Fathy Attia | Mansoura University (original) (raw)

Papers by Fathy Attia

Research paper thumbnail of Zinc Chloride Catalyzed Regioselective Nitration of Aromatic Hydrocarbons Using Tetrachlorosilane-Sodium Nitrate Homogeneous System

International Journal of Organic Chemistry, 2015

The development of a new silane reagent derived from tetrachlorosilane (TCS) was applied in the p... more The development of a new silane reagent derived from tetrachlorosilane (TCS) was applied in the present work. TCS-sodium nitrate (NaNO 3) binary reagent and zinc chloride (ZnCl 2) were reported here as a homogeneous nitrating system. The later was used for the efficient mono nitration, in most cases, with high para-regioselectivity. The nitration proceeded smoothly under mild condition, fairly clean and in good yields. This readily available and inexpensive system is superior to other methods by avoidance of the use of corrosive nitrating reagents and therefore considered to be convenient in terms of risk reduction, economic advantages and environment protection. The present protocol was convenient and applicable to a variety of aromatic hydrocarbons and could be amenable to high throughput synthesis of combinatorial libraries for potential drug development, which needs to be studied as part of future investigations.

Research paper thumbnail of Asymmetric Dual Anchoring Sensitizers/Cosensitizers for Dye Sensitized Solar Cell Application: An Insight into Various Fundamental Processes inside the Cell

Journal of Physical Chemistry C, Sep 16, 2019

In order to study the various fundamental processes occurring inside the DSSC, we have fabricated... more In order to study the various fundamental processes occurring inside the DSSC, we have fabricated devices employing newly synthesized diphenylamine based organic dyes with AD -π-A configuration, carrying four different anchoring groups, viz. cyanoacetic acid (DDC), rhodanine acetic acid (DDR), 4-hydrazinylbenzoic acid (DDH), and barbituric acid (DDB), as effective sensitizers/co-sensitizers. In the present work, all the bi-anchoring dyes were subjected to photophysical, electrochemical, thermodynamic, photoelectrochemical and theoretical studies. All of them displayed characteristic λ abs and λ emi in the range of 415-480 and 570-680 nm, respectively. Their optical and electrochemical band gaps were calculated to be in the order of 2.1 to 2.3 eV. The calculated driving forces for electron injection (ΔG inj), recombination (ΔG inj) and regeneration (ΔG reg) processes were found to be negative, showing the feasibility of these processes, while their DFT studies clearly indicated the directional flow of electrons within the dye in the cell. The devices with DDC as sensitizer displayed the highest conversion efficiency of 2.53%, whereas DDB exhibited the maximum of 7.69% when employed as a co-sensitizer along with Ru (II) based HD-2 dye. Finally, EIS circuit fitting was carried out in order to obtain different interface resistance values to study the fundamental processes of energy conversion.

Research paper thumbnail of Asymmetric Dual Anchoring Sensitizers/Co-Sensitizers for DSSC Application: An Insight into Various Fundamental Processes inside the Cell

The Journal of Physical Chemistry C, 2019

In order to study the various fundamental processes occurring inside the DSSC, we have fabricated... more In order to study the various fundamental processes occurring inside the DSSC, we have fabricated devices employing newly synthesized diphenylamine based organic dyes with AD -π-A configuration, carrying four different anchoring groups, viz. cyanoacetic acid (DDC), rhodanine acetic acid (DDR), 4-hydrazinylbenzoic acid (DDH), and barbituric acid (DDB), as effective sensitizers/co-sensitizers. In the present work, all the bi-anchoring dyes were subjected to photophysical, electrochemical, thermodynamic, photoelectrochemical and theoretical studies. All of them displayed characteristic λ abs and λ emi in the range of 415-480 and 570-680 nm, respectively. Their optical and electrochemical band gaps were calculated to be in the order of 2.1 to 2.3 eV. The calculated driving forces for electron injection (ΔG inj), recombination (ΔG inj) and regeneration (ΔG reg) processes were found to be negative, showing the feasibility of these processes, while their DFT studies clearly indicated the directional flow of electrons within the dye in the cell. The devices with DDC as sensitizer displayed the highest conversion efficiency of 2.53%, whereas DDB exhibited the maximum of 7.69% when employed as a co-sensitizer along with Ru (II) based HD-2 dye. Finally, EIS circuit fitting was carried out in order to obtain different interface resistance values to study the fundamental processes of energy conversion.

