For the global commercialization of highly efficient and stable perovskite solar cells(PSCs),it is necessary to effectively suppress the formation of various defects acting as nonradiative recombination sources in per...For the global commercialization of highly efficient and stable perovskite solar cells(PSCs),it is necessary to effectively suppress the formation of various defects acting as nonradiative recombination sources in perovskite light-harvesting materials.Interfacial defects between the charge-selective layer and the perovskite are easily formed in the solution process used to fabricate perovskite films.In addition,owing to the difference in thermal expansion coefficients between the substrate and the perovskite film,internal residual tensile stress inevitably occurs,resulting in increased nonradiative recombination.Herein,a simple compositional engineering scheme for realizing efficient and stable PSCs,which incorporates acetamidinium bromide(AABr)as an additive into the MAPbI_(3) lattice,is proposed.As an additive,AABr has been found to provide synergistic multiple passivation for both internal and interfacial defects.AABr was found to effectively release the tensile strain of the MAPbI_(3) film by forming a structure stabilized by NH-I hydrogen bonds,as evidenced by calculations based on density functional theory(DFT).Furthermore,the incorporated AABr additives created a charge carrier recombination barrier to enhance charge collection capability by reducing interfacial defects.Accordingly,a power conversion efficiency(PCE)of 20.18%was achieved using a planar device employing AABr-incorporated MAPbI_(3).This was substantially higher than the 18.32% PCE of a pristine MAPbI_(3)-based device.Notably,unencapsulated PSCs using AABr-incorporated MAPbI_(3) absorbers exhibited excellent long-term stability,maintaining>95% of initial PCE up to 1200 hours in ambient air.展开更多
The effect of ultraviolet-ozone(UVO)irradiation on amorphous(am)SnO_(2) and its impact on the photoconversion efficiency of MAPbI3-based perovskite solar cells were investigated in detail.UVO treatment was found to in...The effect of ultraviolet-ozone(UVO)irradiation on amorphous(am)SnO_(2) and its impact on the photoconversion efficiency of MAPbI3-based perovskite solar cells were investigated in detail.UVO treatment was found to increase the amount of chemisorbed oxygen on the am-SnO_(2) surface,reducing the surface energy and contact angle.Physicochemical changes in the am-SnO_(2) surface lowered the Gibbs free energy for the densification of perovskite films and facilitated the formation of homogeneous perovskite grains.In addition,the Fermi energy of the UVO-treated am-SnO_(2) shifted upwards to achieve an ideal band offset for MAPbI3,which was verified by theoretical calculations based on the density functional theory.We achieved a champion efficiency of 19.01% with a statistical reproducibility of 17.01±1.34% owing to improved perovskite film densification and enhanced charge transport/extraction,which is considerably higher than the 13.78±2.15% of the counterpart.Furthermore,UVO-treated,am-SnO_(2)-based devices showed improved stability and less hysteresis,which is encouraging for the future application of up-scaled perovskite solar cells.展开更多
A flexible electromagnetic interference(EMI)shielding film was innovatively fabricated using both low melting temperature solder arrays and amorphous soft magnet particulates consolidated on a polyethylene terephthala...A flexible electromagnetic interference(EMI)shielding film was innovatively fabricated using both low melting temperature solder arrays and amorphous soft magnet particulates consolidated on a polyethylene terephthalate(PET)substrate.First,the IneSneBi solder arrays presented a low melting point of 99.4C,which enabled attachment to the heat-sensitive plastic substrate without any thermal damage,and a low electrical resistivity of 14.1 mU cm,making them very effective at interrupting EM waves.Second,the solder arrays with a high thermal conductivity of 61.2 W/(m$K)at 298.15 K were also useful as a thermal conductor for a heat sink.Thus,the solder arrays provide efficient electrical and thermal channels for electron transport induced by abruptly or consistently created EM waves due to suddenly turning on and the long term operation of electronics,respectively.Third,the Fe-based magnetic particulates were added and resulted in effective saturation magnetization of 161.1 emu/g,remanence of 2.9 emu/g,and coercivity of 12.5 G,thus were able to disturb the EM pathway because of their soft magnetic properties.Consequently,the hybrid EMI shielding film with exceptionally high electrical and thermal conductivity and superior soft magnetic properties provided remarkable shielding effectiveness of 102.5 dB at 10.2 GHz.展开更多
