Toward understanding the degradation without light soaking in hot-wire a-Si:H thin films and solar cells

2003 ◽  
Vol 762 ◽  
Author(s):  
Qi Wang ◽  
Keda Wang ◽  
Daxing Han
Keyword(s):  
Thin Films ◽  
Activation Energy ◽  
Solar Cells ◽  
Fermi Energy ◽  
Fill Factor ◽  
Hot Wire ◽  
Initial Value ◽  
Energy Position ◽  
Reversible Degradation ◽  
P Type

AbstractThe non-reversible degradation without light soaking has been observed in both thin films and solar cells fabricated using the hot-wire CVD technique. For solar cells, a 9.8% initial efficiency became 9.2% when measured after a few weeks of being stored in the dark. For the intrinsic layers, the conductivity increased in the air but remained steady in vacuum up to 700 hours. Also, the conductivity increased and activation energy decreases from an initial ∼0.95 eV to ~∼0.85 eV after several thermal cycles, even in a vacuum. We suggest that the degradation in both materials and solar cells come from the same origin: the upward shift of the Fermi-energy position from its initial value. In other words, the as-grown material is slightly p-type and gradually became slightly n-type after sitting in the air or after thermal annealing cycles in a vacuum. The shift in the Fermi-energy made the fill factor of the solar cell decrease and changes in the electronic properties of the i-layer. It is likely that adsorption of oxygen from water vapor is driving this degradation.

scholarly journals Electrical properties of pure NiO and NiO:Au thin films prepared by using pulsed laser deposition

2019 ◽  
Vol 14 (29) ◽  
pp. 37-43 ◽  
Author(s):  
Raied K. Jamal
Keyword(s):  
Thin Films ◽  
Activation Energy ◽  
Electrical Properties ◽  
Transport Mechanism ◽  
Room Temperature ◽  
Pulsed Laser ◽  
Laser Deposition ◽  
Concentration Increase ◽  
Annealing Temperatures ◽  
P Type

The electrical properties of pure NiO and NiO:Au Films which aredeposited on glass substrate with various dopant concentrations(1wt.%, 2wt%, 3wt.% and 4wt.%) at room temperature 450 Coannealing temperature will be presented. The results of the hall effectshowed that all the films were p-type. The Hall mobility decreaseswhile both carrier concentration and conductivity increases with theincreasing of annealing temperatures and doping percentage, Thus,indicating the behavior of semiconductor, and also the D.Cconductivity from which the activation energy decrease with thedoping concentration increase and transport mechanism of the chargecarriers can be estimated.

Built-in Potential and Open Circuit Voltage of Heterojunction CuIn1-xGaxSe2 Solar Cells

2005 ◽  
Vol 865 ◽  
Author(s):  
Akimasa Yamada ◽  
Koji Matsubara ◽  
Keiichiro Sakurai ◽  
Shogo Ishizuka ◽  
Hitoshi Tampo Hajime ◽  
...  
Keyword(s):  
Solar Cells ◽  
Conduction Band ◽  
Fermi Energy ◽  
Open Circuit Voltage ◽  
Material Selection ◽  
Open Circuit ◽  
Flat Band ◽  
Band Energy ◽  
Low X ◽  
P Type

AbstractThe reasons why the open circuit voltage (Voc) of high-x CuIn1-xGaxSe2 (CIGS)/ZnO solar cells remain low are discussed. Here it is shown that the Voc ceiling can be interpreted simply on the basis of a model that the valence-band energy (Ev) of CIGS is almost immovable irrespective of x. When the conduction-band energy (Ec) of ZnO is lower than that of high-x CIGS (DEc<0), the built-in potential (Vbi) of a CIGS/ZnO junction is equivalent to the flat-band potential (Vbi) that arises from the separation between the Fermi energies of the two materials. If the Ev (and therefore the Fermi energy) of p-type CIGS is constant with increasing x, the Vbi and Voc that follows the Vbi remain unchanged since the Fermi energy of ZnO is constant. This unchangeable Voc reduces the conversion efficiency of high-x CIGS cells in cooperation with reduced photocurrents due to a larger bandgap. A positive offset, ΔEc>o gives rise to a photoelectrons barrier in the conduction-band that partially cancels Voc, thus the Voc of a low-x CIGS cell is governed by the Ec of CIGS. Based upon this concept, a material selection guideline is given for the windows and transparent electrodes appropriate for high-x CIGS absorbers-based solar cells.

