Study On High-performance Photoresponsive Organic And Organic-inorganic Thin Film Field-effect Transistors Based On High Mobility Channel Materials

The emergence of organic semiconductor materials has arisen organic electronics.Due to the simple preparation process,low cost and flexibility,various organic electronic devices such as organic light-emitting diodes,organic solar cells as well as organic field-effect transistors(OFET),have obtained wide attention.Because of the good light absorption properties of organic semiconductor materials,photoresponsive organic field effect trnaisistors(PhOFET)emerged and aroused great interest in the researchers.PhOFET can applied in photodetectors,optical fiber communications and imaging.In this thesis,we used the high mobility channel material,combined with the advantages of organic semiconductor materials to improve the photogenerated carriers transmission efficiency and then greatly improved the performance of PhOFET.The channel materials in this thesis are C60,graphene-like material molybdenum disulfide,zinc oxide.Detals are as follows:(1)High-performance PhOFETs were prepared with C60 channel material and PbPc photosensitive material based on polyvinyl alcohol(PVA)and SiO2 insulating gate dielectric.C60 film growth on the PVA has higher mobility,which is benefical to the transport of the photo generated charge carriers and the performance of PhOFETs.The device based on PVA as insulating gate dielectric achevied a photoresponsivity of 21 A/W and an external quantum efficiency of 3230% under the illumination of 1.69 mW /cm2 at the wavelength of 808 nm.(2)With C60 as channel material and neodymium phthalocyanine(NdPc2)as photosensitive material,we prepared the planar heterojunction Ph OFET,bulk heterostructure PhOFET and hybrid planar-bulk heterojunction Ph OFET and compared thier performances.The results indicate that hybrid planar-bulk heterojunction device is the best with photoresponsivity 108 A/W,the external quantum efficiency 20612% and the maximum light to dark current ratio 3.75 × 104 under the illumination of 5.92 ?W/cm2 at the wavelength of 650 nm.(3)Based on the solution processed C-axis preferred orientation zinc oxide film and PbPc photosensitive material,we prepared photoresponsive organic-inoranic thin-film field-effect transistors(Ph OIFETs)with the structures of conventional bottom-gate top-contact and the bottom-gate buried-electrode.Due to the larger light-absorbing area of the photosensitive layer and better matching of semiconductor/metal energy levels,the performance of the bottom gate buried electrode device is optimal.Under the illumination of 213.93 ?W/cm2 at the wavelength of 808 nm,the photoresponsivity was 3.48 A/W and the external quantum efficiency was 533.81%.Although the performance is not as good as the device above mentioned,the stability of the bottom gate buied electrode structurePhOIFET is the best.(4)We prepared high performance PhOIFETs based on the novel two-dimensional grapheme-like Mo S2 channel material and PbPc photosensitive material with Al,Au,Ag and Cu electrode,respectively.Under the illumination of 0.061 ?W/cm2 at the wavelength of 808 nm,the performances of Al electrode device and Au electrode device are superior with the photoresponsivity of 1263.85 A/W and 444.12 A/W respectively.