Superior Noise Suppression, Response Time, and Device Stability of Non-Fullerene System over Fullerene Counterpart in Organic Photodiode

Herein, non-fullerene acceptor-based organic photodiodes are compared with fullerene acceptor-based organic photodiodes. The non-fullerene acceptor, ethylhexyl-rhodanine-benzothiadiazole-coupled indacenodithiophene (eh-IDTBR)-based organic photodiodes show a higher detectivity (1.61 × 10¹³ cm Hz^1/2 W⁻¹) and a faster response time (≈2.7 µs) than the fullerene acceptor, [6,6]-phenyl C₇₁ butyric acid methyl ester (PC₇₁BM)-based organic photodiodes (3.25 × 10¹² cm Hz^1/2 W⁻¹ and ≈6.24 µs, respectively) owing to the excellent dark current suppression of the carrier injection and the low trap density of eh-IDTBR. Moreover, the eh-IDTBR-based photodetector shows better operational device stability than the fullerene counterpart under electrical and thermal stress. This is corroborated by the morphology and crystallography analyses, both of which reveal that the eh-IDTBR-containing photo-sensitive films remain intact after imposing an external stress. This study elucidates important key advantages of the non-fullerene acceptor, eh-IDTBR, and sets a milestone as it compares the non-fullerene acceptors and fullerene acceptors in organic photodiodes for the first time. This work sets a new record for the performance and stability of solution-processable non-fullerene acceptor-based organic photodiodes.