Effects of Back Contact Treatments on Junction Photoluminescence in CdTe/CdS Solar Cells

1997 ◽  
Vol 485 ◽  
Author(s):  
D. H. Levi ◽  
L. M. Woods ◽  
D. S. Albin ◽  
T. A. Gessert ◽  
D. W. Niles ◽  
...  
Keyword(s):  
Solar Cells ◽  
Qualitative Change ◽  
Back Contact ◽  
Band Bending ◽  
Energy Peak ◽  
Before And After ◽  
Pl Spectrum ◽  
Two Peaks ◽  
Cdte Surface

AbstractDevice performance in CdTe/CdS solar cells is critically linked to the quality of the back contact. In this paper we report on a phenomenon wherein application of the back contact significantly alters the electro-optical properties of the absorber near the junction. We have studied the photoluminescence (PL) spectrum of the near-junction CdTe region in CdTe/CdS solar cells before and after contact application. It is found that the elemental Tellurium layer formed on the CdTe surface by the standard nitric-phosphoric etch process results in a dramatic qualitative change in the junction PL spectrum. Prior to NP etch, the spectrum has two peaks at energies of 1.50 eV and 1.45 eV, corresponding to recombination in bulk CdTe, and in a CdTeS alloy with 9% sulfur content, respectively. After NP etch, the relative intensity of the low-energy peak is reduced, and the peak shifts towards higher energy. These changes are consistent with a model of increased band-bending at the grain boundaries near the CdTe/CdS heterojunction.

The Chloride Annealing for Back Contact Layer Free CdTe Solar Cells

2016 ◽  
Vol 852 ◽  
pp. 799-804
Author(s):  
Meng Jiang ◽  
Zuo Lei Liu ◽  
Zhi Lei ◽  
Qiong Yi Gu ◽  
Jian Guo Zhu
Keyword(s):  
Solar Cells ◽  
Annealing Temperature ◽  
Annealing Treatment ◽  
Contact Layer ◽  
Solution Concentration ◽  
Back Contact ◽  
Cdte Thin Film ◽  
Large Area ◽  
Cdte Solar Cells ◽  
Cdte Surface

The large area CdTe thin film samples were used for chloride annealing. The CuCl2/NH4Cl solution was attached on the CdTe surface. After annealing treatment, the CdTe solar cells were prepared. The structure of the thin films and the properties of the CdTe solar cells were tested for studying the effect of the ratio of Cu/Cl, solution concentration and the annealing temperature. At last the performance of CuCl2/NH4Cl annealing cells, ZnTe back contact cells and C:Te,Cu back contact cells were compared. Without back contact layers the efficiency of the CdTe solar cells reached 11.13% with chloride annealing.

scholarly journals Rear side dielectrics on interdigitating p+-(i)-n+ back-contact solar cells − hydrogenation vs. charge effects

2021 ◽  
Vol 12 ◽  
pp. 6
Author(s):  
Michael Rienäcker ◽  
Yevgeniya Larionova ◽  
Jan Krügener ◽  
Sascha Wolter ◽  
Rolf Brendel ◽  
...  
Keyword(s):  
Solar Cells ◽  
Dielectric Layer ◽  
Negative Charge ◽  
Rear Side ◽  
Back Contact ◽  
Charge Effects ◽  
Conductive Channel ◽  
Negative Charge Density ◽  
Reference Samples

Polysilicon-on-oxide (POLO) passivating contacts and interdigitated back-contact (IBC) cell technologies have recently attracted a lot of interest as candidates for the implementation in the next generation of solar cells. An IBC cell with POLO junctions for both polarities − a POLO2-IBC cell − has to electrically isolate the highly defective p+ and n+ poly-Si regions on the rear side of the cell to avoid parasitic recombination. Inserting an initially undoped, intrinsic (i) region between the p+ and n+ poly-Si regions was demonstrated to successfully prevent the parasitic recombination in the transition region of ISFH's 26.1%-efficient POLO2-IBC cell. In order to further improve the conversion efficiency towards 27%, we apply hydrogen-donating dielectric layer stacks to the p+-(i)-n+ POLO interdigitating rear side to enhance the passivation quality of the POLO junctions. We indeed show a significant improvement of POLO junctions on symmetrical full-area homogenously doped reference samples, but when we apply a hydrogen-donating layer stack on the p+-(i)-n+ POLO interdigitating rear side, we observe a strong degradation in the performance of the POLO2-IBC cell. We attribute this to the formation of a conductive channel between the p+ and n+ poly-Si regions due to the strong negative charge density of the hydrogen-donating layer stack.