Research paper thumbnail of Zinc Chloride Catalyzed Regioselective Nitration of Aromatic Hydrocarbons Using Tetrachlorosilane-Sodium Nitrate Homogeneous System

International Journal of Organic Chemistry

The development of a new silane reagent derived from tetrachlorosilane (TCS) was applied in the p... more The development of a new silane reagent derived from tetrachlorosilane (TCS) was applied in the present work. TCS-sodium nitrate (NaNO 3) binary reagent and zinc chloride (ZnCl 2) were reported here as a homogeneous nitrating system. The later was used for the efficient mono nitration, in most cases, with high para-regioselectivity. The nitration proceeded smoothly under mild condition, fairly clean and in good yields. This readily available and inexpensive system is superior to other methods by avoidance of the use of corrosive nitrating reagents and therefore considered to be convenient in terms of risk reduction, economic advantages and environment protection. The present protocol was convenient and applicable to a variety of aromatic hydrocarbons and could be amenable to high throughput synthesis of combinatorial libraries for potential drug development, which needs to be studied as part of future investigations.

Research paper thumbnail of Asymmetric Dual Anchoring Sensitizers/Cosensitizers for Dye Sensitized Solar Cell Application: An Insight into Various Fundamental Processes inside the Cell

To study the various fundamental processes occurring inside the dye sensitized solar cell (DSSC),... more To study the various fundamental processes occurring inside the dye sensitized solar cell (DSSC), we have fabricated devices employing newly synthesized diphenylamine-based organic dyes with AD -π-A configuration, carrying four different anchoring groups, namely, cyanoacetic acid (DDC), rhodanine acetic acid (DDR), 4-hydrazinylbenzoic acid (DDH), and barbituric acid (DDB), as effective sensitizers/cosensitizers. In the present work, all the bianchoring dyes were subjected to photophysical, electrochemical, thermodynamic, photoelectrochemical, and theoretical studies. All of them displayed characteristic λ abs and λ emi in the range of 415−480 and 570−680 nm, respectively. Their optical and electrochemical band gaps were calculated to be in the order of 2.1 to 2.3 eV. The calculated driving forces for electron injection (ΔG inj), recombination (ΔG inj), and regeneration (ΔG reg) processes were found to be negative, showing the feasibility of these processes, while their DFT studies clearly indicated the directional flow of electrons within the dye in the cell. The devices with DDC as sensitizer displayed the highest conversion efficiency of 2.53%, whereas DDB exhibited the maximum of 7.69% when employed as a cosensitizer along with Ru (II) based HD-2 dye. Finally, EIS circuit fitting was carried out in order to obtain different interface resistance values to study the fundamental processes of energy conversion. ■ INTRODUCTION Globally, the escalating demand for renewable energy sources has led to the necessity of capturing and utilizing solar energy as an alternative energy source. 1−4 Among the various processes of solar energy utilization, the dye sensitized solar cells (DSSCs) process is a promising photovoltaic technology because of its low cost, simple manufacturing process, and tunable optical properties. 5,6 Gratzel and co-workers in 1991 reported DSSCs sensitized with a Ru(II)-complex based dye for the first time. Since then, academics and industry have given considerable attention to DSSCs in efforts to develop highly efficient devices. Among the four major components, the sensitizer (dye) that adsorbs chemically to the semiconductor is a key component in a DSSC. It facilitates the absorption of light and transfer of electrons to the semiconductor , TiO 2. 7,8 An ideal dye requires certain features such as appropriate HOMO and LUMO levels for the regeneration of dye from the electrolyte and charge injection to the conduction band (CB) of TiO 2 , a good anchoring group for binding with TiO 2 , and a broad absorption power in addition to good photostability. During the DSSC operating cycle, the efficient injection of electrons to the CB (0.5 V vs NHE) of TiO 2 by the excited dye (S*) and effective dye regeneration or rereduction bring about the improvement in photovoltaic parameters such as the photocurrent density (J SC), the open circuit photo voltage (V OC), and fill factor (FF), which results in further increase in the power conversion efficiency, PCE(η) of the devices. 1,2,9 However, the unwanted processes, namely, recombination of the injected electrons in CB of TiO 2 by the oxidized sensitizer (recombination) or with I 3 − in the solution (dark current) also exist during the cell operation, which leads to lower J SC and V OC values. Evidently, for an efficient device with greater J SC and V OC , the electron injection and regeneration processes should be faster than recombination and dark current, for which an appropriate dye selection is most essential. 1,2 Even though devices with ruthenium-based chromophores such as HD-2, N3, N719, and black dye are giving high PCE values, the high cost of ruthenium, scarcity of the metal, and tedious