基金supported by the Basic Science Research Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Science and ICT(2020R1F1A1068664)。
文摘For the global commercialization of highly efficient and stable perovskite solar cells(PSCs),it is necessary to effectively suppress the formation of various defects acting as nonradiative recombination sources in perovskite light-harvesting materials.Interfacial defects between the charge-selective layer and the perovskite are easily formed in the solution process used to fabricate perovskite films.In addition,owing to the difference in thermal expansion coefficients between the substrate and the perovskite film,internal residual tensile stress inevitably occurs,resulting in increased nonradiative recombination.Herein,a simple compositional engineering scheme for realizing efficient and stable PSCs,which incorporates acetamidinium bromide(AABr)as an additive into the MAPbI_(3) lattice,is proposed.As an additive,AABr has been found to provide synergistic multiple passivation for both internal and interfacial defects.AABr was found to effectively release the tensile strain of the MAPbI_(3) film by forming a structure stabilized by NH-I hydrogen bonds,as evidenced by calculations based on density functional theory(DFT).Furthermore,the incorporated AABr additives created a charge carrier recombination barrier to enhance charge collection capability by reducing interfacial defects.Accordingly,a power conversion efficiency(PCE)of 20.18%was achieved using a planar device employing AABr-incorporated MAPbI_(3).This was substantially higher than the 18.32% PCE of a pristine MAPbI_(3)-based device.Notably,unencapsulated PSCs using AABr-incorporated MAPbI_(3) absorbers exhibited excellent long-term stability,maintaining>95% of initial PCE up to 1200 hours in ambient air.
基金supported by Basic Science Research Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Science and ICT(2020R1F1A1068664)supported by the Defense Challengeable Future Technology Program of the Agency for Defense Development,Republic of Korea.
文摘The effect of ultraviolet-ozone(UVO)irradiation on amorphous(am)SnO_(2) and its impact on the photoconversion efficiency of MAPbI3-based perovskite solar cells were investigated in detail.UVO treatment was found to increase the amount of chemisorbed oxygen on the am-SnO_(2) surface,reducing the surface energy and contact angle.Physicochemical changes in the am-SnO_(2) surface lowered the Gibbs free energy for the densification of perovskite films and facilitated the formation of homogeneous perovskite grains.In addition,the Fermi energy of the UVO-treated am-SnO_(2) shifted upwards to achieve an ideal band offset for MAPbI3,which was verified by theoretical calculations based on the density functional theory.We achieved a champion efficiency of 19.01% with a statistical reproducibility of 17.01±1.34% owing to improved perovskite film densification and enhanced charge transport/extraction,which is considerably higher than the 13.78±2.15% of the counterpart.Furthermore,UVO-treated,am-SnO_(2)-based devices showed improved stability and less hysteresis,which is encouraging for the future application of up-scaled perovskite solar cells.
基金This study was partially sup-ported by the Korea Institute of Materials Science(KIMS).This work was mainly supported by the National Research Council of Science&Technology(NST)grant(No CRC-15-03-KIMM)of the Ministry of Science,ICTand Future Planning(MSIP)in the Korea government.This research was also supported by the Korea Institute of Industrial Technology(KTTECH)internal project(Grant No.P]A18350).
文摘A flexible electromagnetic interference(EMI)shielding film was innovatively fabricated using both low melting temperature solder arrays and amorphous soft magnet particulates consolidated on a polyethylene terephthalate(PET)substrate.First,the IneSneBi solder arrays presented a low melting point of 99.4C,which enabled attachment to the heat-sensitive plastic substrate without any thermal damage,and a low electrical resistivity of 14.1 mU cm,making them very effective at interrupting EM waves.Second,the solder arrays with a high thermal conductivity of 61.2 W/(m$K)at 298.15 K were also useful as a thermal conductor for a heat sink.Thus,the solder arrays provide efficient electrical and thermal channels for electron transport induced by abruptly or consistently created EM waves due to suddenly turning on and the long term operation of electronics,respectively.Third,the Fe-based magnetic particulates were added and resulted in effective saturation magnetization of 161.1 emu/g,remanence of 2.9 emu/g,and coercivity of 12.5 G,thus were able to disturb the EM pathway because of their soft magnetic properties.Consequently,the hybrid EMI shielding film with exceptionally high electrical and thermal conductivity and superior soft magnetic properties provided remarkable shielding effectiveness of 102.5 dB at 10.2 GHz.
