Hameed Ullah*, Javid Khan, Habib Nasir, Asad Muhammad Khan, Mohsan Nawaz Masroor Ahmad Bangesh an... more Hameed Ullah*, Javid Khan, Habib Nasir, Asad Muhammad Khan, Mohsan Nawaz Masroor Ahmad Bangesh and Muhammad Irfan Department of Chemistry, Hazara University Mansehra, Pakistan. School of Chemical and Materials Engineering, National University Science and Technology Islamabad, Pakistan. Department of Chemistry, COMSATS Institute of Information Technology, Abbottabad, Pakistan. hameedwazir@yahoo.co.uk*
One of the most frequent ways to widen the adsorption range of carbon nitride (CN) is to add a we... more One of the most frequent ways to widen the adsorption range of carbon nitride (CN) is to add a well-known photosensitizer into its basic structure. So far, such attachments have been accomplished by using weak van der Waals forces. However, using strong covalent bonding to attach such photosensitizer with CN is yet to be determined. Here, for the first time, we covalently bonded porphyrin (5,10,15,20-tetrakis(4-(2,4-diamino-1,3,5-triazinyl) phenyl)-Porphyrin (TDP)), a renowned photosensitizer, effectively with CN by thermally balanced molecular strategy. A photoreaction system was set up for the deoxygenated conversion of CO2 to CO under visible light, where cobalt acted as a redox controller to speed up the charge transportation, while CN-TDP worked as a CO2 activating photocatalyst. The subsequent photocatalyst has a broader absorbance range, a greater specific surface area, and intramolecular organic connections that help to decrease the electron-hole pairs’ recombination rate. F...
Three heterometallic Fe6Ln4 clusters were self-assembled by using N-methyldiethanolamine (H2mdea)... more Three heterometallic Fe6Ln4 clusters were self-assembled by using N-methyldiethanolamine (H2mdea) and 3,5-dinitrobenzoic acid (Hdnbz) as principal building blocks ...
Abstract Two new isomorphous Iron(III)-lanthanide(III) coordination clusters of general formula [... more Abstract Two new isomorphous Iron(III)-lanthanide(III) coordination clusters of general formula [Fe4Ln6(bpte)4(μ4-O)4(EG)4(μ3-OMe)3.3(μ3-Cl)0.70Cl2(MeOH)2][Fe4Ln6(bpte)4(μ4-O)4(EG)4(μ3-OMe)4Cl2(MeOH)2]·30H2O·MeOH (H2bpte = 1,2-bis(3-(pyridin-2-yl)-1H-1,2,4-triazol-5-yl)ethane, EG = ethylene glycol, Ln = Dy(1), Ho(2)) have been successfully synthesized under hydrothermal conditions. The crystal structure of 2 consists of two asymmetric units having two isostructural cores {Fe4Ho6(μ4-O)4} of T2 supertetrahedral cluster nuclei ultra-structural unit. Both complexes 1 and 2 are found to be isomorphous which is confirmed by FTIR, elemental analysis, PXRD, and thermal studies. These are the first supertetrahedral T2 coordination clusters reported as 3d-4f system. The magnetic measurements indicate that antiferromagnetic coupling in both of these complexes. The solid-state photoluminescent measurements for 1 and 2 were done but only 1 gave rise to a measurable emission peaks which are associated with the 4f → 4f transitions with a maximum at 574 nm (cyan emission).
Research based on the full water splitting via heterogenous semiconducting photocatalyst is a sig... more Research based on the full water splitting via heterogenous semiconducting photocatalyst is a significant characteristic nevertheless challenging for determining the energy and environmental crises. With respect to this, a photocatalytic water splitting by visible light through heterojunction semiconductors has been anticipated as a route to the sustainable energy. For the first time, we integrate a potential conjugated donor-acceptor (DA) co-monomer such as 2, 3-dichloroquinoxaline (DCQ) within the structure of polymeric carbon nitride (PCN) by a facile one-pot co-polymerization process. The DCQ which is acting as an organic motif that simulates a nucleophilic attack on the hosting PCN semiconductor which extends into a long chain of the polymer having enormous surface area and remarkable photocatalytic activity for H2 and O2 evolution as compared to the parental CNU. The supremacy of molecular geometry with DA ratio is effectively studied by absorbent, calculated band gap and migration of electrons on the photocatalytic performance of as-synthesized CNU-DCQx co-polymer. The density functional theory (DFT) calculation deliver supplementary evidence for the positive incorporation of DCQ in to the PCN matrix with reduced band gap upon copolymerization. Further, the hydrogen evolution rate (HER) for pure CNU with 14.2 μmol/h while for CNU-DCQ18.0 it is estimated at 124.9 μmol/h which remarkably fueled almost eight times more than blank sample. Similarly, the oxygen evolution rate (OER) analysis indicates the production 0.2 μmol/h (visible) and 1.5 μmol/h (non-visible) for CNU. However, the OER of copolymerized CNU-DCQ18.0 is found to be 1.9 μmol/h (visible) and 12.8 μmol/h (non-visible) which almost nine times higher than parental CNU. Hence, the output of this work reflects as an important step on the way to tailor-designed and elucidate the promising role of D-π-A system for the rational motifs of productive photocatalysts for forthcoming request.
