Low‐Threshold Non‐Doped Deep Blue Lasing from Monodisperse Truxene‐Cored Conjugated Starbursts with High Photostability

Abstract

Herein, the photophysical, morphological, optical gain characteristics of a set of trigonal monodisperse starburst conjugated macromolecules (Tr1‐Tr4) have been systematically investigated in order to elucidate the influence of the molecular structures on their optoelectronic performance. With increasing the oligofluorene arm length, absorption spectra were red‐shifted progressively, whereas an increase in photoluminescence quantum yields (PLQYs) and optical gain coefficients, and a corresponding reduction in amplified spontaneous emission (ASE) thresholds and loss coefficients were observed for Tr1‐Tr3 except for Tr4. The results indicate that the effective conjugation length become saturated for Tr3 in this system. Impressively, the resulting molecules manifested very low ASE thresholds (4.4–11.6 μJ cm−2) with high photostability, as well as high thermal stability. One dimensional distributed feedback (DFB) lasers exhibited a minimum lasing threshold of 10.38 nJ pulse−1 (0.86 kW cm−2, 4.325 μJ cm−2) for Tr3. It should be emphasized that the ASE threshold of Tr1‐Tr4 was nearly unchanged from room temperature to 200 °C. The results suggest that this kind of truxene‐cored conjugated starbursts with high photostability and low lasing thresholds are rather promising gain media for organic semiconductor lasers.

From truxenes to heterotruxenes: playing with heteroatoms and the symmetry of molecules

“…148,149 35b has also been tested for amplified spontaneous emission (ASE). 150,151 Similar truxene structures substituted by oligofluorenes 152 and oligofluorenes terminated with pyrenes 153 or diphenylamines 154,155 were tested in a blue laser. The nonlinear properties of truxenes 35b and e reveal significant twophoton absorption (TPA).…”

Quotient of quotient graph a novel approach to compute π‐conjugated dendrimer and predict its properties

“…Conjugated starburst molecules have received particular attention due to their well‐defined structures, high photoluminescence quantum yields, outstanding thermal stability, and excellent optoelectronic properties [2]. Various conjugated starburst materials with various cores, including truxene, pyrene, and triazatruxene have been designed and synthesized to demonstrate effective electroluminescence [3].…”

Effect of structural modifications on the spectral and lasing characteristics of truxene-cored starbursts with/without diphenylamine end-cappers

“…The two key principles in the design and synthesis of typical starburst emitters are as follows [24]. First, the highly rigid core, such as truxene [25][26][27], benzene [28], 1,3,5-triazines [29][30][31], pyrene [32][33][34], and heteroatoms [35], was used to construct starburst dendritic structures to decrease the strong intermolecular interactions and reduce fluorescence quenching. Second, various electroactive moieties [19,36] (diphenylbenzene, naphthalene, or arylamine) were incorporated at the peripheries of the core to increase the solubility in common organic solvents, affect the carrier transport process, and increase the thermal and spectral stability.…”