Single‐Crystalline Optical Microcavities from Luminescent Dendrimers

Abstract

Microcrystallites are promising minute mirrorless laser sources. A variety of luminescent organic compounds have been exploited along this line, but dendrimers have been inapplicable owing to their fragility and extremely poor crystallinity. Now, a dendrimer family that overcomes these difficulties is presented. First‐, second‐, and third‐generation carbazole (Cz) dendrimers with a carbon‐bridged oligo(phenylenevinylene) (COPV2) core (GnCOPV2, n=1–3) assemble to form microcrystals. The COPV2 cores align uni/bidirectionally in the crystals while the Cz units in G2‐ and G3COPV2 align omnidirectionally. The dendrons work as light‐harvesting antennas that absorb non‐polarized light and transfer it to the COPV2 core, from which a polarized luminescence radiates. Furthermore, these crystals act as laser resonators, where the lasing thresholds are strongly coupled with the crystal morphology and the orientation of COPV2, which is in contrast with the conventional amorphous dendrimers.

Superkinetic Growth of Oval Organic Semiconductor Microcrystals for Chaotic Lasing

“…[ 1–4 ] Mesoscopic semiconductor crystals are particularly appealing for the realization of active photonic devices because they combine excellent luminescent and optical properties via dense atomic/molecular packing with very few defects and impurities. [ 5–8 ] So far, a wide variety of mesoscopic semiconductor crystals have been synthesized from the bottom‐up, such as 1D nanowires, [ 9–13 ] nanorods, [ 14 ] and nanoribbons, [ 15,16 ] and 2D microdisks [ 17–20 ] and microplates. [ 21,22 ] With the capability of confining and guiding light, these regular semiconductor micro/nanocrystals naturally form active waveguides and microcavities, [ 23,24 ] which are basic elements for various functional photonic systems.…”

“…DOI: 10.1002/adma.202100484 atomic/molecular packing with very few defects and impurities. [5][6][7][8] So far, a wide variety of mesoscopic semiconductor crystals have been synthesized from the bottom-up, such as 1D nanowires, [9][10][11][12][13] nanorods, [14] and nanoribbons, [15,16] and 2D microdisks [17][18][19][20] and microplates. [21,22] With the capability of confining and guiding light, these regular semiconductor micro/nanocrystals naturally form active waveguides and microcavities, [23,24] which are basic elements for various functional photonic systems.…”

Long-wavelength visible to near infrared photoluminescence from carbon-bridged styrylstilbene and thiadiazole conjugates in organic and aqueous media

“…The strong emission of COPVs in the visible region and their utility as active materials in organic lasers have been demonstrated. [19][20][21][22][23][24][25][26] These compounds also exhibit relatively high HOMO energy levels, which make them suitable as energy donors. 27,28 Herein, we report conjugates of carbon-bridged styrylstilbene (COPV2) and benzo-or naphtho-fused thiadiazole [29][30][31] (Fig.…”

Recent Advances in Organic Whispering‐Gallery Mode Lasers

“…[30] Up to date, a wide range of material candidates have been adopted to fabricate WGM lasers, including inorganic semiconductors, [31][32][33] quantum dots, [34][35][36][37] perovskites, [6,38,39] and organic compounds. [23,24,[40][41][42] Typically, organic materials have various complementary merits compared to their counterparts. The abundant excited-state photophysical and photochemical process endow organic materials with high tunability in photoluminescence (PL) spectra.…”