Unraveling the Singlet Fission Effects on Charge Modulations of Organic Phototransistor Memory Devices Unraveling the Singlet Fission Effects on Charge Modulations of Organic Phototransistor Memory Devices AITranslate

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DOI：https://doi.org/10.1021/acsaelm.1c01345

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Organic phototransistor memory has received significant attention owing to its solution processability and flexibility, and its high transmission speed and low energy consumption with light operation provide a promising future in ultrahigh-density data storage devices. In this study, TIPS-functionalized organic small molecules, 9,10-bis[(triisopropylsilyl)ethynyl]anthracene (TIPS-3), 5,12-bis((triisopropylsilyl)ethynyl)tetracene (TIPS-4), and 6,13-bis(triisopropylsilylethynyl)pentacene (TIPS-5) were introduced and employed as the photogates, while polystyrene (PS) acted as the insulator in the floating gate electrets of phototransistor memory. The TIPS-functionalized structure enabled acenes to be solution-processable, and PS helped to trap charges efficiently. The devices were photowritten with different kinds of light and were electrically erased with a gate voltage of −60 V for 1 s. TIPS-4 exhibited the best memory performance and photoresponse with a stable current contrast of 105 over 104 s and a large shift in threshold voltage of 50 V to 450 nm light. The outstanding charge-trapping capability of TIPS-4 in the phototransistor memory was attributed to the favorable energy level alignment to the semiconducting layer. Notably, the significant photoresponse was ascribed to the singlet fission to triplet photodynamics of TIPS-4, which showed a delayed exciton lifetime providing enough time for charge transfer to the channel layer. The results of this study provide a design concept on organic small molecules in the floating gate electret.