Crystalline TQPP as p-type semiconductor: X-ray crystallographic investigation, OTFT device, and computational analysis of transport properties

• TQPP materials with thermal stability up to 370 °C were synthesized.
• TQPP and TQPP-[CH3]4 show interplanar stacking distances of 3.4 Å using X-ray crystallography.
• OTFT field-effect mobilities of 10−3 cm2/V−1 s−1 for TQPP and 10−5 cm2/V−1 s−1TQPP-[CH3]4.
• Modeling confirms higher electronic coupling constants for TQPP than TQPP-[CH3]4.

Two p-type semiconducting azapyrenoacene materials, quinoxalino[2′,3′:9,10]phenanthro[4,5-abc]phenazine (TQPP) and 6,7,15,16-tetramethylquinoxalino[2′,3′:9,10]phenanthro[4,5-abc]phenazine (TQPP-[CH3]4), were characterized and were found to display high thermal stability and planar molecular geometry as revealed by single-crystal X-ray analysis. In bottom-gate p-channel organic thin-film transistors, field-effect mobilities of 2.5 × 10−3 cm2/V s and 7.5 × 10−5 cm2/V s were measured in ambient air for TQPP and TQPP-[CH3]4, respectively. Computational results of reorganization energies and electronic couplings indicate larger inter and intra-columnar couplings for TQPP-[CH3]4 in comparison to TQPP and predict the suitability of both semiconductors for hole as well as electron transporters.

TQPP (X = H): μ = 2.5 × 10−3 cm2/V s. TQPP (X = CH3): μ = 7 × 10−5 cm2/V s.Figure optionsDownload as PowerPoint slide