Optically pumped lasing in a single crystal cavity of thiophene/phenylene co-oligomers grown via improved crystal growth methods in solution

Abstract

Single crystals of thiophene/phenylene co–oligomers (TPCOs) are promising organic laser media. Owing to their poor solubility in solvents, single crystals of TPCOs have conventionally been grown using sublimation processes. However, the morphology of the grown crystals is not ideal for lasing by the self-cavity effect. In this report, single crystals of 5,5’’’–bis(4-biphenylyl)–2,2’:5’,2’’:5’’,2’’’–quaterthiophene (BP4T), which is one of the longest TPCOs, are grown through improved methods in solution to achieve lasing with a well-shaped single crystal cavity. The high quality factors (5.9×10^3) and group refractive indexes (> 3.5) suggest that obtained crystals are ideal organic laser media.

Lasing in Low-Dimensional Crystals of a Fumaronitrile-Based Luminogen

“…Although PICs generally require complicated device construction techniques based on microfabrication, organic molecules possess the potential to construct device components through self-assembly processes. Single crystals of organic π-conjugated molecules that function as optical waveguides, cavities, and lasers have been developed as PIC components that exhibit unique functions for use in information technology. − For example, single-mode lasing has been demonstrated in a heterojunction structure constructed via a self-assembly process. , Lasing under optical pumping has been observed from organic single crystals with a high photoluminescence quantum efficiency (Φ PL ). The lasing behavior depends on the morphology of the organic single crystals.…”

Efficient optical waveguiding and lasing in needle crystals of thiophene/phenylene co-oligomers grown in solution

“…Organic single crystals of light-emitting π-conjugated molecules are expected to be suitable for constructing components for miniaturized and highly efficient optical devices, even using bottom-up fabrication processes. Their application in optical waveguides (OWGs), [1][2][3][4][5][6][7][8][9][10][11][12][13][14] cavities, 7,13,[15][16][17] and lasing, [16][17][18][19][20][21][22][23][24][25][26] has been reported recently. Moreover, hetero-structures consisting of several organic single crystals and highly aligned structures on substrates have been constructed for practical applications in optical circuits.…”

“…30) Optically pumped lasing and amplified spontaneous emission have been observed for a variety of TPCOs, as well as lasing based on stimulated resonance Raman scattering or the formation of exciton polaritons. [19][20][21][22][23] Although TPCOs possess superior optoelectronic characteristics as mentioned, these molecules have a large number of thiophene or phenylene units (more than four units), and large π-conjugated molecules are generally hardly soluble in any organic solvents. Instead, TPCOs have conventionally been grown in the vapor phase.…”

“…To obtain TPCO crystals in the solution phase, some techniques such as the mini-emulsion method or the high temperature growth method have been reported. 20,[31][32][33][34] However, there are only a few examples of obtaining TPCO crystals in the solution phase, and morphological control of the crystals has hardly been achieved. Organic crystals generally grow via kinetic processes in the vapor phase or thermodynamic processes in the solution phase, which lead to various functional materials based on various polymorphs or crystal topologies.…”