Research paper thumbnail of Zinc Chloride Catalyzed Regioselective Nitration of Aromatic Hydrocarbons Using Tetrachlorosilane-Sodium Nitrate Homogeneous System

International Journal of Organic Chemistry 05(02):49-56, 2015

The development of a new silane reagent derived from tetrachlorosilane (TCS) was applied in the p... more The development of a new silane reagent derived from tetrachlorosilane (TCS) was applied in the present work. TCS-sodium nitrate (NaNO 3) binary reagent and zinc chloride (ZnCl 2) were reported here as a homogeneous nitrating system. The later was used for the efficient mono nitration, in most cases, with high para-regioselectivity. The nitration proceeded smoothly under mild condition , fairly clean and in good yields. This readily available and inexpensive system is superior to other methods by avoidance of the use of corrosive nitrating reagents and therefore considered to be convenient in terms of risk reduction, economic advantages and environment protection. The present protocol was convenient and applicable to a variety of aromatic hydrocarbons and could be amenable to high throughput synthesis of combinatorial libraries for potential drug development , which needs to be studied as part of future investigations.

Research paper thumbnail of Zinc Chloride Catalyzed Regioselective Nitration of Aromatic Hydrocarbons Using Tetrachlorosilane-Sodium Nitrate Homogeneous System

International Journal of Organic Chemistry, 2015

The development of a new silane reagent derived from tetrachlorosilane (TCS) was applied in the p... more The development of a new silane reagent derived from tetrachlorosilane (TCS) was applied in the present work. TCS-sodium nitrate (NaNO 3) binary reagent and zinc chloride (ZnCl 2) were reported here as a homogeneous nitrating system. The later was used for the efficient mono nitration, in most cases, with high para-regioselectivity. The nitration proceeded smoothly under mild condition, fairly clean and in good yields. This readily available and inexpensive system is superior to other methods by avoidance of the use of corrosive nitrating reagents and therefore considered to be convenient in terms of risk reduction, economic advantages and environment protection. The present protocol was convenient and applicable to a variety of aromatic hydrocarbons and could be amenable to high throughput synthesis of combinatorial libraries for potential drug development, which needs to be studied as part of future investigations.

Research paper thumbnail of Asymmetric Dual Anchoring Sensitizers/Cosensitizers for Dye Sensitized Solar Cell Application: An Insight into Various Fundamental Processes inside the Cell

