In this study we employed the B3LYP/6-311++G(d,p) method combined with the CIS/6-311++G(d,p) calculation to investigate the effects of the type and the number of alkali metal atoms(Li, Na, K) on the geometric, electro...In this study we employed the B3LYP/6-311++G(d,p) method combined with the CIS/6-311++G(d,p) calculation to investigate the effects of the type and the number of alkali metal atoms(Li, Na, K) on the geometric, electronic, and optical properties of alkali metals substituted into adamantanes. Substituting alkali metal(Li, Na, K)atoms caused significant changes in the electronic and optical properties of adamantane. The Ad-1Li, Ad-1Na,and Ad-1K structures showed a dramatically decreased energy gap and ionization potential, while adding more alkali metal atoms slightly decreased these properties. Substituting more alkali metals led to a shift in the maximum absorption wavelength from the visible to the infrared region, depending on the type of alkali metal atom substituted. The magnitude of shift occurred in the following order: Li b Na b K. These characteristics suggest the possibility of tunable electronic structures of this material for optoelectronic device applications.展开更多
Deep-blue perovskite light-emitting diodes(PeLEDs)based on reduced-dimensional perovskites(RDPs)still face a few challenges including severe trap-assisted nonradiative recombination,sluggish exciton transfer,and undes...Deep-blue perovskite light-emitting diodes(PeLEDs)based on reduced-dimensional perovskites(RDPs)still face a few challenges including severe trap-assisted nonradiative recombination,sluggish exciton transfer,and undesirable bathochromic shift of the electroluminescence spectra,impeding the realization of high-performance PeLEDs.Herein,an in situ chlorination(isCl)post-treatment strategy was employed to regulate phase reconstruction and renovate multiple defects of RDPs,leading to superior carrier cooling of 0.88 ps,extraordinary exciton binding energy of 122.53 meV,and higher photoluminescence quantum yield of 60.9%for RDP films with deep-blue emission at 450 nm.The phase regulation is accomplished via fluorine-derived hydrogen bonds that suppress the formation of small-n phases.Multiple defects,including halide vacancies(shallow-state defects)and lead-chloride antisite defects(deepstate defects),are renovated via C=O coordination and hydroxy-group-derived hydrogen bonds.Consequently,deepblue PeLEDs with a record maximum external quantum efficiency of 6.17%and stable electroluminescence at 454 nm were demonstrated,representing the best-performing deep-blue PeLEDs.展开更多
基金financial support from the Thailand Research Fund and Khon Kaen University [Grant Number MRG5580165]the Higher Education Research Promotion and National Research University Project of Thailand,Office of the Higher Education Commission, through the Advanced Functional Materials Center of Khon Kaen University, Nanotechnology Center (NANOTEC), NSTDA Ministry of Science and Technology, Thailandpartial support from Thailand Center of Excellence in Physics (ThEP)
文摘In this study we employed the B3LYP/6-311++G(d,p) method combined with the CIS/6-311++G(d,p) calculation to investigate the effects of the type and the number of alkali metal atoms(Li, Na, K) on the geometric, electronic, and optical properties of alkali metals substituted into adamantanes. Substituting alkali metal(Li, Na, K)atoms caused significant changes in the electronic and optical properties of adamantane. The Ad-1Li, Ad-1Na,and Ad-1K structures showed a dramatically decreased energy gap and ionization potential, while adding more alkali metal atoms slightly decreased these properties. Substituting more alkali metals led to a shift in the maximum absorption wavelength from the visible to the infrared region, depending on the type of alkali metal atom substituted. The magnitude of shift occurred in the following order: Li b Na b K. These characteristics suggest the possibility of tunable electronic structures of this material for optoelectronic device applications.
基金supported by the following grants:the National Youth Science Funds of China(Grant No.52302172)the Key Program of the National Natural Science Foundation of China(Grant No.52032004)+2 种基金the National Natural Science Foundation of China(Grant No.21902135,92056204)Y.B.Zhao would like to acknowledge the support of the National Natural Science Foundation of China(Grant No.61905206,12364054,and 11804294)Besides,we extend gratitude to the Theoretical and Computational Chemistry Team from Shiyanjia Lab for providing invaluable assistance(www.shiyanjia.com).
文摘Deep-blue perovskite light-emitting diodes(PeLEDs)based on reduced-dimensional perovskites(RDPs)still face a few challenges including severe trap-assisted nonradiative recombination,sluggish exciton transfer,and undesirable bathochromic shift of the electroluminescence spectra,impeding the realization of high-performance PeLEDs.Herein,an in situ chlorination(isCl)post-treatment strategy was employed to regulate phase reconstruction and renovate multiple defects of RDPs,leading to superior carrier cooling of 0.88 ps,extraordinary exciton binding energy of 122.53 meV,and higher photoluminescence quantum yield of 60.9%for RDP films with deep-blue emission at 450 nm.The phase regulation is accomplished via fluorine-derived hydrogen bonds that suppress the formation of small-n phases.Multiple defects,including halide vacancies(shallow-state defects)and lead-chloride antisite defects(deepstate defects),are renovated via C=O coordination and hydroxy-group-derived hydrogen bonds.Consequently,deepblue PeLEDs with a record maximum external quantum efficiency of 6.17%and stable electroluminescence at 454 nm were demonstrated,representing the best-performing deep-blue PeLEDs.
