| Photodetectors are a class of devices that can convert optical radiation into electrical signals,and are widely used in medical imaging,environmental monitoring,biological sensing,and automated production.With the development of science and technology,the demand for high-response sensitivity,wide-spectrum detection and fast-response high-performance photodetectors is gradually increasing.As a new type of semiconductor ionic compound material,perovskite has excellent optoelectronic properties such as high sensitivity,wide spectral response,large optical absorption coefficient,direct band gap,etc.,and its high processability,low cost,and easy preparation.Photoelectric detection and other fields have broad application prospects.According to its element composition and proportion,crystal structure and dimension,many perovskite species with different properties,structures and morphologies can be formed,and their optoelectronic properties will also undergo significant changes.However,most perovskite materials prepared by solution methods have problems of low mobility,poor stability,and high non-radiative charge recombination,which limit their development in the field of photodetection to a certain extent.By combining perovskite materials with two-dimensional materials,metal oxides and organic semiconductor materials to form heterostructures,it is expected to overcome the above problems,and perovskite makes up for the weak light absorption of photodetectors based on these materials.In order to improve the performance of perovskite heterostructure photodetectors,and construct diversified perovskite heterostructure photodetectors.In this work,we mainly focus on perovskite and two-dimensional materials or metal oxide heterostructures,and combine their respective characteristics to construct InGaZnO-ITO/CsPbBr3 hybrid phototransistors,perovskite/BP/Mo S2photogate photodiode and BP top-gate transistor with PMMA/Al2O3/2D perovskite heterostructure dielectric,the specific work is as follows:（1）Construction of InGaZnO-ITO/CsPbBr3 phototransistor.All-inorganic halide perovskites attracte extensive attention because of their high intrinsic light absorption coefficient and extraordinary environmental stability,however,the responsivity of all-inorganic perovskite-based photodetectors is limited due to their low electrical conductivity.Therefore,we combined the CsPbBr3 film with the high-conductivity InGaZnO-ITO film to fabricate heterostructured photoelectric crystals.Metal ITO nanowires are used as electron pumps and charge transport high-speed channels to extract photogenerated carriers efficiently from CsPbBr3 and inject electrons into InGaZnO,thereby further improving the detection capability of weak light.The fabricated device has a responsivity of 4.9×106A/W,which is about 100 times higher than the optimal responsivity of a pure CsPbBr3-based photodetector,with a fast response time of 0.45/0.55 s and an ultra-high detectivity of 7.6×1013 Jones.And since both are prepared by solution spin coating,which is not only beneficial for large-area fabrication but also suitable for flexible substrates,our fabricated flexible InGaZnO-ITO/CsPbBr3 phototransistors exhibited 200-hour air exposure stability and excellent mechanical flexibility property.（2）Construction of perovskite/BP/Mo S2 photogate photodiode.Traditional photodetectors designed using photovoltaic or photogating mechanisms have a situation where high responsivity and fast response cannot be achieved.In this work,our designed perovskite/BP/Mo S2 photogate photodiode is not affected by the above mechanism,the perovskite acts as an efficient light absorption layer to provide a large number of photogenerated carriers,and the BP/Mo S2 PN junction acts as a carrier.The flow particles are quickly separated from the channel,so that the coexistence of fast response and high responsivity can be achieved.The responsivity of the perovskite/BP/Mo S2 photogate photodiode device can be improved to 11 A/W and the response time of the device can be optimized to 400 ms when the diode is operated at a reverse bias of-2 V,It is several orders of magnitude faster than high-gain photogating devices,and the corresponding detectivity is as high as 1.3×1012 Jones.Furthermore,the photogate photodiode is very suitable for self-driven broadband photodetection due to the efficient light absorption capability of perovskite and the existence of the built-in electric field of the BP/Mo S2 PN junction.Under the condition of 457 nm laser irradiation and zero bias,the device has a detectivity of 3×1011 Jones,a photocurrent/dark current ratio of 3×107,and exhibits an efficient photovoltaic power conversion performance with a peak EQE of 80%.（3）Construction of BP top-gate transistor with PMMA/Al2O3/2D perovskite heterostructure dielectric.Top-gate transistors can individually control the switching of each device to be compatible with current integrated circuit technology.BP is a P-type material with high mobility and a suitable on/off ratio direct bandgap.It can form logic complementary circuits with other N-type materials.However,its transistors are often trapped by charges at the interface of the gate dielectric layer,resulting in a large hysteresis phenomenon,thereby affecting the stability and reliability of logic devices,sensors,and drive circuits.The 2D perovskite has excellent environmental stability,and its organic spacer layer inhibits the internal charge movement,which makes the2D perovskite have excellent dielectric properties,while the perovskite-based photodetector is unstable due to ion migration.The hysteresis is the opposite of the hysteresis caused by charge trapping.Therefore,we use it together with PMMA/Al2O3to construct a transistor heterostructure dielectric layer to prepare a PMMA/Al2O3/2D perovskite heterostructure dielectric BP top-gate transistor.The device exhibits a small hysteresis voltage of 0.13 V,and exhibits good stability in different scan speeds,gate bias stress stability,and multi-cycle tests.At the same time,due to the strong light absorption properties of the two-dimensional perovskite layer,the transistor exhibits a ultra-high photoresponsivity of 1.5×107 A/W and an excellent detectivity of 1012 Jones. |
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