Search or add a thesis

Advanced Search (Beta)
Home > Novel Materials for Dye Sensitized Solar Cells

Novel Materials for Dye Sensitized Solar Cells

Thesis Info

Access Option

External Link

Author

Javed, Sofia

Program

PhD

Institute

National University of Sciences & Technology

City

Islamabad

Province

Islamabad

Country

Pakistan

Thesis Completing Year

2015

Thesis Completion Status

Completed

Subject

Applied Sciences

Language

English

Link

http://prr.hec.gov.pk/jspui/bitstream/123456789/6735/1/Sofia_Javed_HSR_Materials_%26_Surface_Engineering_2015_NUST_25.11.2016.pdf

Added

2021-02-17 19:49:13

Modified

2024-03-24 20:25:49

ARI ID

1676726767874

Asian Research Index Whatsapp Chanel
Asian Research Index Whatsapp Chanel

Join our Whatsapp Channel to get regular updates.

Similar


Dye sensitized solar cells (DSSCs) being third generation photovoltaics are inexpensive renewable energy resource and recently been a hot topic of research. The objective of the present research work was to develop photoanode materials for low cost efficient DSSCs. This thesis presents some novel materials for the photoanode including semiconductor material with different nanostructures such as nanoparticles, nanoflowers and nanorods and new sensitizers. Synthesis method of titanium dioxide nanoflowers is reported here. Such hierarchical morphology led to the improved device performance due to greater absorption of light through scattering; a novel photoanode with one dimensional sandwich configuration of ZnO/Au/TiO2, incorporating plasmon resonance and charging effects of Au nanoparticles for enhanced efficiency in DSSCs. New metal free calixarene sensitizers with directed flow of electrons are also studied for DSSCs. Titania nanoflowers are highly desirable in light driven applications due to their large surface area and greater light absorption capabilities. Microwave synthesis of nanomaterials is an energy efficient and quick method. Microwave treatment of titania nanopowders under alkaline conditions is carried out to see the effect of treatment duration. An instant, simple, inexpensive and environment friendly method of preparing titanium dioxide nanoflowers or hierarchical nanostructures (HNSs) is thus achieved. Production of sub-micron sized HNSs without any surfactant or hydrofluoric acid is discovered. From FESEM and TEM analysis the titania nanoflowers are found to be made of few nanometers thick radially arranged nanosheets. XRD and Raman spectra reveal no phase change during the microwave treatment. The mechanism of formation of these hierarchical nanostructures involves sheet formation under strong alkaline conditions and their radial growth under the effect of microwave radiation. The hierarchical morphology provides huge surface area for maximum exposure for light driven reactions and 3 D folding morphology allows further scattering of light to get its maximum utilization. This is evident in improved DSSC performance with synthesized nanoflowers. The HNSs produced in a time as short as 5 minutes show improvement in DSSC efficiency by about 216%. vii One dimensional nanostructures of TiO2 and ZnO have also been vastly studied for application in DSSCs. As a novelty in configuration of 1D core/shell nanostructures, the effect of Au nanoparticles inclusion as a sandwiched layer is studied. The sputter coated gold nanolayers of various sizes are applied over ZnO nanorods grown by seed assisted route. 1D Au/ZnO nanoarrays are covered with a few nanometers thick spin coated TiO2 film to make TiO2/Au/ZnO sandwich nanorod arrays. The uniform morphology and dimensions of the nanorod arrays are studied by SEM. HRTEM studies depict the Au nanoparticle size and distribution within the sandwich nanorods and they are found to be embedded at the interface of ZnO/TiO2 coreshell nanorods. The UV/Vis spectra reveal the plasmon resonance effects due to Au nanoparticles, which are also improving the solar cell efficiencies. The observed enhancement in the photocurrent density is attributed to the Localized Surface Plasmon Resonance (LSPR) effects due to sputter coated Au layers. An increase in the open circuit voltage of DSSCs is also observed due to Fermi level alignment between the Au bridged ZnO and TiO2 in the photoanodes of devices. With 2nm sputter coated Au in TiO2/Au/ZnO 1D nanostructures, a relative efficiency enhancement factor of 2.05 is achieved. Further in search of new inexpensive materials for DSSCs, a new class of metal free Donor-π-bridge-Acceptor (D-π-A) dyes based on basket shaped molecules “calixarenes” is introduced for DSSCs. As in calixarenes the flow of electrons is directed along the length of the molecules by resonance and induction effects and there is no conjugation around the molecular cup. This fact can prevent the recombination of charge carriers to a great extent. p-(6-chloro-2- benzothiazolylazo)calix[4]arene (pcb calix) and p-(1,3,4-thiadiazol-2-thiol-5- ylazo)-calix[4]arene (ptt calix) are synthesized and after characterization by FTIR, UV/Vis, NMR spectroscopy and cyclic voltametry are employed in DSSCs to sensitize titania. The HOMO LUMO levels of the dyes are found consistent with the requirement of DSSCs. An efficiency of 0.3% and 0.47% is achieved with dyes pcb-calix and ptt-calix respectively. The attachment of better absorbing chromophores to calixarene can result in obtaining better efficiencies in DSSCs.
Loading...
Loading...

