Metal halide perovskites,particularly the quasi-two-dimensional perovskite subclass,have exhibited considerable potential for next-generation electroluminescent materials for lighting and display.Nevertheless,the pres...Metal halide perovskites,particularly the quasi-two-dimensional perovskite subclass,have exhibited considerable potential for next-generation electroluminescent materials for lighting and display.Nevertheless,the presence of defects within these perovskites has a substantial influence on the emission efficiency and durability of the devices.In this study,we revealed a synergistic passivation mechanism on perovskite films by using a dual-functional compound of potassium bromide.The dual functional potassium bromide on the one hand can passivate the defects of halide vacancies with bromine anions and,on the other hand,can screen the charged defects at the grain boundaries with potassium cations.This approach effectively reduces the probability of carriers quenching resulting from charged defects capture and consequently enhances the radiative recombination efficiency of perovskite thin films,leading to a significant enhancement of photoluminescence quantum yield to near-unity values(95%).Meanwhile,the potassium bromide treatment promoted the growth of homogeneous and smooth film,facilitating the charge carrier injection in the devices.Consequently,the perovskite light-emitting diodes based on this strategy achieve a maximum external quantum efficiency of~21%and maximum luminance of~60,000 cd m^(-2).This work provides a deeper insight into the passivation mechanism of ionic compound additives in perovskite with the solution method.展开更多
Nonlinear optical frequency mixing,which describes new frequencies generation by exciting nonlinear materials with intense light field,has drawn vast interests in the field of photonic devices,material characterizatio...Nonlinear optical frequency mixing,which describes new frequencies generation by exciting nonlinear materials with intense light field,has drawn vast interests in the field of photonic devices,material characterization,and optical imaging.Investigating and manipulating the nonlinear optical response of target materials lead us to reveal hidden physics and develop applications in optical devices.Here,we report the realization of facile manipulation of nonlinear optical responses in the example system of MoS_(2) monolayer by van der Waals interfacial engineering.We found that,the interfacing of monolayer graphene will weaken the exciton oscillator strength in MoS_(2) monolayer and correspondingly suppress the second harmonic generation(SHG)intensity to 30%under band-gap resonance excitation.While with off-resonance excitation,the SHG intensity would enhance up to 130%,which is conjectured to be induced by the interlayer excitation between MoS_(2) and graphene.Our investigation provides an effective method for controlling nonlinear optical properties of two-dimensional materials and therefore facilitates their future applications in optoelectronic and photonic devices.展开更多
基金supported by the Science and Technology Development Fund,Macao SAR(File no.FDCT-0082/2021/A2,0010/2022/AMJ,006/2022/ALC)UM's research fund(File no.MYRG2022-00241-IAPME,MYRGCRG2022-00009-FHS)+2 种基金the research fund from Wuyi University(EF38/IAPME-XGC/2022/WYU)the Natural Science Foundation of China(61935017,62175268)Science,Technology and Innovation Commission of Shenzhen Municipality(Project Nos.JCYJ20220530113015035,JCYJ20210324120204011,and KQTD2015071710313656).
文摘Metal halide perovskites,particularly the quasi-two-dimensional perovskite subclass,have exhibited considerable potential for next-generation electroluminescent materials for lighting and display.Nevertheless,the presence of defects within these perovskites has a substantial influence on the emission efficiency and durability of the devices.In this study,we revealed a synergistic passivation mechanism on perovskite films by using a dual-functional compound of potassium bromide.The dual functional potassium bromide on the one hand can passivate the defects of halide vacancies with bromine anions and,on the other hand,can screen the charged defects at the grain boundaries with potassium cations.This approach effectively reduces the probability of carriers quenching resulting from charged defects capture and consequently enhances the radiative recombination efficiency of perovskite thin films,leading to a significant enhancement of photoluminescence quantum yield to near-unity values(95%).Meanwhile,the potassium bromide treatment promoted the growth of homogeneous and smooth film,facilitating the charge carrier injection in the devices.Consequently,the perovskite light-emitting diodes based on this strategy achieve a maximum external quantum efficiency of~21%and maximum luminance of~60,000 cd m^(-2).This work provides a deeper insight into the passivation mechanism of ionic compound additives in perovskite with the solution method.
基金Project supported by Beijing Natural Science Foundation,China(Grant No.JQ19004)Beijing Excellent Talents Training Support,China(Grant No.2017000026833ZK11)+8 种基金the National Natural Science Foundation of China(Grant Nos.52025023,51991340,and 51991342)the National Key Research and Development Program of China(Grant Nos.2016YFA0300903 and 2016YFA0300804)the Key R&D Program of Guangdong Province,China(Grant Nos.2019B010931001,2020B010189001,2018B010109009,and 2018B030327001)the Beijing Municipal Science&Technology Commission,China(Grant No.Z191100007219005)the Beijing Graphene Innovation Program(Grant No.Z181100004818003)Bureau of Industry and Information Technology of Shenzhen(Graphene platform 201901161512)Guangdong Innovative and Entrepreneurial Research Team Program(Grant No.2016ZT06D348)the Science,Technology and Innovation Commission of Shenzhen Municipality(Grant No.KYTDPT20181011104202253)the China Postdoctoral Science Foundation(Grant No.2020M680177)。
文摘Nonlinear optical frequency mixing,which describes new frequencies generation by exciting nonlinear materials with intense light field,has drawn vast interests in the field of photonic devices,material characterization,and optical imaging.Investigating and manipulating the nonlinear optical response of target materials lead us to reveal hidden physics and develop applications in optical devices.Here,we report the realization of facile manipulation of nonlinear optical responses in the example system of MoS_(2) monolayer by van der Waals interfacial engineering.We found that,the interfacing of monolayer graphene will weaken the exciton oscillator strength in MoS_(2) monolayer and correspondingly suppress the second harmonic generation(SHG)intensity to 30%under band-gap resonance excitation.While with off-resonance excitation,the SHG intensity would enhance up to 130%,which is conjectured to be induced by the interlayer excitation between MoS_(2) and graphene.Our investigation provides an effective method for controlling nonlinear optical properties of two-dimensional materials and therefore facilitates their future applications in optoelectronic and photonic devices.
基金supported by the National Key Research and Development Program of China(2020YFB1506400)the National Natural Science Foundation of China(51922074,22075194,and 51820105003)+3 种基金the Natural Science Foundation of the Jiangsu Higher Education Institutions of China(20KJA430010)the Tang Scholarthe Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)the Collaborative Innovation Center of Suzhou Nano Science and Technology。