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1.
J Maxillofac Oral Surg ; 22(1): 159-164, 2023 Mar.
Article in English | MEDLINE | ID: mdl-36703666

ABSTRACT

Background: The oral cavity is a unique environment where wound healing needs to occur in the presence of heavily contaminated oral fluid often leading to infections at the suture site. Topical antimicrobial agents have proven to be effective in controlling intraoral infections. One such antimicrobial combination is Metronidazole-Chlorhexidine which has commonly been used to treat oral ulcers and gingival inflammation; however, there are no studies of its use in the healing of oral incisions. Methodology: This split-mouth study comprised of 15 participants who received 30 intraoral incisions. Incisions were placed either simultaneously (Group 1) or at spaced intervals (Group 2) for various minor and major surgical procedures. Metronidazole -Chlorhexidine gel was applied to the study sites while the control sites were allowed to heal naturally. Pain, inflammation, and healing were assessed using visual analogue scale and healing index by Landry et al. Results: The study sites showed better wound healing and decreased postoperative inflammation. There was a statistically significant decrease in post-operative pain in the study site in Group 1 but not in Group 2. Conclusion: Metronidazole-Chlorhexidine combination gel is a cost-effective, readily available, and safe medicament to improve healing of intraoral incisions and reduce post-operative inflammation and pain.

2.
Ann R Coll Surg Engl ; 105(3): 247-251, 2023 Mar.
Article in English | MEDLINE | ID: mdl-35175143

ABSTRACT

INTRODUCTION: Reconstruction of a surgical defect is an important part of the management of oral cancers. Microvascular free flap construction provides better functional and cosmetic outcomes. METHODS: Between 2014 and 2020, some 524 patients underwent microvascular reconstruction. Comorbidity variables were scored using the Charlson Comorbidity Index (CCI). Complications were recorded using Clavien-Dindo criteria. RESULTS: Eighty-three (15.84%), 339 (64.69%) and 102 (19.47%) patients underwent free radial forearm flap, free anterolateral thigh flap and free fibula osteocutaneous flap (FFOCF), respectively. Clavien-Dindo complications of grade III and above were seen in 39 (7.44%) patients. Total flap loss was seen in 18 patients and of these, 16 were salvaged using alternative free flaps or pedicled flaps. On univariate analysis, overall and major complication rates were higher in FFOCF (p=0.171). Major complications significantly more common in patients with a CCI score >4 (p=0.001). Patients aged >65 years had higher rates of complications (p=0.03). CONCLUSION: Microvascular free tissue transfer is a reliable, safe and gold standard modality in surgical reconstruction and can be replicated in non-institutional settings.


Subject(s)
Free Tissue Flaps , Mouth Neoplasms , Humans , Mouth Neoplasms/surgery , Postoperative Complications/epidemiology , Postoperative Complications/etiology , Thigh/surgery , Lower Extremity
3.
Cureus ; 14(10): e29905, 2022 Oct.
Article in English | MEDLINE | ID: mdl-36348827

ABSTRACT

The studies on bibliometric analyses of case reports usually give valuable information regarding various aspects of case reports but lack investigation analysing these publications. This is the first-ever study to examine the bibliometric articles on case reports; hence, it is hypothesized to provide a valuable contribution to this gap. PubMed and SCOPUS databases were searched, and a total of 119 articles were obtained, but only five were analyzed matching the inclusion criteria. The keywords involved in the search were "Bibliometrics", "analysis", "case reports", "case series", and "articles" whereas, the time range in which the case reports were searched for was between 2011-2021. Common parameters from these five articles were employed for bibliometric analysis, which included publication year, publication type, the number of case reports per article, theme or subject of the article, citation, and impact factor (IF). Out of the five articles identified, four were published in 2021. One out of five was a case report, and the rest were review-type of articles. The overall citation number of these articles was less than 10, and the IF of these articles was between 0-0.007. The number of citations of the articles was in a period of one to two years or less than one year. A comprehensive overview of the parametrises, as well as the recent trends that are being used to conduct bibliometric analysis on case reports was acquired.

