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Home > Ln3+ Ions Doped Phosphate Glasses for Solid State Lighting Applications

Ln3+ Ions Doped Phosphate Glasses for Solid State Lighting Applications

Thesis Info

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Author

Shoaib, Muhammad

Program

PhD

Institute

Abdul Wali Khan University

City

Mardan

Province

KPK

Country

Pakistan

Thesis Completing Year

2019

Thesis Completion Status

Completed

Subject

Physics

Language

English

Link

http://prr.hec.gov.pk/jspui/bitstream/123456789/12208/1/Muhammad%20shoaib%20physics%202019%20awk%20prr.pdf

Added

2021-02-17 19:49:13

Modified

2024-03-24 20:25:49

ARI ID

1676726590981

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In present study, Lanthanide ions doped oxide and oxyfluoride phosphate glasses were prepared through melt quenching technique. Subsequently, properly cut and polished samples were studied through XRD, FTIR, density, refractive index, absorption spectra, photoluminescence spectra, X-rays induced luminescence spectra, JO analysis, lifetime study and CIE coordinates analysis. The recorded XRD pattern show broad bands without any sharp peaks which show that these glasses are amorphous in nature. The FTIR results show that the band corresponding to OH vibrations decrease in oxyfluoride glass samples compared to the oxide glasses. The decrease in the intensity of OH group bands, is due to the decrease of amounts of OH in the glass composition by reaction with fluorene to produce HF. The measured density shows the overall increasing trend with increase in the rear earth concentrations and also the densities of oxide glasses are higher than the oxyfluoride glasses which show that the structures of oxide glasses are more compact than the oxyfluoride glasses. The absorption spectra (Uv-Vis-NIR region) contain the corresponding doped rare earth ions transitions peaks. For Dysprosium (Dy3+), Samarium (Sm3+) and Europium (Eu3+) ions doped glasses most intense peaks correspond to 6H15→6H9/2+6F11/2, 6H5/2→6F7/2 and 7F0→5L6 transitions, respectively. The positions of the absorption bands are slightly change with change in the glass compositions. Similarly, the recorded excitation spectra of present glasses have corresponding Sm3+, Eu3+ and Dy3+ transition peaks along with the Gd3+ ions transitions peaks. Subsequently, the recorded emission spectra show the energy transfer from excited Gd3+ ions to Dy3+, Sm3+ or Eu3+ ions present in glass compositions. The transitions 8H5/2→6P3/2, 7F0 →5L6 and 6H15/2→ 4M15/2 + 6P7/2 are the hyper sensitive transition for Dy3+, Sm3+ and Eu3+ respectively. The emission spectra recorded at the respective wavelength observed for hypersensitive transitions in excitation spectra demonstrate that the oxyfluoride glass samples show comparatively higher emission intensity. The emission intensities increase with increasing RE3+ ions concentrations up to 1 mol% in the case of Dy3+ and Sm3+ ions doping there after start decreasing. While in the case of Eu3+ ions, the emission intensity upsurges and no luminescence quenching observed in 0.0 to 2.0 mol% concentration range. It is believed that the concentration quenching occurs due to non-radiative energy transfer among the RE3+ ions through cross relaxation channels. In X-rays induce luminescence spectra studied in present work show same trend and number of emission peaks as that of photoluminescence emission spectra but with different intensity and slightly different peaks positions due to the different irradiation sources. Several radiative properties i.e., Branching ratio, quantum efficiency, radiative lifetime, stimulated emission cross sections and radiative transition probabilities were calculated with JO theory. Lifetime of present glasses were recorded with respective emission and excitations wavelength and it is found that lifetime decrease with increasing concentration of Dy3+ and Sm3+ ions, while for Eu3+ ions no significant variations observed in lifetime values. Moreover, lifetime curve shows single exponential nature at lo wer concentration of rare earth and deviate from the single exponential behavior as the concertation of rare earth increase. This non-single exponential behavior of lifetime curves are fitted in the framework of Inokuti-Hirayama (IH) model to understand energy transfer mechanism involved in respective case. Subsequently, the color of emitted light was compared with 1931 CIE (Commission International de I’Eclairage) chromatic color coordinates.
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شہرِ نبیؐ میں مکہ سے ہو کر چلیں گے ہم


