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12 May 06:18

Low-Threshold Wavelength-Switchable Organic Nanowire Lasers Based on Excited-State Intramolecular Proton Transfer

by Wei Zhang, Yongli Yan, Jianmin Gu, Jiannian Yao, Yong Sheng Zhao

Abstract

Coherent light signals generated at the nanoscale are crucial to the realization of photonic integrated circuits. Self-assembled nanowires from organic dyes can provide both a gain medium and an effective resonant cavity, which have been utilized for fulfilling miniaturized lasers. Excited-state intramolecular proton transfer (ESIPT), a classical molecular photoisomerization process, can be used to build a typical four-level system, which is more favorable for population inversion. Low-power driven lasing in proton-transfer molecular nanowires with an optimized ESIPT energy-level process has been achieved. With high gain and low loss from the ESIPT, the wires can be applied as effective FP-type resonators, which generated single-mode lasing with a very low threshold. The lasing wavelength can be reversibly switched based on a conformation conversion of the excited keto form in the ESIPT process.

Thumbnail image of graphical abstract

Low-threshold single-mode lasing was achieved via excited-state intramolecular proton transfer (ESIPT)-assisted population inversion in crystal organic nanowires fabricated by the self-assembly of proton-transfer dye molecules. The lasing wavelength can be reversibly switched based on the photoinduced conformation conversion of the excited keto form in the ESIPT process.

09 May 03:12

Remarkable and Crystal-Structure-Dependent Piezoelectric and Piezoresistive Effects of InAs Nanowires

by Xing Li, Xianlong Wei, Tingting Xu, Dong Pan, Jianhua Zhao, Qing Chen
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The piezoelectric and piezoresistive effects of InAs nanowires are experimentally demonstrated for the first time and are observed to strongly depend on the NW crystal structure. While single-crystalline 〈0001〉 oriented wurtzite nano­wires exhibit remarkable piezoelectric and piezoresistive effects, they are negligible in single-crystalline wurtzite inline image, zinc blende 〈011〉, 〈103〉, inline image oriented nanowires, and significantly suppressed by the presence of stacking faults.