4.
Luminescence ; 37(4): 524-542, 2022 Apr.
Article in English | MEDLINE | ID: mdl-35102701

ABSTRACT

The article briefly reports the fundamental scientific principles and landmarks in the field of luminescence and further enlightens the importance of persistent phosphor that is now widely used in luminous paints. Its main focus is on phosphorescence that makes use of lanthanides that have gained paramount importance in various cross-sections of luminescent applications. Both inorganic and organic afterglow materials, synthesis and characterization along with skilled researchers' essential updates on emerging trends and efforts are elucidated at length. It exclusively reviews the red/green/blue organic/inorganic/hybrid phosphorescent materials and the latest advances in the development of novel long afterglow materials that can accelerate the green technology in the world of luminescence.


Subject(s)
Lanthanoid Series Elements , Luminescent Agents , Luminescence , Paint
6.
Ann R Coll Surg Engl ; 103(4): 278-281, 2021 Apr.
Article in English | MEDLINE | ID: mdl-33682450

ABSTRACT

INTRODUCTION: Microvascular reconstruction is the gold standard for reconstruction in oral cavity cancers. Age and comorbidities determine the type of reconstruction. We aimed to analyse the impact of high-risk comorbidities on perioperative morbidity. METHODS: This is a retrospective study of 317 patients undergoing microvascular reconstruction from January 2014 to December 2017. High risk patients were based on age, American Society of Anaesthesiologists (ASA) grade (III/IV) and Charlson comorbidity index (CCI) score >4; overall, 73 out of 317 patients were evaluated. RESULTS: Median age was 59 years. Five patients (6.8%) had complete flap failures and seven (9.5%) had minor complications (wound breakdown, bleeding, wound dehiscence, partial flap loss). ASA score of IV was significantly associated with morbidity while age >65 years and CCI >4 was not associated. The overall flap success rate was 93.2%. CONCLUSIONS: A high-risk population has nearly similar outcomes for microvascular reconstruction as a younger age group. High ASA score adversely affects surgery-related outcomes.


Subject(s)
Head and Neck Neoplasms/surgery , Microsurgery/methods , Plastic Surgery Procedures/methods , Squamous Cell Carcinoma of Head and Neck/surgery , Vascular Surgical Procedures/methods , Adult , Aged , Aged, 80 and over , Female , Humans , Male , Middle Aged , Postoperative Complications/epidemiology , Postoperative Complications/etiology , Retrospective Studies , Risk Factors , Severity of Illness Index , Surgical Flaps , Treatment Outcome
7.
Luminescence ; 36(8): 1878-1884, 2021 Dec.
Article in English | MEDLINE | ID: mdl-33332724

ABSTRACT

An attempt has been made to synthesize orange-red light-emitting rare earth-doped polymer matrices Eu0.5 Sm0.5 (TTA)3 tppo (Eu = europium, Sm = samarium, TTA = thenoyltrifluoroacetone, tppo = triphenylphosphine oxide) hybrid organic complex by solution technique. Blended thin films were made by molecularly doping the complex in polymethylmethacrylate (PMMA) and polystyrene (PS) polymers at different weight percentages (5%, 10%). These films were solvated in basic and acidic media to explore the effect of solvent on its luminescence properties. UV-visible absorption spectra of these solvated films portray two peaks corresponding to π→π* and n→π* optical transitions in the range 240-275 nm and 370-390 nm in basic medium. Energy band gap of these thin films in basic medium was found between 3.16 eV to 3.20 eV and 3.12 eV to 3.22 eV in acidic medium. Photoluminescence spectra of all films in dichloromethane showed an intense peak at 614 nm, whereas in formic acid, the same were found at 475 nm, which fell in the orange-red and blue region of the visible spectrum, respectively. CIE coordinates of these solvated films in various solvents and at different weight percentages revealed tunable orange-red to blue light emission with change in polarity of the solvent. Therefore the synthesized complexes blended in the polymers can be shaped into flexible films for fabrication of organic light-emitting diodes (OLEDs) with consistent results, proving their prospect as colour tunable light emissive materials for OLED devices, lasers, displays, and solid-state lighting.