Journal of Physical Chemistry C, Sep 16, 2019

In order to study the various fundamental processes occurring inside the DSSC, we have fabricated... more In order to study the various fundamental processes occurring inside the DSSC, we have fabricated devices employing newly synthesized diphenylamine based organic dyes with AD -π-A configuration, carrying four different anchoring groups, viz. cyanoacetic acid (DDC), rhodanine acetic acid (DDR), 4-hydrazinylbenzoic acid (DDH), and barbituric acid (DDB), as effective sensitizers/co-sensitizers. In the present work, all the bi-anchoring dyes were subjected to photophysical, electrochemical, thermodynamic, photoelectrochemical and theoretical studies. All of them displayed characteristic λ abs and λ emi in the range of 415-480 and 570-680 nm, respectively. Their optical and electrochemical band gaps were calculated to be in the order of 2.1 to 2.3 eV. The calculated driving forces for electron injection (ΔG inj), recombination (ΔG inj) and regeneration (ΔG reg) processes were found to be negative, showing the feasibility of these processes, while their DFT studies clearly indicated the directional flow of electrons within the dye in the cell. The devices with DDC as sensitizer displayed the highest conversion efficiency of 2.53%, whereas DDB exhibited the maximum of 7.69% when employed as a co-sensitizer along with Ru (II) based HD-2 dye. Finally, EIS circuit fitting was carried out in order to obtain different interface resistance values to study the fundamental processes of energy conversion.

Research paper thumbnail of Asymmetric Dual Anchoring Sensitizers/Co-Sensitizers for DSSC Application: An Insight into Various Fundamental Processes inside the Cell

The Journal of Physical Chemistry C, 2019

In order to study the various fundamental processes occurring inside the DSSC, we have fabricated... more In order to study the various fundamental processes occurring inside the DSSC, we have fabricated devices employing newly synthesized diphenylamine based organic dyes with AD -π-A configuration, carrying four different anchoring groups, viz. cyanoacetic acid (DDC), rhodanine acetic acid (DDR), 4-hydrazinylbenzoic acid (DDH), and barbituric acid (DDB), as effective sensitizers/co-sensitizers. In the present work, all the bi-anchoring dyes were subjected to photophysical, electrochemical, thermodynamic, photoelectrochemical and theoretical studies. All of them displayed characteristic λ abs and λ emi in the range of 415-480 and 570-680 nm, respectively. Their optical and electrochemical band gaps were calculated to be in the order of 2.1 to 2.3 eV. The calculated driving forces for electron injection (ΔG inj), recombination (ΔG inj) and regeneration (ΔG reg) processes were found to be negative, showing the feasibility of these processes, while their DFT studies clearly indicated the directional flow of electrons within the dye in the cell. The devices with DDC as sensitizer displayed the highest conversion efficiency of 2.53%, whereas DDB exhibited the maximum of 7.69% when employed as a co-sensitizer along with Ru (II) based HD-2 dye. Finally, EIS circuit fitting was carried out in order to obtain different interface resistance values to study the fundamental processes of energy conversion.

Research paper thumbnail of Zinc Chloride Catalyzed Regioselective Nitration of Aromatic Hydrocarbons Using Tetrachlorosilane-Sodium Nitrate Homogeneous System

International Journal of Organic Chemistry

The development of a new silane reagent derived from tetrachlorosilane (TCS) was applied in the p... more The development of a new silane reagent derived from tetrachlorosilane (TCS) was applied in the present work. TCS-sodium nitrate (NaNO 3) binary reagent and zinc chloride (ZnCl 2) were reported here as a homogeneous nitrating system. The later was used for the efficient mono nitration, in most cases, with high para-regioselectivity. The nitration proceeded smoothly under mild condition, fairly clean and in good yields. This readily available and inexpensive system is superior to other methods by avoidance of the use of corrosive nitrating reagents and therefore considered to be convenient in terms of risk reduction, economic advantages and environment protection. The present protocol was convenient and applicable to a variety of aromatic hydrocarbons and could be amenable to high throughput synthesis of combinatorial libraries for potential drug development, which needs to be studied as part of future investigations.

Research paper thumbnail of Asymmetric Dual Anchoring Sensitizers/Cosensitizers for Dye Sensitized Solar Cell Application: An Insight into Various Fundamental Processes inside the Cell

