◽

Short Circuit ◽

Short Circuit Current ◽

Open Circuit ◽

Diphenylmethane Diisocyanate ◽

Solid State Electrolyte ◽

Dye Sensitized ◽

Low Reaction Temperature

In this study, quasi-solid state electrolyte (QSE) was prepared by blending the polyethylene glycol (PEG) with molecular weight of 400, 4,4’-diphenylmethane diisocyanate (MDI), potassium iodide (KI) and iodine (I2) under a low reaction temperature (50oC) for two hours. QSEs with a different ratio of PEG to MDI were formulated. Adding 15 vol% of MDl into the QSE was found to give the highest open circuit voltage, short circuit current and energy conversion efficient, which were 360 mV, 0.077 mA/cm2 and 0.02% respectively.

Download Full-text

TiO2/Solid State Polymer Junction for Photovoltaic Application

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.576.623 ◽

2012 ◽

Vol 576 ◽

pp. 623-625 ◽

Cited By ~ 1

Author(s):

Iraj Alaei ◽

Souad A.M. Al-Bat’hi

Keyword(s):

Solid State ◽

Polymer Electrolyte ◽

Short Circuit ◽

Short Circuit Current ◽

Short Circuit Current Density ◽

Open Circuit ◽

Photovoltaic System ◽

Light Illumination ◽

Photovoltaic Application ◽

Solution Cast

Solid state polymer electrolyte blend of polyethylene oxide, chitosan, ammonium iodide, and iodine crystals has been prepared by solution cast technique. The highest ionic conductivity of the polymer electrolyte was 1.18 × 10−5 S cm−1 at room temperature. Addition of chitosan to the electrolyte has improved its mechanical properties. A photovoltaic junction with configuration ITO/TiO2-solid state polymer blend electrolyte/ITO has been constructed. The open circuit voltage Voc, short circuit current density Jsc, and fill factor FF% obtained from the photovoltaic system under white light illumination of 100W Tungsten lamp are 320-350 mV, 0.59-2.5μAcm-2 and 42%-59% respectively.

Download Full-text

Lock-in Thermography-Based Local Efficiency Analysis of Solar Cells

ISTFA 2012: Conference Proceedings from the 38th International Symposium for Testing and Failure Analysis ◽

10.31399/asm.cp.istfa2012p0250 ◽

2012 ◽

Author(s):

Otwin Breitenstein

Keyword(s):

Solar Cells ◽

Short Circuit ◽

Efficiency Analysis ◽

Open Circuit ◽

Local Defect ◽

Whole Cell ◽

Local Efficiency ◽

Cell Efficiency ◽

Lock In ◽

Efficiency Data

Abstract The electronic properties of solar cells, particularly multicrystalline silicon-based ones, are distributed spatially inhomogeneous, where regions of poor quality may degrade the performance of the whole cell. These inhomogeneities mostly affect the dark current-voltage (I-V) characteristic, which decisively affects the efficiency. Since the grid distributes the local voltage homogeneously across the cell and leads to lateral balancing currents, local light beam-induced current methods alone cannot be used to image local cell efficiency parameters. Lock-in thermography (LIT) is the method of choice for imaging inhomogeneities of the dark I-V characteristic. This contribution introduces a novel method for evaluating a number of LIT images taken at different applied biases. By pixel-wise fitting the data to a two diode model and taking into account local series resistance and short circuit current density data, realistically simulated images of the other cell efficiency parameters (open circuit voltage, fill factor, and efficiency) are obtained. Moreover, simulated local and global dark and illuminated I-V characteristics are obtained, also for various illumination intensities. These local efficiency data are expectation values, which would hold if a homogeneous solar cell had the properties of the selected region of the inhomogeneous cell. Alternatively, also local efficiency data holding for the cell working at its own maximum power point may be generated. The amount of degradation of different cell efficiency parameters in some local defect positions is an indication how dangerous these defects are for degrading this parameter of the whole cell. The method allows to virtually 'cut out' certain defects for checking their influence on the global characteristics. Thus, by applying this method, a detailed local efficiency analysis of locally inhomogeneous solar cells is possible. It can be reliably predicted how a cell would improve if certain defects could be avoided. This method is implemented in a software code, which is available.

Download Full-text

Calcium transport in turtle bladder

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.1987.253.6.r917 ◽

1987 ◽

Vol 253 (6) ◽

pp. R917-R921

Author(s):

S. Sabatini ◽

N. A. Kurtzman

Keyword(s):

Calcium Transport ◽

Calcium Absorption ◽

Short Circuit ◽

Open Circuit ◽

Calcium Flux ◽

Bladder Epithelium ◽

Control Value ◽

Sodium Calcium ◽

Turtle Bladder ◽

Absorptive Flux

Unidirectional 45Ca fluxes were measured in the turtle bladder under open-circuit and short-circuit conditions. In the open-circuited state net calcium flux (JnetCa) was secretory (serosa to mucosa) and was 388.3 +/- 84.5 pmol.mg-1.h-1 (n = 20, P less than 0.001). Ouabain (5 X 10(-4) M) reversed JnetCa to an absorptive flux (serosal minus mucosal flux = -195.8 +/- 41.3 pmol.mg-1.h-1; n = 20, P less than 0.001). Amiloride (1 X 10(-5) M) reduced both fluxes such that JnetCa was not significantly different from zero. Removal of mucosal sodium caused net calcium absorption; removal of serosal sodium caused calcium secretion. When bladders were short circuited, JnetCa decreased to approximately one-third of control value but remained secretory (138.4 +/- 54.3 pmol.mg-1.h-1; n = 9, P less than 0.025). When ouabain was added under short-circuit conditions, JnetCa was similar in magnitude and direction to ouabain under open-circuited conditions (i.e., absorptive). Tissue 45Ca content was approximately equal to 30-fold lower when the isotope was placed in the mucosal bath, suggesting that the apical membrane is the resistance barrier to calcium transport. The results obtained in this study are best explained by postulating a Ca2+-ATPase on the serosa of the turtle bladder epithelium and a sodium-calcium antiporter on the mucosa. In this model, the energy for calcium movement would be supplied, in large part, by the Na+-K+-ATPase. By increasing cell sodium, ouabain would decrease the activity of the mucosal sodium-calcium exchanger (or reverse it), uncovering active calcium transport across the serosa.

Download Full-text