Subject(s)
Polymethyl Methacrylate , Porphyrins , Europium , Polystyrenes
8.
Indian J Anaesth ; 64(4): 310-315, 2020 Apr.
Article in English | MEDLINE | ID: mdl-32489206

ABSTRACT

BACKGROUND AND AIMS: Axillary brachial plexus block is commonly performed for surgeries on the hand and forearm. However, there are very few studies on the use of magnesium sulphate in axillary brachial plexus block and, hence, the study was designed to evaluate magnesium as an adjuvant to ropivacaine-induced axillary block with respect to onset and duration of sensorimotor block and postoperative analgesia. METHODS: Sixty patients of the American Society of Anesthesiologists (ASA) physical status I and II, undergoing surgeries on the hand and forearm were randomly recruited to receive ultrasound-guided axillary block with either 150 mg magnesium sulphate or 1 mL normal saline added to 0.5% ropivacaine. The primary outcome measure was to compare block characteristics including postoperative analgesia and the secondary outcome was to compare the use of rescue analgesia and the side-effect profile. Data were statistically analysed using Statistical Package for Social Sciences (SPSS version 21.0). Categorical variables were compared using the Chi-square test or Fisher's exact probability test; continuous variables compared using unpaired t-test or Mann-Whitney U test. RESULTS: Onset of sensory (9.93 ± 1.31 vs 8.83 ± 1.12 min) as well as motor block (13.37 ± 1.63 vs 11.57 ± 1.30 min) was significantly hastened with addition of magnesium to ropivacaine (p < 0.001) and so was the duration (sensory 386.60 ± 18.26 vs 526.37 ± 27.43, motor 323.73 ± 15.17 vs 436.97 ± 18.99 min) (p < 0.001) and postoperative analgesia (425 ± 21.39 vs 572.83 ± 32.04 min) (p < 0.001) which reflected in decreased requirement of rescue analgesic and total postoperative analgesic dosage. CONCLUSIONS: Magnesium is an effective and safe adjuvant to local anaesthetics and improves all characteristics of axillary brachial plexus block along with postoperative analgesia.

9.
Ann R Coll Surg Engl ; 102(7): 514-518, 2020 Sep.
Article in English | MEDLINE | ID: mdl-32436723

ABSTRACT

INTRODUCTION: Major glossectomy is the treatment of choice in locally advanced tongue cancer. It remains the only option in the presence of recurrent or residual disease. The long-term outcomes for patients undergoing major glossectomy have traditionally been poor, with significant morbidity and poor oncological outcomes. The aim of this study was to report on oncological outcomes in patients undergoing major glossectomy. METHODS: All patients undergoing major glossectomy between 2014 and 2018 were included in the study. The data of 85 patients with advanced carcinoma of the oral tongue were evaluated. All were under the care of a single surgical and reconstructive team at two hospitals in Mumbai. RESULTS: The median patient age was 45 years. At the most recent follow-up, 55 patients (65%) were alive, 47 of whom were disease free. Twenty-nine patients (34%) had locoregional recurrence and twenty-five (29%) had distant metastasis. At a median follow-up of 19 months, rates for 2-year locoregional control, disease free survival (DFS) and overall survival (OS) were 69%, 61% and 62% respectively. Perinodal extension demonstrated a trend towards poor DFS (p=0.060), as did perineural invasion (p=0.055). Node positivity was a significant factor for poor OS, DFS and locoregional control. Multiple node involvement was significantly associated with poor OS on multivariate analysis (p=0.002). CONCLUSIONS: Node positivity and multiple node involvement were associated with poor outcomes. Major glossectomy may be offered as a curative option for selected patients with advanced carcinoma of the oral tongue with node negative or limited neck nodal disease (N1).


