Quaternary Ag-In-Ga-S(AIGS)quantum dot(QD)is considered a promising,spectral-tunable,and environmentally friendly luminescent display material.However,the more complex surface defect states of AIGS QDs resulting from ...Quaternary Ag-In-Ga-S(AIGS)quantum dot(QD)is considered a promising,spectral-tunable,and environmentally friendly luminescent display material.However,the more complex surface defect states of AIGS QDs resulting from the coexistence of multiple elements lead to a low(<60%)photoluminescence quantum yield(PLQY).Here,we develop a novel convenient method to introduce Z-type ligands ZnX_(2)(X=Cl,Br,I)for passivating the surface defects of AIGS QDs to dramatically enhance the PLQY and stability without affecting the crystalline structure and morphology.Results show that the addition of ZnCl_(2) during the purified process of AIGS QDs leads to a 3-fold increase of PLQY(from 28.5% to 87%).Impressively,the highest PLQY is up to a recorded value of 92%,which is comparable to typical heavy metal QDs.Exciton dynamics studies have shown that the rapid annihilation process of excitons in treated QDs is inhibited.We also confirm that the improvement in PLQY is a result of the effective passivation of the non-coordinating atom on the QD surface by building a new bonding between sulfur dangling and Zn2+.The realization of high PLQY will further promote the application of AIGS QDs in luminescent displays.展开更多
Ag-In-Ga-S(AIGS)quantum dots(QDs)have recently attracted great interests due to the outstanding optical properties and eco-friendly components,which are considered as an alternative replacement for toxic Pb-and Cd-bas...Ag-In-Ga-S(AIGS)quantum dots(QDs)have recently attracted great interests due to the outstanding optical properties and eco-friendly components,which are considered as an alternative replacement for toxic Pb-and Cd-based QDs.However,enormous attention has been paid to how to narrow their broadband spectra,ignoring the application advantages of the broadband emission.In this work,the AIGS QDs with controllable broad green-red dual-emission are first reported,which is achieved through adjusting the size distribution of QDs by controlling the nucleation and growth of AIGS crystals.Resultantly,the AIGS QDs exhibit broad dual-emission at green-and red-band evidenced by photoluminescence(PL)spectra,and the PL relative intensity and peak position can be finely adjusted.Furthermore,the dual-emission is the intrinsic characteristics from the difference in confinement effect of large particles and tiny particles confirmed by temperature-dependent PL spectra.Accordingly,the AIGS QDs(the size consists of 17 nm and 3.7 nm)with 530 nm and 630 nm emission could successfully be synthesized at 220°C.By combining the blue light-emitting diode(LED)chips and dual-emission AIGS QDs,the constructed white light-emitting devices(WLEDs)exhibit a continuous and broad spectrum like natural sunlight with the Commission Internationale de l’Eclairage(CIE)chromaticity coordinates of(0.33,0.31),a correlated color temperature(CCT)of 5425 K,color rendering index(CRI)of 90,and luminous efficacy of radiation(LER)of 129 lm/W,which indicates that the AIGS QDs have huge potential for lighting applications.展开更多
基金supported by the National Natural Science Foundation of China(Nos.62374089,61904081 and 51672132)the Natural Science Foundation of Jiangsu Province(No.BK20190449)+1 种基金the Postdoctoral Research Funding Program of Jiangsu Province(No.2020Z144)the Fundamental Research Funds for the Central Universities(No.30923010928).
文摘Quaternary Ag-In-Ga-S(AIGS)quantum dot(QD)is considered a promising,spectral-tunable,and environmentally friendly luminescent display material.However,the more complex surface defect states of AIGS QDs resulting from the coexistence of multiple elements lead to a low(<60%)photoluminescence quantum yield(PLQY).Here,we develop a novel convenient method to introduce Z-type ligands ZnX_(2)(X=Cl,Br,I)for passivating the surface defects of AIGS QDs to dramatically enhance the PLQY and stability without affecting the crystalline structure and morphology.Results show that the addition of ZnCl_(2) during the purified process of AIGS QDs leads to a 3-fold increase of PLQY(from 28.5% to 87%).Impressively,the highest PLQY is up to a recorded value of 92%,which is comparable to typical heavy metal QDs.Exciton dynamics studies have shown that the rapid annihilation process of excitons in treated QDs is inhibited.We also confirm that the improvement in PLQY is a result of the effective passivation of the non-coordinating atom on the QD surface by building a new bonding between sulfur dangling and Zn2+.The realization of high PLQY will further promote the application of AIGS QDs in luminescent displays.
基金supported by National Natural Science Foundation of China(Grant Nos.52272166,22205214,and 12204427).
文摘Ag-In-Ga-S(AIGS)quantum dots(QDs)have recently attracted great interests due to the outstanding optical properties and eco-friendly components,which are considered as an alternative replacement for toxic Pb-and Cd-based QDs.However,enormous attention has been paid to how to narrow their broadband spectra,ignoring the application advantages of the broadband emission.In this work,the AIGS QDs with controllable broad green-red dual-emission are first reported,which is achieved through adjusting the size distribution of QDs by controlling the nucleation and growth of AIGS crystals.Resultantly,the AIGS QDs exhibit broad dual-emission at green-and red-band evidenced by photoluminescence(PL)spectra,and the PL relative intensity and peak position can be finely adjusted.Furthermore,the dual-emission is the intrinsic characteristics from the difference in confinement effect of large particles and tiny particles confirmed by temperature-dependent PL spectra.Accordingly,the AIGS QDs(the size consists of 17 nm and 3.7 nm)with 530 nm and 630 nm emission could successfully be synthesized at 220°C.By combining the blue light-emitting diode(LED)chips and dual-emission AIGS QDs,the constructed white light-emitting devices(WLEDs)exhibit a continuous and broad spectrum like natural sunlight with the Commission Internationale de l’Eclairage(CIE)chromaticity coordinates of(0.33,0.31),a correlated color temperature(CCT)of 5425 K,color rendering index(CRI)of 90,and luminous efficacy of radiation(LER)of 129 lm/W,which indicates that the AIGS QDs have huge potential for lighting applications.