Anatase TiO2 hollow nanoboxes were synthesized and combined with the graphene oxide to get nanoco... more Anatase TiO2 hollow nanoboxes were synthesized and combined with the graphene oxide to get nanocomposite of TiO2/rGO (TG). Graphene oxide was used to modify the Oxygen-Clusters and bulk to surface defects. Anatase and TG composite were characterized with the positron annihilation, XPS, EPR, EIS and photocurrent response analysis. The relative affects of defects on the photocatalytic reduction (CO2 to CH4) were studied. The TG composites showed highest photo-catalytic activity after GO coupling (49 µmol g−1 h−1), 28.6 times higher photocurrent yields much higher quantum efficiency (3.17%@400 nm) when compared to the TiO2 nanoboxes. The mechanism of enhanced photo-catalytic CO2 conversion to CH4 elucidated through electrochemical and photo-catalytic experiments with traceable isotope containing carbon dioxide (13CO2). For the first time we discovered that diminishing the comparative concentration ratio of anatase from the bulk to surface defects could significantly increase the conver...
The intertwined exploring of solar water driven into chemical energy configurated by a constitute... more The intertwined exploring of solar water driven into chemical energy configurated by a constituted semiconductor photocatalyst under sunlight approach toward a remediation eager method that solve the environmental issues. Currently we optimized polymeric carbon nitride PCN by a sophisticated molecular co-polymerization process which diffused with a mirror organic conjugated heterocyclic monomer to maximize its photocatalytic activity. Herein, for the 1st time we report an organic π-electron stacking conjugated thiazolothiazole (TT) as a small molecule within the framework of PCN to enhance the conductive optical and photocatalytic properties of PCN under solar energy irradiation. The fusion of this bicyclic thiazolothiazole (TT) co-monomer within PCN remarkably enhanced the charge carrier motilities and giving a rigid packing due to sulfur contents. Excitingly the as-synthesized samples were processed under different liberated characterization such as XRD, FTIR, BET, SEM, TEM, XPS, PL, DRS and EPR under both regions respectively. Results reflect that the integration of thiazolothiazole (TT) in the heptazine structure of PCN alter a prodigious delocalization in its π-conjugated system and similarly demonstrating an apparent fluctuation in its surface area, electronic structure, its calculated band gap, chemical composition analysis and maximize the process of generation of electrons under solar light from ground state (HOMO) to the excited state (LUMO) of polymeric carbon nitride (PCN). Beside, this unique integrity of TT co-monomer with in PCN matrix remarkably improve the photocatalytic activity toward prosperity and the amount optimized CNU-TT12.0 demonstrated an outstanding photocatalytic activity of water reduction for H2 evolution and as well of RhB pollutant photodegradation. The sample optimized display 10.6 enhancement comparatively pure pristine sample.
This work incorporates a variety of conjugated donor-acceptor (DA) co-monomers such as 2,6-diamin... more This work incorporates a variety of conjugated donor-acceptor (DA) co-monomers such as 2,6-diaminopurine (DP) into the structure of a polymeric carbon nitride (PCN) backbone using a unique nanostructure co-polymerization strategy and examines its photocatalytic activity performance in the field of photocatalytic CO2 reduction to CO and H2 under visible light irradiation. The as-synthesized samples were successfully analyzed using different characterization methods to explain their electronic and optical properties, crystal phase, microstructure, and their morphology that influenced the performance due to the interactions between the PCN and the DPco-monomer. Based on the density functional theory (DFT) calculation result, pure PCN and CNU-DP15.0 trimers (interpreted as incorporation of the co-monomer at two different positions) were extensively evaluated and exhibited remarkable structural optimization without the inclusion of any symmetry constraints (the non-modified sample derive...