Subject(s)
Glossectomy/methods , Neoplasm Recurrence, Local/epidemiology , Neoplasm Staging , Tongue Neoplasms/surgery , Tongue/pathology , Adolescent , Adult , Aged , Disease-Free Survival , Female , Follow-Up Studies , Humans , India/epidemiology , Lymphatic Metastasis , Male , Middle Aged , Neoplasm Recurrence, Local/diagnosis , Retrospective Studies , Survival Rate/trends , Tongue/surgery , Tongue Neoplasms/diagnosis , Tongue Neoplasms/secondary , Young Adult
10.
Ann R Coll Surg Engl ; 102(3): 232-235, 2020 Mar.
Article in English | MEDLINE | ID: mdl-31841025

ABSTRACT

INTRODUCTION: Surgical management of oral cavity carcinoma involves composite resection with reconstruction. Comorbidities increase the risk of perioperative complications. Objective stratification is important for uneventful recovery. The Charlson Comorbidity Index and the Washington University Head and Neck Comorbidity Index were used to assess perioperative morbidity and mortality. MATERIALS AND METHODS: This was a prospective study of 531 patients with head and neck squamous cell carcinoma who were treated between January 2014 and December 2017. Patients' comorbidity scores on the Charlson Comorbidity Index and Washington University Head and Neck Comorbidity Index were recorded. RESULTS: The median age of the cohort was 49 years. Median Charlson Comorbidity Index score was 3 and Washington University Head and Neck Comorbidity Index was 0. There were five mortalities with a Charlson Comorbidity Index score of 4 or more. Fifteen patients had either infection, leak or postoperative bleeding. A Charlson Comorbidity Index of 4 or more was associated with higher event rate and poor overall survival (p=0.001). CONCLUSION: Higher Charlson Comorbidity Index score is associated with increased incidence of peri-operative morbidity and mortality, while the Washington University Head and Neck Comorbidity Index is a poor predictor of the same.


Subject(s)
Mouth Neoplasms/surgery , Postoperative Hemorrhage/etiology , Squamous Cell Carcinoma of Head and Neck/surgery , Adolescent , Adult , Aged , Aged, 80 and over , Anastomotic Leak/etiology , Comorbidity , Female , Humans , Infections/etiology , Male , Middle Aged , Mouth Neoplasms/mortality , Prospective Studies , Squamous Cell Carcinoma of Head and Neck/mortality , Survival Rate , Young Adult
11.
Luminescence ; 33(8): 1415-1422, 2018 Dec.
Article in English | MEDLINE | ID: mdl-30378243

ABSTRACT

We designed and synthesized a 2-(4-bromophenyl)-1-phenyl-1H-benzimidazole (pbi-Br) ligand, which was then employed to create an innovative phosphorescent cyclometallated iridium(III) (pbi-Br)2 Ir(acac) metal complex with acetyl acetone as an ancillary ligand using the Suzuki coupling reaction. The complex was then characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectra and thermogravimetric analysis (TGA)/differential thermal analysis (DTA) for structural and thermal analysis, respectively. XRD confirmed its amorphous nature and the FTIR spectrum revealed the molecular structure confirmation of the metal complex. The TGA/DTA curve disclosed its thermal stability up to 310°C. Ultraviolet (UV)-vis absorption and photoluminescence (PL) spectra were measured to explore the photo-physical properties of the (pbi-Br)2 Ir(acac) complex in basic and acidic media respectively. With the variation in solvent from acidic to basic media, optical absorption peaks blue shifted with variation in optical densities. These results facilitated the calculation of various photo-physical parameters. When excited at 379 nm in the solid state, the synthesized complex gave out a green light emission, peaking at λemi  = 552 nm. Staggering differences in optical density were observed in the PL spectra of the solvated complex. A Stokes' shift of 7140.45 cm-1 and 7364.94 cm-1 was observed when the complex was solvated in acetic acid and chloroform, respectively. Hence the synthesized iridium metal complex can be considered as promising green emissive material for optoelectronic applications.


Subject(s)
Benzimidazoles/chemistry , Coordination Complexes/chemistry , Iridium/chemistry , Light , Luminescent Agents/chemistry , Coordination Complexes/chemical synthesis , Ligands , Luminescent Agents/chemical synthesis , Spectroscopy, Fourier Transform Infrared , X-Ray Diffraction
12.
Luminescence ; 33(6): 999-1009, 2018 Sep.
Article in English | MEDLINE | ID: mdl-29851221

