Tetraphenylethene(TPE),a star building block with promising aggregationinduced emission,has received much interest.Given that its intramolecular Woodward-Hoffmann cyclic intermediate instantaneously converts back to t...Tetraphenylethene(TPE),a star building block with promising aggregationinduced emission,has received much interest.Given that its intramolecular Woodward-Hoffmann cyclic intermediate instantaneously converts back to the original state within several picoseconds,the essentially photochromic characteristic of TPE is little investigated.Achieving a visible photocyclization of TPE is still an unsolved issue and considered as the bottleneck in the further advancement of applications.We report a strategy of attaching carbonate ester onto the TPE skeleton(TPE-4C)to enhance TPE photocyclization stability.As demonstrated,the incorporated cholesteryloxycarbonyloxy substituents in TPE-4C can increase the energy barrier for cycloreversion,thereby exhibiting extremely thermal stability of photocyclic intermediate upon UV irradiation,prolonging its lifetime from 63 picoseconds to 46 s by 7.2×10^(11)-fold.The photoinduced cyclization of TPE-4C could be monitored with naked eyes,and the photocyclization/cycloreversion is achieved by turning on/off UV light along with a relative fatigue resistance.Encapsulation of TPE-4C into the liquid crystal can induce a striking phase transformation(achiral↔chiral),which can be applicable to encode optical information.Employing carbonate ester into the TPE unit plays a vital role in enhancing the unprecedented TPE photocyclization stability,providing a toolbox to allow TPE-based photocyclization to be visually monitored.展开更多
Perovskite nanocrystals （NCs） have strong nonlinear optical responses with a number of potential applications, ranging from upconverted blue-lasing to the tagging of specific cellular components in multicolor fluore...Perovskite nanocrystals （NCs） have strong nonlinear optical responses with a number of potential applications, ranging from upconverted blue-lasing to the tagging of specific cellular components in multicolor fluorescence microscopy. Here, we determine the one-photon linear absorption cross section of two kinds of blue-emitting perovskite NCs, i.e., CsPbCl3 and CsPb（C10.53Br0.47）3, by utilizing femtosecond transient absorption spectroscopy. The wavelength-dependent nonlinear refraction and two-photon absorption have been measured at wavelengths from 620 to 720 nm by performing Z-scan measurements. The nonlinear optical responses of CsPb（C10.53Br0.47）3 are much more pronounced than those of CsPbCl3 due to the larger structural destahilization of the former.展开更多
In this work,one kind of typeⅡZnSe/CdS/ZnS core/shell/shell nanocrystals(NCs)is synthesized,and their linear and nonlinear photophysical properties are investigated.Through measurements of the temperaturedependent ph...In this work,one kind of typeⅡZnSe/CdS/ZnS core/shell/shell nanocrystals(NCs)is synthesized,and their linear and nonlinear photophysical properties are investigated.Through measurements of the temperaturedependent photoluminescence spectra of NCs,their excitonic properties,including the coefficient of the bandgap change,coupling strength of the exciton acoustic phonons,exciton longitudinal optical(LO)phonons,and LO–phonon energy are revealed.Femtosecond transient absorption spectroscopy was employed to obtain insight into ultrafast processes occurring at the interface of ZnSe and CdS,such as those involving the injection of photoinduced electrons into the CdS shell,interfacial state bleaching,and charge separation time.At the end,their multiphoton absorption spectra were determined by using the z-scan technique,which yielded a maximum twophoton absorption cross section of 3717 GM at 820 nm and three-photon absorption cross section up to 3.9×10^-77cm^6·s^2·photon^-2at 1220 nm,respectively.The photophysical properties presented here may be important for exploiting their relevant applications in optoelectronic devices and deep-tissue bioimaging.展开更多
We have studied the two-and three-photon absorption(2PA and 3PA) properties of Mn-doped CsPbCl_3 twodimensional nanoplatelets(2D NPs) and cubic nanocrystals. Compared with their cubic counterparts, the Mn-doped 2D NPs...We have studied the two-and three-photon absorption(2PA and 3PA) properties of Mn-doped CsPbCl_3 twodimensional nanoplatelets(2D NPs) and cubic nanocrystals. Compared with their cubic counterparts, the Mn-doped 2D NPs exhibit stronger quantum confinement effects that can more efficiently enhance their dopantcarrier exchange interactions and multiphoton absorption. More specifically, the maximum volume-normalized 2PA and 3PA cross sections of the 2D NPs were 6.8 and 7.2 times greater than those of their cubic counterparts,respectively, reaching up to 1237 GM∕nm^3 in the visible light band and 2.24 × 10^(-78) cm^6· s^2· photon^(-2)∕nm^3 in the second biological window, respectively.展开更多
基金supported by NSFC/China(21788102,21636002,21622602,21875143,21908146,and 21908060)Shanghai Municipal Science and Technology Major Project(2018SHZDZX03)+3 种基金Innovation Program of Shanghai Municipal Education Commission,Scientific Committee of Shanghai(15XD1501400)Programme of Introducing Talents of Discipline to Universities(B16017)China Postdoctoral Science Foundation(2019M651417)Innovation Research Foundation of Shenzhen(JCYJ20180507182229597).