شہرِ نبیؐ میں مکّہ سے ہو کر چلیں گے ہم
دامانِ داغدار کو دھو کر چلیں گے ہم

تر دامنی کو اشکِ ندامت سے دھوئیں گے
عشقِ نبیؐ میں خود کو ڈبو کر چلیں گے ہم

روئیں گے خوب شہرِ مدینہ کی یاد میں
اشکوں کے خوب ہار پرو کر چلیں گے ہم

روح و دل و دماغ میں طیبہ کی ہو فضا
یوں صحنِ جاں میں شوق کو بو کر چلیں گے ہم

’’ماذاغ‘‘ کی ادا کا تکلّم کلیمؑ سے
تم کام کر نہ پائے تھے جو ؛ کر چلیں گے ہم

آغوش میں یوں نیند نے لے کر مجھے کہا
آؤ درِ رسولؐ پہ سو کر چلیں گے ہم

عرفانؔ ! اب تو عزم یہی چشمِ تر کا ہے
داغِ غمِ فراق کو دھو کر چلیں گے ہم

من مشاكل الشباب اليوم فقدان العلم والتربية وكيفية معالجتها

Youth is asset of a nation and it’s our luck that Muslim Ummah and specially Pakistan consists of 60% youngsters. Therefore, we thank to Almighty Allah but with great the passage of time due to our lack of intrest this asset is going to deteacked, which is a great loss of Muslim Ummah.. This article is an effort to determine the difficulties and issues of Muslim youngsters and then their solution in the light of the Holy Quran and the Sunnah of the prophet (r). As well as this study also points out the solutions of the current issues of youngsters. If we try to know the reasons of the difficulties of youngsters bared on ignorance and illiteracy and we should give them prior importerne. We cannot ignore the significance of the role of youngsters in the development of Islamic society. This paper tells the Islamic knowledge, Islamic education and love to Allah and his kind prophet (r) as role model and ethical grooming on the basis of faith, Islamic worships and morality are necessary tools for that grooming and reformation. Side by side we cannot forget the role of family system, mosques and madrasas, friends and the society in character building of youngsters and specially the role of mosques to educate the society, especially youngsters.

Investigation on Factor Affecting in Vitro Gonadotrophin Secretion from Buffalo Adenohypophysis

This project was planned to investigate effects of estrogen and progesterone along with insulin in optimizing the in vitro production of pituitary gonadotropins from buffalo adenohypophysis. Attempts were also made to monitor bioactivity of in vitro produced FSH and LH in prepubertal female rabbits and buffaloes. In the first experiment, gonadotropins i.e. FSH and LH were produced by treating in vitro culture of buffalo adenohypophysis with two levels of estrogen (0.5, 1.0 mg) and progesterone (2.5, 5.0 mg). Insulin and liver extract were added in the culture medium as growth promoting factors. The amounts of FSH and LH produced were estimated by ELISA and HPLC techniques. Results showed significant (P<0.05) increase in the secretion of FSH and LH in cultures treated with estrogen and progesterone, respectively compared with control. The FSH and LH obtained were estimated to be 33.0 IU/ml and 68.67 IU/ml, respectively, in proportionate to standard of FSH being 100.0 IU/ml and LH being 1500.0 IU/ml. Experiment was repeated and sufficient amount of FSH and LH was obtained. Repeated procedure proved that the technique can be used for further production of FSH and LH. In the second experiment four groups of pre-pubertal female rabbits were treated with in vitro produced FSH≈4.0, 40.0 IU; LH≈8.5 and 85 IU (s/c), twice daily in divided dose at an interval of 12 hours for five days. Similarly, one group of rabbits was treated with placebo as control-1 and one was untreated kept as control-2. There was no treatment-related mortality; no hypersensitivity or toxic sign was seen in any of the experimental rabbit. None, of the experimental rabbits showed change in general behavior, aggressiveness/lethargy and weight. The in vitro produced FSH≈4.0, 40 IU, LH≈8.5 and 85 IU did not affect body weight and most of the blood parameters i.e. RBC and WBC count, PCV and hemoglobin (Hb) concentration of female rabbits. FSH≈4.0 and 40 IU resulted (P<0.05) on increased number of GF’s along with increased mean length, width, weight and volume of ovaries compared with rabbits treated with LH≈8.5, 85.0 IU and control. Moreover, treating rabbits with in vitro produced FSH≈40 IU, LH≈85.0 IU resulted in significantly (P<0.001) increased serum FSH (260-470 Vs 4-6 mlU/ml) and serum LH (28-48 Vs 4-5 mlU/ml), compared with rabbits of control group. In third experiment, two groups A and B (three in each group) of healthy but acyclic dairy buffaloes were treated with in vitro produced FSH≈500 IU and Folltropin-V≈5mg (s/c), twice daily and buffaloes in group C were treated with placebo/control. Treating buffaloes with in vitro produced FSH and Folltropin-V resulted in significantly (P<0.01) higher serum FSH, LH and estrogen concentration at day 5 to 6, whereas progesterone concentration was decreased (P<0.01). Day to day increase in serum FSH was also significant (P<0.01). Increase in serum LH was observed at day 5 to 6. Though the size of ovaries was increased showing numerous small GF’s, however, no one attained ovulatory capability. Hormones obtained from the culture materials showed bioactivity in the experimental animals without any toxicity.