Analysis of Strain Compensation in Quantum Dot Embedded GaAs Solar Cells

2007 ◽  
Vol 1031 ◽  
Author(s):  
Christopher Bailey ◽  
Cory Cress ◽  
Ryne Raffaelle ◽  
Seth Hubbard ◽  
William Maurer ◽  
...  

AbstractThe effects of strain within stacked layers of InAs quantum dots (QDs) were investigated. InAs QD test structures with and without strain compensation (SC) were analyzed using atomic force microscopy, transmission electron microscopy, and X-ray diffraction. The affects of strain compensation on test structure morphology and on GaAs-based QD solar cell performance was studied as a function of the thickness of the SC layer. X-ray diffraction analysis of the QD embedded test structures reveals a relationship between the SC thickness and the observed crystalline quality. Air mass zero illuminated current vs. voltage data and spectral responsivity measurements were used for the solar cell comparison. When SC is employed, QD insertion shows a lower open circuit voltage, in reference to a baseline device without QDs, but leads to an enhancement in the short circuit current of the device.

Crystals ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 609 ◽  
Author(s):  
Charith Jayathilaka ◽  
Loku Singgappulige Rosantha Kumara ◽  
Koji Ohara ◽  
Chulho Song ◽  
Shinji Kohara ◽  
...  

Cuprous oxide (Cu2O) homojunction thin films on Ti substrates were fabricated by an electrochemical deposition in which a p-Cu2O layer was deposited on an n-Cu2O layer by carefully controlled bath conditions. It was found that the open-circuit voltage of the homojunction solar cell was significantly influenced by the pH of the lactate bath. The variation of the pH was used to achieve the best possible crystal orientation for homojunctions. The crystallinity and morphology of the products were characterized by X-ray diffraction (XRD), high-energy x-ray diffraction (HEXRD), and scanning electron microscopy (SEM). The current density voltage (J-V) analysis showed that the sulfur treatment and annealing enhanced the photocurrent by ten-fold compared to the untreated and unannealed homojunction solar cell. X-ray photoelectron spectroscopy (XPS) studies confirmed that the sulfur treatment eliminated the surface CuO and formed a thin layer of CuS, which was very useful to make the front Ohmic contact. Transient measurements confirmed that the p-type Cu2O layer, which was subjected to sulfur treatment, significantly reduced the recombination, thus enhancing the efficiency of the solar cell. The best sulfur treated annealed Ti/n-Cu2O/p-Cu2O/Au solar cell produced an energy conversion efficiency of 2.64% with an open-circuit voltage of 490 mV and a short circuit current density of 12.8 mA cm−2 under AM 1.5 illumination.


Author(s):  
Mingqiang Zhong ◽  
Qin Feng ◽  
Changlai Yuan ◽  
Xiao Liu ◽  
Baohua Zhu ◽  
...  

AbstractIn this work, the (1−x)Bi0.5Na0.5TiO3-xBaNi0.5Nb0.5O3 (BNT-BNN; 0.00 ⩽ x ⩽ 0.20) ceramics were prepared via a high-temperature solid-state method. The crystalline structures, photovoltaic effect, and electrical properties of the ceramics were investigated. According to X-ray diffraction, the system shows a single perovskite structure. The samples show the normal ferroelectric loops. With the increase of BNN content, the remnant polarization (Pr) and coercive field (Ec) decrease gradually. The optical band gap of the samples narrows from 3.10 to 2.27 eV. The conductive species of grains and grain boundaries in the ceramics are ascribed to the double ionized oxygen vacancies. The open-circuit voltage (Voc) of ∼15.7 V and short-circuit current (Jsc) of ∼1450 nA/cm2 are obtained in the 0.95BNT-0.05BNN ceramic under 1 sun illumination (AM1.5G, 100 mW/cm2). A larger Voc of 23 V and a higher Jsc of 5500 nA/cm2 are achieved at the poling field of 60 kV/cm under the same light conditions. The study shows this system has great application prospects in the photovoltaic field.


2021 ◽  
Vol 21 (7) ◽  
pp. 3800-3805
Author(s):  
Abdul Razzaq ◽  
Muhammad Zafar ◽  
Tahir Saif ◽  
Jun Young Lee ◽  
Jung Ki Park ◽  
...  