文摘Tetraphenylethene(TPE),a star building block with promising aggregationinduced emission,has received much interest.Given that its intramolecular Woodward-Hoffmann cyclic intermediate instantaneously converts back to the original state within several picoseconds,the essentially photochromic characteristic of TPE is little investigated.Achieving a visible photocyclization of TPE is still an unsolved issue and considered as the bottleneck in the further advancement of applications.We report a strategy of attaching carbonate ester onto the TPE skeleton(TPE-4C)to enhance TPE photocyclization stability.As demonstrated,the incorporated cholesteryloxycarbonyloxy substituents in TPE-4C can increase the energy barrier for cycloreversion,thereby exhibiting extremely thermal stability of photocyclic intermediate upon UV irradiation,prolonging its lifetime from 63 picoseconds to 46 s by 7.2×10^(11)-fold.The photoinduced cyclization of TPE-4C could be monitored with naked eyes,and the photocyclization/cycloreversion is achieved by turning on/off UV light along with a relative fatigue resistance.Encapsulation of TPE-4C into the liquid crystal can induce a striking phase transformation(achiral↔chiral),which can be applicable to encode optical information.Employing carbonate ester into the TPE unit plays a vital role in enhancing the unprecedented TPE photocyclization stability,providing a toolbox to allow TPE-based photocyclization to be visually monitored.
基金Shenzhen Basic Research Project of Science and Technology(JCYJ2015032414171163,JCYJ20170302142433007)National Natural Science Foundation of China(NSFC)(11404092,11404219,11574130)
文摘Perovskite nanocrystals （NCs） have strong nonlinear optical responses with a number of potential applications, ranging from upconverted blue-lasing to the tagging of specific cellular components in multicolor fluorescence microscopy. Here, we determine the one-photon linear absorption cross section of two kinds of blue-emitting perovskite NCs, i.e., CsPbCl3 and CsPb（C10.53Br0.47）3, by utilizing femtosecond transient absorption spectroscopy. The wavelength-dependent nonlinear refraction and two-photon absorption have been measured at wavelengths from 620 to 720 nm by performing Z-scan measurements. The nonlinear optical responses of CsPb（C10.53Br0.47）3 are much more pronounced than those of CsPbCl3 due to the larger structural destahilization of the former.
基金Natural Science Foundation of Guangdong Province(2018A030310637,2019A1515012094)Department of Education of Guangdong Province(2018KTSCX19)。
文摘In this work,one kind of typeⅡZnSe/CdS/ZnS core/shell/shell nanocrystals(NCs)is synthesized,and their linear and nonlinear photophysical properties are investigated.Through measurements of the temperaturedependent photoluminescence spectra of NCs,their excitonic properties,including the coefficient of the bandgap change,coupling strength of the exciton acoustic phonons,exciton longitudinal optical(LO)phonons,and LO–phonon energy are revealed.Femtosecond transient absorption spectroscopy was employed to obtain insight into ultrafast processes occurring at the interface of ZnSe and CdS,such as those involving the injection of photoinduced electrons into the CdS shell,interfacial state bleaching,and charge separation time.At the end,their multiphoton absorption spectra were determined by using the z-scan technique,which yielded a maximum twophoton absorption cross section of 3717 GM at 820 nm and three-photon absorption cross section up to 3.9×10^-77cm^6·s^2·photon^-2at 1220 nm,respectively.The photophysical properties presented here may be important for exploiting their relevant applications in optoelectronic devices and deep-tissue bioimaging.
基金Shenzhen Basic Research Project of Science and Technology(JCYJ20150324141711581,JCYJ20170302142433007)Postgraduate Innovation Development Fund Project of Shenzhen University(PIDFPZR2018007)
文摘We have studied the two-and three-photon absorption(2PA and 3PA) properties of Mn-doped CsPbCl_3 twodimensional nanoplatelets(2D NPs) and cubic nanocrystals. Compared with their cubic counterparts, the Mn-doped 2D NPs exhibit stronger quantum confinement effects that can more efficiently enhance their dopantcarrier exchange interactions and multiphoton absorption. More specifically, the maximum volume-normalized 2PA and 3PA cross sections of the 2D NPs were 6.8 and 7.2 times greater than those of their cubic counterparts,respectively, reaching up to 1237 GM∕nm^3 in the visible light band and 2.24 × 10^(-78) cm^6· s^2· photon^(-2)∕nm^3 in the second biological window, respectively.
