Flexible low-voltage organic phototransistors based on air-stable dinaphtho[2,3-b:2′,3′-f]thieno[3,2-b]thiophene (DNTT)

Charge-integrating organic heterojunction phototransistors for wide-dynamic-range image sensors

“…The channel architecture of the phototransistor is essential for maximizing photodetector performance. Phototransistors using only a BHJ channel have been shown to exhibit broad absorption spectra 34 , but the disordered nature of BHJs makes it difficult to approach mobilities of 1 18,29 and various metal oxides 35 operate as phototransistors, but their photonic performance is limited by low absorption outside the ultraviolet region due to their wide bandgaps. On the other hand, the properties of these devices can be combined by forming a heterojunction between a good absorber that efficiently generates electron-hole pairs and high-mobility semiconductor to rapidly transport the carriers out of the device 19,28,36,37 .…”

“…Monolithic integration of OPDs and TFTs is complicated by differences in geometries, electrodes and active layers, and requires heterogeneous assembly. On the other hand, a phototransistor capable of charge integration 18,26 and a fast response time 17,27,28 can operate at higher efficiencies, have a wider dynamic range, and simplify pixel fabrication. Previous developments in high-detectivity solution-processed phototransistors for image sensing show high EQEs using direct photocurrent sampling 15,19,29 or integration on the order of seconds 18,26 .…”

Performance improvement of organic phototransistors by using polystyrene microspheres

“…PS powders with average molar mass (M w ) of 35,000 g mol −1 was purchased from Aldrich. DNTT was synthesized in our lab according to the previous report, followed by vacuum sublimation for purification [29]. C8BTBT was purchased from Suna Tech.…”

“…Dinaphtho[2,3-b:2ʹ,3ʹf]thieno [3, 2-b]thiophene (DNTT) and 2,7-dioctyl [1]benzothieno [3,2-b][1]benzothiophene (C8BTBT) were selected because of their relatively high mobility and stability [29,30]. By incorporating PS microspheres, PS microspheres/DNTT-based phototransistors (PS/DNTT OPTs) enhanced photosensitivity (ratio of photo current to dark current, simplified as I light /I dark ratio) by two orders of magnitude compared with DNTT OPTs.…”

Transparent, conformable, active multielectrode array using organic electrochemical transistors

“…First, many transparent conductors and transistors exhibit large changes of electric performances under the illumination of light. Such photosensitivity, which is usually ascribed to the charge traps or band gaps in transparent materials (34,35), makes it difficult to detect small changes of active potentials of neurons by photoexcitation. Second, the integration of transparent conductors and transparent transistors requires sophisticated engineering of device designs, because transparency and conductivity of transparent conductors have a tradeoff relation (36,37).…”