Spectral Calibrated and Confocal Photoluminescence of Cu2S Thin-Film Absorber

2013 ◽  
Vol 1538 ◽  
pp. 191-196 ◽  
Author(s):  
Hendrik Sträter ◽  
Rudolf Brüggemann ◽  
Sebastian Siol ◽  
Andreas Klein ◽  
Wolfram Jaegermann ◽  
...  
Keyword(s):  
Band Gap ◽  
Physical Vapor Deposition ◽  
Urbach Energy ◽  
High Energy ◽  
Lateral Variation ◽  
Defect States ◽  
Energy Peak ◽  
Two Peaks ◽  
Comprehensive Indicator

ABSTRACTWe have studied Cu2S absorber layers prepared by physical vapor deposition (PVD) by calibrated spectral photoluminescence (PL) and by confocal PL as function of temperature T and excitation fluxes to obtain the absolute PL-yield at an excitation flux equivalent to the AM1.5 spectrum and to calculate the splitting of the quasi-Fermi levels (QFL) µ = Ef,n-Ef,p and the absorption coefficient α(E), both in the temperature range 20 K ≤ T ≤ 400 K. The PL-spectra reveal two peaks at E1 = 1.17 eV and E2 = 1.3 eV, of which the low energy peak is only detectable at temperatures T < 200 K. The samples show an impressive QFL-splitting of µ > 700 meV at 300 K associated with a pseudo band gap of Eg = 1.25 eV. The high energy peak shows an unexpected temperature behavior, namely an increase of the PL-yield with rising temperature at variance with the behavior of QFL-splitting that decreases with rising T from extrapolated T = 0K value of µ = 1.3 eV. The PL-yield versus temperature will be discussed in terms of different defect states in the band gap. Our observations indicate that, contrary to common believe, it is not the PL-yield, but rather the QFL-splitting that is the comprehensive indicator of the quality of the excited state in an illuminated semiconductor. A further examination of the lateral variation of the opto-electronic properties by confocal PL shows a strong correlation between the QFL-splitting, the Urbach energy EU and the optical band gap Eopt, respectively.

scholarly journals Study on the Stability of Unpackaged CdS/CdTe Solar Cells with Different Structures

2019 ◽  
Vol 2019 ◽  
pp. 1-8
Author(s):  
Guanggen Zeng ◽  
Xiaolan Liu ◽  
Yubo Zhao ◽  
Yuanmao Shi ◽  
Bing Li ◽  
...  
Keyword(s):  
Solar Cells ◽  
Thermal Cycling ◽  
Thermal Aging ◽  
Short Circuit ◽  
Temperature Cycling ◽  
International Electrotechnical Commission ◽  
Back Contact ◽  
Cdte Solar Cells ◽  
Before And After ◽  
The Stability

In this work, the stability of unpackaged CdTe solar cells with different configurations was investigated according to the International Electrotechnical Commission IEC 61215-2016. The measurements of thermal cycling from -40°C to +85°C and 24-hour temperature cycling from -40°C to +85°C withstanding the effects of 20-hour penetration of 85°C were carried out in CdS/CdTe solar cells with structures of FTO/CdS/CdTe/Au, FTO/CdS/CdTe/back contact/Au, and FTO/MZO/CdS/CdTe/back contact/Au, respectively. The performances of these cells before and after the thermal aging experiments were investigated by using light and dark I‐V together with C‐V. The results reveal varied performance degradation before and after thermal aging in the cells with different structures. Among these, the most deteriorated device is the one without back contact (BC), whose efficiency decreased by 25.12% after thermal cycling accompanying an obvious roll-over phenomenon when forward bias was greater than open circuit voltage. On the contrary, the reduction in the efficiency was about 16.80% in the case cells with BC, and the roll-over phenomenon was not so significant. Furthermore, for the devices with optimized front contact of FTO/MZO, the thermal stability was improved obviously. Interestingly, short-circuit current density associated with the carrier concentration of cells remained relatively small variations compared with the change of Voc and fill factor. All the results indicated that an efficient back contact layer and an optimized front electrode were the indispensable structural elements to attain high stabilization in the CdS/CdTe solar cells.

