Fabrication and characterization of vertical microcavities containing a submicron particle film of 5,5′-di(4-biphenylyl)-2,2′-bithiophene

Abstract

We show the first experimental evidence that submicron particles (diameter: approximately 400 nm) using 5,5′-di(4-biphenylyl)-2,2′-bithiophene (BP2T) prepared by a miniemulsion technique are effective active media for vertical microcavities. Selected area electron diffraction patterns confirm that crystalline BP2T submicron particles are obtained. In a distributed Bragg reflector-Au microcavity with BP2T submicron particles embedded in a poly(vinyl alcohol) (PVA) matrix (thickness: ∼780 nm), gain-narrowed emissions are observed at the 0–3 emission band of BP2T above an excitation density of 107 μJ cm−2. The light amplification of 0–3 photoluminescence band obtained in the present study demonstrates that the PVA film containing the BP2T submicron particles is useful as an active medium for microcavities.

Observation of Size‐Dependent Optical Properties Based on Surface and Quantum Effects in Nanocrystals of 5,5′‐Bis(4‐Biphenylyl)‐2,2′‐Bithiophene

“…BP2T nanocrystals were prepared using a modified miniemulsion technique. [ 21 ] By adjusting the amount of sodium dodecyl sulfate (SDS) (C 12 H 25 NaO 4 S), which is a surfactant and BP2T powder, nanocrystals with sizes ranging from ≈100 to 1000 nm were prepared. The molecular structure of BP2T is shown in Figure a.…”

“…[17] Especially for organic nanocrystals, although the origin of spectral shifts has been attributed to surface effects such as lattice softening, [1][2][3]7,10,13,17] the details of the influence of surface effects on the size-dependent optical properties are not yet understood. In this article, we report the observation of absorption and photoluminescence (PL) blue-shifts in nanocrystals with decreasing crystal size using 5,5 0 -bis(4-biphenylyl)-2,2 0 -bithiophene (BP2T or PPTTPP), [21,29,30] which is a species of thiophene/ phenylene co-oligomer (TPCO). [21,[29][30][31][32][33][34][35][36][37][38][39][40] The impact of the surface effects and quantum effects (internal effects) on the BP2T nanocrystals were investigated.…”

“…In this article, we report the observation of absorption and photoluminescence (PL) blue-shifts in nanocrystals with decreasing crystal size using 5,5 0 -bis(4-biphenylyl)-2,2 0 -bithiophene (BP2T or PPTTPP), [21,29,30] which is a species of thiophene/ phenylene co-oligomer (TPCO). [21,[29][30][31][32][33][34][35][36][37][38][39][40] The impact of the surface effects and quantum effects (internal effects) on the BP2T nanocrystals were investigated. Moreover, the rarely reported light amplification properties in organic nanocrystals has been demonstrated using BP2T nanocrystals.…”

“…The size‐dependent spectroscopic behavior of organic molecular nanoparticles/nanocrystals provides considerable versatility and flexibility in the design and fabrication of optoelectronic devices. [ 1–21 ] The size‐dependent optical properties of organic crystals have not yet been investigated in sufficient detail compared to those of inorganic crystals. [ 22–24 ] Therefore, the need for enhancing our understanding of the optical properties, such as surface and quantum effects, including quantum confinement effects manifesting in the organic nanocrystals, [ 22–24 ] leads to the stimulation of novel nanoscience studies.…”

Polymorph- and molecular alignment-dependent lasing behaviors of a cyano-substituted thiophene/phenylene co-oligomer

“…Meanwhile, the occurrence of aggregation-induced emission and aggregation quenching (concentration quenching) has been reported in many organic crystals and aggregates. 14 Among various organic crystals, single crystals of thiophene/ phenylene co-oligomers (TPCOs) 21,[34][35][36][37][38][39][40][41][42][43][44][45][46][47][48] exhibit high PLQYs ranging from 40 to 63% even in the solid state. To develop high-performance organic lasers and organic light-emitting devices, materials that exhibit high PLQYs, irrespective of conformational and molecular packing changes, are required.…”