ABSTRACT

This paper reports the synthesis and characterization of 2-(4-ethoxyphenyl)-4-phenyl quinoline (OEt-DPQ) organic phosphor using an acid-catalyzed Friedlander reaction and the preparation of blended thin films by molecularly doping OEt-DPQ in poly(methyl methacrylate) (PMMA) at different wt%. The molecular structure of the synthesized phosphor was confirmed by Fourier transform infra-red (FTIR) spectroscopy and nuclear magnetic resonance spectra (NMR). Surface morphology and percent composition of the elements were assessed by scanning electron microscopy (SEM) and energy dispersive analysis of X-rays (EDAX). The thermal stability and melting point of OEt-DPQ and thin films were probed by thermo-gravimetric analysis (TGA)/differential thermal analysis (DTA) and were found to be 80°C and 113.6°C, respectively. UV-visible optical absorption spectra of OEt-DPQ in the solid state and blended films produced absorption bands in the range 260-340 nm, while photoluminescence (PL) spectra of OEt-DPQ in the solid state and blended thin films demonstrated blue emission that was registered at 432 nm when excited at 363-369 nm. However, solvated OEt-DPQ in chloroform, tetrahydrofuran or dichloromethane showed a blue shift of 31-43 nm. Optical absorption and emission parameters such as molar extinction coefficient (ε), energy gap (Eg ), transmittance (T), reflectance (R), refractive index (n), oscillator energy (E0 ) and oscillator strength (f), quantum yield (φf ), oscillator energy (E0 ), dispersion energy (Ed ), Commission Internationale de l'Éclairage (CIE) co-ordinates and energy yield fluorescence (EF ) were calculated to assess the phosphor's suitability as a blue emissive material for opto-electronic applications such as organic light-emitting diodes (OLEDs), flexible displays and solid-state lighting technology.


Subject(s)
Light , Luminescent Agents/chemistry , Quinolines/chemistry , Luminescent Agents/chemical synthesis , Luminescent Measurements , Molecular Structure , Quinolines/chemical synthesis , Solutions
13.
Luminescence ; 33(5): 968-980, 2018 Aug.
Article in English | MEDLINE | ID: mdl-29851237

ABSTRACT

We report on the comprehension of novel europium activated hybrid organic Eu(dmh)3 phen (Eu: europium, dmh: 2,6-dimethyl-3,5-heptanedione, phen: 1,10 phenanthroline) organo-metallic complexes, synthesized at different pH values by the solution technique. Photo physical properties of these complexes in various basic and acidic solvents were probed by UV-vis optical absorption and photoluminescence (PL) spectra. Minute differences in optical absorption peaks with variable optical densities were encountered with the variation in solvent from basic (chloroform, toluene, tetrahydrofuran) to acidic (acetic acid) media, revealing bathochromic shift in the absorption peaks. The PL spectra of the complex in various acidic and basic organic solvents revealed the position of the emission peak at 613 nm irrespective of the changes in solvents whereas the excitation spectrum almost matched with that of the UV-vis absorption data. The optical density was found to be maximum for the complex with pH 7.0 whereas it gradually decreased when pH was lowered to 6.0 or raised to 8.0 at an interval of 0.5, demonstrating its pH sensitive nature. Several spectroscopic parameters related to probability of transition such as absorbance A(λ), Napierian absorption coefficient α(λ), molecular absorption cross-section σ(λ), radiative lifetime (τ0 ) and oscillator strength (f) were calculated from UV-vis spectra. The relative intensity ratio (R-ratio), calculated from the emission spectra was found to be almost the same in all the organic solvents. The optical energy gap, calculated for the designed complexes were found to be well in accordance with the ideal acceptance value of energy gap of the emissive materials used for fabrication of red organic light-emitting diode (OLED). The relation between Stoke's shift and solvent polarity function was established by Lippert-Mataga plot. This remarkable independence of the electronic absorption spectra of Eu complexes on the nature of the solvent with unique emission wavelength furnishes its potential to serve as a red light emitter for solution processed OLEDs, display panels and solid-state lighting.


