Nanomaterials with intense near-infrared （NIR） absorption exhibit effective photon-to-thermal energy transfer capabilities and can generate heat to ablate cancer cells, thus playing a pivotal role in photothermal ca...Nanomaterials with intense near-infrared （NIR） absorption exhibit effective photon-to-thermal energy transfer capabilities and can generate heat to ablate cancer cells, thus playing a pivotal role in photothermal cancer therapeutics. Herein, hydrophilic flower-like bismuth sulfur （Bi2S3） superstructures with uniform size and improved NIR absorption were controllably synthesized via a facile solvothermal procedure assisted by polyvinylpyrrolidone （PVP）, which could adjust the product morphology. Induced by an 808-nm laser, the as-prepared Bi2S3 nanoflowers exhibited much higher photothermal conversion efficiency （64.3%） than that of Bi2S3 nanobelts （36.5%） prepared in the absence of PVP. This can be attributed not only to the Bi2S3 nanoflower superstructures assembled by 3-dimensional crumpled-paper-like nanosheets serving as many laser-cavity mirrors with improved reflectivity and absorption of NIR light but also to the amorphous structures with a lower band gap. Thus, to achieve the same temperature increase, the concentration or laser power density could be greatly reduced when using Bi2S3 nanoflowers compared to when using Bi2S3 nanobelts, which makes them more favorable for use in therapy due to decreased toxicity. Furthermore, these Bi2S3 nanoflowers effectively achieved photothermal ablation of cancer ceils in vitro and in vivo. These results not only supported the Bi2S3 nanoflowers as a promising photothermal agent for cancer therapy but also paved an approach to exploit new agents with improved photothermal efficiency.展开更多
ZnO has received tremendous attention for applications in photoelectrochemical water splitting, photocatalysis, and photovoltaic devices. However, the photoelectric conversion efficiency of ZnO is limited by the rapid...ZnO has received tremendous attention for applications in photoelectrochemical water splitting, photocatalysis, and photovoltaic devices. However, the photoelectric conversion efficiency of ZnO is limited by the rapid recombination of photoexcited electron-hole pairs and the wide band gap, which allows only a small fraction of the solar spectrum to be absorbed. Recently, substantial research efforts have aimed to increase the photoelectric conversion efficiency across the entire ultraviolet-visible （UV-vis） spectrum by coupling semiconductors such as ZnO with noble metal nanoparticles （NPs）. In this stud~ we compare the performance of a pure ZnO film and ZnO/Ag nanostructured films as photoelectrodes. We show that under broad-spectrum UV-vis illumination, the photocurrent generated in the ZnO/Ag three-dimensional （3D） nanostructured films increases 3.75 times relative to the photocurrent generated in the pure ZnO films. We attribute the high photocurrent to the electric-field enhancement associated with the localized surface plasmon resonance of the Ag NPs, which are present at a high density in the 3D nanostructured films, and to the creation of photoexcited hot electrons in Ag that are transferred to ZnO, promoting electron-hole pair separation. We propose a mechanism to explain the observed enhancement of the photoelectric conversion efficiency.展开更多
An interesitng class of organicA-π-D-π-A dyes based on an N,N,N＇,N＇-tetraphenylbenzidine（TPD） unit as donor was designed and synthesized for dye-sensitized solar cells（DSSCs）. TPD-4-based DSSCs gave a short c...An interesitng class of organicA-π-D-π-A dyes based on an N,N,N＇,N＇-tetraphenylbenzidine（TPD） unit as donor was designed and synthesized for dye-sensitized solar cells（DSSCs）. TPD-4-based DSSCs gave a short circuit photocurrent density（Jsc） of 16.67 mA/cm2, a open circuit voltage（Voc） of 0.635 V and a fill factor（f/） of 0.68, achieving a solar-to-electricity conversion efficiency（r/） of 7.22% in preliminary tests. The N3-sensitized device gave an η value of 8.02% with a Jsc of 18.81 mA/cm2, a Voc of 0.630 V and anffof 0.68 under the same conditions. The incident photo-to-current efficiency（IPCE） values above 70% observed in a range of 460 to 600 nm with a maximum value of 80% at 500 nm indicate that the TPD-4-based DSSC shows a high performance. Under the same conditions, the DSSC based on N3 provided the IPCE values above 70% in a range of 490 to 580 nm with a maximum value of 76% at 500 nm. Both further optimization of the device processing and structural modification of these dyes are an- ticipated to make the device give even better performances.展开更多
基金We thank the financial support of the National Natural Science Foundation of China （Nos. 21171035 and 51472049）, the Key Grant Project of the Chinese Ministry of Education （No. 313015）, the PhD Programs Foundation of the Ministry of Education of China （No. 20130075120001） and the National High-tech R＆D Program of China （No. 2013AA031903）.