Similar Books

Loading...

Similar Chapters

Loading...

Similar News

Loading...

Similar Articles

Loading...

Similar Article Headings

Loading...

پلاٹ

پلاٹ

                ناول کا پلاٹ بہت خوبصورت انداز میں گتھا ہوا ترتیب دیا گیا ہے۔ناطق جس پس ماندگی کو عیاں کرنے میں کامیاب رہے ہیں۔اسے شروع میں اس طرح دکھایا گیا ہے کہ اصل میں ایک معمولی جڑ کیسے ایک مضبوط تناور درخت  بن جاتی ہیاور جب اس تناور درخت نے اپنی جڑیں اور شاخیں پھیلا دی ہوتی ہیں۔تو اسے ہٹانا کتنا مشکل عمل ہے۔لوطی حرکات سے شروع ہوتی یہ کہانی پھر سیکس انڈسٹری تک جا پہنچی  یہ معاشرتی پس ماندگی ایک مضبوط جڑ کی  طرح معاشرے کو کھوکھلا کر رہی ہے۔اس نے بہت اعلیٰ طریقے سے پردہ سرکایا ہے۔کہانی کا پلاٹ  بہت مضبوط ومنظم ہے مصنف کی گرفت کہانی کے پلاٹ کے علاوہ مکالمے اور جزئیات نگاری پر بھی آخر تک قائم رہی۔تلخ حقائق کو نمایا ں کرنے میں ناطق نے ایک دلیرانہ جسارت کرکے معاشرے کے سماجی مسائل کی عکاسی کی ہے۔عظیم الشان صدیقی لکھتے ہیں :

’’کہانی اگر قصہ کی بنیاد ہے تو پلاٹ اس کی ترئین وآرائش ہیں‘‘(2)

                مصنف نے اس غیر عادلانہ اور استحصال پذیر معاشرے میں اپنی کہانی کیذریعے غیر انسانی رویوں کو بے نقاب کیا ہے اور اس بے حس معاشرے کی بہتری کے لئے ایک مضبوط پلاٹ مرتب کیا ہے۔جس میں شروع سے آخر تک مسلسل ایک سحر بھی قاری پہ قائم رہتا ہے اور دوسرا معاشرے میں موجود غیر انسانی رویوں اور اخلاقی پس ماندگیوں کو سمجھنے کے قابل ہوجاتا ہے۔

کردار

                ناطق کے ناول’’کماری والا‘‘میں تمام کردار متحرک دکھائی دیتے ہیں۔ ’’ضامن‘‘کہانی کا مرکزی کردار ہے۔’’طلال‘‘نے جو کردار پیش کیا یقیناوہ بھی ایک بھاری ذمہ داری پوری کر رہا ہے جس کی وجہ سے باقی تمام کردار متحرک دکھائی دیتے ہیں۔شروع میں قاری کو...