Subject(s)
Europium/chemistry , Luminescent Agents/chemistry , Organometallic Compounds/chemistry , Hydrogen-Ion Concentration , Luminescence , Luminescent Measurements , Phenanthrolines/chemistry , Solvents/chemistry , Spectrophotometry, Ultraviolet
14.
Luminescence ; 33(2): 297-304, 2018 Mar.
Article in English | MEDLINE | ID: mdl-29044939

ABSTRACT

A novel blue luminescent 6-chloro-2-(4-cynophenyl) substituted diphenyl quinoline (Cl-CN DPQ) organic phosphor has been synthesized by the acid-catalyzed Friedlander reaction and then characterized to confirm structural, optical and thermal properties. Structural properties of Cl-CN-DPQ were analyzed by Fourier transform infrared (FTIR), nuclear magnetic resonance (NMR) spectroscopy, X-ray diffraction technique (XRD) and scanning electron microscopy (SEM) and energy dispersive analysis of X-ray (EDAX) spectroscopy. FTIR spectra confirmed the presence of different functional groups and bond stretching. 1 H-NMR and 13 C-NMR confirmed the formation of an organic Cl-CN-DPQ compound. X-ray diffraction study provided its crystalline nature. The surface morphology of Cl-CN-DPQ was analyzed by SEM, while EDAX spectroscopy revealed the elemental analysis. Differential thermal analysis (TGA/DTA) disclosed its thermal stability up to 250°C. The optical properties of Cl-CN-DPQ were investigated by UV-vis absorption and photoluminescence (PL) measurements. Cl-CN-DPQ exhibits intense blue emission at 434 nm in a solid-state crystalline powder with CIE co-ordinates (0.157, 0.027), when excited at 373 nm. Cl-CN-DPQ shows remarkable Stokes shift in the range 14800-5100 cm-1 , which is the characteristic feature of intense light emission. A narrow full width at half-maximum (FWHM) value of PL spectra in the range 42-48 nm was observed. Oscillator strength, energy band gap, quantum yield, and fluorescence energy yield were also examined using UV-vis absorption and photoluminescence spectra. These results prove its applications towards developing organic luminescence devices and displays, organic phosphor-based solar cells and displays, organic lasers, chemical sensors and many more.


Subject(s)
Luminescent Agents/chemistry , Quantum Dots/chemistry , Quinolines/chemistry , Hot Temperature , Luminescence , Luminescent Agents/chemical synthesis , Luminescent Measurements , Magnetic Resonance Spectroscopy , Quantum Dots/ultrastructure , Quinolines/chemical synthesis , Spectroscopy, Fourier Transform Infrared , X-Ray Diffraction
15.
Indian J Cancer ; 53(1): 96-101, 2016.
Article in English | MEDLINE | ID: mdl-27146753

ABSTRACT

BACKGROUND: Lung cancer most commonly presents in advanced stages in developing countries, where combined modality treatment using chemo-radiotherapy (CTRT) is the standard of care. MATERIALS AND METHODS: A retrospective audit of patients of nonsmall cell lung cancer (NSCLC) treated at a single Institute from January 2008 to December 2012 was conducted. Various prognostic factors affecting disease-free survival (DFS) and overall survival (OS) were studied by univariate and multivariate analysis. All patients were meticulously followed-up clinically and telephonic contacts. RESULTS: Overall 171 patients of NSCLC were treated with definitive CTRT using concurrent chemotherapy in 66% patients and sequential therapy in 28% patients. The actuarial 2 years DFS was 17.5% and 2 years OS was 61.5%. Complete response to treatment resulted in significantly better DFS and OS. Definitive CTRT was very well-tolerated in these patients with good compliance. CONCLUSION: Definitive CTRT, sequence being individualized depending on performance status and disease stage at presentation, is a feasible and effective treatment modality for locally advanced NSCLC patients in the developing world. Response to treatment is an important prognostic factor for treatment outcomes.


Subject(s)
Carcinoma, Non-Small-Cell Lung/drug therapy , Carcinoma, Non-Small-Cell Lung/radiotherapy , Lung Neoplasms/drug therapy , Lung Neoplasms/radiotherapy , Adult , Aged , Aged, 80 and over , Chemoradiotherapy , Developing Countries , Disease-Free Survival , Female , Humans , Male , Middle Aged , Prognosis , Radiotherapy Planning, Computer-Assisted/methods , Retrospective Studies
16.
Luminescence ; 30(3): 251-6, 2015 May.
Article in English | MEDLINE | ID: mdl-25045087