Journal of Photochemistry and Photobiology A: Chemistry
Abstract In this work, we report the fabrication of polypyrrole/g-C3N4 (PPy/g-C3N4) nanocomposite... more Abstract In this work, we report the fabrication of polypyrrole/g-C3N4 (PPy/g-C3N4) nanocomposites via simple wet-chemical method. The photocatalytic activities of the composites are evaluated for water splitting to evolve H2, Rhodamine B dye (RhB) and 2,4-dichlorophenol (2,4-DCP) degradation under visible-light. The results reveal that the photocatalytic performance of g-C3N4 for H2 evolution, RhB dye and 2, 4-DCP degradation are significantly improved after coupling polypyrrole (PPy). Worth noting, the amount optimized (1 wt%PPy/g-C3N4) photocatalyst showed highest photoactivity compared to the other photocatalysts. Further, it is confirmed by means of radical trapping experiments that superoxide radical (O2 −) is the dominant specie involved in the degradation of pollutants over PPy/g-C3N4 nano-composites. Moreover, clear photocatalytic reactions for H2 evolution and pollutants degradation are proposed. This work would help us to deeply understand the reaction mechanism and will provide feasible routes to fabricate g-C3N4 based highly efficient photocatalysts for energy and environmental applications.
The conjugated co-monomer, trimesic acid (TMA) was integrated into the triazine framework of poly... more The conjugated co-monomer, trimesic acid (TMA) was integrated into the triazine framework of polymeric carbon nitride (PCN), synthesized through chemical condensation of urea. The TMA-modified carbon nitride samples obtained were named as CNU-TMA and it was utilized for the photocatalytic reduction of carbon dioxide (CO2) under visible light illumination. The induction of such electron donor-acceptor co-monomer (TMA) dominates the intramolecular structure of PCN by acting as a nucleophilic substitution substrate to facilitate the electron density in the π-electron conjugated system of PCN and thus elevate its photocatalytic activity. Also, this process of copolymerization with TMA, not only cause a significant diversion in the specific area, band gap, chemical composition, and structure of PCN but also promote efficient charge transport from ground state (HOMO) to the excited state (LUMO) of the PCN. For comparison, CNU samples modified with other co-monomers were prepared by the same method and were named as CNU-FDA (2,5-Furandicarboxylic acid), CNU-PDA (2,6-pyridinedicarboxylic acid), CNU-PTA (Phthalic acid). Similarly, co-monomer TMA was incorporated in other PCN precursors such as dyandicyanamide (DCDA), thiourea (SCN) and ammonium thiocyanate (NH2SCN) and was named as CND-TMA13.0, CNT-TMA13.0, and CNA-TMA13.0, respectively. Besides, the average weight ratio between urea and TMA was well tuned and also CNU-TMA13.0 gain a fabulous 16 fold-enhanced photocatalytic performance than blank CNU.
Abstract Recently, organo-metal halide perovskite (e.g., CH3NH3PbI3) solar cells have shown a sig... more Abstract Recently, organo-metal halide perovskite (e.g., CH3NH3PbI3) solar cells have shown a significant surge in progress and efficiency. The photovoltaic performance of perovskite solar cells (PSC) extensively depends on the morphology of the materials at nano-level, because the intrinsic electrical, optical and electrochemical properties also change with a change in morphology. Different TiO2 nanostructures with diverse dimensionalities, 0D hollow TiO2 nanoparticles (HTNPs), 3D hollow TiO2 mesospheres (HTMSs) and 3D hierarchical TiO2 spheres (HTSs) were synthesized hydrothermally. The PSCs based on 3D HTSs or 3D HTMSs as electron transport layers (ETLs) shows better performance than the PSCs fabricated with 0D HTNPs as ETL. The enhanced results can be attributed to the better penetration of the perovskite materials in the porous network of the HTSs or HTMSs and decreased interfacial recombination due to superior charge extraction and electron transport at the HTSs/CH3NH3PbI or HTMSs/CH3NH3Pb interfaces. By using a self-assembled TiO2 compact layer (c-TiO2), followed by a mesoporous layer of HTSs, produces PSCs with an excellent efficiency of 15.08%. Such c-TiO2-ETL films may improve PSCs performance by enhancing electron extraction and block the photogenerated holes.
Metal halide perovskites solar cells (PSCs) have been studied over the past years and achieved hi... more Metal halide perovskites solar cells (PSCs) have been studied over the past years and achieved high power conversion efficiency (PCE). However, the adverse instability remains a key factor restricting wider...
