Flexible and Air-Stable Near-Infra red Sensors Based on Solution-Processed Inorganic-Organic Hybrid Phototransistors

摘要

Flexible and air-stable phototransistors are highly demanded for wearable near-infrared (NIR) image sensors. However, advanced NIR sensors via low-cost, solution-based processes remained a challenge. Herein, high-performance inorganic-organic hybrid phototransistors are achieved based on solution processed n-type metal oxide/polymer semiconductor heterostructures of In2O3/poly{5,5 '-bis3,5-bis(thienyl)phenyl-2,2 '-bithiophene-3-ethylesterthiophene} (PTPBT-ET). The In2O3/PTPBT-ET hybrid phototransistor combines the advantages of both fast electron transport in In2O3 and high photoresponse in PTPBT-ET, showing high saturation mobility of 7.1 cm(2) V-1 s(-1) and large current on/off ratio of 10(7). As a result, the phototransistor exhibits high performance towards NIR light sensing with a responsivity of 200 A W-1, a specific detectivity of 1.2 x 10(13) Jones, and fast photoresponse with rise/fall time of 5/120 ms. Remarkably, the hybrid phototransistor, without any passivation, demonstrates excellent electrical stability without performance degradation even after 160 days in air. A 10 x 10 phototransistor array is also enabled by virtue of the high device uniformity. Lastly, flexible In2O3/PTPBT-ET phototransistor on polyimide substrate is attained, exhibiting outstanding mechanical flexibility up to 1000 bending/releasing cycles at a bending radius of 5 mm. These achievements pave the way for constructing air-stable hybrid phototransistors for flexible NIR image sensor applications.