Photoconductivity and FET performance of an n-type porphyrazine semiconductor, tetrakis(thiadiazole)porphyrazine

Photoconductivity and field effect transistor (FET) performance of thin films of a thiadiazole-annulated porphyrazine compound, tetrakis(thiadiazole)porphyrazine (abbreviated as H2TTDPz) were examined. The photocurrent-action spectra for ITO/H2TTDPz/Au photocell exhibited symbatic and antibatic responses, depending on the bias polarity. This characteristic difference in photocurrent responses was interpreted as a filter effect in Schottky-type photocells; the dissociation of the excitons generated near the negative electrode can effectively produce photocurrent in n-type semiconductors. We also found n-type semiconductor behavior of H2TTDPz in the thin-film FETs operated by the gates of an ionic liquid and SiO2, and obtained a field effect mobility of 7.2 × 10−4 cm2 V−1 s−1 and an on/off ratio of 104.

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► A porphyrazine compound, H2TTDPz, is an n-type semiconductor.
► H2TTDPz photocells exhibit symbatic and antibatic responses.
► H2TTDPz forms a Schottky contact with ITO and Au electrodes.
► Thin-film H2TTDPz FETs works with the gates of an ionic liquid and SiO2.