High Thermally Stable n-Type Semiconductor up to 850 K Based on Dianionic Naphthalenediimide Derivative

Abstract

Electrostatic cation–anion interaction is effective to form a tightly bounded π-molecular assembly, which enhances the thermal stability and carrier transport property. Dianionic bis­(benzenesulfonate)–naphthalenediimide (BSNDI 2– ) formed simple 2:1 cation–anion pairs of (Na+)2(BSNDI 2– ) (1), (K+)2(BSNDI 2– ) (2), and (NH4 +)2(BSNDI 2– ) (3), and their redox behaviors, thermal stabilities, crystal structures, electron transport properties, and dielectric constants were compared to those of neutral bis­(phenyl)–naphthalenediimide (4). Crystals 1, 2, and 3 had quite high thermal stabilities up to 850, 810, and 600 K, respectively, even though organic molecules. A two-dimensional (2D) n-type electron transport layer consisting of NDI π cores was sandwiched between networks of highly polarized electrostatic cation–anion pairs showing 2D herringbone (1), one-dimensional π-stacking (2), and brickstone-like 2D π-stacking (3) interactions. The values of electron mobility in polycrystalline 1, 2, 3, and 4 reached 0.22, >0.0003, 0.036, and >0.028 cm2 V–1 s–1, respectively, according to flash-photolysis time-resolved microwave conductivity measurements. The electron mobility of crystal 1 was 1 order of magnitude higher than those of crystals 2, 3, and 4 owing to the tight intermolecular interactions within the 2D transport layer. The real part dielectric constants of crystals 1, 2, 3, and 4 were ∼4, ∼50, ∼20, and ∼4 at 450 K, respectively, which affected the electron transport property. The chemical design of highly polarized electrostatic cation–anion pair formed the 2D transport layer and also has high thermal stability up to ∼850 K in the ionic n-type semiconducting materials.

Electrostatic versus van der Waals Interactions in an n-Type Semiconducting Dianionic Naphthalenediimide Derivative with CnH2n+1NH3+ (n = 1–16)

“…Simple (C n H 2 n +1 NH 3 + ) 2 ( BSNDI 2– ) salts were obtained by the cation exchange reaction from (Na + ) 2 ( BSNDI 2– ) and (TBA + ) 2 ( BSNDI 2– ) or by direct mixing of H 2 BSNDI in the solution phase to prepare 16 kinds of salts with n = 1–16. Among them, we have already reported the crystal structures and physical properties of C1-BSNDI and C2-BSNDI . The solubility of Cn-BSNDIs for the common organic solvent such as CH 3 CN, C 2 H 5 OH, CHCl 3 , toluene, THF, and so on was quite low because of the effective intermolecular electrostatic and van der Waals interactions, which restricted the fabrication of high-quality thin film devices using a typical spin-coating technique.…”

“…Among them, we have already reported the crystal structures and physical properties of C1-BSNDI and C2-BSNDI. 68 The solubility of Cn-BSNDIs for the common organic solvent such as CH 3 CN, C 2 H 5 OH, CHCl 3 , toluene, THF, and so on was quite low because of the effective intermolecular electrostatic and van der Waals interactions, which restricted the fabrication of high-quality thin film devices using a typical spin-coating technique. The short-chain compounds of Cn-BSNDI (n = 1∼5) were soluble in H 2 O and were insoluble in CH 3 OH, while the long-chain ones with n = 8∼16 were soluble in DMSO (∼ mM) or CH 3 OH (∼ mM).…”

“…The dianionic NDI derivative of bis­(benzenesulfonate)-naphthalenediimide ( BSNDI 2– ) formed simple salts of (M + ) 2 ( BSNDI 2– ) with M + = Na + , K + , and NH 4 + . Crystals of (Na + ) 2 ( BSNDI 2– ) showed an electron mobility of 0.22 V cm –2 s –1 at 298 K and extremely high thermal stability up to 850 K . Instead of rigid benzene sulfonate units, two flexible propionate (−C 2 H 5 COO – ) groups were introduced into a NDI π-core to form dianionic bis­(propionate)-naphthalenediimide (PCNDI 2– ). , Single-crystal X-ray structural analyses were performed for the hydrated (M + ) 2 ( PCNDI 2– )•(H 2 O) n with M + = Na + , K + , Rb + , and Cs + and revealed not just H 2 O-tolerant but H 2 O-responsive n-type semiconducting behavior coupled with the reversible H 2 O adsorption–desorption behavior and electron mobility switching.…”

“…+ . Crystals of (Na + ) 2 (BSNDI 2− ) showed an electron mobility of 0.22 V cm −2 s −1 at 298 K and extremely high thermal stability up to 850 K. 68 Instead of rigid benzene sulfonate units, two flexible propionate (−C 2 H 5 COO − ) groups were introduced into a NDI π-core to form dianionic bis(propionate)-naphthalenediimide (PCNDI 2− ). 69,70 Singlecrystal X-ray structural analyses were performed for the hydrated (M + ) 2 (PCNDI + , and (C 2 H 5 ) 3 NH + .…”

Highly Proton-Conducting Mixed Proton-Transferred [(H2PO4–)(H3PO4)]∞ Networks Supported by 2,2′-Diaminobithiazolium in Crystals

“…Conversely, in solids, the Na + cations and Cl – anions are tightly bonded due to the strong electrostatic interaction between the charged ions; this drastically suppresses ionic mobility. The hybridization of ionic and covalent bonds form a rigid three-dimensional (3D) crystal lattice in inorganic crystals, while a variety of intermolecular interactions such as electrostatic, charger-transfer, hydrogen-bonding, and van der Waals interactions play an essential role in determining the crystal lattice and enhancing the variation of the structural dimension in the molecular crystals. − Therefore, the chemical design of a variety of crystal lattices is conventionally possible to ensure a suitable H + -conducting pathway for achieving a high μ H+ value in the molecular crystal where the freedom of motion of H + in the crystal lattice can be thermally activated even at a relatively low temperature. , …”