Synthesis of visible-light-absorptive and hole-transporting periodic mesoporous organosilica thin films for organic solar cells

2014 ◽  
Vol 2 (30) ◽  
pp. 11857-11865 ◽  
Author(s):  
Masamichi Ikai ◽  
Yoshifumi Maegawa ◽  
Yasutomo Goto ◽  
Takao Tani ◽  
Shinji Inagaki
Keyword(s):  
Thin Films ◽  
Solar Cells ◽  
Visible Light ◽  
Organic Solar Cells ◽  
Mesoporous Films ◽  
Periodic Mesoporous Organosilica ◽  
Mesoporous Organosilica ◽  
Type Layer ◽  
Hole Transporting ◽  
P Type

Mesoporous films containing 4,7-dithienyl-2,1,3-benzothiadiazole units in the frameworks were synthesized and demonstrated to function as a p-type layer for organic solar cells by filling an n-type PCBM in the mesopores.

CHEMICAL BATH DEPOSITION: A PROMISING TECHNOLOGY TO BUILD LOW COST SOLAR CELLS

2001 ◽  
Vol 15 (17n19) ◽  
pp. 605-608 ◽  
Author(s):  
A. NUÑEZ ◽  
P. K. NAIR ◽  
M. T. S. NAIR
Keyword(s):  
Thin Films ◽  
Solar Cells ◽  
Chemical Bath Deposition ◽  
Low Cost ◽  
Promising Technology ◽  
Cds Thin Films ◽  
P Type ◽  
Spectral Factor

Following the model of DeVos and Pauwels (1981), we calculated the spectral factor of efficiencies (η1) for n +-p or n +-i-p heterojunctions that can be formed by different thin absorber materials (p-type or intrinsic(i)) with n +-type CdS thin films produced by conversion of chemically deposited CdS thin films by doping with Cl or In as reported before. The materials with η1 comparable to that of CuInSe 2 (Eg, 1.01 eV: 57%) are AgBiS 2 (Eg, 0.9 eV: 56%), Cu 2 SnS 3 (Eg, 0.91 eV: 57%), PbSnS 3 (Eg, 1.05 eV: 57%), PbSbS 4 (Eg, 1.13 eV: 56%).

P-Type CuInSe2 Thin Films and Solar Cells Prepared by One-Step Electrodeposition

2008 ◽  
pp. 1308-1311
Author(s):  
Lei Wan ◽  
Zhizhong Bai ◽  
Bo Chen ◽  
Renliang Sun ◽  
Guoshun Jiang ◽  
...  
Keyword(s):  
Thin Films ◽  
Solar Cells ◽  
One Step ◽  
P Type

scholarly journals A simple synthesis of transparent and highly conducting p-type CuxAl1−xSy nanocomposite thin films as the hole transporting layer for organic solar cells

RSC Advances ◽  
2018 ◽  
Vol 8 (30) ◽  
pp. 16887-16896 ◽  
Author(s):  
Xin Dai ◽  
Hongwei Lei ◽  
Cong Chen ◽  
Yaxiong Guo ◽  
Guojia Fang
Keyword(s):  
Thin Films ◽  
Solar Cells ◽  
Organic Solar Cells ◽  
High Mobility ◽  
Simple Synthesis ◽  
Inorganic P ◽  
Nanocomposite Thin Films ◽  
Hole Transporting ◽  
P Type

Inorganic p-type films with high mobility are very important for opto-electronic applications.

Efficiency Enhancement in Organic Solar Cells by Use of Cobalt Phthalocyanine (CoPc) Thin Films

2020 ◽  
Vol 20 (6) ◽  
pp. 3703-3709 ◽  
Author(s):  
S. S. Rawat ◽  
Ashish Kumar ◽  
R. Srivastava ◽  
C. K. Suman
Keyword(s):  
Thin Films ◽  
Solar Cells ◽  
Energy Level ◽  
Buffer Layer ◽  
Organic Solar Cells ◽  
Fill Factor ◽  
Series Resistance ◽  
Short Circuit ◽  
Acid Methyl Ester ◽  
Cobalt Phthalocyanine