امنا عائشة ملكة العفاف رضي االله عنها

This research aims to explore various features of Syyidah some highlights paper This. Personage noble s'(ر الله عا) ishah‘A’ distinguished aspects of her biographical account, her extraordinary intelligence, eminent rank amongst other wives of the Prophet Muḥammad (r), excellence over women of the world and being mentioned in the Qur’ān for her praiseworthy character. The scholarly areas, in which, she outshone others in Islamic intellectual heritage, include the Quranic exegesis, Ḥadīth narratives, jurisprudence, scholastic reasoning: analysis of jurisprudential methodology and principles of deduction of rulings and opinions. She adopted multifarious modes in this regards including explicit, direct, generalized, inductive and analogous approaches in the Islamic intellectual scholarship. By acknowledged was (ر الله عا) ishah‘A of grandeur The the companions of the Prophet, her scholarly point of view in conciliation of the problems of the Qur'ān and Ḥadīth made her stand out amongst all. She was a keen researcher, peaceful preacher and the greatest scholar of Islām of all times. Her knowledge and command over religious and social matters made her one of the most reliable experts of the Qur'ān, Ḥadīth and Fiqh. Such was her stature as the archangel Jibrā’īl presented his salutation to her.

Tendencies of Consumer’S Compulsive Buying Behavior

Compulsive buying is a phenomenon that has received considerable attention from psychologists, behavioral and marketing researchers as well. Compulsive buying behavior as an addictive tendency or compulsive attribute, insistently arising from rushing, repetitive motive(s) for buying that might or might not be irresistible, gratifying or relieving but for sure it is essentially disturbing to normal functioning. Concurrently, consumer’s compulsive buying behavior is also considered as planned or goal oriented behavior that is shaped by different social and psychological influences. In collectivist culture of Pakistan, social environment or social factors such as individual’s social values and their conformity to group’s norms motivate to fulfill certain social needs. This typical social fabric and proliferation of the culture of excessive consumption/buying makes it, both a need and opportunity, to analyze compulsive buying behavior as well as its process that has not been holistically and systematically studied in the existing literature. The current study identifies the social and psychological perspectives of consumer’s compulsive buying behavior and analyzes the cognitive decision process regarding appearance products. Hence, individual’s social influences studied in this research comprise of social values and attention-to-social-comparison-information, whereas, psychological influences consist of hedonic shopping motives, materialistic attitude, purchase decision involvement and impulsive buying intention. The study, adds significant value to the literature in three ways: first, it provides comprehensive discussion on compulsive buying behavior construct and also the role of motivational forces in the formation of compulsive buying behavior is discussed from two perspectives i.e. social and psychological. Second, Stimulus-Organism-Response framework is used to conceptualize and propose that an individual’s social influences affect the psychological influences, thus leading to the development of compulsive buying behavior. Third, conceptual framework is used to verify the model of consumer’s planned behavior theory and it is established that consumer’s social and psychological characteristics influence impulsive buying intention which ultimately effects compulsive buying behavior.In current study, data was collected from a sample of 1,120 consumers and a total of 1,010 responses were analyzed using structural equation modeling. The results suggest that consumer’s social and psychological influences play a significant role in the development of compulsive buying behavior. The finding indicate that consumers’ attention-to-social-comparison-information is, in-general, a significant motivator/stimulator of their hedonic shopping motives, materialistic attitude and purchase decision involvement, whereas, social values have significant impact only on hedonic motives and which ultimately results in impulsive buying intention as well as compulsive buying behavior. Consequently, consumer’s social values, attention-to-social-comparison- information, hedonic shopping motives and materialistic attitude have indirect, whereas, purchase decision involvement and impulsive buying intention have direct effect on the development of consumer’s compulsive buying behavior. Finally, the overall results of the current study contribute in building a rigor of social cognitive theory and consumer planned behavior theory in the context of consumer’s compulsive buying behavior. This research is a valuable addition in the domain of S-O-R model and the findings of the research would be helpful in making different selling and retailing decisions. At policy level, the findings would be helpful in shaping consumer protection laws. Marketers and policy makers are also advised to consider consumer education programs to safeguard consumers against the possible ills of compulsive buying behavior and enable them to overcome any financial woes resulting from it. To the knowledge of the researcher, the study of compulsive buying behavior simultaneously in social and psychological contexts is almost ignored. Neither it has been studied quantitatively. So, the current study provides an empirically valid S-O-R conceptual framework to understand the cognitive process of consumer’s compulsive buying behavior and the dissertation also opens new doors of inquiry especially in the context of collectivist societies.