Özgün Perilen-3,4,9,10-tetrakarboksilik asit türevlerinin sentezi ve karakterizasyonu

Increasing demand and high consumption of energy lead the researchers to think about the alternative renewable and sustainable source that could fulfil the energy requirement. For this purpose smooth transition to renewable technologies are necessary. There are several alternative technologies available, among them Dye Sensitized Solar Cell (DSSC) can be the promising one. DSSC has achieved around 12% power conversion efficiency, hence improvement is possible if new materials are synthesized. Our study aims to synthesize and characterization of novel isomerically pure perylene-3,4,9,10-tetracarboxylic acid derivatives that are promising family of organic dyes as light harvesting material (sensitizer). The study involves the synthesis of novel antisymmetric compounds and investigation of their structural, and photo-physical properties. This work demonstrates that perylene tetracarboxylic ester unit is a versatile building block for the synthesis of variety of light harvesting systems. The resulting compounds are soluble in variety of organic solvents, and show broad absorption bands extending up to near infrared region.Artan enerji talebi ve kullanımı araştırmacıları bu talebe karşılık verecek alternatif yenilenebilir ve sürdürülebilir enerji kaynakları üzerinde çalışmaya itmektedir. Bu amaçla yenilenebilir enerji teknolojilerine sorunsuz geçiş yapılabilmesi ihtiyacı bulunmaktadır.Mevcut alternatif teknolojiler arasında Boya Duyarlı Güneş Pilleri (DSSC) umut vaat eden teknoloji olarak öne çıkmaktadır. Mevcut DSSC verimlilikleri %12 dolaylarındadır, dolayısıyla yeni malzemelerin sentezlenmesi ile verimlilikleri arttırılabilir. Bu çalışmada izomerik saflıkta, ışık hasat edebilen, perilen-3,4,9,10-tetrakarboksilik asit türevlerinin sentezi ve karakterizasyonu amaçlanmaktadır. Çalışma özgün antisimetrik perilen türevlerinin sentezini, ve bu bileşiklerin fotokimyasal ve fotofiziksel özelliklerinin araştırılmasını hedeflemektedir.M.S. - Master of Scienc

Improvement in dye sensitized solar cells from past to present

Several emerging renewable technologies are available to satisfy the current energy demand and to minimize the effect of environmental degradation caused by high consumption of fossil fuels. These technologies are not mature enough to solve this problem but require more time for improving the efficiency, and cost reduction to become the economical alternative of fossil fuels. In this paper Dye-sensitized solar cell (DSSC) has been discussed in detail owing to advancement in the technology. Since each component of DSSC is responsible for a specific function, therefore, comprehensive literature studies has been done on individual section to understand the technology in depth. All the advancement in sensitizer, semiconductors, electrolyte, electrodes, additives, sealing and anchoring groups are included in this review with performance parameter of DSSC. Focus of this article is to provide summary of all available literature since beginning to date

The relationship between carbon dioxide emissions, energy consumption, and GDP: A recent evidence from Pakistan

In this study an attempt was made to investigate carbon dioxide emissions, energy consumption (EC), GDP, and electricity production from oil, coal and natural gas, a recent evidence from Pakistan by employing a time series data spanning from 1971 to 2013. The study employed the vector error correction model to estimate the long-run equilibrium relationship. There was evidence of long-run equilibrium relationship running from EC, electricity production from coal, electricity production from natural gas, electricity production from oil and GDP to carbon dioxide emissions. The policy implication of the VEC model means that a 1% increase in energy production from oil in Pakistan will increase carbon dioxide emissions by 13.7% in the long-run. There was evidence of a unidirectional causality running from EC to carbon dioxide emissions, electricity production from natural gas to EC, EC to electricity production from oil, electricity production from natural gas to GDP and GDP to electricity production from oil. Evidence from the generalized impulse-response analysis shows that three components contribute to carbon dioxide emissions in Pakistan, which include EC, energy production from gas and GDP

Synthesis, photophysical, structural and electronic properties of novel regioisomerically pure 1,7-disubstituted perylene-3,4,9,10-tetracarboxylic monoimide dibutylester derivatives

Three new isomerically pure 1,7-disubstituted perylene-3,4,9,10-tetracarboxylic monoimide dibutylester derivatives namely; N-[2-(diethylamino)ethy1]-1,7-dibromoperylene-3,4,9,10-tetracarboxy monoimide dibutylester (PMD-1), N-[2-(diethylamino)ethy1]-1,7-di(4-tert-butylphenoxy)perylene-3,4,9,10-tetracarboxy monoimide dibutylester (PMD-2) and N-[2-(diethylamino)ethy1]-1,7-di(pyrrolidinyl) perylene-3,4,9,10-tetracarboxy monoimide dibutylester (PMD-3), have been synthesized and their electronic absorption spectra, and steady-state fluorescence were investigated experimentally as well as by using density functional theory (DFT) calculations. All three compounds show good solubility in toluene and chloroform. Attachment of two tert-butylphenoxy groups at the 1,7-positions in PMD-2 resulted in a red shifted absorption band with an absorption maximum at 518 nm. UV/Vis absorption spectrum of PMD-3 bearing electron donating pyrrolidinyl groups at the 1,7-positions shows a broad absorption band within the visible region, extending to red region. Absorption maximum of lowest energy transition now shifts to 653 nm. In addition to the S-0 -> S-1 absorption bands, bands belonging to S-0 -> S-2 electronic transitions were observed at 378, 386, and 411 nm for PMD-1, PMD-2, and PMD-3 respectively. Compounds PMD-1, PMD-2 and PMD-3 display low fluorescence quantum yields of 0.027, 0.040 and 0.001, respectively in chloroform. DFT calculations revealed that the attachment of electron donating groups at 1,7-positions of perylene core, results in an increase in frontier orbitals energy levels. Observed energy increase in HOMO level is larger in each case, compared to the energy increase in LUMO levels, due to the higher contribution of side groups to HOMO. DFT calculated band gaps for PMD-1, PMD-2 and PMD-3 are 2.68, 2.63 and 2.29 eV respectively