Hameed Ullah*, Javid Khan, Habib Nasir, Asad Muhammad Khan, Mohsan Nawaz Masroor Ahmad Bangesh an... more Hameed Ullah*, Javid Khan, Habib Nasir, Asad Muhammad Khan, Mohsan Nawaz Masroor Ahmad Bangesh and Muhammad Irfan Department of Chemistry, Hazara University Mansehra, Pakistan. School of Chemical and Materials Engineering, National University Science and Technology Islamabad, Pakistan. Department of Chemistry, COMSATS Institute of Information Technology, Abbottabad, Pakistan. hameedwazir@yahoo.co.uk*
One of the most frequent ways to widen the adsorption range of carbon nitride (CN) is to add a we... more One of the most frequent ways to widen the adsorption range of carbon nitride (CN) is to add a well-known photosensitizer into its basic structure. So far, such attachments have been accomplished by using weak van der Waals forces. However, using strong covalent bonding to attach such photosensitizer with CN is yet to be determined. Here, for the first time, we covalently bonded porphyrin (5,10,15,20-tetrakis(4-(2,4-diamino-1,3,5-triazinyl) phenyl)-Porphyrin (TDP)), a renowned photosensitizer, effectively with CN by thermally balanced molecular strategy. A photoreaction system was set up for the deoxygenated conversion of CO2 to CO under visible light, where cobalt acted as a redox controller to speed up the charge transportation, while CN-TDP worked as a CO2 activating photocatalyst. The subsequent photocatalyst has a broader absorbance range, a greater specific surface area, and intramolecular organic connections that help to decrease the electron-hole pairs’ recombination rate. F...
Three heterometallic Fe6Ln4 clusters were self-assembled by using N-methyldiethanolamine (H2mdea)... more Three heterometallic Fe6Ln4 clusters were self-assembled by using N-methyldiethanolamine (H2mdea) and 3,5-dinitrobenzoic acid (Hdnbz) as principal building blocks ...
Abstract Two new isomorphous Iron(III)-lanthanide(III) coordination clusters of general formula [... more Abstract Two new isomorphous Iron(III)-lanthanide(III) coordination clusters of general formula [Fe4Ln6(bpte)4(μ4-O)4(EG)4(μ3-OMe)3.3(μ3-Cl)0.70Cl2(MeOH)2][Fe4Ln6(bpte)4(μ4-O)4(EG)4(μ3-OMe)4Cl2(MeOH)2]·30H2O·MeOH (H2bpte = 1,2-bis(3-(pyridin-2-yl)-1H-1,2,4-triazol-5-yl)ethane, EG = ethylene glycol, Ln = Dy(1), Ho(2)) have been successfully synthesized under hydrothermal conditions. The crystal structure of 2 consists of two asymmetric units having two isostructural cores {Fe4Ho6(μ4-O)4} of T2 supertetrahedral cluster nuclei ultra-structural unit. Both complexes 1 and 2 are found to be isomorphous which is confirmed by FTIR, elemental analysis, PXRD, and thermal studies. These are the first supertetrahedral T2 coordination clusters reported as 3d-4f system. The magnetic measurements indicate that antiferromagnetic coupling in both of these complexes. The solid-state photoluminescent measurements for 1 and 2 were done but only 1 gave rise to a measurable emission peaks which are associated with the 4f → 4f transitions with a maximum at 574 nm (cyan emission).
Research based on the full water splitting via heterogenous semiconducting photocatalyst is a sig... more Research based on the full water splitting via heterogenous semiconducting photocatalyst is a significant characteristic nevertheless challenging for determining the energy and environmental crises. With respect to this, a photocatalytic water splitting by visible light through heterojunction semiconductors has been anticipated as a route to the sustainable energy. For the first time, we integrate a potential conjugated donor-acceptor (DA) co-monomer such as 2, 3-dichloroquinoxaline (DCQ) within the structure of polymeric carbon nitride (PCN) by a facile one-pot co-polymerization process. The DCQ which is acting as an organic motif that simulates a nucleophilic attack on the hosting PCN semiconductor which extends into a long chain of the polymer having enormous surface area and remarkable photocatalytic activity for H2 and O2 evolution as compared to the parental CNU. The supremacy of molecular geometry with DA ratio is effectively studied by absorbent, calculated band gap and migration of electrons on the photocatalytic performance of as-synthesized CNU-DCQx co-polymer. The density functional theory (DFT) calculation deliver supplementary evidence for the positive incorporation of DCQ in to the PCN matrix with reduced band gap upon copolymerization. Further, the hydrogen evolution rate (HER) for pure CNU with 14.2 μmol/h while for CNU-DCQ18.0 it is estimated at 124.9 μmol/h which remarkably fueled almost eight times more than blank sample. Similarly, the oxygen evolution rate (OER) analysis indicates the production 0.2 μmol/h (visible) and 1.5 μmol/h (non-visible) for CNU. However, the OER of copolymerized CNU-DCQ18.0 is found to be 1.9 μmol/h (visible) and 12.8 μmol/h (non-visible) which almost nine times higher than parental CNU. Hence, the output of this work reflects as an important step on the way to tailor-designed and elucidate the promising role of D-π-A system for the rational motifs of productive photocatalysts for forthcoming request.
