Kinetics of Light Induced Changes in Protocrystalline Thin Film Materials and Solar Cells

2000 ◽  
Vol 609 ◽  
Author(s):  
Randy Koval ◽  
Xinwei Niu ◽  
Joshua Pearce ◽  
Lihong Jiao ◽  
Gautam Ganguly ◽  
...  

ABSTRACTStudies have been carried out on the kinetics of light induced changes in thin films and solar cells fabricated in different laboratories. Unlike the many studies on undiluted a-Si:H films the kinetics reported here are for 1 sun illuminations carried out to the degraded steady state (DSS). The light induced changes at temperatures from 25 to 100°C were characterized with electron mobility lifetime products and subgap absorption in films and fill factors in solar cells. The significant changes in the degradation kinetics that occur in these materials in this t mperature range have further confirmed the importance of charged defects, not only in the annealed state, but also in the degraded steady states. Results are also presented on corresponding solar cell structures, which also indicate that defects other than neutral dangling bonds have to be taken into account if any meaningful evaluation is to be made of their solar cell properties.

1997 ◽  
Vol 467 ◽  
Author(s):  
Yeeheng Lee ◽  
Lihong Jiao ◽  
Joohyun Koh ◽  
Hiroyuki Fujiwara ◽  
Zhou Lu ◽  
...  

ABSTRACTStudies have been carried out on a-Si:H materials and corresponding solar cells fabricated with and without hydrogen dilution of silane by rf PECVD. The effect of hydrogen dilution on the growth kinetics and microstructures and their dependence on the substrate temperature have been studied. Hydrogen diluted a-Si:H materials and solar cells exhibit improved properties and higher stability to light induced changes. Distinct differences are found in the electron mobility lifetime (μτ) products and subgap absorption over a wide range of generation rates. Striking differences are also found in the kinetics of light induced degradation in both the materials and their corresponding solar cells. Direct correlations are presented between the degradation kinetics of p(a-SiC:H)/i(a-Si:H)/n(μc-Si) solar cells and those of thin film materials constituting the i-layers.


1997 ◽  
Vol 467 ◽  
Author(s):  
C. R. Wronski

ABSTRACTThe quest for understanding and especially controlling the reversible light induced changes in a-Si:H based materials has been ongoing for the last twenty years. This has been accompanied by a corresponding large effort in minimizing their effects on more efficient a-Si:H based solar cells. Despite the complexities in both the phenomena as well as the solar cells, progress has been made in both the scientific and technological arenas. This paper briefly reviews primarily studies on the characterization and reduction of the metastable changes in materials and the correlation of these changes with those in efficient solar cells. It will discuss the impact of studies on materials as well as the continuous advances made with “engineering” of solar cell structures on their improved stabilized performance.


1999 ◽  
Vol 557 ◽  
Author(s):  
R.J. Koval ◽  
J. Koh ◽  
Z. Lu ◽  
Y. Lee ◽  
L. Jiao ◽  
...  

AbstractStudies have been carried out on the thickness dependent transition between the amorphous and microcrystalline phases in intrinsic Si:H materials (i-layers) and its effect on p-i-n solar cell performance [1]. P(a-SiC:H)-i(a-Si:H)-n(μcSi:H) cell structures were deposited with the intrinsic Si:H layer thickness and the flow ratio of hydrogen to silane, R=[H2]/[SiH4], guided by an evolutionary phase diagram obtained from real-time spectroscopic ellipsometry. The thickness range over which the fill factors are controlled by the bulk was established and their characteristics investigated with different protocrystalline i-layer materials (i.e., materials prepared near the amorphous to microcrystalline boundary but on the amorphous side). Insights into the properties of these materials and the effects of the transition to the microcrystalline phase were obtained from the systematic changes in the initial fill factors, their light-induced changes, and their degraded steady states for cells with i-layers of different thickness and H2 dilution.


2015 ◽  
Vol 3 (38) ◽  
pp. 19263-19267 ◽  
Author(s):  
Dandan Zhao ◽  
Qingwen Tian ◽  
Zhengji Zhou ◽  
Gang Wang ◽  
Yuena Meng ◽  
...  

A novel, robust and low-toxicity solution route to deposit CIGSe thin films for solar cell applications is proposed. The solvent of 1,2-ethanedithiol and 1,2-ethylenediamine is employed for the first time to simultaneously dissolve elemental Cu, In, Ga, and Se. With this solution-processed CIGSe thin film solar cell, an efficiency of 9.5% was achieved.


RSC Advances ◽  
2016 ◽  
Vol 6 (44) ◽  
pp. 37621-37627 ◽  
Author(s):  
Dhruba B. Khadka ◽  
SeongYeon Kim ◽  
JunHo Kim

We report a promising fabrication approach for the synthesis of Ge-alloyed Cu2Zn(GexSn1−x)Se4 (CZGTSe) thin films using molecular precursors by spray pyrolysis to obtain band gap tuned kesterite solar cells.


