Searching for light and miniaturized functional device structures for sustainable energy gathering from the environment is the focus of energy society with the development of the internet of things.The proposal of a d...Searching for light and miniaturized functional device structures for sustainable energy gathering from the environment is the focus of energy society with the development of the internet of things.The proposal of a dynamic heterojunction-based direct current generator builds up new platforms for developing in situ energy.However,the requirement of different semiconductors in dynamic heterojunction is too complex to wide applications,generating energy loss for crystal structure mismatch.Herein,dynamic homojunction generators are explored,with the same semiconductor and majority carrier type.Systematic experiments reveal that the majority of carrier directional separation originates from the breaking symmetry between carrier distribution,leading to the rebounding effect of carriers by the interfacial electric field.Strikingly,NN Si homojunction with different Fermi levels can also output the electricity with higher current density than PP/PN homojunction,attributing to higher carrier mobility.The current density is as high as 214.0 A/m^(2),and internal impedance is as low as 3.6 kΩ,matching well with the impedance of electron components.Furthermore,the N-i-N structure is explored,whose output voltage can be further improved to 1.3V in the case of the N-Si/Al2O3/N-Si structure,attributing to the enhanced interfacial barrier.This approach provides a simple and feasible way of converting low-frequency disordered mechanical motion into electricity.展开更多
Solid-state thermoelectric energy conversion devices attract broad research interests because of their great promises in waste heat recycling,space power generation,deep water power generation,and temperature control,...Solid-state thermoelectric energy conversion devices attract broad research interests because of their great promises in waste heat recycling,space power generation,deep water power generation,and temperature control,but the search for essential thermoelectric materials with high performance still remains a great challenge.As an emerging low cost,solution-processed thermoelectric material,inorganic metal halide perovskites CsPb(I_(1–x)Br_(x))_(3) under mechanical deformation is systematically investigated using the first-principle calculations and the Boltzmann transport theory.It is demonstrated that halogen mixing and mechanical deformation are efficient methods to tailor electronic structures and charge transport properties in CsPb(I_(1–x)Br_(x))_(3) synergistically.Halogen mixing leads to band splitting and anisotropic charge transport due to symmetry-breakinginduced intrinsic strains.Such band splitting reconstructs the band edge and can decrease the charge carrier effective mass,leading to excellent charge transport properties.Mechanical deformation can further push the orbital energies apart from each other in a more controllable manner,surpassing the impact from intrinsic strains.Both anisotropic charge transport properties and ZT values are sensitive to the direction and magnitude of strain,showing a wide range of variation from 20%to 400%(with a ZT value of up to 1.85)compared with unstrained cases.The power generation efficiency of the thermoelectric device can reach as high as approximately 12%using mixed halide perovskites under tailored mechanical deformation when the heat-source is at 500 K and the cold side is maintained at 300 K,surpassing the performance of many existing bulk thermoelectric materials.展开更多
基金This work was funded by the National Natural Science Foundation of China(Nos.51202216,51502264,and 61774135)Special Foundation of Young Professor of Zhejiang University(No.2013QNA5007)Y.Wen thanks the support from the Science and Technology Project of Jiangsu Province Special Equipment Safety Supervision and Inspection Institute(KJY2017016).
文摘Searching for light and miniaturized functional device structures for sustainable energy gathering from the environment is the focus of energy society with the development of the internet of things.The proposal of a dynamic heterojunction-based direct current generator builds up new platforms for developing in situ energy.However,the requirement of different semiconductors in dynamic heterojunction is too complex to wide applications,generating energy loss for crystal structure mismatch.Herein,dynamic homojunction generators are explored,with the same semiconductor and majority carrier type.Systematic experiments reveal that the majority of carrier directional separation originates from the breaking symmetry between carrier distribution,leading to the rebounding effect of carriers by the interfacial electric field.Strikingly,NN Si homojunction with different Fermi levels can also output the electricity with higher current density than PP/PN homojunction,attributing to higher carrier mobility.The current density is as high as 214.0 A/m^(2),and internal impedance is as low as 3.6 kΩ,matching well with the impedance of electron components.Furthermore,the N-i-N structure is explored,whose output voltage can be further improved to 1.3V in the case of the N-Si/Al2O3/N-Si structure,attributing to the enhanced interfacial barrier.This approach provides a simple and feasible way of converting low-frequency disordered mechanical motion into electricity.
基金supported by the Thousand Talent Young Scholar Program(BE0200006)Shanghai Aerospace Science and Technology Innovation Fund(USCAST2020-13)+1 种基金the Oceanic Interdisciplinary Program from Shanghai Jiao Tong University(SL2020MS008)the National Natural Science Foundation of China(Grant No.51776041).
文摘Solid-state thermoelectric energy conversion devices attract broad research interests because of their great promises in waste heat recycling,space power generation,deep water power generation,and temperature control,but the search for essential thermoelectric materials with high performance still remains a great challenge.As an emerging low cost,solution-processed thermoelectric material,inorganic metal halide perovskites CsPb(I_(1–x)Br_(x))_(3) under mechanical deformation is systematically investigated using the first-principle calculations and the Boltzmann transport theory.It is demonstrated that halogen mixing and mechanical deformation are efficient methods to tailor electronic structures and charge transport properties in CsPb(I_(1–x)Br_(x))_(3) synergistically.Halogen mixing leads to band splitting and anisotropic charge transport due to symmetry-breakinginduced intrinsic strains.Such band splitting reconstructs the band edge and can decrease the charge carrier effective mass,leading to excellent charge transport properties.Mechanical deformation can further push the orbital energies apart from each other in a more controllable manner,surpassing the impact from intrinsic strains.Both anisotropic charge transport properties and ZT values are sensitive to the direction and magnitude of strain,showing a wide range of variation from 20%to 400%(with a ZT value of up to 1.85)compared with unstrained cases.The power generation efficiency of the thermoelectric device can reach as high as approximately 12%using mixed halide perovskites under tailored mechanical deformation when the heat-source is at 500 K and the cold side is maintained at 300 K,surpassing the performance of many existing bulk thermoelectric materials.
