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Highly Sensitive and Broadband Organic Photodetectors with Fast Speed Gain and Large Linear Dynamic Range at Low Forward Bias
Author(s) -
Nie Riming,
Deng Xianyu,
Feng Lei,
Hu Guiguang,
Wang Yangyang,
Yu Gang,
Xu Jianbin
Publication year - 2017
Publication title -
small
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.785
H-Index - 236
eISSN - 1613-6829
pISSN - 1613-6810
DOI - 10.1002/smll.201603260
Subject(s) - photodetector , photodiode , optoelectronics , biasing , quantum efficiency , ultraviolet , materials science , detector , dynamic range , photon counting , photoresistor , realization (probability) , voltage , wide dynamic range , physics , optics , range (aeronautics) , response time , infrared , statistics , mathematics , computer graphics (images) , quantum mechanics , computer science , composite material
Photodetectors with high photoelectronic gain generally require a high negative working voltage and a very low environment temperature. They also exhibit low response speed and narrow linear dynamic range (LDR). Here, an organic photodiode is demonstrated, which shows a large amount of photon to electron multiplication at room temperature with highest external quantum efficiency (EQE) from ultraviolet (UV) to near‐infrared region of 5.02 × 10 3 % (29.55 A W −1 ) under a very low positive voltage of 1.0 V, accompanied with a fast response speed and a high LDR from 10 −7 to 10 1 mW cm −2 . At a relatively high positive bias of 10 V, the EQE is up to 1.59 × 10 5 % (936.05 A W −1 ). Inversely, no gain is found at negative bias. The gain behavior is exactly similar to a bipolar phototransistor, which is attributed to the photoinduced release of accumulated carriers. The devices at a low voltage exhibit a normalized detectivity ( D *) over 10 14 Jones by actual measurements, which is about two or three order of magnitudes higher than that of the highest existing photodetectors. These pave a new way for realization of high sensitive detectors with fast response toward the single photon detection.