Anatase TiO2 hollow nanoboxes were synthesized and combined with the graphene oxide to get nanoco... more Anatase TiO2 hollow nanoboxes were synthesized and combined with the graphene oxide to get nanocomposite of TiO2/rGO (TG). Graphene oxide was used to modify the Oxygen-Clusters and bulk to surface defects. Anatase and TG composite were characterized with the positron annihilation, XPS, EPR, EIS and photocurrent response analysis. The relative affects of defects on the photocatalytic reduction (CO2 to CH4) were studied. The TG composites showed highest photo-catalytic activity after GO coupling (49 µmol g−1 h−1), 28.6 times higher photocurrent yields much higher quantum efficiency (3.17%@400 nm) when compared to the TiO2 nanoboxes. The mechanism of enhanced photo-catalytic CO2 conversion to CH4 elucidated through electrochemical and photo-catalytic experiments with traceable isotope containing carbon dioxide (13CO2). For the first time we discovered that diminishing the comparative concentration ratio of anatase from the bulk to surface defects could significantly increase the conver...
The intertwined exploring of solar water driven into chemical energy configurated by a constitute... more The intertwined exploring of solar water driven into chemical energy configurated by a constituted semiconductor photocatalyst under sunlight approach toward a remediation eager method that solve the environmental issues. Currently we optimized polymeric carbon nitride PCN by a sophisticated molecular co-polymerization process which diffused with a mirror organic conjugated heterocyclic monomer to maximize its photocatalytic activity. Herein, for the 1st time we report an organic π-electron stacking conjugated thiazolothiazole (TT) as a small molecule within the framework of PCN to enhance the conductive optical and photocatalytic properties of PCN under solar energy irradiation. The fusion of this bicyclic thiazolothiazole (TT) co-monomer within PCN remarkably enhanced the charge carrier motilities and giving a rigid packing due to sulfur contents. Excitingly the as-synthesized samples were processed under different liberated characterization such as XRD, FTIR, BET, SEM, TEM, XPS, PL, DRS and EPR under both regions respectively. Results reflect that the integration of thiazolothiazole (TT) in the heptazine structure of PCN alter a prodigious delocalization in its π-conjugated system and similarly demonstrating an apparent fluctuation in its surface area, electronic structure, its calculated band gap, chemical composition analysis and maximize the process of generation of electrons under solar light from ground state (HOMO) to the excited state (LUMO) of polymeric carbon nitride (PCN). Beside, this unique integrity of TT co-monomer with in PCN matrix remarkably improve the photocatalytic activity toward prosperity and the amount optimized CNU-TT12.0 demonstrated an outstanding photocatalytic activity of water reduction for H2 evolution and as well of RhB pollutant photodegradation. The sample optimized display 10.6 enhancement comparatively pure pristine sample.
This work incorporates a variety of conjugated donor-acceptor (DA) co-monomers such as 2,6-diamin... more This work incorporates a variety of conjugated donor-acceptor (DA) co-monomers such as 2,6-diaminopurine (DP) into the structure of a polymeric carbon nitride (PCN) backbone using a unique nanostructure co-polymerization strategy and examines its photocatalytic activity performance in the field of photocatalytic CO2 reduction to CO and H2 under visible light irradiation. The as-synthesized samples were successfully analyzed using different characterization methods to explain their electronic and optical properties, crystal phase, microstructure, and their morphology that influenced the performance due to the interactions between the PCN and the DPco-monomer. Based on the density functional theory (DFT) calculation result, pure PCN and CNU-DP15.0 trimers (interpreted as incorporation of the co-monomer at two different positions) were extensively evaluated and exhibited remarkable structural optimization without the inclusion of any symmetry constraints (the non-modified sample derive...
