Alkali metal doping or sulfurization are commonly applied in Cu_(2)ZnSnSe_(4) (CZTSe) solar cell to improve the open-circuit voltage (VOC). However, alkali metal sulfide affording both alkali metal and sulfur is seldo...Alkali metal doping or sulfurization are commonly applied in Cu_(2)ZnSnSe_(4) (CZTSe) solar cell to improve the open-circuit voltage (VOC). However, alkali metal sulfide affording both alkali metal and sulfur is seldom to be studied, which restrains the development of kesterite solar cells. In this study, we evaporate Li_(2)S during selenization process and hope to provide both alkali metal and sulfur to CZTSe film. The result indicates that Li shows a gradient distribution near the surface of CZTSe film and the content of S is slight. The film quality is improved and the recombination at grain boundaries is decreased after Li_(2)S treatment. Besides, the bandgap of the absorber gets wider. Under the synergy of sulfur and lithium (mainly from lithium), the work function of the treated absorber gets higher and the conduction band offset (CBO) is in the ideal range. Combined with these contributions, the V_(OC) of the champion device treated by Li_(2)S dramatically increase by 120 mV. This study discloses that alkali metal brings the main effect on the performance of the kesterite solar cell even an alkali metal sulfide is evaporated, which deepens the understanding of sulfurization of CZTSe and also promote the progress of kesterite solar cells.展开更多
The synthesis method of Al2OC by adding B2O3 was studied to modulate the traditional synthesis process.The mixtures of active carbon,alumina and boron oxide with different carbon contents were heated at 1 700 ℃ for 2...The synthesis method of Al2OC by adding B2O3 was studied to modulate the traditional synthesis process.The mixtures of active carbon,alumina and boron oxide with different carbon contents were heated at 1 700 ℃ for 2 h in flowing argon atmosphere to get the Al2OC product.The results indicate that the addition of B203 promotes the formation of Al2OC,which is dependent on the addition of B2 O3,and the Al2 OC content in the products increases with the increase of carbon.By systematically exploring the ratio of active carbon,alumina and boron oxide,the best formulation and the corresponding reaction mechanism were determined.展开更多
The reaction mechanism of photochemical reaction between Br2 (1Σ ) and OCS (1Σ ) is predicted by means of theoretical methods. The calculated results indicate that the direct addition of Br2 to the CS bond of OCS ...The reaction mechanism of photochemical reaction between Br2 (1Σ ) and OCS (1Σ ) is predicted by means of theoretical methods. The calculated results indicate that the direct addition of Br2 to the CS bond of OCS molecule is more favorable in energy than the direct addition of Br2 to the CO bond. Furthermore, the intermediate isomer syn-BrC(O)SBr is more stable thermodynamically and kinetically than anti-BrC(O)SBr. The original resultant anti-BrC(O)SBr formed in the most favorable reaction channel can easily isomerize into the final product syn-BrC(O)SBr with only 31.72 kJ/mol reaction barrier height. The suggested mechanism is in good agreement with previous experimental study.展开更多
The metaphosphate anion, PO_3, was detected in the negative-ion chemicalionization mass spectra of 2,6,7-trioxa-1-phospbabicyclo[2.2. 2] octane-1-oxides.
基金This work was supported by the National Key R&D Program of China(2018YFB1500200,2019YFB1503500)the National Natural Science Foundation of China(U1902218,11774187)the 111 Project(B16027).
文摘Alkali metal doping or sulfurization are commonly applied in Cu_(2)ZnSnSe_(4) (CZTSe) solar cell to improve the open-circuit voltage (VOC). However, alkali metal sulfide affording both alkali metal and sulfur is seldom to be studied, which restrains the development of kesterite solar cells. In this study, we evaporate Li_(2)S during selenization process and hope to provide both alkali metal and sulfur to CZTSe film. The result indicates that Li shows a gradient distribution near the surface of CZTSe film and the content of S is slight. The film quality is improved and the recombination at grain boundaries is decreased after Li_(2)S treatment. Besides, the bandgap of the absorber gets wider. Under the synergy of sulfur and lithium (mainly from lithium), the work function of the treated absorber gets higher and the conduction band offset (CBO) is in the ideal range. Combined with these contributions, the V_(OC) of the champion device treated by Li_(2)S dramatically increase by 120 mV. This study discloses that alkali metal brings the main effect on the performance of the kesterite solar cell even an alkali metal sulfide is evaporated, which deepens the understanding of sulfurization of CZTSe and also promote the progress of kesterite solar cells.
基金financially supported by National Natural Science Foundation of China ( 51274156)
文摘The synthesis method of Al2OC by adding B2O3 was studied to modulate the traditional synthesis process.The mixtures of active carbon,alumina and boron oxide with different carbon contents were heated at 1 700 ℃ for 2 h in flowing argon atmosphere to get the Al2OC product.The results indicate that the addition of B203 promotes the formation of Al2OC,which is dependent on the addition of B2 O3,and the Al2 OC content in the products increases with the increase of carbon.By systematically exploring the ratio of active carbon,alumina and boron oxide,the best formulation and the corresponding reaction mechanism were determined.
基金supported by the National Namral Science Foundation of China(Nos.20301006,20271019)the Doctoral Foundation of Heilongjiang University(2002).
文摘The reaction mechanism of photochemical reaction between Br2 (1Σ ) and OCS (1Σ ) is predicted by means of theoretical methods. The calculated results indicate that the direct addition of Br2 to the CS bond of OCS molecule is more favorable in energy than the direct addition of Br2 to the CO bond. Furthermore, the intermediate isomer syn-BrC(O)SBr is more stable thermodynamically and kinetically than anti-BrC(O)SBr. The original resultant anti-BrC(O)SBr formed in the most favorable reaction channel can easily isomerize into the final product syn-BrC(O)SBr with only 31.72 kJ/mol reaction barrier height. The suggested mechanism is in good agreement with previous experimental study.
文摘The metaphosphate anion, PO_3, was detected in the negative-ion chemicalionization mass spectra of 2,6,7-trioxa-1-phospbabicyclo[2.2. 2] octane-1-oxides.
