Improved Thin‐Film Transistor Performance Through a Melt of Poly(para‐phenyleneethynylene)

Abstract

The performance of polymer field-effect transistors (PFETs) based on short rigid rod semiconducting poly(2,5-didodecyloxy-p-phenyleneethynylene) (D-OPPE) is highlighted. The controlled heating and cooling of thin films of D-OPPE allows for a recrystallization from the melt, boosting the performance of D-OPPE-based transistors. The improved film properties induced by controlled annealing lead to a hole field-effect mobility around 0.014 cm V s , an on/off ratio of 10 , a sub-threshold swing of 3 V dec and a threshold voltage of -35 V, employing a poly(methyl methacrylate) (PMMA) gate dielectric. Thus, PFETs out of D-OPPE compete now with spin-coated, polycrystalline poly(3-hexylthiophene)-based PFETs.

Dipole‐Switchable Poly(para‐phenyleneethynylene)s: Ferroelectric Conjugated Polymers

“…While no polarization hysteresis was found for HH-, FH-, or HPPE derivatives ( Figure S6) such hysteretic P-E characteristics were observed for FF-HPPE when the applied voltage exceeded AE 5Vmm À1 .A tAE 20 V mm À1 ,t his behavior was much more significant and remanent polarization (P r )ofcirca 0.3 mCcm À2 was observed (Figure 5a). [32][33][34] The optoelectronic properties of the three PPEs are shown in Figure S1 and Tables S1 and S2. Ac oercive electric field can be determined as 5.3 V mm À1 (from the hysteresis), but the remanent polarization cannot be determined because it depends on the frequency.T he molecular reorientation requires time to saturate and the pure remanent polarization can be obtained at al ow-enough frequency.C onsequently,apositive-up, negative-down (PUND), DC voltage technique for full saturation was performed to obtain the correct value (Figure S9).…”

Synthesis and Properties of Functional Twisted Tolanes

“…The obtained solid was washed by decantation with toluene ( 6 10 5, 49.5, 91.4, 117.3 (q; 1 J CF 301 Hz;C F 3 ), 122. 5, 129.2, 129.5, 129.7, 132.8, 133.3, 158.4 (q; 2 6,k] [1,5]diazacyclotridecine-7,9(6 H,8H)-dione (4): As olution of N,N-diisopropylethylamine (0.60 mL, 3.448 mmol, 6.0 equiv) in dry dichloromethane (120 mL) was prepared at rt under nitrogen. To this solution, solutions of 3 (0.283 g, 0.575 mmol, 1.0 equiv) in amixture of dry dichloromethane, and acetonitrile (40 mL, 1:1, v/v) and malonyl chloride (61 mL, 0.632 mmol, 1.1 equiv) in dry dichloromethane (40 mL), were added simultaneously during 4h.A fter stirring overnight, the reaction mixture was quenched by addition of saturated NaHCO 3 solution (30 mL) and the water phase was extracted with dichloromethane (3 20 mL).…”

“…The presence of the iodo substituents in 11 increases thei ntersystem-crossing rate owing to the heavy-atome ffect, [10] leadingt ot he intense phosphorescence in 11.C ompounds 4 and 7 show some phosphorescence in the cryogenicm atrix, but it is considerably weaker than that of the diiodo 11.A second interesting observation is the change of the emission spectrumo f12 under cryogenic conditions (Figures 4,5,6,and 7). The absorption data in hexane suggest that 12 is fully twisted at room temperature, while the dimer 14 should be planar.T he twisting of 12 is also corroborated by its singlecrystal structure, the crystal structureo f14 ( Figure 2), and computational data.…”

“…Tolane, or diphenylacetylene, is one of the fundamental organic motifs and the main building block for the preparation of conjugated polymers of the poly( para ‐phenyleneethynylene) (PPE) type . PPE are of great importance in sensory applications, and are also useful in organic electronics . Owing to the rigidity of the PPE backbone, they possess only one degree of freedom: the twisting of adjacent phenyl rings with respect to each other .…”

“…[4] PPE are of great importance in sensory applications, and are also useful in organice lectronics. [5,6] Owing to the rigidity of the PPE backbone, they possess only one degree of freedom: the twisting of adjacent phenyl rings with respect to each other. [7] This twisting motion has al ow activation energy barrier, whereby the fully twistedc onformation in tolane,a nd also in PPEs, is less than 0.5 kcal mol À1 above that of the planar conformation.…”