文摘Nanomaterials with intense near-infrared （NIR） absorption exhibit effective photon-to-thermal energy transfer capabilities and can generate heat to ablate cancer cells, thus playing a pivotal role in photothermal cancer therapeutics. Herein, hydrophilic flower-like bismuth sulfur （Bi2S3） superstructures with uniform size and improved NIR absorption were controllably synthesized via a facile solvothermal procedure assisted by polyvinylpyrrolidone （PVP）, which could adjust the product morphology. Induced by an 808-nm laser, the as-prepared Bi2S3 nanoflowers exhibited much higher photothermal conversion efficiency （64.3%） than that of Bi2S3 nanobelts （36.5%） prepared in the absence of PVP. This can be attributed not only to the Bi2S3 nanoflower superstructures assembled by 3-dimensional crumpled-paper-like nanosheets serving as many laser-cavity mirrors with improved reflectivity and absorption of NIR light but also to the amorphous structures with a lower band gap. Thus, to achieve the same temperature increase, the concentration or laser power density could be greatly reduced when using Bi2S3 nanoflowers compared to when using Bi2S3 nanobelts, which makes them more favorable for use in therapy due to decreased toxicity. Furthermore, these Bi2S3 nanoflowers effectively achieved photothermal ablation of cancer ceils in vitro and in vivo. These results not only supported the Bi2S3 nanoflowers as a promising photothermal agent for cancer therapy but also paved an approach to exploit new agents with improved photothermal efficiency.
文摘ZnO has received tremendous attention for applications in photoelectrochemical water splitting, photocatalysis, and photovoltaic devices. However, the photoelectric conversion efficiency of ZnO is limited by the rapid recombination of photoexcited electron-hole pairs and the wide band gap, which allows only a small fraction of the solar spectrum to be absorbed. Recently, substantial research efforts have aimed to increase the photoelectric conversion efficiency across the entire ultraviolet-visible （UV-vis） spectrum by coupling semiconductors such as ZnO with noble metal nanoparticles （NPs）. In this stud~ we compare the performance of a pure ZnO film and ZnO/Ag nanostructured films as photoelectrodes. We show that under broad-spectrum UV-vis illumination, the photocurrent generated in the ZnO/Ag three-dimensional （3D） nanostructured films increases 3.75 times relative to the photocurrent generated in the pure ZnO films. We attribute the high photocurrent to the electric-field enhancement associated with the localized surface plasmon resonance of the Ag NPs, which are present at a high density in the 3D nanostructured films, and to the creation of photoexcited hot electrons in Ag that are transferred to ZnO, promoting electron-hole pair separation. We propose a mechanism to explain the observed enhancement of the photoelectric conversion efficiency.
基金Supported by the National Natural Science Foundation of China （No. 20872142）.
文摘An interesitng class of organicA-π-D-π-A dyes based on an N,N,N＇,N＇-tetraphenylbenzidine（TPD） unit as donor was designed and synthesized for dye-sensitized solar cells（DSSCs）. TPD-4-based DSSCs gave a short circuit photocurrent density（Jsc） of 16.67 mA/cm2, a open circuit voltage（Voc） of 0.635 V and a fill factor（f/） of 0.68, achieving a solar-to-electricity conversion efficiency（r/） of 7.22% in preliminary tests. The N3-sensitized device gave an η value of 8.02% with a Jsc of 18.81 mA/cm2, a Voc of 0.630 V and anffof 0.68 under the same conditions. The incident photo-to-current efficiency（IPCE） values above 70% observed in a range of 460 to 600 nm with a maximum value of 80% at 500 nm indicate that the TPD-4-based DSSC shows a high performance. Under the same conditions, the DSSC based on N3 provided the IPCE values above 70% in a range of 490 to 580 nm with a maximum value of 76% at 500 nm. Both further optimization of the device processing and structural modification of these dyes are an- ticipated to make the device give even better performances.
