Molecular engineering of triphenylamine functionalized phenoxazine sensitizers for highly efficient solid-state dye sensitized solar cells

Abstract

Two novel organic dyes POZ7 and POZ8, with D35 donor functionalized phenoxazine (POZ) derivative as donor and cyanoacrylic acid as acceptor, have been developed and applied in the solid-state dye-sensitized solar cells (s-DSCs). Compared with the dye POZ7 without π-bridge (6.24%), an impressive overall conversion efficiency of 7.37% for s-DSCs device based on POZ8 containing one thiophene unit as π-bridge, was obtained under standard AM 1.5 illumination (100 mW cm−2) by using 2, 2‘, 7, 7‘-tetrakis-(N, N-di-pmethoxyphenyl-amine)9, 9‘-spiro-bifluorene (Spiro-OMeTAD) as hole-transport materials (HTMs). This can be attributed to the impressive panchromatic photocurrent response over the whole visible range (380 nm–720 nm), which is much broader than that of POZ7, resulting in a much higher Jsc for POZ8 based device. The results clearly show that POZ derivative could be a promising donor unit to construct efficient dyes for s-DSCs.