Kepuasan Masyarakat Terhadap Pelayanan Kelurahan Setelah Pemekaran Di Tangerang Selatan

Liquidity ◽  
2018 ◽  
Vol 2 (2) ◽  
pp. 151-159
Author(s):  
Pitri Yandri
Keyword(s):  
Public Perception ◽  
Service Personnel ◽  
Urban Services ◽  
Hospitality Workers ◽  
Care Workers ◽  
Before And After ◽  
Cartesian Diagram ◽  
Better Than

The purpose of this study is (1) to analyze public perception on urban services before and after the expansion of the region, (2) analyze the level of people's satisfaction with urban services, and (3) analyze the determinants of the variables that determine what level of people's satisfaction urban services. This study concluded that first, after the expansion, the quality of urban services in South Tangerang City is better than before. Secondly, however, public satisfaction with the services only reached 48.53% (poor scale). Third, by using a Cartesian Diagram, the second priority that must be addressed are: (1) clarity of service personnel, (2) the discipline of service personnel, (3) responsibility for care workers; (4) the speed of service, (5) the ability of officers services, (6) obtain justice services, and (7) the courtesy and hospitality workers.

Strategic Role of Zakat in Multidimensional Quality of Life in Sijunjung, Indonesia

2018 ◽  
Vol 15 (1) ◽  
pp. 55-72
Author(s):  
Herlin Hamimi ◽  
Abdul Ghafar Ismail ◽  
Muhammad Hasbi Zaenal
Keyword(s):  
Quality Of Life ◽  
Positive Impact ◽  
Wealth Distribution ◽  
Absolute Poverty ◽  
Before And After ◽  
The Status ◽  
Being There ◽  
The Impact

Zakat is one of the five pillars of Islam which has a function of faith, social and economic functions. Muslims who can pay zakat are required to give at least 2.5 per cent of their wealth. The problem of poverty prevalent in disadvantaged regions because of the difficulty of access to information and communication led to a gap that is so high in wealth and resources. The instrument of zakat provides a paradigm in the achievement of equitable wealth distribution and healthy circulation. Zakat potentially offers a better life and improves the quality of human being. There is a human quality improvement not only in economic terms but also in spiritual terms such as improving religiousity. This study aims to examine the role of zakat to alleviate humanitarian issues in disadvantaged regions such as Sijunjung, one of zakat beneficiaries and impoverished areas in Indonesia. The researcher attempted a Cibest method to capture the impact of zakat beneficiaries before and after becoming a member of Zakat Community Development (ZCD) Program in material and spiritual value. The overall analysis shows that zakat has a positive impact on disadvantaged regions development and enhance the quality of life of the community. There is an improvement in the average of mustahik household incomes after becoming a member of ZCD Program. Cibest model demonstrates that material, spiritual, and absolute poverty index decreased by 10, 5, and 6 per cent. Meanwhile, the welfare index is increased by 21 per cent. These findings have significant implications for developing the quality of life in disadvantaged regions in Sijunjung. Therefore, zakat is one of the instruments to change the status of disadvantaged areas to be equivalent to other areas.

Effect of new dietary supplement on sperm quality

2012 ◽  
Vol 153 (45) ◽  
pp. 1787-1792 ◽  
Author(s):  
Mária Horváth ◽  
Endre Czeizel
Keyword(s):  
Adverse Effect ◽  
Clinical Trial ◽  
Dietary Supplement ◽  
Male Fertility ◽  
Sperm Quality ◽  
Sperm Count ◽  
Before And After ◽  
The Usa ◽  
New Treatments

Introduction: There is a decline in male fertility thus new treatments are needed. Aims: To test the efficacy of a new dietary supplement developed in the USA and registered as a curing drug in Hungary (OGYI). Methods: In a clinical trial 100 men with low sperm quality (spermium count 5–20 M/ml, good motility 10–40%, and adverse shape 30–50%) were examined. Results: Sperm parameters were measured before and after a 3-month treatment and after another 3-month without treatment. This dietary supplement statistically and clinically significantly improved sperm count and motility. In 74 cases this dietary supplement demonstrated a beneficial effect on sperm quality (more than 10% increase in sperm count, or quality of motility, or shape); in 16 cases the improvement exceeded 30%. No adverse effect could be accounted for this treatment. Conclusions: This new dietary supplement may contribute to the treatment of male infertility. Orv. Hetil., 2012, 153, 1787–1792.

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