High-mobility semiconducting polymers with different spin ground states

Abstract

Organic semiconductors with high-spin ground states are fascinating because they could enable fundamental understanding on the spin-related phenomenon in light element and provide opportunities for organic magnetic and quantum materials. Although high-spin ground states have been observed in some quinoidal type small molecules or doped organic semiconductors, semiconducting polymers with high-spin at their neutral ground state are rarely reported. Here we report three high-mobility semiconducting polymers with different spin ground states. We show that polymer building blocks with small singlet-triplet energy gap (ΔES-T) could enable small ΔES-T gap and increase the diradical character in copolymers. We demonstrate that the electronic structure, spin density, and solid-state interchain interactions in the high-spin polymers are crucial for their ground states. Polymers with a triplet ground state (S = 1) could exhibit doublet (S = 1/2) behavior due to different spin distributions and solid-state interchain spin-spin interactions. Besides, these polymers showed outstanding charge transport properties with high hole/electron mobilities and can be both n- and p-doped with superior conductivities. Our results demonstrate a rational approach to obtain high-mobility semiconducting polymers with different spin ground states.

n-Type Conjugated Polymers Based on an Indandione-Terminated Quinoidal Building Block

“…Conjugated polymers (CPs) have been extensively studied for their applications in various organic electronic devices, such as organic thin-film transistors (OTFTs) and organic thermoelectrics (OTEs). − Both p-type and n-type CPs are essential for these applications, but the development of the latter lags far behind that of the former. − Therefore, growing research efforts are being directed toward developing n-type CPs. Generally, the lowest unoccupied molecular orbital (LUMO) energy level ( E LUMO ) of an n-type CP must be below −4.0 eV to enable efficient electron injection and stable electron transport in OTFTs and to facilitate efficient, stable n-doping in OTEs. ,,− …”

Structural influences of proquinoidal acceptor moieties on transistor performance and doping capability for diketopyrrolopyrrole-based dual-acceptor conjugated polymers

“…As mentioned earlier, the proquinoidal characteristics of the NN/NS/SS units can make the resulting polymers possess free radicals. 30–32 To confirm this, we conducted the EPR measurement of these polymers in the solid state. As shown in Fig.…”

“…These comonomers were synthesized based on the modified methods reported in the literature. 29,31 The synthetic details and their corresponding 1 H NMR spectra are provided in the ESI †. The signals at 9.0, 7.3, and 4.1 ppm in the 1 H NMR spectrum of DPP-2T (Fig.…”

“…1a and b). 30–32 On the other hand, the interactions between the DPP unit and its companion acceptor can be investigated since the acceptor strength of these acceptor units can be modulated through a rational design. As shown in Fig.…”

Molecular mechanism of rigidity- and planarity-promoted, state-dependent doping of conjugated ladder-type molecules

“…22–27 Over the past decade, doping strategies using organic compounds have emerged as an alternative approach for addressing these issues. 28–30 In these cases, neutral organic molecular species serve as either electron-accepting or -donating dopants. 22–26 In addition, this class of strategies offers the advantages of processing versatility and structural flexibility for tailored properties.…”