RSC Advances ◽  
2015 ◽  
Vol 5 (109) ◽  
pp. 89635-89643 ◽  
Author(s):  
Priyanka U. Londhe ◽  
Ashwini B. Rohom ◽  
Nandu B. Chaure

Highly crystalline and stoichiometric CIS thin films have been electrodeposited from non-aqueous bath at temperature 130 °C. Superstrate solar cell structure (FTO/CdS/CIS/Au) exhibited 4.5% power conversion efficiency.


2011 ◽  
Vol 1352 ◽  
Author(s):  
Jiguang Li ◽  
Lin Pu ◽  
Mool C. Gupta

ABSTRACTRecently, few tens of nanometer thin films of TiOx have been intensively studied in applications for organic solar cells as optical spacers, environmental protection and hole blocking. In this paper we provide initial measurements of optical and electrical properties of TiOx thin films and it’s applications in solar cell and sensor devices. The TiOx material was made through hydrolysis of the precursor synthesized from titanium isopropoxide, 2-methoxyethanol, and ethanolamine. The TiOx thin films of thickness between 20 nm to 120 nm were obtained by spin coating process. The refractive index of TiOx thin films were measured using an ellipsometric technique and an optical reflection method. At room temperature, the refractive index of TiOx thin film was found to be 1.77 at a wavelength of 600 nm. The variation of refractive index under various thermal annealing conditions was also studied. The increase in refractive index with high temperature thermal annealing process was observed, allowing the opportunity to obtain refractive index values between 1.77 and 2.57 at a wavelength 600 nm. The refractive index variation is due to the TiOx phase and density changes under thermal annealing.The electrical resistance was measured by depositing a thin film of TiOx between ITO and Al electrode. The electrical resistivity of TiOx thin film was found to be 1.7×107 Ω.cm as measured by vertical transmission line method. We have also studied the variation of electrical resistivity with temperature. The temperature coefficient of electrical resistance for 60 nm TiOx thin film was demonstrated as - 6×10-3/°C. A linear temperature dependence of resistivity between the temperature values of 20 – 100 °C was observed.The TiOx thin films have been demonstrated as a low cost solution processable antireflection layer for Si solar cells. The results indicate that the TiOx layer can reduce the surface reflection of the silicon as low as commonly used vacuum deposited Si3N4 thin films.


2019 ◽  
Vol 793 ◽  
pp. 35-39
Author(s):  
Luan Hong Sun ◽  
Hong Lie Shen ◽  
Hu Lin Huang ◽  
Hui Rong Shang

To reveal the effects of annealing condition on CZTSSe thin film solar cells, co-sputtering and subsequent selenization were used to prepare CZTSSe thin films. Structural, morphological and optical properties of CZTSSe thin films were investigated. CZTSSe thin films with various Se/(S+Se) ratio ranging from 0.69-0.78 were obtained. Representative peaks corresponding to CZTSSe in XRD and Raman results showed a slight shift to lower diffraction angle and wavenumbers. Selenization time significantly influenced the morphologies of CZTSSe films and the gradual grown up grain size was observed. VOCdeficit values down to 839 mV was achieved for the best cell. CZTSSe solar cell with the selenization time of 10 min showed a best conversion efficiency of 5.32%, which presented a 50% enhancement comparing to the solar cells with insufficient and over-selenized absorbers.


2009 ◽  
Vol 1165 ◽  
Author(s):  
Vasilios Palekis ◽  
Deidra Ranel Hodges ◽  
Don L Morel ◽  
Lee Stefanakos ◽  
Chris S Ferekides

AbstractCadmium telluride (CdTe) is a leading thin film photovoltaic (PV) material due to its near ideal band gap of 1.45 eV and its high optical absorption coefficient. The typical CdTe thin film solar cell is of the superstrate configuration where a window layer (CdS), the absorber (CdTe), and a back contact are deposited onto a glass slide coated with a transparent electrode. Substrate CdTe solar cells where the above listed films are deposited in reverse order are not common. In this study, the growth of CdTe thin films deposited on foil substrates by the close-spaced sublimation (CSS) has been investigated for the purpose of fabricating substrate based CdTe solar cells. The CdTe films were deposited at substrate temperatures (TSUB) in the range of 300 to 600°C, and source temperatures (TSRC) in the 600 to 650°C range. The effect of the substrate-source temperature variations on the growth rate, film structure and morphology were studied using XRD and SEM. It was found that for low substrate temperature and as the growth rate increases, grain size was the same but the films appeared to be more uniform and more densely packed with less or no pinholes. The growth rate increased as the source temperature increased. The substrate temperature clearly influences the grain growth and the preferred orientation. As the substrate temperature increased the growth rate decreased and the grain size varied from 2 to 6 μm. XRD analysis showed that with the increase in substrate temperature film orientation changes from preferential along the (111) direction to a mix of (111) (220) and (311).


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