Boron-oxygen defects can cause serious lightinduced degradation （LID） of commercial solar cells based on the boron-doped crystalline silicon （c-Si）, which are formed under the injection of excess carriers induced ...Boron-oxygen defects can cause serious lightinduced degradation （LID） of commercial solar cells based on the boron-doped crystalline silicon （c-Si）, which are formed under the injection of excess carriers induced either by illumination or applying forward bias. In this contribution, we have demonstrated that the passivation process of boron-oxygen defects can be induced by applying forward bias for a large quantity of solar cells, which is much more economic than light illumination. We have used this strategy to trigger the passivation process of batches of aluminum back surface field （A1-BSF） solar cells and passivated emitter and rear contact （PERC） solar cells. Both kinds of the treated solar cells show high stability in efficiency and suffer from very little LID under further illumination at room temperature. This technology is of significance for the suppression of LID of c-Si solar cells for the industrial manufacture.展开更多
Carb on nanospheres(XC-72R)were functionalized by boron-oxygen(B-O)through coannealing with boric acid,to which highly dispersed palladium nanoparticles(Pd NPs)(-1.7 nm)were immobilized by a wet chemical reduction for...Carb on nanospheres(XC-72R)were functionalized by boron-oxygen(B-O)through coannealing with boric acid,to which highly dispersed palladium nanoparticles(Pd NPs)(-1.7 nm)were immobilized by a wet chemical reduction for the first time.The resultant Pd/OB-C catalystexhibits significantly improved activity for the dehydrogenation from formic acid(FA)compared to pristine XC-72R supported Pd NPs(Pd/C).Impressively,by adding melamine precursor,the B-0 and nitrogen(N)-functionalized product OB-C-N displays an extremely high B content,ca.34 times higher than OB-C.The Pd/OB-C-N catalyst with an ultrafine Pd particle size of-1.4 nm shows a superb activity,with a turnoverfrequency(TOF)as high as 5,354 h^-1 at 323 K,owing to the uniform ultrafine Pd NPs and the effect from B-0 and N functionalities.展开更多
This paper presents the application of lifetime spectroscopy to the study of carrier-induced degradation ascribed to the boron-oxygen （BO） defect. Specifically, a large data set of p-type silicon samples is used to ...This paper presents the application of lifetime spectroscopy to the study of carrier-induced degradation ascribed to the boron-oxygen （BO） defect. Specifically, a large data set of p-type silicon samples is used to investigate two important aspects of carrier lifetime analysis： ① the methods used to extract the recombination lifetime associated with the defect and ② the underlying assumption that cartier injection does not affect lifetime components unrelated to the defect. The results demonstrate that the capture cross section ratio associated with the donor level of the BO defect （kl） vary widely depending on the specific method used to extract the defect-specific recombination lifetime. For the data set studied here, it was also found that illumination used to form the defect caused minor, but statistically significant changes in the surface passivation used. This violation of the fundamental assumption could be accounted for by applying appropriate curve fitting methods, resulting in an improved estimate of k1 （11.90±0.45） for the fully formed BO defect when modeled using the donor level alone. Illumination also appeared to cause a minor, apparently injectionindependent change in lifetime that could not be attributed to the donor level of the BO defect alone and is likely related to the acceptor level of the BO defect. While specific to the BO defect, this study has implications for the use of lifetime spectroscopy to study other carrier induced defects. Finally, we demonstrate the use of a unit-less regression goodness-of-fit metric for lifetime data that is easy to interpret and accounts for repeatability error.展开更多
This work investigates the suppression and compensation effect of oxygen on the behaviors and characteristics of heavily boron-doped microwave plasma chemical vapor deposition(MPCVD)diamond films.The suppression effec...This work investigates the suppression and compensation effect of oxygen on the behaviors and characteristics of heavily boron-doped microwave plasma chemical vapor deposition(MPCVD)diamond films.The suppression effect of oxygen on boron incorporation is observed by an improvement in crystal quality when oxygen is added during the diamond doping process.A relatively low hole concentration is expected and verified by Hall effect measurements due to the compensation effect of oxygen as a deep donor in diamond.A low acceptor concentration,high compensation donor concentration and relatively larger acceptor ionization energy are then induced by the incorporation of oxygen;however,a heavily boron-doped diamond film with high crystal quality can also be expected.The formation of an oxygen–boron complex structure instead of oxygen substitution,as indicated by the results of x-ray photoelectron spectroscopy,is suggested to be more responsible for the observed enhanced compensation effect due to its predicted low formation energy.Meanwhile,density functional theory calculations show that the boron–oxygen complex structure is easily formed in diamond with a formation energy of-0.83 eV.This work provides a comprehensive understanding of oxygen compensation in heavily boron-doped diamond.展开更多
Boron-doped Ketjenblack is attempted as cathode catalyst for non-aqueous rechargeable Li–O2 batteries. The boron-doped Ketjenblack delivers an extremely high discharge capacity of 7193 m Ah/g at a current density of ...Boron-doped Ketjenblack is attempted as cathode catalyst for non-aqueous rechargeable Li–O2 batteries. The boron-doped Ketjenblack delivers an extremely high discharge capacity of 7193 m Ah/g at a current density of 0.1 m A/cm2, and the capacity is about 2.3 times as that of the pristine KB. When the batteries are cycled with different restricted capacity, the boron-doped Ketjenblack based cathodes exhibits higher discharge platform and longer cycle life than Ketjenblack based cathodes. Additionally, the boron-doped Ketjenblack also shows a superior electrocatalytic activity for oxygen reduction in 0.1 mol/L KOH aqueous solution. The improvement in catalytic activity results from the defects and activation sites introduced by boron doping.展开更多
基金Acknowledgements This work was supported by the National Natural Science Foundation of China （Grant Nos. 51532007, 61574124 and 51472219）, the Program for Innovative Research Team in University of Ministry of Education of China （IRT13R54）, and State Key Laboratory of Optoelectronic Materials and Technologies （Sun Yat-sen University）.
