Solution‐Grown, Macroscopic Organic Single Crystals Exhibiting Three‐Dimensional Anisotropic Charge‐Transport Properties

Macroscopic single crystals of 4-hydroxy-cyanobenzene (4HCB) grown from solution exhibit reproducible and marked 3D mobility anisotropy. Air-gap OFET measurements along the planar axes a and b deliver average mobilities of 3 × 10−2 and 6 × 10−3 cm2 V−1 s−1, respectively. Space-charge-limited current (SCLC) experiments reveal an average mobility along the c axis of 4 × 10−6 cm2 V−1 s−1.