scholarly journals Alumina and Hafnia ALD Layers for a Niobium-Doped Titanium Oxide Photoanode

2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Naji Al Dahoudi ◽  
Qifeng Zhang ◽  
Guozhong Cao

Niobium-doped titanium dioxide (TiO2) nanoparticles were used as a photoanode in dye-sensitized solar cells (DSCs). They showed a high photocurrent density due to their higher conductivity; however, a low open-circuit voltage was exhibited due to the back-reaction of photogenerated electrons. Atomic layer deposition is a useful technique to form a conformal ultrathin layer of Al2O3and HfO, which act as an energy barrier to suppress the back electrons from reaching the redox medium. This resulted in an increase of the open-circuit voltage and therefore led to higher performance. HfO showed an improvement of the light-to-current conversion efficiency by 74%, higher than the 21% enhancement obtained by utilizing Al2O3layers.

Nano Letters ◽  
2012 ◽  
Vol 12 (8) ◽  
pp. 3941-3947 ◽  
Author(s):  
Aravind Kumar Chandiran ◽  
Nicolas Tetreault ◽  
Robin Humphry-Baker ◽  
Florian Kessler ◽  
Etienne Baranoff ◽  
...  

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Jeum-Jong Kim ◽  
Mangu Kang ◽  
Ock Keum Kwak ◽  
Yong-Jin Yoon ◽  
Kil Sik Min ◽  
...  

We have developed dye-sensitized solar cells using novel sensitizers with enhanced transmittance of red (625–675 nm) and blue (425–475 nm) wavebands to control the illumination condition in the greenhouse. Novel ruthenium bipyridyl sensitizers with general formulas (Me3PhN)4[Ru(dcbpy)2(NCS)2] (JJ-7) and (Me3BnN)4[Ru(dcbpy)2(NCS)2] (JJ-9) have been synthesized and demonstrated as efficient sensitizers in dye-sensitized solar cells for greenhouse application. Under standard AM 1.5 sunlight, the solar cell ofJJ-7using a liquid-based electrolyte exhibits a short-circuit photocurrent density of 8.49 mA/cm2, an open-circuit voltage of 0.83 V, and a fill factor of 0.71, corresponding to an overall conversion efficiency of 4.96% on 5 μm TiO2film. The transmittance ofJJ-7andJJ-9shows 62.0% and 61.0% at 660 nm and 18.0% and 15.0% at 440 nm for cultivation on 5 μm TiO2film, respectively.


2018 ◽  
Vol 382 ◽  
pp. 369-373
Author(s):  
Usana Mahanitipong ◽  
Preeyapat Prompan ◽  
Rukkiat Jitchati

The four thiocyanate free ruthenium(II) complexes; [Ru(N^N)2(C^N)]PF6were synthesized and characterized for dye sensitized solar cells (DSSCs). The results showed that the broad absorptions covered the visible region from metal to ligand charge transfer (MLCT) were obtained with the main peaks at 560, 490 and 400 nm. The materials were studied DSSC performance under standard AM 1.5. Compound PP1 showed the power conversion efficiency (PCE) at 3.10%, with a short-circuit photocurrent density (Jsc) of 7.99 mA cm-2, an open-circuit photovoltage (Voc) of 563 mV and a high fill factor (ff) of 0.690.


2017 ◽  
Vol 80 (1) ◽  
Author(s):  
Zainal Arifin ◽  
Sudjito Soeparman ◽  
Denny Widhiyanuriyawan ◽  
Suyitno Suyitno ◽  
Argatya Tara Setyaji

Natural dyes have attracted much researcher’s attention due to their low-cost production, simple synthesis processes and high natural abundance. However the dye-sensitized solar cells (DSSCs) based natural dyes have higher tendency to degradation. This article reports on the enhancement of performance and stability of dye-sensitized solar cells (DSSCs) using natural dyes. The natural dyes were extracted from papaya leaves by ethanol solvent at a temperature of 50 °C. Then the extracted dyes were isolated and modified into Mg-chlorophyll using column chromatography. Mg-chlorophyll was then synthesized into Fe-chlorophyll to improve stability. The natural dyes were characterized using ultraviolet-visible spectrometry, Fourier transform infrared spectroscopy, and cyclic voltammetry. The performance of DSSCs was tested using a solar simulator. The results showed the open-circuit voltage, the short-circuit current density, and the efficiency of the extracted papaya leaves-based DSSCs to be 325 mV, 0.36 mA/cm2, and 0.07%, respectively. Furthermore, the DSSCs with purified chlorophyll provide high open-circuit voltage of 425 mV and short-circuit current density of 0.45 mA/cm2. The use of Fe-chlorophyll for sensitizing the DSSCs increases the efficiency up to 2.5 times and the stability up to two times. The DSSCs with Fe-chlorophyll dyes provide open-circuit voltage, short-circuit current density, and efficiency of 500 mV, 0.62 mA/cm2, and 0.16%, respectively. Further studies to improve the current density and stability of natural dye-based DSSCs along with an improvement in the anchor between dyes and semiconducting layers are required.


2012 ◽  
Vol 476-478 ◽  
pp. 1767-1770
Author(s):  
Yu Li Lin ◽  
Cheng Yi Hsu ◽  
Chang Lun Tai

The task of this study is to prepare the TiO2 film electrode for dye-sensitized solar cells (DSSC) on ITO PET substrate using a general jet-printer. The results were compared with that obtained using ITO glass substrate. In this study, the dispersion of TiO2 slurry was manipulated by changing the pH value of the solution to avoid agglomeration of TiO2 particles. The average TiO2 particles used in this study were measured about 130nm. The experimental results show that it has the best performance when the thickness of the TiO2 film was about 10μm. In ITO glass substrate, the measured short circuit current was about 5.03mA, the open circuit voltage was measured to be 0.65V. In ITO-PET substrate, the measured short circuit current was about 2.73mA, the open circuit voltage was measured to be 0.68V.


2010 ◽  
Vol 1270 ◽  
Author(s):  
Braden Bills ◽  
Mariyappan Shanmugam ◽  
Mahdi Farrokh Baroughi ◽  
David Galipeau

AbstractThe performance of dye-sensitized solar cells (DSSCs) is limited by the back-reaction of photogenerated electrons from the porous titanium oxide (TiO2) nanoparticles back into the electrolyte solution, which occurs almost exclusively through the interface. This and the fact that DSSCs have a very large interfacial area makes their performance greatly dependant on the density and activity of TiO2 surface states. Thus, effectively engineering the TiO2/dye/electrolyte interface to reduce carrier losses is critically important for improving the photovoltaic performance of the solar cell. Atomic layer deposition (ALD), which uses high purity gas precursors that can rapidly diffuse through the porous network, was used to grow a conformal and controllable aluminum oxide (Al2O3) and hafnium oxide (HfO2) ultra thin layer on the TiO2 surface. The effects of this interfacial treatment on the DSSC performance was studied with dark and illuminated current-voltage and electrochemical impedance spectroscopy (EIS) measurements.


2011 ◽  
Vol 50 (6) ◽  
pp. 06GF08 ◽  
Author(s):  
Shyam S. Pandey ◽  
Kyung-Young Lee ◽  
Azwar Hayat ◽  
Yuhei Ogomi ◽  
Shuzi Hayase

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