文摘Boron-oxygen defects can cause serious lightinduced degradation （LID） of commercial solar cells based on the boron-doped crystalline silicon （c-Si）, which are formed under the injection of excess carriers induced either by illumination or applying forward bias. In this contribution, we have demonstrated that the passivation process of boron-oxygen defects can be induced by applying forward bias for a large quantity of solar cells, which is much more economic than light illumination. We have used this strategy to trigger the passivation process of batches of aluminum back surface field （A1-BSF） solar cells and passivated emitter and rear contact （PERC） solar cells. Both kinds of the treated solar cells show high stability in efficiency and suffer from very little LID under further illumination at room temperature. This technology is of significance for the suppression of LID of c-Si solar cells for the industrial manufacture.
文摘Carb on nanospheres(XC-72R)were functionalized by boron-oxygen(B-O)through coannealing with boric acid,to which highly dispersed palladium nanoparticles(Pd NPs)(-1.7 nm)were immobilized by a wet chemical reduction for the first time.The resultant Pd/OB-C catalystexhibits significantly improved activity for the dehydrogenation from formic acid(FA)compared to pristine XC-72R supported Pd NPs(Pd/C).Impressively,by adding melamine precursor,the B-0 and nitrogen(N)-functionalized product OB-C-N displays an extremely high B content,ca.34 times higher than OB-C.The Pd/OB-C-N catalyst with an ultrafine Pd particle size of-1.4 nm shows a superb activity,with a turnoverfrequency(TOF)as high as 5,354 h^-1 at 323 K,owing to the uniform ultrafine Pd NPs and the effect from B-0 and N functionalities.
文摘This paper presents the application of lifetime spectroscopy to the study of carrier-induced degradation ascribed to the boron-oxygen （BO） defect. Specifically, a large data set of p-type silicon samples is used to investigate two important aspects of carrier lifetime analysis： ① the methods used to extract the recombination lifetime associated with the defect and ② the underlying assumption that cartier injection does not affect lifetime components unrelated to the defect. The results demonstrate that the capture cross section ratio associated with the donor level of the BO defect （kl） vary widely depending on the specific method used to extract the defect-specific recombination lifetime. For the data set studied here, it was also found that illumination used to form the defect caused minor, but statistically significant changes in the surface passivation used. This violation of the fundamental assumption could be accounted for by applying appropriate curve fitting methods, resulting in an improved estimate of k1 （11.90±0.45） for the fully formed BO defect when modeled using the donor level alone. Illumination also appeared to cause a minor, apparently injectionindependent change in lifetime that could not be attributed to the donor level of the BO defect alone and is likely related to the acceptor level of the BO defect. While specific to the BO defect, this study has implications for the use of lifetime spectroscopy to study other carrier induced defects. Finally, we demonstrate the use of a unit-less regression goodness-of-fit metric for lifetime data that is easy to interpret and accounts for repeatability error.
基金the National Key Research and Development Program of China(Grant Nos.2018YFB0406502,2017YFF0210800,and 2017YFB0403003)the National Natural Science Foundation of China(Grant Nos.61774081,61775203,61574075,61974059,61674077,61774081,and 91850112)+2 种基金the State Key Research and Development Project of Jiangsu,China(Grant No.BE2018115)State Key Laboratory of Wide-Bandgap Semiconductor Power Electric Devices(Grant No.2017KF001)Anhui University Natural Science Research Project(Grant No.KJ2021A0037).
文摘This work investigates the suppression and compensation effect of oxygen on the behaviors and characteristics of heavily boron-doped microwave plasma chemical vapor deposition(MPCVD)diamond films.The suppression effect of oxygen on boron incorporation is observed by an improvement in crystal quality when oxygen is added during the diamond doping process.A relatively low hole concentration is expected and verified by Hall effect measurements due to the compensation effect of oxygen as a deep donor in diamond.A low acceptor concentration,high compensation donor concentration and relatively larger acceptor ionization energy are then induced by the incorporation of oxygen;however,a heavily boron-doped diamond film with high crystal quality can also be expected.The formation of an oxygen–boron complex structure instead of oxygen substitution,as indicated by the results of x-ray photoelectron spectroscopy,is suggested to be more responsible for the observed enhanced compensation effect due to its predicted low formation energy.Meanwhile,density functional theory calculations show that the boron–oxygen complex structure is easily formed in diamond with a formation energy of-0.83 eV.This work provides a comprehensive understanding of oxygen compensation in heavily boron-doped diamond.
基金supported by the MOST(Grant nos.2013CB934000and 2014DFG71590)Beijing Municipal Program(Grant no.YETP0157)
文摘Boron-doped Ketjenblack is attempted as cathode catalyst for non-aqueous rechargeable Li–O2 batteries. The boron-doped Ketjenblack delivers an extremely high discharge capacity of 7193 m Ah/g at a current density of 0.1 m A/cm2, and the capacity is about 2.3 times as that of the pristine KB. When the batteries are cycled with different restricted capacity, the boron-doped Ketjenblack based cathodes exhibits higher discharge platform and longer cycle life than Ketjenblack based cathodes. Additionally, the boron-doped Ketjenblack also shows a superior electrocatalytic activity for oxygen reduction in 0.1 mol/L KOH aqueous solution. The improvement in catalytic activity results from the defects and activation sites introduced by boron doping.
