A Novel P-Type Nanocrystalline Si Buffer at the P/I Interface of A-SI Solar Cells for High Stabilized Efficiency

1999 ◽  
Vol 557 ◽  
Author(s):  
Chang Hyun Lee ◽  
Koeng Su Lim
Keyword(s):  
Solar Cells ◽  
Life Time ◽  
Open Circuit ◽  
Initial Growth ◽  
Si Solar Cells ◽  
Defective Region ◽  
P Type ◽  
Silicon Based ◽  
Si Nanocrystallites ◽  
Nanocrystalline Si

AbstractWe investigated the properties of a novel p-type nanocrystalline Si (p-nc-Si) prepared onto p-a-SiC and the effect of using the buffer with an energy bandgap over 1.9 eV at the p/i interface on the performance of p/i/n type amorphous silicon based solar cells. At the initial growth stage of the p-nc-Si onto p-a-SiC, Si nanocrystallites are proved to be formed in amorphous matrix within the thickness of less than 100Å. The open circuit voltage and the blue response of the cell were improved significantly by inserting the film at the p/i interface as a buffer as compared with the bufferless cell. We found from a numerical simulation using the Gummel-Sharfetter method that the buffering effect of the p-nc-Si is originated from the reduction of highly defective region with a short life-time in the vicinity of the p/i interface.

17.8%-efficient Amorphous Silicon Heterojunction Solar Cells on p-type Silicon Wafers

2006 ◽  
Vol 910 ◽  
Author(s):  
Qi Wang ◽  
Matt P. Page ◽  
Eugene Iwancizko ◽  
Yueqin Xu ◽  
Yanfa Yan ◽  
...  
Keyword(s):  
Solar Cells ◽  
Solar Cell ◽  
Amorphous Silicon ◽  
High Efficiency ◽  
Short Circuit ◽  
Open Circuit ◽  
Layer Growth ◽  
Surface Recombination Velocity ◽  
Back Contact ◽  
P Type

AbstractWe have achieved an independently-confirmed 17.8% conversion efficiency in a 1-cm2, p-type, float-zone silicon (FZ-Si) based heterojunction solar cell. Both the front emitter and back contact are hydrogenated amorphous silicon (a-Si:H) deposited by hot-wire chemical vapor deposition (HWCVD). This is the highest reported efficiency for a HWCVD silicon heterojunction (SHJ) solar cell. Two main improvements lead to our most recent increases in efficiency: 1) the use of textured Si wafers, and 2) the application of a-Si:H heterojunctions on both sides of the cell. Despite the use of textured c-Si to increase the short-circuit current, we were able to maintain the same 0.65 V open-circuit voltage as on flat c-Si. This is achieved by coating a-Si:H conformally on the c-Si surfaces, including covering the tips of the anisotropically-etched pyramids. A brief atomic H treatment before emitter deposition is not necessary on the textured wafers, though it was helpful in the flat wafers. It is essential to high efficiency SHJ solar cells that the emitter grows abruptly as amorphous silicon, instead of as microcrystalline or epitaxial Si. The contact on each side of the cell comprises a thin (< 5 nm) low substrate temperature (~100°C) intrinsic a-Si:H layer, followed by a doped layer. Our intrinsic layers are deposited at 0.3-1.2 nm/s. The doped emitter and back-contact layers were deposited at a higher temperature (>200°C) and grown from PH3/SiH4/H2 and B2H6/SiH4/H2 doping gas mixtures, respectively. This combination of low (intrinsic) and high (doped layer) growth temperatures was optimized by lifetime and surface recombination velocity measurements. Our rapid efficiency advance suggests that HWCVD may have advantages over plasma-enhanced (PE) CVD in fabrication of high-efficiency heterojunction c-Si cells; there is no need for process optimization to avoid plasma damage to the delicate, high-quality, Si wafers.

Liquid-Phase Crystallized Silicon Solar Cells on Glass: Increasing the Open-Circuit Voltage by Optimized Interlayers for n- and p-Type Absorbers

2015 ◽  
Vol 5 (6) ◽  
pp. 1757-1761 ◽  
Author(s):  
Daniel Amkreutz ◽  
William D. Barker ◽  
Sven Kuhnapfel ◽  
Paul Sonntag ◽  
Onno Gabriel ◽  
...  
Keyword(s):  
Solar Cells ◽  
Liquid Phase ◽  
Open Circuit Voltage ◽  
Open Circuit ◽  
Silicon Solar Cells ◽  
P Type

Solar Cell Contacts Using Nano-Sized Dispersions

1999 ◽  
Vol 581 ◽  
Author(s):  
Doug Schulz ◽  
R. Ribelin ◽  
X. Wu ◽  
K.M. Jones ◽  
R.J. Matson ◽  
...  
Keyword(s):  
Solar Cells ◽  
Spray Deposition ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Cdte Layer ◽  
Open Circuit ◽  
Alloy Formation ◽  
Current Densities ◽  
P Type ◽  
Open Circuit Voltages

ABSTRACTNano-sized dispersions have been employed as precursor inks for the spray deposition of contacts to both Si and CdTe materials. In the case of Si, nano-sized Al particles (nano-Al) were dispersed and spray deposited onto p-type Si. Annealing above the eutectic temperature causes alloy formation yielding a p+ layer with p ∼ 10−4 Ω•cm. For CdTe, nano-sized Te particles (nano-Te) were dispersed and sprayed onto CdTe/CdS/SnO2/glass heterostructures. Contact to the CdTe layer occurred during a 30 min anneal in He (T = 215 to 255 °C). These solar cells were finished by spin-coating the Te layer with Ag paint and subsequently annealing in air (100 °C / 1 h). This approach produces solar cells with open circuit voltages (Voc) from 720 to 800 mV, short circuit current densities (Jsc) from 18 to 20 mA/cm2 and efficiencies up to 10.3%. The performance of these cells was similar to those produced using the standard NREL contact.