Journal of Photochemistry and Photobiology A: Chemistry
Abstract In this work, we report the fabrication of polypyrrole/g-C3N4 (PPy/g-C3N4) nanocomposite... more Abstract In this work, we report the fabrication of polypyrrole/g-C3N4 (PPy/g-C3N4) nanocomposites via simple wet-chemical method. The photocatalytic activities of the composites are evaluated for water splitting to evolve H2, Rhodamine B dye (RhB) and 2,4-dichlorophenol (2,4-DCP) degradation under visible-light. The results reveal that the photocatalytic performance of g-C3N4 for H2 evolution, RhB dye and 2, 4-DCP degradation are significantly improved after coupling polypyrrole (PPy). Worth noting, the amount optimized (1 wt%PPy/g-C3N4) photocatalyst showed highest photoactivity compared to the other photocatalysts. Further, it is confirmed by means of radical trapping experiments that superoxide radical (O2 −) is the dominant specie involved in the degradation of pollutants over PPy/g-C3N4 nano-composites. Moreover, clear photocatalytic reactions for H2 evolution and pollutants degradation are proposed. This work would help us to deeply understand the reaction mechanism and will provide feasible routes to fabricate g-C3N4 based highly efficient photocatalysts for energy and environmental applications.
The conjugated co-monomer, trimesic acid (TMA) was integrated into the triazine framework of poly... more The conjugated co-monomer, trimesic acid (TMA) was integrated into the triazine framework of polymeric carbon nitride (PCN), synthesized through chemical condensation of urea. The TMA-modified carbon nitride samples obtained were named as CNU-TMA and it was utilized for the photocatalytic reduction of carbon dioxide (CO2) under visible light illumination. The induction of such electron donor-acceptor co-monomer (TMA) dominates the intramolecular structure of PCN by acting as a nucleophilic substitution substrate to facilitate the electron density in the π-electron conjugated system of PCN and thus elevate its photocatalytic activity. Also, this process of copolymerization with TMA, not only cause a significant diversion in the specific area, band gap, chemical composition, and structure of PCN but also promote efficient charge transport from ground state (HOMO) to the excited state (LUMO) of the PCN. For comparison, CNU samples modified with other co-monomers were prepared by the same method and were named as CNU-FDA (2,5-Furandicarboxylic acid), CNU-PDA (2,6-pyridinedicarboxylic acid), CNU-PTA (Phthalic acid). Similarly, co-monomer TMA was incorporated in other PCN precursors such as dyandicyanamide (DCDA), thiourea (SCN) and ammonium thiocyanate (NH2SCN) and was named as CND-TMA13.0, CNT-TMA13.0, and CNA-TMA13.0, respectively. Besides, the average weight ratio between urea and TMA was well tuned and also CNU-TMA13.0 gain a fabulous 16 fold-enhanced photocatalytic performance than blank CNU.
Abstract Recently, organo-metal halide perovskite (e.g., CH3NH3PbI3) solar cells have shown a sig... more Abstract Recently, organo-metal halide perovskite (e.g., CH3NH3PbI3) solar cells have shown a significant surge in progress and efficiency. The photovoltaic performance of perovskite solar cells (PSC) extensively depends on the morphology of the materials at nano-level, because the intrinsic electrical, optical and electrochemical properties also change with a change in morphology. Different TiO2 nanostructures with diverse dimensionalities, 0D hollow TiO2 nanoparticles (HTNPs), 3D hollow TiO2 mesospheres (HTMSs) and 3D hierarchical TiO2 spheres (HTSs) were synthesized hydrothermally. The PSCs based on 3D HTSs or 3D HTMSs as electron transport layers (ETLs) shows better performance than the PSCs fabricated with 0D HTNPs as ETL. The enhanced results can be attributed to the better penetration of the perovskite materials in the porous network of the HTSs or HTMSs and decreased interfacial recombination due to superior charge extraction and electron transport at the HTSs/CH3NH3PbI or HTMSs/CH3NH3Pb interfaces. By using a self-assembled TiO2 compact layer (c-TiO2), followed by a mesoporous layer of HTSs, produces PSCs with an excellent efficiency of 15.08%. Such c-TiO2-ETL films may improve PSCs performance by enhancing electron extraction and block the photogenerated holes.
Metal halide perovskites solar cells (PSCs) have been studied over the past years and achieved hi... more Metal halide perovskites solar cells (PSCs) have been studied over the past years and achieved high power conversion efficiency (PCE). However, the adverse instability remains a key factor restricting wider...
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