ABSTRACT

Pure and Na(+) -doped Alq3 complexes were synthesized by a simple precipitation method at room temperature, maintaining a stoichiometric ratio. These complexes were characterized by X-ray diffraction, Fourier transform infrared (FTIR), UV/Vis absorption and photoluminescence (PL) spectra. The X-ray diffractogram exhibits well-resolved peaks, revealing the crystalline nature of the synthesized complexes, FTIR confirms the molecular structure and the completion of quinoline ring formation in the metal complex. UV/Vis absorption and PL spectra of sodium-doped Alq3 complexes exhibit high emission intensity in comparison with Alq3 phosphor, proving that when doped in Alq3 , Na(+) enhances PL emission intensity. The excitation spectra of the synthesized complexes lie in the range 242-457 nm when weak shoulders are also considered. Because the sharp excitation peak falls in the blue region of visible radiation, the complexes can be employed for blue chip excitation. The emission wavelength of all the synthesized complexes lies in the bluish green/green region ranging between 485 and 531 nm. The intensity of the emission wavelength was found to be elevated when Na(+) is doped into Alq3 . Because both the excitation and emission wavelengths fall in the visible region of electromagnetic radiation, these phosphors can also be employed to improve the power conversion efficiency of photovoltaic cells by using the solar spectral conversion principle. Thus, the synthesized phosphors can be used as bluish green/green light-emitting phosphors for organic light-emitting diodes, flat panel displays, solid-state lighting technology - a step towards the desire to reduce energy consumption and generate pollution free light.


Subject(s)
Luminescent Agents/chemistry , Aluminum/chemistry , Chemistry Techniques, Synthetic , Electronics/instrumentation , Luminescent Agents/chemical synthesis , Luminescent Measurements , Molecular Structure , Organometallic Compounds/chemistry , Sodium , Spectrophotometry, Ultraviolet , Spectroscopy, Fourier Transform Infrared , X-Ray Diffraction
17.
Luminescence ; 29(6): 674-8, 2014 Sep.
Article in English | MEDLINE | ID: mdl-24265233

ABSTRACT

Yttrium is stoichiometrically doped into europium by mole percentage, during the synthesis of Y(1-x) Eu(x) (TTA)3 (Phen), using solution techniques (where x = 0.2, 0.4, 0.5, 0.6 and 0.8, TTA = thenoyltrifluoroacetone and Phen = 1,10-phenanthroline).These complexes were characterized using different techniques such as X-ray diffraction, thermogravimetric/differential thermal analysis, optical absorption and emission spectra. Thin films of the doped Eu-Y complexes were prepared on a glass substrate under a high vacuum of 10(-6) Torr. The photoluminescence spectra of these thin films were recorded by exciting the sample at a wavelength of 360 nm. The emission peak for all the synthesized complexes centered at 611 nm; maximum emission intensity was obtained from Y0.6 Eu0.4 (TTA)3 (Phen). The results proved that these doped complexes are more economical than pure Eu(TTA)3 (Phen) and are best suited as red emissive material for energy-efficient and eco-friendly organic light-emitting diodes and displays.


Subject(s)
Europium/chemistry , Organometallic Compounds/chemistry , Organometallic Compounds/chemical synthesis , Phenanthrolines/chemistry , Thenoyltrifluoroacetone/chemistry , Yttrium/chemistry , Luminescent Measurements , Molecular Structure , Thermogravimetry , X-Ray Diffraction
18.
Luminescence ; 29(5): 433-9, 2014 Aug.
Article in English | MEDLINE | ID: mdl-23946097

ABSTRACT

Pure and Li(+)-doped Alq3 complexes were synthesized by simple precipitation method at room temperature, maintaining the stoichiometric ratio. These complexes were characterized by X-ray diffraction, ultraviolet-visible absorption and Fourier transform infrared and photoluminescence (PL) spectra. X-ray diffraction analysis reveals the crystalline nature of the synthesized complexes, while Fourier transform infrared spectroscopy confirm the molecular structure, the completion of quinoline ring formation and presence of quinoline structure in the metal complex. Ultraviolet-visible and PL spectra revealed that Li(+) activated Alq3 complexes exhibit the highest intensity in comparison to pure Alq3 phosphor. Thus, Li(+) enhances PL emission intensity when doped into Alq3 phosphor. The excitation spectra lie in the range of 383-456 nm. All the synthesized complexes other than Liq give green emission, while Liq gives blue emission with enhanced intensity. Thus, he synthesized phosphors are the best suitable candidates for green- and blue-emitting organic light emitting diode, PL liquid-crystal display and solid-state lighting applications.


