Optoelectronic synaptic transistors with hybrid heterostructure channels have been extensively developed to construct artificial visual systems, inspired by the human visual system. However, optoelectronic transistors taking full advantages of superior optoelectronic synaptic behaviors, low-cost processes, low-power consumption, and environmental benignity remained a challenge. Herein, we report a fully printed, high-performance optoelectronic synaptic transistor based on hybrid heterostructures of heavy-metal-free InP/ZnSe core/shell quantum dots (QDs) and n-type SnO 2 amorphous oxide semiconductors (AOSs). The elaborately designed heterojunction improves the separation efficiency of photoexcited charges, leading to high photoresponsivity and tunable synaptic weight changes. Under the coordinated modulation of electrical and optical modes, important biological synaptic behaviors, including excitatory postsynaptic current, short/long-term plasticity, and paired-pulse facilitation, were demonstrated with a low power consumption (∼5.6 pJ per event). The InP/ZnSe QD/SnO 2 based artificial vision system illustrated a significantly improved accuracy of 91% in image recognition, compared to that of bare SnO 2 based counterparts (58%). Combining the outstanding synaptic characteristics of both AOS materials and heterojunction structures, this work provides a printable, low-cost, and high-efficiency strategy to achieve advanced optoelectronic synapses for neuromorphic electronics and artificial intelligence.

Narrow-band-gap organic semiconductors have emerged as appealing near-infrared (NIR) sensing materials by virtue of their unique optoelectronic properties. However, their limited carrier mobility impedes the implementation of large-area, dynamic NIR sensor arrays. In this work, high-performance inorganic–organic hybrid phototransistor arrays are achieved for NIR sensing, by taking advantage of the high electron mobility of In2O3 and the strong NIR absorption of a BTPV-4F:PTB7-Th bulk heterojunction (BHJ) with an enhanced photogating effect. As a result, the hybrid phototransistors reach a high responsivity of 1393.0 A W–1, a high specific detectivity of 4.8 × 1012 jones, and a fast response of 0.72 ms to NIR light (900 nm). Meanwhile, an integrated 16 × 16 phototransistor array with a one-transistor–one-phototransistor (1T1PT) architecture is achieved. On the basis of the enhanced photogating effect, the phototransistor array can not only achieve real-time, dynamic NIR light mapping but also implement image preprocessing, which is promising for advanced NIR image sensors.

Developing techniques of advanced patterning for colloidal nanocrystals (NCs) is essential to construct high-performance electronic/optoelectronic devices. However, conventional NC patterning methods require complicated photolithography processes and/or delicately designed photocrosslinkers. Here, we develop a direct, photoresist-free method to pattern functional NCs while avoiding any photosensitive molecules. In our approach, the solubility of NCs is switched through cleaving native organic ligands under UV light exposure. Developing with the mother solvent produces fine patterns with feature sizes (as low as 10 μm) comparable to that of conventional photolithography. Importantly, the obtained patterns of NCs allow postpatterning ligand exchange. As representatives, we demonstrate patterned NC-based thin-film transistors (TFTs) and quantum dot light-emitting diodes (QLEDs). The In2O3 NC-based TFTs are turned from inactive to active using the patterning process and display substantially enhanced electronic performances upon ligand exchange with inorganic ligands. Furthermore, exquisite fluorescence quantum dot (QD) patterns are enabled. The QLEDs fabricated with ZnCl2-treated green QD patterns exhibit electroluminescence performances that are comparable to those of unpatterned QLEDs. Our strategy offers a powerful yet simple patterning technique for fabricating low-temperature thin-film electronics and optoelectronics, which is expected to be a versatile and extensible approach for solution-processed NC-based thin-film device manufacturing.