| Photodetector is a basic device in the field of optical communication,security monitoring and biosensor.Organic and inorganic hybrid perovskite photoconductive detector has the advantages of quick response,high visible light sensitivity,good stability,low temperature preparation and so on.The combination of photo generated electrons and holes in photoconductive detectors will have an important effect on photoelectric current,but this property is rarely studied.In this paper,the photoelectric response characteristics of perovskite films or the addition of electron transport layers and charge absorbing materials are studied to reveal the influence of charge extraction on the performance and working mechanism of photoconductive perovskite detectors.The main achievements are as follows:1.By introducing SnO2 and SnO2/PCBM electron transport layers between MAPbI3 and the substrate,the spatial separation of photogenerated electrons and holes is achieved,thus extending the carrier life and increasing the carrier concentration and carrier life inside the perovskite film to improve the photoconductive photodetector's optical response.The results showed that(1)the fluorescence quenching of perovskite film was sharped after the introduction of electron transport layer,and the fluorescence life was reduced(2)electronic extraction at the interface of electron transport layer and MAPbI3 can improve photocurrent and respon siveness,and the higher the extraction efficiency of electrons in the electron tran sport layer,the greater the increase of photocurrent and responsiveness.Under the illumination of 460 nm,the photocurrent of glass/MAPbI3 device is 2.30 ?A,and that of glass/SnO2/MAPbI3 and glass/SnO2/PCBM/MAPbI3 increases to 4.55?A and 6.0?A,respectively(3)the closer the photogenic electron hole pairs are to MAPbI3 perovskite film and electron transport layer,the more the photocurrent increases.The photon energy generated by the 635 nm light source is low and distributed in the whole perovskite film,while the photon energy of 460 nm i s high and mainly distributed at the top of the film,so the 635 nm photon is closer to the interface and easier to be extracted.The maximum photocurrent meas ured at 460 nm and 635 nm reached 4.55 ?A and 6.0 ?A respectively,1.98 tim es and 2.64 times of the control sample photocurrent value,and the responsiveness increased from 2 mA/W to 5.25 mA/W and from 1.34 mA/W to 4.47 mA/W,respectively.2.Doped with C60 of different concentrations in the perovskite precursor solution,in situ photogenerated carriers were extracted to obtain higher photoelectric detection efficiency.The results showed that(1)the photocurrent of the device added with 5 ?LC60 reached 3.5 ?A under 460 nm light,which was 2.33 times of the control sample.(2)the maximum photocurrent measured by adding C60 to 515 nm light in the body is 4.0 ?A,and the one introduced at the interface is 3.0 ?A,while the control sample photocurrent is only 2 ?A.This is because the added C60 can extract electrons in situ and at the interface,thus obtaining A higher photocurrent.(3)the increase of C60 in vivo and at the interface at the same time can bring the electrons closer to the interface.The photocurrent under 515 nm illumination is 2.8 ?A,1.4 times that of the control sample. |
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