Photodetector without Electron Transport Layer Based on Hexane-1,6-Diammonium Pentaiodobismuth (HDA-BiI5) Molecular Semiconductor

Abstract

With the development of the semiconductor industry, research on photoelectronic devices has been emphasized. In this paper, a molecular semiconductor material with a narrow bandgap of hexane-1,6-diammonium pentaiodobismuth (HDA-BiI5) was utilized to prepare photodetectors without electron transport layers. Using a single light source, the effects of different wavelengths and different powers on the photoresponsivity, switching ratio, specific detectivity, and external quantum efficiency of the device were investigated. It is demonstrated that this device has excellent responsivity, specific detectivity, stability, and repeatability, and this work will help expand the application of molecular semiconductor materials for photodetection.

Investigation of the Photoresponse and Time-Response Characteristics of HDA-BiI5-Based Photodetectors

“…Through Figure 1 a,b,e, we can see that the grain boundaries are obvious, the grains are extruded together with each other, the pinholes are less but the surface is not too flat, and overall, the thin HDA-BiI 5 film is of good quality, the film thickness is about 750 nm, and the good film quality can reduce the occurrences of short-circuiting and enhance the light absorption ability, thus improving the performance of the device [ 11 , 18 , 19 ]. Then, a layer of Spiro-MeOTAD is spin-coated on the light-absorbing layer to prepare the device structure as in Figure 1 c. In addition, from Figure 1 d it can be clearly seen that the wavelength of the absorbed light is less than 660 nm and the absorption edge is about 640 nm, indicating a bandgap of about 1.93 eV, which corresponds to the previously reported literature [ 12 ].…”

“…In this paper, we use the organic–inorganic hybrid semiconductor material hexane-1,6-diammonium pentaiodobismuth (HDA-BiI 5 ) as the light-absorbing layer to prepare photodetectors with ITO/SnO 2 /HDA-BiI 5 /Spiro-MeOTAD/Au structures and explore the photoresponse and time-response characteristics of the HAD-BiI 5 -based photodetectors. The photoresponsivity of the device can reach 1.45 × 10 −3 A/W and 8.5 × 10 −3 A/W under laser irradiation at 375 nm and 532 nm wavelengths, which is more than two-times higher than that of the recently reported literature [ 12 ], showing high photoresponsivity and a fast response time. In addition, the effects of different powers on the switching ratio, specific detectivity, and external quantum efficiency are further discussed, which provide a reference for the preparation of photodetectors with organic–inorganic hybrid semiconductor materials in the future, thus further expanding the application of organic–inorganic hybrid semiconductor materials.…”

“…After the preparation of HDA-BiI 5 film and its characterization—for XRD data see the previous article [ 12 ]. Through Figure 1 a,b,e, we can see that the grain boundaries are obvious, the grains are extruded together with each other, the pinholes are less but the surface is not too flat, and overall, the thin HDA-BiI 5 film is of good quality, the film thickness is about 750 nm, and the good film quality can reduce the occurrences of short-circuiting and enhance the light absorption ability, thus improving the performance of the device [ 11 , 18 , 19 ].…”

“…Details of the material preparation, characterization, and optoelectronic test platform are available in the previously reported literature [ 12 ].…”

“…In addition, Liu et al prepared conventionally structured solar devices using organic–inorganic hybrid semiconductor material hexane-1,6-diammonium pentaiodobismuth (HDA-BiI 5 ) and tested the relevant photovoltaic performance under solar light conditions [ 11 ]. Wang et al then prepared photodetectors without electron transport layers on this basis and found that the high photoresponsivity and specific detectivity made the performance of photodetectors based on HDA-BiI 5 material greatly improved [ 12 ]. The selection of suitable materials and the change of device structure can greatly improve the performance of photodetectors [ 13 , 14 , 15 , 16 , 17 ].…”