In this investigation we report the formation of thin ZnO recombination barrier layer at TiO2/CdS interface aimed for the improvement in performance of CdS sensitized solar cell. The film was deposited upon nanocrystalline mesoporous TiO2 surface by following a simple chemical process and characterized, using UV-Visible spectroscopy, X-ray diffraction and electron dispersive X-ray measurements. The insertion of ZnO thin layer enhances the QDSC (Quantum dot sensitized solar cell) performance, contributed mainly by an increase in open circuit voltage (Voc) due to reduced electron back transfer from TiO2 conduction band. Moreover, the analysis of photovoltaic characteristics upon increasing the thickness of the ZnO film reveals that the ZnO recombination barrier layer with optimum thickness at porous TiO2/CdS interface proved to be an effective potential barrier for minimizing electron back recombination.


Energies ◽  
2020 ◽  
Vol 13 (11) ◽  
pp. 2690
Author(s):  
Dariusz Augustowski ◽  
Paweł Kwaśnicki ◽  
Justyna Dziedzic ◽  
Jakub Rysz

The main efficiency loss is caused by an intensive recombination process at the interface of fluorine-doped tin oxide (FTO) and electrolyte in dye-sensitized solar cells. Electrons from the photoanode can be injected back to the redox electrolyte and, thus, can reduce the short circuit current. To avoid this, the effect of the electron blocking layer (EBL) was studied. An additional thin film of magnetron sputtered TiO2 was deposited directly onto the FTO glass. The obtained EBL was characterized by atomic force microscopy, scanning electron microscopy, optical profilometry, energy dispersive spectroscopy, Raman spectroscopy and UV-VIS-NIR spectrophotometry. The results of the current–voltage characteristics showed that both the short circuit current (Isc) and fill factor (FF) increased. Compared to traditional dye-sensitized solar cell (DSSC) architecture, the power conversion efficiency (η) increased from 4.67% to 6.07% for samples with a 7 × 7 mm2 active area and from 2.62% to 3.06% for those with an area of 7 × 80 mm2.


2012 ◽  
Vol 479-481 ◽  
pp. 166-169
Author(s):  
Peng Wang ◽  
Li Bo Fan ◽  
Zhen Hua Zhang ◽  
Yan Lei ◽  
Yan Ge Zhang ◽  
...  

Cubic-like lead sulfide (PbS) films were in situ fabricated on lead (Pb) foil on a large scale by solvothermal method. Ethanol and ethylenediamine were used as the solvent. The films were characterized by X-ray diffraction (XRD), Scanning electron microscopy (SEM), absorption and the Fourier transformation-infrared (FT-IR) spectra. A solar cell was made by the hybrid film of P3HT and cubic-like PbS. The solar cells are photosensitive in a large spectral range (visible and near infrared regions). The cell with the area of 0.20 cm2 without any special treatment has shown the values of open-circuit voltage (Voc) of 250 mV and short circuit current (Jsc) of 0.01 mA/cm2 with the efficiency of 0.01 % and the fill factor (FF) is 0.36 under illumination intensity of 100 mW/cm2.


2014 ◽  
Vol 1070-1072 ◽  
pp. 616-619
Author(s):  
Wen Bo Xiao ◽  
Jin Dai ◽  
Guo Hua Tu ◽  
Hua Ming Wu

The dye-sensitized solar cell performances influenced by radiant intensity and illuminated area in concentrating photovoltaic system are investigated experimentally and discussed theoretically. The results show that, under the same irradiated cells area, the short-circuit current is linearly increasing with the radiant intensity and the open-circuit voltage follows a logarithmic function of the radiant intensity. And, it is turned out that the short-circuit current and open-circuit voltage are obviously enhanced by increasing the illuminated cells surface area at the same radiant intensity. However, that growth trends will decline with an increase of the illuminated area. The reason is more defects involved in the process of increasing illumination area. All results can be interpreted using an equivalent circuit of a single diode model. A good agreement can be observed from the fitting curves. It is of great significance for current photovoltaic research.


2013 ◽  
Vol 743-744 ◽  
pp. 920-925
Author(s):  
Hong Zhou Yan ◽  
Jun You Yang ◽  
Shuang Long Feng ◽  
Ming Liu ◽  
Jiang Ying Peng ◽  
...  