Electricity production potential and social benefits from rice husk, a case study in Pakistan

Pakistan has been experiencing energy crisis owing to its sole dependence on fossil fuels. Reduction in local fossil fuel reserves has led to an increase in their prices, thereby increasing the cost of electricity. Since the tariff remains the same, Pakistan is over-burdened with circular debts and observes a daily power shortfall of about 12–14 h. Being an Agra-economic country, many major and minor crops are produced and exported in large quantities. This results in a bulk of the agricultural waste which are not utilized. The waste can be utilized to meet the country’s energy demand while mitigating climate change and its impact. The study examines the electricity production potential and social benefits of rice husk in Pakistan. It is estimated in this study that if 70% of rice husk residues are utilized, there will be annual electricity production of 1,328 GWh and the cost of per unit electricity by rice husk is found at 47.36 cents/kWh as compared to 55.22 cents/kWh of electricity generated by coal. Importantly, the study will increase the awareness of the benefits of utilizing agricultural waste for useful products such as silica, with several social and environmental benefits such as a reduction of 36,042 tCO_2e/yr of methane, reducing carbon dioxide emissions, improving the air quality, and providing 4.5 k new jobs. The paper concludes with the policy recommendations based on this study

Investigating the impact of different sport trainings on particulate matter resuspension in a sport center using well-characterized reference instruments and a low-cost monitor

Abstract The present study investigated the exposure of teenagers, adults, and students to PM1, PM2.5, PM4, PM10, particle number concentration at two sport facilities of Nazarbayev University including Gymnastics Hall and Multi-purpose Hall. Measurements were conducted during variety of sport training sessions including soccer, basketball, volleyball, Mixed Martial Arts (MMA), boxing, table tennis, etc. A low-cost instrument, Dylos was employed to compare its performance against two TSI instruments. In overall, the Dylos showed acceptable peaks when the source of particle resuspension was present. However, no correlation was observed between Dylos data and Dusttrak fine and coarse particle data. The average PM2,5 and PM10 concentrations were found to be below the WHO limits. The number of participants during the training sessions and sports involving balls including basketball, soccer and volleyball were the two factors responsible for the observed increased particle resuspension

Novel derivatives of regioisomerically pure 1,7-disubstituted perylene diimide dyes bearing phenoxy and pyrrolidinyl substituents: Synthesis, photophysical, thermal, and structural properties

Two new isomerically pure 1,7-substituted perylene-bisimide derivatives namely; 1,7-Di(4-tert-butylphenoxy)N,N'-bis[2-(diethylamino)ethyl]-3,4,9,10-perylene-tetracarboxylic diimide (6) and 1,7-Di(pyrrolidinyl)-N,N'-bis [2-(diethylamino)ethyl]-3,4,9,10-perylene- tetracarboxylic diimide (7), have been synthesized and their electronic absorption, steady-state fluorescence, and thermal properties were studied. Both compounds show good solubility in a range of organic solvents. Attachment of two electron donating tert-butyl-phenoxy groups at the 1,7-positions in (6) resulted in a red shifted absorption band with absorption maximum at 543 nm. UV-visible absorption spectrum of (7) shows a broad absorption band within the red region. Absorption maximum of lowest energy transition now shifts to 704 nm. Both compounds (6) and (7) exhibit low fluorescence quantum yields of 0.133 and 0.007, respectively. Density functional theory (DFT) calculations revealed that the attachment of electron donating groups at 1,7-positions of PDIs, results in an increase in frontier orbitals energy levels. Observed energy increase in HOMO is larger in each case, compared to the energy increase in LUMO levels. Calculated band gaps for (6) and (7) are 2.462 and 2.128 eV respectively

Novel derivatives of regioisomerically pure 1,7-disubstituted perylene diimide dyes bearing phenoxy and pyrrolidinyl substituents: Synthesis, photophysical, thermal, and structural properties

Two new isomerically pure 1,7-substituted perylene-bisimide derivatives namely; 1,7-Di(4-tert-butylphenoxy)N,N'-bis[2-(diethylamino)ethyl]-3,4,9,10-perylene-tetracarboxylic diimide (6) and 1,7-Di(pyrrolidinyl)-N,N'-bis [2-(diethylamino)ethyl]-3,4,9,10-perylene- tetracarboxylic diimide (7), have been synthesized and their electronic absorption, steady-state fluorescence, and thermal properties were studied. Both compounds show good solubility in a range of organic solvents. Attachment of two electron donating tert-butyl-phenoxy groups at the 1,7-positions in (6) resulted in a red shifted absorption band with absorption maximum at 543 nm. UV-visible absorption spectrum of (7) shows a broad absorption band within the red region. Absorption maximum of lowest energy transition now shifts to 704 nm. Both compounds (6) and (7) exhibit low fluorescence quantum yields of 0.133 and 0.007, respectively. Density functional theory (DFT) calculations revealed that the attachment of electron donating groups at 1,7-positions of PDIs, results in an increase in frontier orbitals energy levels. Observed energy increase in HOMO is larger in each case, compared to the energy increase in LUMO levels. Calculated band gaps for (6) and (7) are 2.462 and 2.128 eV respectively