Electrically Switchable Amplified Spontaneous Emission from Liquid Crystalline Phase of an AIEE‐Active ESIPT Molecule

Abstract

Use of organic molecules as lasing media has much potential to develop next‐generation optical devices as soft‐matter photonics with wideband tunability and large coherence area. Although mirrorless lasing was theoretically predicted and practically demonstrated in helical cholesteric liquid crystalline (LC) phases of organic compounds, recent studies on optical confinement have been much focused into hard‐crystalline phases of the molecules. Aggregation‐induced emission (AIE) and enhancement (AIEE) provides one of the optimal molecular systems for light amplification in condensed phases, and herein AIEE activity and excited‐state intramolecular proton transfer (ESIPT) are successfully coupled in a room temperature (RT) nematic LC. Suppressing the effect of concentration quenching/self‐absorption and attaining four‐level system for population inversion by the combination of AIEE and ESIPT in LC phases, lead to the amplified spontaneous emission (ASE) from a newly designed molecule: C5Ph‐HBT dispersed in RT LC matrix with the pumping energy threshold of 20 mJ cm–2. Moreover, the nematic LC allows the orientation of the molecular dipoles in response to external electric fields. Hence, the fluorescence as well as the ASE switching is attained at RT, demonstrating the potential of these composite materials as “switchable” ASE media for technological progress.

Dendritic‐Like Molecules Built on a Pillar[5]arene Core as Hole Transporting Materials for Perovskite Solar Cells

“…To evaluate their potential as HTM, the hole mobility was examined by flash-photolysis time resolved microwave conductivity (FP-TRMC) measurements with spiro-OMeTAD as a reference. [30,31] Clear and competitive signature of electrical conductivity transients were observed for both PA02 and PA03, relative to spiro-OMeTAD, as depicted in Figure 4. The results obtained for spiro-OMeTAD are shown in Figure S11.…”

“…The potential application of PA02 and PA03 as optoelectronic materials is supported by their transparent nature in the visible spectrum as well as the appropriate HOMO levels. To evaluate their potential as HTM, the hole mobility was examined by flash‐photolysis time resolved microwave conductivity (FP‐TRMC) measurements with spiro‐OMeTAD as a reference [30,31] . Clear and competitive signature of electrical conductivity transients were observed for both PA02 and PA03 , relative to spiro‐OMeTAD, as depicted in Figure 4.…”

Excited-State Intramolecular Proton Transfer: A Short Introductory Review

“…Probe molecules in various biological systems, based on this mechanism, have also been suggested recently [ 10 , 11 ]. Moreover, ESIPT systems have found applicability in sensors for humidity [ 12 , 13 ], luminescent solar collectors [ 14 ], proton transfer lasers [ 15 , 16 , 17 , 18 , 19 ], photo stabilizers [ 20 ], devices based on thermally activated delayed fluorescence [ 21 , 22 ], white light generation [ 23 , 24 , 25 ], organic light-emitting diodes (WOLED) [ 26 ] as well as suitability in sensing of anion and cations [ 27 , 28 , 29 , 30 ], photochromic switching [ 31 , 32 ] and even understanding of fading of colorants in art [ 33 ].…”

2,6‐Dicarbonitrile Diphenyl‐1λ5‐Phosphinine (DCNP)—A Robust Conjugated Building Block for Multi‐Functional Dyes Exhibiting Tunable Amplified Spontaneous Emission

“…While the pioneering work of organic molecule-based lasers was demonstrated by Sorokin and Lankard in 1966, [1,2] recent advanced studies on organic thin-film based laser devices have been extensively investigated owing to their outstanding merits such as solution processing, mechanical flexibility, lightweight, and the feasibility of spectral tuning through the fine modification of chemical structures. [3][4][5][6][7][8][9] As pursuing the color-tuning capability has promising implications in the fields of ultimate laser display techniques with full-color gamut, biological imaging, as well as wide-range sensing applications, a concerted effort has been devoted to exploiting the effective colorcontrolled strategies for covering the whole spectral regime from violet to nearinfrared (NIR) emission. [6,[10][11][12][13][14][15] On the other hand, diverse categories of organic gain media based on specific molecular cores correspond to the limited spectral regime even by modifying various functional moieties and substituents.…”