TiO2 nanotubes array was fabricated by anodization. Effect of reaction duration on the morphology of TiO2 nanotube arrays was studied detailedly. The structure and morphology of the prepared nanotubes array was characterized by X-ray diffraction and scanning electron microscopy, respectively. The fabricated TiO2 arrays were peeled off and adhered to FTO glass with adhesive (mixture of tetrabutyl titanate and polyethylene glycol), then they were sintered at 450 for photoanode of DSSC. The photovoltaic performance of the prepared sample as the DSSC anode was investigated. An open circuit voltage of 0.69V and a short circuit current density of 7.78mA/cm2 were obtained, and the fill factor and the convert efficiency were 0.517 and 2.78%, respectively.


2014 ◽  
Vol 925 ◽  
pp. 605-609 ◽  
Author(s):  
A.S. Obaid ◽  
Alaa Ahmed Dihe ◽  
B.M. Salih ◽  
Z. Hassan ◽  
Y. Al-Douri ◽  
...  

This study reports on the fabrication of a Schottky solar cell with a cross-sectional schematic: ITO/PbS/Al with a commercial transparent conductive ITO and a p-type PbS absorber layer deposited by using a thermal evaporator. The structural and optical properties of constituent films are presented. X-ray diffraction showed that the thin films are polycrystalline. By using scanning electron microscopy, this study showed that the films possessed a uniform surface morphology over the substrate, and the films exhibit a nanocoral structure. Open circuit voltage,short-circuit current density and characteristics were studied under 30 mW/cm2 solar radiation.


2019 ◽  
Vol 150 (11) ◽  
pp. 1921-1927 ◽  
Author(s):  
Stefan Weber ◽  
Thomas Rath ◽  
Birgit Kunert ◽  
Roland Resel ◽  
Theodoros Dimopoulos ◽  
...  

Abstract In this work, the influence of a partial introduction of bromide (x = 0–0.33) into MA0.75FA0.15PEA0.1Sn(BrxI1−x)3 (MA: methylammonium, FA: formamidinium, PEA: phenylethylammonium) triple cation tin perovskite on the material properties and photovoltaic performance is investigated and characterized. The introduction of bromide shifts the optical band gap of the perovskite films from 1.29 eV for the iodide-based perovskite to 1.50 eV for the perovskite with a bromide content of x = 0.33. X-ray diffraction measurements reveal that the size of the unit cell is also gradually reduced based on the incorporation of bromide. Regarding the photovoltaic performance of the perovskite films, it is shown that already small amounts of bromide (x = 0.08) in the perovskite system increase the open circuit voltage, short circuit current density and fill factor. The maximum power conversion efficiency of 4.63% was obtained with a bromide content of x = 0.25, which can be ascribed to the formation of homogeneous thin films in combination with higher values of the open circuit voltage. Upon introduction of a higher amount of bromide (x = 0.33), the perovskite absorber layers form pinholes, thus reducing the overall device performance. Graphic abstract


2004 ◽  
Vol 808 ◽  
Author(s):  
Keda Wang ◽  
Anthon Canning ◽  
J.R. Weinberg-Wolf ◽  
E.C.T. Harley ◽  
Daxing Han ◽  
...  

ABSTRACTWe used Raman and photoluminescence (PL) spectroscopy to study the relationship between the material properties and the solar cell performance of hydrogenated nanocrystalline silicon (nc-Si:H). The crystalline volume fraction (fc) was deduced from the Raman spectrum. Generally, a high fc leads to a high short circuit current density and a low open circuit voltage. PL spectra were measured using 632.8-nm and 442-nm laser lines. There are two distinguished PL peaks at 80 K, one at ∼1.4 eV originating from the amorphous region, while the other at = 0.9 eV from the nanocrystalline grain boundary regions. Generally, the intensity fraction of this low energy PL peak, IPLc/(IPLa+IPLc), was larger for 442-nm than 632.8-nm excitation, indicating an increase in crystallinity along the growth direction. However, for the best initial performance cells obtained by H2 dilution profiling and the i/p buffer layer, the intensity fraction IPLc/(IPLa+IPLc) decreased from the bulk to the topi/p interface. The Raman and PL results give insight into the correlation between the microstructures and the cell performance, and verified that properly-controlled crystallinity in the intrinsic layer and buffer layer at the i/p interface layer are important for optimizing nc-Si:H solar cells.


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