High performance Fe-Gd-P tri-doped TiO2 nanoparticles （1 at% for each dopant） were successfully synthesized by a modified sol-gel method. Various analytical and spectroscopic techniques were carried out to determine...High performance Fe-Gd-P tri-doped TiO2 nanoparticles （1 at% for each dopant） were successfully synthesized by a modified sol-gel method. Various analytical and spectroscopic techniques were carried out to determine the physicochemical properties of the prepared samples, including XRD, EDX, FESEM, BET, FFIR, XPS, PL, EIS and UV-Vis diffuse reflectance spectroscopy. The photocatalytic activities of prepared samples were evaluated by photo degradation of methyl orange （MO） and 4-chlorophenol （4- CP） as model pollutants under visible light irradiation. Effects of each dopant on different properties of TiO2 nanoparticles were investigated. Results show that Gd and P doping enhances Ti02 surface textural properties by forming Ti O Gd and Ti-O-P bonds. It is found that Gd plays a superior role in increasing oxygen vacancies and organic species on TiO2 surface. Gd doping also facilitates transferring of the photo-induced charge carriers to the surface adsorbed species. The enhanced electronic band structure and visible light response, as well as high electron lifetime of Fe-Gd-P tri-doped sample is mainly attributed to Fe and Gd doping. The tri-doped TiO2 with rate constant ofkapp - 1.28 ~ 10-2 min-1 for MO and kapp ~ 0.94 ~ 10-2 min-1 for 4-CP, shows the highest photodegradation rate among all samples including undoped and single doped samples. The improved photocatalytic performance of Fe-Gd-P tri- doped Ti02 is due to the synergistic effect of enhanced surface chemistry and textural properties, increased number of surface adsorbed hydroxyl groups and organic species, improved visible light ab- sorption, increased lifetime of the photo-induced electron/hole pairs and boosted interfacial charge transfer.展开更多
Perovskite solar cells are known to have a power conversion efficiency dependent on subtle variation in chemical composition and crystal and microstructures of materials,processing conditions,and device fabrication pr...Perovskite solar cells are known to have a power conversion efficiency dependent on subtle variation in chemical composition and crystal and microstructures of materials,processing conditions,and device fabrication procedures and conditions.The present work demonstrates such strong dependence of power conversion efficiency on a TiO_2 film made of the same sol with various aging time.A dense and conformal TiO_2 film was prepared by sol-gel method,and the influences of its surface morphology and thickness on performance of perovskite solar cells have been investigated.The surface morphology and thickness of the TiO_2 film were tuned by adjusting the aging time of sol,resulting in enhanced short-circuit current density and fill factor of the perovskite solar cells due to increased coverage and roughness of perovskite films,light refraction,and effective charge recombination blocking effect,which were verified by means of the light absorption spectra,photoluminescence of perovskite films with and without hole transport layer,cyclic voltammogram,and electrochemical impedance spectra.The cells with a dense and conformal TiO_2 compact layer derived from the sol aged for 4 h exhibit a power conversion efficiency of 15.7%,50% higher than the efficiency based on TiO_2 layer derived from 0 h aging sol and 3 times of the efficiency with TiO_2 layer made from 8 h aged sol.展开更多
基金Project supported by the Research office of the Sharif University of Technology(90212681)
文摘High performance Fe-Gd-P tri-doped TiO2 nanoparticles （1 at% for each dopant） were successfully synthesized by a modified sol-gel method. Various analytical and spectroscopic techniques were carried out to determine the physicochemical properties of the prepared samples, including XRD, EDX, FESEM, BET, FFIR, XPS, PL, EIS and UV-Vis diffuse reflectance spectroscopy. The photocatalytic activities of prepared samples were evaluated by photo degradation of methyl orange （MO） and 4-chlorophenol （4- CP） as model pollutants under visible light irradiation. Effects of each dopant on different properties of TiO2 nanoparticles were investigated. Results show that Gd and P doping enhances Ti02 surface textural properties by forming Ti O Gd and Ti-O-P bonds. It is found that Gd plays a superior role in increasing oxygen vacancies and organic species on TiO2 surface. Gd doping also facilitates transferring of the photo-induced charge carriers to the surface adsorbed species. The enhanced electronic band structure and visible light response, as well as high electron lifetime of Fe-Gd-P tri-doped sample is mainly attributed to Fe and Gd doping. The tri-doped TiO2 with rate constant ofkapp - 1.28 ~ 10-2 min-1 for MO and kapp ~ 0.94 ~ 10-2 min-1 for 4-CP, shows the highest photodegradation rate among all samples including undoped and single doped samples. The improved photocatalytic performance of Fe-Gd-P tri- doped Ti02 is due to the synergistic effect of enhanced surface chemistry and textural properties, increased number of surface adsorbed hydroxyl groups and organic species, improved visible light ab- sorption, increased lifetime of the photo-induced electron/hole pairs and boosted interfacial charge transfer.
基金supported by the"Thousands Talents"program for pioneer researcher and his innovation team,Chinathe National Natural Science Foundation of China(51374029 and 91433102)+1 种基金the Program for New Century Excellent Talents in the University(NCET-13-0668)the Fundamental Research Funds for the Central Universities(FRF-TP-14-008C1)
文摘Perovskite solar cells are known to have a power conversion efficiency dependent on subtle variation in chemical composition and crystal and microstructures of materials,processing conditions,and device fabrication procedures and conditions.The present work demonstrates such strong dependence of power conversion efficiency on a TiO_2 film made of the same sol with various aging time.A dense and conformal TiO_2 film was prepared by sol-gel method,and the influences of its surface morphology and thickness on performance of perovskite solar cells have been investigated.The surface morphology and thickness of the TiO_2 film were tuned by adjusting the aging time of sol,resulting in enhanced short-circuit current density and fill factor of the perovskite solar cells due to increased coverage and roughness of perovskite films,light refraction,and effective charge recombination blocking effect,which were verified by means of the light absorption spectra,photoluminescence of perovskite films with and without hole transport layer,cyclic voltammogram,and electrochemical impedance spectra.The cells with a dense and conformal TiO_2 compact layer derived from the sol aged for 4 h exhibit a power conversion efficiency of 15.7%,50% higher than the efficiency based on TiO_2 layer derived from 0 h aging sol and 3 times of the efficiency with TiO_2 layer made from 8 h aged sol.
