Self‐Waveguided Photoemission and Lasing of Organic Crystalline Wires Obtained by an Improved Expitaxial Growth Method

Abstract

Self‐cavity lasing from organic crystalline wires of a thiophene/phenylene co‐oligomer (BP3T), which is clearly evident in the inset spectrum (see picture), is reported. The BP3T crystalline wires show self‐waveguided photoluminescence with a high internal quantum efficiency of photoluminescence. The efficiency at 300 K is estimated to be 0.8. The crystalline wires are epitaxially grown on KCl substrates using an improved growth technique.

High Mobility and Luminescent Efficiency in Organic Single‐Crystal Light‐Emitting Transistors

“…They are also comparable to those of ambipolar single-crystal LETs made from tetracene [19] and rubrene, [20] which have PL efficiencies of less than 1% (Table 1). In contrast, with a reported PL efficiency of 80% in the form of a single crystal, [10] the BP3T single-crystal LETs can achieve both high-mobility ambipolar transport and high PL efficiency. Encouragingly, it opens the possibility for realizing ambipolar LETs based on highly luminescent single crystals, with current densities in the order of hundreds or thousands of amperes per square centimeter, as performed by rubrene and tetracene [20] single-crystal LETs.…”

“…These emission characteristics are clearly depicted in Figure 3 and were consistent with those observed by photoexcitation. [10,13] The propagated emission along the wide crystal plane was detected by tilting the microscope, so that its axis became parallel with the crystal plane (Fig. 4).…”

“…[10] Several reports have demonstrated that BP3T in the form of amorphous thin films can be used for LETs in ambipolar devices [11] and single-crystal unipolar transistor devices; [12] the latter having hole mobilities up to the order of 10 À1 cm 2 V À1 s À1 .…”

The effect of thiophene sequence separation on air-stable organic thin-film transistor materials

“…Thiophene oligomers, which consist of several thiophene rings, have been reported to have charge carrier mobilities comparable to that of amorphous silicon [8][9][10][11]. Research has also been done on improving their electrical characteristics using crystal growth [12,13] including by self-assembly from solution [14]. Thiophene oligomers are also known as good photonic materials due to their excellent π-conjugation [15,16].…”

Synthesis of functionalized thiophene/phenyl co-oligomers by direct arylation of thiophenes

“…[2][3][4][5][6][7][8][9][10][11][12] In this respect, the combination of phenylenes and thiophenes has proven to be very successful in order to access optoelectronic devices with improved properties. [17][18][19][20][21][22][23][24][25][26][27][28] Compounds that are exclusively functionalized in position 4 of a terminal phenyl group and/or in position 2 of a terminal thiophene unit, however, are fairly rare, although they are also very promising candidates for the formation of nanoaggregates. Therefore, we started to develop a general approach for the synthesis of thiophenyl-phenylenes hybrid oligomers containing a total of three aromatic units and (at least) one biphenyl group as a reasonable compromise between interesting optical and optoelectronical properties on the one hand and solubility on the other hand.…”