Organic-inorganic 3D halide perovskite materials recently have become one of the major players of hybrid semiconductors for photovoltaic and optoelectronic applications.The diffusion length of charge carriers is one o...Organic-inorganic 3D halide perovskite materials recently have become one of the major players of hybrid semiconductors for photovoltaic and optoelectronic applications.The diffusion length of charge carriers is one of the critical parameters for justifying photovoltaic applications of materials.In this work,we propose a realistic kinetic model in order to fully understand carrier relaxation rate of photoexcited organic perovskites with a negligible exciton formation in photoluminescence lifetime measurements.We find that the extraction of carrier relaxation rate has to be made from multiple fluence-dependent photoluminescence lifetime measurements with global fittings,instead of a traditional single fluence lifetime measurement.To demonstrate the validity of the model,two kinds of p-doped CH3NH3PbI3 single crystals were grown up by intentionally increasing defects.Global fittings of the kinetic model to the two kinds of single crystals yield doping density,trap density,and recombination constants.Our methodology provides a self-contained approach to determine diffusion lengths of organic 3D halide perovskite materials.展开更多
As a key factor leading to the pressure-dependent R1-line-shift reversal and R1-state lifetime, at 10 K, the pressure-dependent variation of mixing-degree of ｜t2^2（^3T1）e^4T2） and ｜t2^32E〉 base-wavefunetions in ...As a key factor leading to the pressure-dependent R1-line-shift reversal and R1-state lifetime, at 10 K, the pressure-dependent variation of mixing-degree of ｜t2^2（^3T1）e^4T2） and ｜t2^32E〉 base-wavefunetions in the wavefunction of R1 state of LLGG：Cr^3＋ has been calculated and analyzed. From this, the physical origin of the pressure-dependent R1-line-shift reversal has been revealed. Furthermore, by using the pressure-dependent values of the sum of all square mixlng-coefficients of ｜t2^2 （^3T1）e^4T2〉 in the wavefunction of R1 state, the lifetimes of R1 state of LLG G：Cr^3＋ at various pressures have been calculat, ed, which arc in good agreement with observed results. The quantum anticrossing effect between t2^32E and t2^2 （^3T1）e^4T2 levels due to both spin-orbital interaction and electron-phonon interaction is remarkable, which is related to the admixture of ｜t2^2（^3T1）e^4T2） and ｜t2^32E〉 as well as the low high crystal-field transition.展开更多
The surface of silicon was passivated by A1203 and acidify using nitric acid with SiOx as the bi-layer, it was expected that hydrogen bonding reduce interface states and negative field effect which yields maximum pass...The surface of silicon was passivated by A1203 and acidify using nitric acid with SiOx as the bi-layer, it was expected that hydrogen bonding reduce interface states and negative field effect which yields maximum passivation. By optimizing the thickness of passivation layer and annealing condition, the minority carrier lifetime of p-type single crystalline Czochralski wafer could be improved from 10 μs to 190 μs. The formation and variation of hillock defect on passivation layer was founded to be affected by the thermal annealing temperature. For the purpose of obtaining high minority carrier lifetime and low hillock defect density simultaneously, using a lower heating and cooling speed in thermal annealing process is suggested.展开更多
基金supported by the National Natural Science Foundation of China (No.21773221 and No.21827804)the National Key R&D Program of China (2017YFA0303502)Fundamental Research Funds for the Central Universities of China(WK2340000078).
文摘Organic-inorganic 3D halide perovskite materials recently have become one of the major players of hybrid semiconductors for photovoltaic and optoelectronic applications.The diffusion length of charge carriers is one of the critical parameters for justifying photovoltaic applications of materials.In this work,we propose a realistic kinetic model in order to fully understand carrier relaxation rate of photoexcited organic perovskites with a negligible exciton formation in photoluminescence lifetime measurements.We find that the extraction of carrier relaxation rate has to be made from multiple fluence-dependent photoluminescence lifetime measurements with global fittings,instead of a traditional single fluence lifetime measurement.To demonstrate the validity of the model,two kinds of p-doped CH3NH3PbI3 single crystals were grown up by intentionally increasing defects.Global fittings of the kinetic model to the two kinds of single crystals yield doping density,trap density,and recombination constants.Our methodology provides a self-contained approach to determine diffusion lengths of organic 3D halide perovskite materials.
文摘As a key factor leading to the pressure-dependent R1-line-shift reversal and R1-state lifetime, at 10 K, the pressure-dependent variation of mixing-degree of ｜t2^2（^3T1）e^4T2） and ｜t2^32E〉 base-wavefunetions in the wavefunction of R1 state of LLGG：Cr^3＋ has been calculated and analyzed. From this, the physical origin of the pressure-dependent R1-line-shift reversal has been revealed. Furthermore, by using the pressure-dependent values of the sum of all square mixlng-coefficients of ｜t2^2 （^3T1）e^4T2〉 in the wavefunction of R1 state, the lifetimes of R1 state of LLG G：Cr^3＋ at various pressures have been calculat, ed, which arc in good agreement with observed results. The quantum anticrossing effect between t2^32E and t2^2 （^3T1）e^4T2 levels due to both spin-orbital interaction and electron-phonon interaction is remarkable, which is related to the admixture of ｜t2^2（^3T1）e^4T2） and ｜t2^32E〉 as well as the low high crystal-field transition.
文摘The surface of silicon was passivated by A1203 and acidify using nitric acid with SiOx as the bi-layer, it was expected that hydrogen bonding reduce interface states and negative field effect which yields maximum passivation. By optimizing the thickness of passivation layer and annealing condition, the minority carrier lifetime of p-type single crystalline Czochralski wafer could be improved from 10 μs to 190 μs. The formation and variation of hillock defect on passivation layer was founded to be affected by the thermal annealing temperature. For the purpose of obtaining high minority carrier lifetime and low hillock defect density simultaneously, using a lower heating and cooling speed in thermal annealing process is suggested.