Cobalt phthalocyanine (CoPc) nano thin films have been introduced as a hole buffer layer in organic solar cells with active layer of Poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl-C61-butyric acid methyl ester (PCBM). The surface morphology and opto-electrical properties of the CoPc thin films have made it an applicable materials for organic solar cells. The nano-thin films of CoPc are continuously distributed over the studied area and the roughness are around 5 to 7 nm for all thickness. The dominant optical absorptions are in the visible range of wavelengths 500 to 800 nm. The CoPc buffer layer is suitable for energy level matching in energy level diagram and enhances the absorption spectrum as well, which facilitate the charge carrier generation, increases charge transport, decreases charge recombination, hence enhance the all device parameters short circuit current density (Jsc), open circuit voltage (Voc) and fill factor (FF). The solar cells efficiency increases by ˜70% and the fill factor increases by ˜45% in comparison to the standard cells. The increase in efficiency and the fill factors of the solar cells may also be attributed to the increasing of shunt and lowering the series resistance of the cells. The cole–cole plots of the devices may be modeled in electrical circuit as a single parallel resistance Rb and capacitance Cb network with a series resistance Rc.

scholarly journals Properties of Arsenic–Doped ZnTe Thin Films as a Back Contact for CdTe Solar Cells

Materials ◽  
2019 ◽  
Vol 12 (22) ◽  
pp. 3706 ◽  
Author(s):  
Ochai Oklobia ◽  
Giray Kartopu ◽  
Stuart J. C. Irvine
Keyword(s):  
Thin Films ◽  
Solar Cells ◽  
Open Circuit ◽  
Activation Process ◽  
Back Contact ◽  
Contact Activation ◽  
Doping Density ◽  
Cdte Solar Cells ◽  
Absorber Doping ◽  
P Type

As-doped polycrystalline ZnTe layers grown by metalorganic chemical vapor deposition (MOCVD) have been investigated as a back contact for CdTe solar cells. While undoped ZnTe films were essentially insulating, the doped layers showed significant rise in conductivity with increasing As concentration. High p-type carrier densities up 4.5 × 1018 cm−3 was measured by the Hall-effect in heavily doped ZnTe:As films, displaying electrical properties comparable to epitaxial ZnTe single crystalline thin films in the literature. Device incorporation with as-deposited ZnTe:As yielded lower photovoltaic (PV) performance compared to reference devices, due to losses in the open-circuit potential (VOC) and fill factor (FF) related to reducing p-type doping density (NA) in the absorber layer. Some minor recovery observed in absorber doping following a Cl-free post–ZnTe:As deposition anneal in hydrogen at 420 °C contributed to a slight improvement in VOC and NA, highlighting the significance of back contact activation. A mild CdCl2 activation process on the ZnTe:As back contact layer via a sacrificial CdS cap layer has been assessed to suppress Zn losses, which occur in the case of standard CdCl2 anneal treatments (CHT) via formation of volatile ZnCl2. The CdS sacrificial cap was effective in minimising the Zn loss. Compared to untreated and non-capped, mild CHT processed ZnTe:As back contacted devices, mild CHT with a CdS barrier showed the highest recovery in absorber doping and an ~10 mV gain in VOC, with the best cell efficiency approaching the baseline devices.

Effect of Boron Doping on Microcrystalline Germanium Carbon Thin Films

2007 ◽  
Vol 989 ◽  
Author(s):  
Yasutoshi YASHIKI ◽  
Seiichi KOUKETSU ◽  
Shinsuke MIYAJIMA ◽  
Akira YAMADA ◽  
Makoto KONAGAI
Keyword(s):  
Thin Films ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Boron Doping ◽  
Dark Conductivity ◽  
Hot Wire ◽  
Boron Doped ◽  
Vapor Deposition Technique ◽  
Type C ◽  
P Type

AbstractEffects of boron doping on microcrystalline germanium carbon alloy (μc-Ge1-xCx:H) thin films have been investigated. We deposited boron-doped p-type μc-Ge1-xCx:H thin films by hot-wire chemical vapor deposition technique using hydrogen diluted monomethylgermane (MMG) and diborane (B2H6). A dark conductivity of 1.3 S/cm and carrier concentration of 1.7 x 1020 cm-3 were achieved with B2H6/MMG ratio of 0.1. Furthermore, the activation energy decreased from 0.37 to 0.037 eV with increasing B2H6/MMG ratio from 0 to 0.1. We also fabricated p-type μc-Ge1-xCx:H/n-type c-Si heterojunction diodes. The diodes showed rectifying characteristics. The typical ideality factor and rectifying ratio were 1.4 and 3.7 x 103 at ¡Ó 0.5 V, respectively.

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