All-perovskite tandem solar cells have the potential to surpass the theoretical efficiency limit of single junction solar cells by reducing thermalization losses.However,the challenges encompass the oxidation of Sn^(2...All-perovskite tandem solar cells have the potential to surpass the theoretical efficiency limit of single junction solar cells by reducing thermalization losses.However,the challenges encompass the oxidation of Sn^(2+)to Sn^(4+)and uncontrolled crystallization kinetics in Sn-Pb perovskites,leading to nonradiative recombination and compositional heterogeneity to decrease photovoltaic efficiency and operational stability.Herein,we introduced an ionic liquid additive,1-ethyl-3-methylimidazolium iodide (EMIMI) into Sn-Pb perovskite precursor to form low-dimensional Sn-rich/pure-Sn perovskites at grain boundaries,which mitigates oxidation of Sn^(2+)to Sn^(4+)and regulates the film-forming dynamics of Sn/Pb-based perovskite films.The optimized single-junction Sn-Pb perovskite devices incorporating EMIMI achieved a high efficiency of 22.87%.Furthermore,combined with wide-bandgap perovskite sub-cells in tandem device,we demonstrate 2-terminal all-perovskite tandem solar cells with a power conversion efficiency of 28.34%,achieving improved operational stability.展开更多
The interaction relation between lanthanum and the constituent elements of Sn-Pb alloy system was analyzed by using the thermodynamic models including Miedema formation energy model for binary system, Tanaka modificat...The interaction relation between lanthanum and the constituent elements of Sn-Pb alloy system was analyzed by using the thermodynamic models including Miedema formation energy model for binary system, Tanaka modification by excess entropy and the Chou geometric model for ternary system. The thermodynamic calculaton results show that lanthanum has higher affinity for Sn in the Sn-Pb system. This is an important foundation for the improvement of the metallurgical properties of Sn-Pb solder alloy by adding rare earth elements.展开更多
In situ synchrotron X-ray radiography was used to study the effect of direct current（DC） on the grain nucleation and growth of Sn-50 wt.%Pb alloy. The results showed that applying DC adequately during solidification...In situ synchrotron X-ray radiography was used to study the effect of direct current（DC） on the grain nucleation and growth of Sn-50 wt.%Pb alloy. The results showed that applying DC adequately during solidification could effectively enhance the grain nucleation and inhibit its growth. Imaging of comparative experiments with varying DC intensity indicated that the final grain size, determined by the competition between grain nucleation and growth, was sensitively dependent on the DC intensity. It was found that the average grain size was decreased from 1632 to 567 μm with DC density of 1.5 A/mm^2 compared to the case without DC. Beyond this value, raising the current density may cause a significant decrease in the nucleation rate, and thus lead to a coarsening of the grain structure.展开更多
基金National Key Research and Development Program of China (2022YFB420030)National Natural Science Foundation of China (2227903)+1 种基金Innovation Project of Optics Valley Laboratory (OVL2021BG008)Foundation of State Key Laboratory of New Textile Materials and Advanced Processing Technologies (FZ2021011)。
文摘All-perovskite tandem solar cells have the potential to surpass the theoretical efficiency limit of single junction solar cells by reducing thermalization losses.However,the challenges encompass the oxidation of Sn^(2+)to Sn^(4+)and uncontrolled crystallization kinetics in Sn-Pb perovskites,leading to nonradiative recombination and compositional heterogeneity to decrease photovoltaic efficiency and operational stability.Herein,we introduced an ionic liquid additive,1-ethyl-3-methylimidazolium iodide (EMIMI) into Sn-Pb perovskite precursor to form low-dimensional Sn-rich/pure-Sn perovskites at grain boundaries,which mitigates oxidation of Sn^(2+)to Sn^(4+)and regulates the film-forming dynamics of Sn/Pb-based perovskite films.The optimized single-junction Sn-Pb perovskite devices incorporating EMIMI achieved a high efficiency of 22.87%.Furthermore,combined with wide-bandgap perovskite sub-cells in tandem device,we demonstrate 2-terminal all-perovskite tandem solar cells with a power conversion efficiency of 28.34%,achieving improved operational stability.
文摘The interaction relation between lanthanum and the constituent elements of Sn-Pb alloy system was analyzed by using the thermodynamic models including Miedema formation energy model for binary system, Tanaka modification by excess entropy and the Chou geometric model for ternary system. The thermodynamic calculaton results show that lanthanum has higher affinity for Sn in the Sn-Pb system. This is an important foundation for the improvement of the metallurgical properties of Sn-Pb solder alloy by adding rare earth elements.
基金supported by the National Key Research and Development Program of China (No. 2016YFB0701203)the National Natural Science Foundation of China (Nos. 51525401, 51690163, 51601028, 51401044)Dalian Support Plan for Innovation of High-level Talents (Top and Leading Talents, 2015R013)
文摘In situ synchrotron X-ray radiography was used to study the effect of direct current（DC） on the grain nucleation and growth of Sn-50 wt.%Pb alloy. The results showed that applying DC adequately during solidification could effectively enhance the grain nucleation and inhibit its growth. Imaging of comparative experiments with varying DC intensity indicated that the final grain size, determined by the competition between grain nucleation and growth, was sensitively dependent on the DC intensity. It was found that the average grain size was decreased from 1632 to 567 μm with DC density of 1.5 A/mm^2 compared to the case without DC. Beyond this value, raising the current density may cause a significant decrease in the nucleation rate, and thus lead to a coarsening of the grain structure.