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.

scholarly journals Analytical Study of the Electrical Output Characteristics of c-Si Solar Cells by Cut and Shading Phenomena

Energies ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 3397 ◽  
Author(s):  
Jong Lim ◽  
Woo Shin ◽  
Hyemi Hwang ◽  
Young-Chul Ju ◽  
Suk Ko ◽  
...  
Keyword(s):  
Solar Cells ◽  
Solar Cell ◽  
Crystalline Silicon ◽  
Short Circuit ◽  
Incident Light ◽  
Short Circuit Current ◽  
Open Circuit ◽  
Si Solar Cell ◽  
Si Solar Cells ◽  
Electrical Output

Cut solar cells have received considerable attention recently as they can reduce electrical output degradation when the c-Si solar cells (crystalline-silicon solar cells) are shaded. Cut c-Si solar cells have a lower short-circuit current than normal solar cells and the decrease in short-circuit currents is similar to the shading effect of c-Si solar cells. However, the results of this study’s experiment show that the shadow effect of a c-Si solar cell reduces the V o c (open circuit voltage) in the c-Si solar cell but the V o c does not change when the c-Si solar cell is cut because the amount of incident light does not change. In this paper, the limitations of the electrical power analysis of the cut solar cells were identified when only photo current was considered and the analysis of the electric output of the cut c-Si solar cells was interpreted with a method different from that used in previous analyses. Electrical output was measured when the shaded and cut rates of c-Si solar cells were increased from 0% to 25, 50 and 75%, and a new theoretical model was compared with the experimental results using MATLAB.

Increase in Open-circuit Voltage and Improved Stability of Organic Solar Cells by Inserting a Molybdenum Trioxide Buffer Layer

2009 ◽  
Vol 1154 ◽  
Author(s):  
Hideyuki Murata ◽  
Yoshiki Kinoshita ◽  
Yoshihiro Kanai ◽  
Toshinori Matsushima ◽  
Yuya Ishii
Keyword(s):  
Solar Cells ◽  
Buffer Layer ◽  
Organic Solar Cells ◽  
Open Circuit Voltage ◽  
Open Circuit ◽  
Type Material ◽  
Type Layer ◽  
Improved Stability ◽  
The Stability ◽  
P Type

AbstractWe report the increase in open-circuit voltage (Voc) by inserting of MoO3 layer on ITO substrate to improve built-in potential of organic solar cells (OSCs). In the OSCs using 5,10,15,20-tetraphenylporphyrine (H2TPP) as a p-type material and C60 as a n-type material, the Voc effectively increased from 0.57 to 0.97 V as increasing MoO3 thickness. The obtained highest Voc (0.97 V) is consistent with the theoretical value estimated from the energy difference between the LUMO (−4.50 eV) of C60 and the HOMO (−5.50 eV) of H2TPP layer. Importantly, the enhancement in the Voc was achieved without affecting the short-circuit current density (Jsc) and the fill-factor (FF). Thus, the power conversion efficiency of the device linearly increased from 1.24% to 1.88%. We also demonstrated that a MoO3 buffer layer enhances the stability of OSCs after photo-irradiation. We have investigated the stability of OSCs using H2TPP and N,N′-di(1-naphthyl)-N,N′-diphenylbenzidine as a p-type layer. The both devices with MoO3 layer showed improved stability. These results clearly suggest that the interface at ITO/p-type layer affects the device stability.

Boron liquid solution deposited by spray method for p-type emitter formation in crystalline Si solar cells

2016 ◽  
Author(s):  
Piotr Panek ◽  
Barbara Swatowska ◽  
Wojciech Dawidowski ◽  
Mari Juel ◽  
Paweł Zięba
Keyword(s):  
Solar Cells ◽  
Liquid Solution ◽  
Si Solar Cells ◽  
Spray Method ◽  
P Type

IMPACT OF WIDE BANDGAP P-TYPE NC-SI ON THE PERFORMANCE OF A-SI SOLAR CELLS

2002 ◽  
Vol 16 (01n02) ◽  
pp. 57-63 ◽  
Author(s):  
X. DENG ◽  
W. WANG ◽  
S. HAN ◽  
H. POVOLNY ◽  
W. DU ◽  
...  
Keyword(s):  
Solar Cells ◽  
Density Functional ◽  
Nanocrystalline Silicon ◽  
Functional Approach ◽  
Wide Bandgap ◽  
Quantum Size ◽  
Si Solar Cells ◽  
P Type ◽  
The Impact ◽  
Hydrogenated Amorphous

This paper reports the impact of a wide bandgap p-type hydrogenated nanocrystalline silicon (nc-Si:H) on the performances of hydrogenated amorphous silicon (a-Si:H) based solar cells. The p-layer consists of nanometer-sized Si Crystallites and has a wide effective bandgap determined mainly by the quantum size-confinement effect (QSE). By incorporation of this p-layer into the devices we have obtained high performances of a-Si:H top solar cells with V oc = 1.045 V and FF = 70.3%, and much improved mid and bottom a-SiGe:H cells, deposited on stainless steel (SS) substrate. The effects of the band-edge mismatch at the p/i-interface on the I-V characteristics of the solar cells are discussed on the bases on the bases of the density-functional approach and the AMPS model.

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