Subject(s)
Lithium/chemistry , Luminescent Agents/chemistry , Organometallic Compounds/chemistry , Luminescent Agents/chemical synthesis , Spectroscopy, Fourier Transform Infrared , X-Ray Diffraction
19.
Luminescence ; 28(1): 63-8, 2013.
Article in English | MEDLINE | ID: mdl-22733610

ABSTRACT

The tris(8-hydroxyquinoline)-aluminium complex is the most important and widely studied as electron transporting and green light emitting material. Alq(3) and Tb(x) Al((1-x)) q(3) have been synthesized (where x = 0.1, 0.3, 0.5, 0.7 and 0.9) and blended films of Alq(3) and Tb(x) Al((1-x)) q(3) with PMMA and PS at different percentage weight (wt%) concentrations (e.g., 0.1, 1, 5, 10, 25 and 50 wt%) have been prepared. The synthesized materials and their blended thin films have been characterized by a photoluminescence (PL) technique; the synthesis and PL characterization are reported in this paper. The synthesized metal complex shows bright emission of green light with blue light excitation (440 nm) and the prepared Tb(x) Al((1-x)) q(3) phosphor may be applicable in blue chip-excited OLEDs for the newly developed wallpaper lighting technology.


Subject(s)
Aluminum/chemistry , Luminescent Agents/chemistry , Luminescent Measurements/instrumentation , Oxyquinoline/chemistry , Terbium/chemistry , Electron Transport , Light , Luminescent Agents/chemical synthesis
20.
Luminescence ; 28(2): 183-9, 2013.
Article in English | MEDLINE | ID: mdl-22733618

ABSTRACT

Volatile Eu complexes, namely Eu(TTA)3Phen, Eu(x)Y(1-x)(TTA)3Phen; Eu(x)Tb(1-x)(TTA)3Phen; Eu, europium; Y, yttrium; Tb, Terbium; TTA, thenoyltrifluoroacetone; and Phen, 1,10 phenanthroline were synthesized by maintaining stichiometric ratio. Various characterization techniques such as X-ray diffraction (XRD), photoluminescence (PL) and thermo gravimetric analysis/differential thermal analysis (TGA/DTA) were carried out for the synthesized complexes. Diffractograms of all the synthesized complexes showed well-resolved peaks, which revealed that pure and doped organic Eu(3+) complexes were crystalline in nature. Of all the synthesized complexes, Eu0.5Tb0.5(TTA)3Phen showed maximum peak intensity, while the angle of maximum peak intensity for all complexes was almost the same with slightly different d-values. A prominent sharp red emission line was observed at 611 nm when excited with light at 370 nm. It was observed that the intensity of red emissions increased for doped europium complexes Eu(x)Y(1-x)(TTA)3Phen and Eu(x)Tb(1-x)(TTA)3Phen, when compared with Eu complexes. Emission intensity increased in the following order: Eu(TTA)3Phen > Eu0.5Tb0.5(TTA)3Phen > Eu0.4Tb0.6(TTA)3Phen > Eu0.5Y0.5(TTA)3Phen > Eu0.4Y0.6(TTA)3Phen, proving their potential application in organic light-emitting diodes (OLEDs). TGA showed that Eu complexes doped in Y(3+) and Tb(3+) have better thermal stability than pure Eu complex. DTA analysis showed that the melting temperature of Eu(TTA)3Phen was lower than doped Eu complexes. These measurements infer that all complexes were highly stable and could be used as emissive materials for the fabrication of OLEDs.


Subject(s)
Fluorescent Dyes/chemistry , Polymers/chemistry , Europium/chemistry , Fluorescent Dyes/chemical synthesis , Polymers/chemical synthesis , Spectrometry, Fluorescence , Terbium/chemistry , X-Ray Diffraction , Yttrium/chemistry
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