Rice is an important dietary source of the toxic mineral cadmium(Cd) for populations in which rice is the main staple food.When grown in agricultural soils that are contaminated with Cd,rice often accumulates excessiv...Rice is an important dietary source of the toxic mineral cadmium(Cd) for populations in which rice is the main staple food.When grown in agricultural soils that are contaminated with Cd,rice often accumulates excessive Cd into the grains,which is a serious threat to agricultural sustainability and human health.To limit Cd accumulation in rice grains,studies on the genetic basis of Cd accumulation in rice have been carried out extensively,and some low-Cd rice varieties have also been developed in recent years.However,the challenges in low-Cd rice breeding still exist because the outcomes of the current genetic improvements for low-Cd rice cannot fully meet the requirements for the development of Cd-safe rice at present.In this review,we outline the progress in understanding the physiological mechanisms and the genetic nature of Cd accumulation in rice and summarize the strategies and outcomes of low-Cd rice breeding over the past decade.By graphing the physiological mechanism of Cd transport in the rice plant,three key steps and some underlying genes are summarized and discussed.Also,two genetic features of the natural variation in rice grain-Cd accumulation,the phenotypic plasticity and subspecies divergence,and the potential genetic explanations for these features are also discussed.Finally,we summarize and discuss current progress and the potential issues in low-Cd rice breeding using different breeding strategies.We hope to propose strategies for future success in the breeding of low-Cd rice varieties over the next decade.展开更多
The Zn(O,S)thin film is considered a most promising candidate for a cadmium-free buffer layer of the Cu(In,Ga)Se_(2)(CIGS)thin-film solar cell due to its advantages of optical responses in the short-wavelength region ...The Zn(O,S)thin film is considered a most promising candidate for a cadmium-free buffer layer of the Cu(In,Ga)Se_(2)(CIGS)thin-film solar cell due to its advantages of optical responses in the short-wavelength region and adjustable bandgap.In this paper,the thin-film growth mechanism and process optimization of Zn(O,S)films fabricated using the chemical bath deposition method are sys-tematically investigated.The thickness and quality of Zn(O,S)films were found to be strongly affected by the concentration variation of the precursor chemicals.It was also revealed that different surface morphologies of Zn(O,S)films would appear if the reaction time were changed and,subsequently,the optimum reaction time was defined.The film-growth curve suggested that the growth rate varied linearly with the deposition temperature and some defects appeared when the temperature was too high.In addition,to further improve the film quality,an effective post-treatment approach was proposed and the experimental results showed that the microstructure of the Zn(O,S)thin film was improved by an ammonia etching process followed by an annealing process.For com-parison purposes,both Zn(O,S)-based and CdS-based devices were fabricated and characterized.The device with a Zn(O,S)-CIGS solar cell after post-treatment showed near conversion efficiency comparable to that of the device with the CdS-CIGS cell.展开更多
Aqueous synthesis is a green but challenging pathway to produce cadmium-free,bright,and near-infrared(NIR)emitting quantum dots(QDs).Herein,we develop a straightforward aqueous phase approach to prepare Zn-Cu-In-Se QD...Aqueous synthesis is a green but challenging pathway to produce cadmium-free,bright,and near-infrared(NIR)emitting quantum dots(QDs).Herein,we develop a straightforward aqueous phase approach to prepare Zn-Cu-In-Se QDs with tunable emission from 630 to 800 nm through varying the molar ratio of Zn and Cu.The ultrasmall nanoparticle size remains nearly fixed(~2.6 nm)when the QD composition is varied,allowing for the effects of composition on the optical properties of QDs to be decoupled from the impact of particle size.By leveraging the off-stoichiometric effect on photoluminescence(PL),Zn-Cu-In-Se QDs with a Zn:Cu molar ratio of 1.0 show a long PL decay lifetime of 211 ns and an absolute photoluminescence quantum yield(PLQY)of 14.2%.The PLQY is further enhanced by overcoating a ZnS shell,reaching up to 25.8%.Based on the bright,biocompatible,and emission-tunable QDs,nanoprobes with targeting capability for multiple tumor markers are further constructed and employed to simultaneously ascertain targets in the cytoplasm and cell membrane.This study provides a green and effective strategy for achieving bright and biocompatible NIR quantum dots for multiplexed biodetection applications.展开更多
Copper indium gallium selenium （CIGS） thin film solar cells have become one of the hottest topics in solar energy due to their high photoelectric transformation efficiency. To real applications, CIGS thin film is co...Copper indium gallium selenium （CIGS） thin film solar cells have become one of the hottest topics in solar energy due to their high photoelectric transformation efficiency. To real applications, CIGS thin film is covered by the buffer layer and absorption layer. Traditionally, cadmium sulfide （CdS） is inserted into the middle of the window layer （ZnO） and absorption layer （CIGS） as a buffer layer. However, the application of the GIGS/CdS thin film solar cells has been limited because of the environmental pollution resulting from the toxic cadmium atom. Although zinc sulfide （ZnS） has been proposed to be one of the candidates, the performance of such battery cells has not been investigated. Here, in this paper, we systematically study the possibility of using zinc sulfide （ZnS） as a buffer layer. By including the effects of thickness, concentration of a buffer layer, intrinsic layer and the absorbing layer, we find that photoelectric transformation efficiency of ZnO/ZnS（n）/CIGS（i）/CIGS（p） solar cell is about 17.22%, which is qualified as a commercial solar cell. Moreover, we also find that the open-circuit voltage is -0.60 V, the short-circuit current is -36.99 mA/cm2 and the filled factor is -77.44%. Therefore, our results suggest that zinc sulfide may be the potential candidate of CdS as a buffer layer.展开更多
基金supported by the National Natural Science Foundation of China (U19A2026 and 31972490)。
文摘Rice is an important dietary source of the toxic mineral cadmium(Cd) for populations in which rice is the main staple food.When grown in agricultural soils that are contaminated with Cd,rice often accumulates excessive Cd into the grains,which is a serious threat to agricultural sustainability and human health.To limit Cd accumulation in rice grains,studies on the genetic basis of Cd accumulation in rice have been carried out extensively,and some low-Cd rice varieties have also been developed in recent years.However,the challenges in low-Cd rice breeding still exist because the outcomes of the current genetic improvements for low-Cd rice cannot fully meet the requirements for the development of Cd-safe rice at present.In this review,we outline the progress in understanding the physiological mechanisms and the genetic nature of Cd accumulation in rice and summarize the strategies and outcomes of low-Cd rice breeding over the past decade.By graphing the physiological mechanism of Cd transport in the rice plant,three key steps and some underlying genes are summarized and discussed.Also,two genetic features of the natural variation in rice grain-Cd accumulation,the phenotypic plasticity and subspecies divergence,and the potential genetic explanations for these features are also discussed.Finally,we summarize and discuss current progress and the potential issues in low-Cd rice breeding using different breeding strategies.We hope to propose strategies for future success in the breeding of low-Cd rice varieties over the next decade.