To study the various fundamental processes occurring inside the dye sensitized solar cell (DSSC),... more To study the various fundamental processes occurring inside the dye sensitized solar cell (DSSC), we have fabricated devices employing newly synthesized diphenylamine-based organic dyes with AD -π-A configuration, carrying four different anchoring groups, namely, cyanoacetic acid (DDC), rhodanine acetic acid (DDR), 4-hydrazinylbenzoic acid (DDH), and barbituric acid (DDB), as effective sensitizers/cosensitizers. In the present work, all the bianchoring dyes were subjected to photophysical, electrochemical, thermodynamic, photoelectrochemical, and theoretical studies. All of them displayed characteristic λ abs and λ emi in the range of 415−480 and 570−680 nm, respectively. Their optical and electrochemical band gaps were calculated to be in the order of 2.1 to 2.3 eV. The calculated driving forces for electron injection (ΔG inj), recombination (ΔG inj), and regeneration (ΔG reg) processes were found to be negative, showing the feasibility of these processes, while their DFT studies clearly indicated the directional flow of electrons within the dye in the cell. The devices with DDC as sensitizer displayed the highest conversion efficiency of 2.53%, whereas DDB exhibited the maximum of 7.69% when employed as a cosensitizer along with Ru (II) based HD-2 dye. Finally, EIS circuit fitting was carried out in order to obtain different interface resistance values to study the fundamental processes of energy conversion. ■ INTRODUCTION Globally, the escalating demand for renewable energy sources has led to the necessity of capturing and utilizing solar energy as an alternative energy source. 1−4 Among the various processes of solar energy utilization, the dye sensitized solar cells (DSSCs) process is a promising photovoltaic technology because of its low cost, simple manufacturing process, and tunable optical properties. 5,6 Gratzel and co-workers in 1991 reported DSSCs sensitized with a Ru(II)-complex based dye for the first time. Since then, academics and industry have given considerable attention to DSSCs in efforts to develop highly efficient devices. Among the four major components, the sensitizer (dye) that adsorbs chemically to the semiconductor is a key component in a DSSC. It facilitates the absorption of light and transfer of electrons to the semiconductor , TiO 2. 7,8 An ideal dye requires certain features such as appropriate HOMO and LUMO levels for the regeneration of dye from the electrolyte and charge injection to the conduction band (CB) of TiO 2 , a good anchoring group for binding with TiO 2 , and a broad absorption power in addition to good photostability. During the DSSC operating cycle, the efficient injection of electrons to the CB (0.5 V vs NHE) of TiO 2 by the excited dye (S*) and effective dye regeneration or rereduction bring about the improvement in photovoltaic parameters such as the photocurrent density (J SC), the open circuit photo voltage (V OC), and fill factor (FF), which results in further increase in the power conversion efficiency, PCE(η) of the devices. 1,2,9 However, the unwanted processes, namely, recombination of the injected electrons in CB of TiO 2 by the oxidized sensitizer (recombination) or with I 3 − in the solution (dark current) also exist during the cell operation, which leads to lower J SC and V OC values. Evidently, for an efficient device with greater J SC and V OC , the electron injection and regeneration processes should be faster than recombination and dark current, for which an appropriate dye selection is most essential. 1,2 Even though devices with ruthenium-based chromophores such as HD-2, N3, N719, and black dye are giving high PCE values, the high cost of ruthenium, scarcity of the metal, and tedious

Research paper thumbnail of Zinc Chloride Catalyzed Regioselective Nitration of Aromatic Hydrocarbons Using Tetrachlorosilane-Sodium Nitrate Homogeneous System

International Journal of Organic Chemistry 05(02):49-56, 2015

The development of a new silane reagent derived from tetrachlorosilane (TCS) was applied in the p... more The development of a new silane reagent derived from tetrachlorosilane (TCS) was applied in the present work. TCS-sodium nitrate (NaNO 3) binary reagent and zinc chloride (ZnCl 2) were reported here as a homogeneous nitrating system. The later was used for the efficient mono nitration, in most cases, with high para-regioselectivity. The nitration proceeded smoothly under mild condition , fairly clean and in good yields. This readily available and inexpensive system is superior to other methods by avoidance of the use of corrosive nitrating reagents and therefore considered to be convenient in terms of risk reduction, economic advantages and environment protection. The present protocol was convenient and applicable to a variety of aromatic hydrocarbons and could be amenable to high throughput synthesis of combinatorial libraries for potential drug development , which needs to be studied as part of future investigations.