基金financially supported by National Key R&D Program of China(grant no.2018YFB1500200).
文摘The Zn(O,S)thin film is considered a most promising candidate for a cadmium-free buffer layer of the Cu(In,Ga)Se_(2)(CIGS)thin-film solar cell due to its advantages of optical responses in the short-wavelength region and adjustable bandgap.In this paper,the thin-film growth mechanism and process optimization of Zn(O,S)films fabricated using the chemical bath deposition method are sys-tematically investigated.The thickness and quality of Zn(O,S)films were found to be strongly affected by the concentration variation of the precursor chemicals.It was also revealed that different surface morphologies of Zn(O,S)films would appear if the reaction time were changed and,subsequently,the optimum reaction time was defined.The film-growth curve suggested that the growth rate varied linearly with the deposition temperature and some defects appeared when the temperature was too high.In addition,to further improve the film quality,an effective post-treatment approach was proposed and the experimental results showed that the microstructure of the Zn(O,S)thin film was improved by an ammonia etching process followed by an annealing process.For com-parison purposes,both Zn(O,S)-based and CdS-based devices were fabricated and characterized.The device with a Zn(O,S)-CIGS solar cell after post-treatment showed near conversion efficiency comparable to that of the device with the CdS-CIGS cell.
基金the National Key Research and Development Program of China(No.2018YFA0208800)the National Natural Science Foundation of China(NSFC)(Nos.22177115,81671755,and 21802083)+2 种基金the Youth Innovation Promotion Association CAS(No.2018042)the Taishan Scholar Program of Shandong Province of China(No.ts20110829)Cancer Prevention&Research Institute of Texas(No.RR190056).
文摘Aqueous synthesis is a green but challenging pathway to produce cadmium-free,bright,and near-infrared(NIR)emitting quantum dots(QDs).Herein,we develop a straightforward aqueous phase approach to prepare Zn-Cu-In-Se QDs with tunable emission from 630 to 800 nm through varying the molar ratio of Zn and Cu.The ultrasmall nanoparticle size remains nearly fixed(~2.6 nm)when the QD composition is varied,allowing for the effects of composition on the optical properties of QDs to be decoupled from the impact of particle size.By leveraging the off-stoichiometric effect on photoluminescence(PL),Zn-Cu-In-Se QDs with a Zn:Cu molar ratio of 1.0 show a long PL decay lifetime of 211 ns and an absolute photoluminescence quantum yield(PLQY)of 14.2%.The PLQY is further enhanced by overcoating a ZnS shell,reaching up to 25.8%.Based on the bright,biocompatible,and emission-tunable QDs,nanoprobes with targeting capability for multiple tumor markers are further constructed and employed to simultaneously ascertain targets in the cytoplasm and cell membrane.This study provides a green and effective strategy for achieving bright and biocompatible NIR quantum dots for multiplexed biodetection applications.
基金supported by the NSF of Jiangsu Province(No.BK.20131420)the Postgraduate Innovation Project of Jiangsu Province(No.KYLX15_0926)the NJFU Outstanding Young Scholars Funding
文摘Copper indium gallium selenium （CIGS） thin film solar cells have become one of the hottest topics in solar energy due to their high photoelectric transformation efficiency. To real applications, CIGS thin film is covered by the buffer layer and absorption layer. Traditionally, cadmium sulfide （CdS） is inserted into the middle of the window layer （ZnO） and absorption layer （CIGS） as a buffer layer. However, the application of the GIGS/CdS thin film solar cells has been limited because of the environmental pollution resulting from the toxic cadmium atom. Although zinc sulfide （ZnS） has been proposed to be one of the candidates, the performance of such battery cells has not been investigated. Here, in this paper, we systematically study the possibility of using zinc sulfide （ZnS） as a buffer layer. By including the effects of thickness, concentration of a buffer layer, intrinsic layer and the absorbing layer, we find that photoelectric transformation efficiency of ZnO/ZnS（n）/CIGS（i）/CIGS（p） solar cell is about 17.22%, which is qualified as a commercial solar cell. Moreover, we also find that the open-circuit voltage is -0.60 V, the short-circuit current is -36.99 mA/cm2 and the filled factor is -77.44%. Therefore, our results suggest that zinc sulfide may be the potential candidate of CdS as a buffer layer.
