Spin‐On‐Patterning of Sn–Pb Perovskite Photodiodes on IGZO Transistor Arrays for Fast Active‐Matrix Near‐Infrared Imaging

Abstract

features for developing high-performance X-ray imagers and ultraviolet sensors. [3] For imaging application, IGZO TFTs were mainly integrated with amorphous silicon and organic photodiodes, [3c,e,4] the spectral of which were usually limited to visible light detection. Large-area, active-matrix infrared sensing, therefore, remains a challenge.Organic-inorganic hybrid perovskites possess excellent optoelectronic properties with high absorption coefficient, high charge carrier mobility, long carrier diffusion lengths, and tunable bandgaps, [5] rendering it a promising material for across-the-board optoelectronic devices, [6] including photovoltaic cells, [7] light-emitting, lasing devices, [8] and high-performance photodetectors. [9] In particular, compared with predominant photodetectors made of inorganic semiconductors, solution-processable perovskite is more promising for lowcost, flexible, and large-area scenarios. [6d] Conventional lead-based perovskite photodiodes (PDs) provide a detection spectral range from 300 to 800 nm. [10] To further extend the spectral response to the near-infrared (NIR) range, there are normally two approaches. One is to combine perovskite with narrow bandgap polymers or quantum dots such as PDPP3T [11] and PbS quantum dots. [12] Another approach is to introduce an Sn-Pb binary perovskite PDs. [13] The smaller ionic radii of Sn 2+ than Pb 2+ (Sn 2+ :1.35 Å and Pb 2+ : 1.49 Å) [14] reduces the bandgap of perovskites due to the bowing effect, [15] so that Sn-Pb hybrid perovskite has lower bandgap to extend the light absorption to ≈1000 nm. Recently Xiaobao et al. reported MA 0.5 FA 0.5 Pb 0.5 Sn 0.5 I 3 perovskite photodetector, exhibiting a detectivity of over 10 12 Jones ranging from 800 to 970 nm. [13c] Wang et al. fabricated mixed Sn-Pb perovskite photodetectors with a broadband response from 300 to 1000 nm, responsivity (R) of over 0.4 A W −1 , and detectivity (D*) of over 10 12 Jones in the near-infrared region. [13b] Encouraging improvements in the Sn-Pb based perovskite stability have also been reported very recently, such as using GuaSCN passivation to achieve 1 µs carrier lifetime with long-term stability. [16] The above development of low bandgap organic-inorganic perovskite materials has brought new opportunity for developing advanced flat-panel Flat-panel imagers have wide applications in industrial and medical inspections. Nonetheless, large area infrared imaging remains a challenge due to the fact that the state-of-the-art infrared sensors are usually based on silicon or germanium technologies, which are limited by the wafer size. Recent advances in low bandgap Sn-Pb perovskite photodiodes (PDs) and indium gallium zinc oxide (IGZO) thin-film transistors (TFTs) matrix backplane bring new opportunity for developing the large area near-infrared image sensor. As a proof of concept, a 12 × 12 pixels array with each pixel independently controlled by the gate voltage of a TFT are constructed. Arrays of Sn-Pb based perovskite PDs are spin deposited onto the IGZO TF...

Recent Advances in Perovskite Photodetectors for Image Sensing

“…Although many lowcost fabrication methods, such as the inkjet printing method, [53] blade coating method, [48] rolltoroll printing method, [88] and spraycoating method, [49] have been exploited to prepare the largearea perovskite photo detector arrays, the crystallization quality of asfabricated perovskites is still poor and the crosstalk between pixels is also a problem, which need to be further improved. In addi tion, the templateguided selfassembly method [47,54,55,85,86] and the hydrophilic-hydrophobic surfaceinduced selfassembled patterning method [51,57,58,102] also need to be further developed for the industrial production of perovskite image sensors due to their great potential for the fabrication of highresolution perovskite image sensors. Thirdly, color image sensing is also very significant for the practical applications of perov skite image sensors.…”

“…The image sensor with a 6 × 6 photodetector array also demonstrated the potential imaging application by detecting the red light (650 nm) image of the letter "H" (Figure 12f). Then, Wang et al [102] reported the synthesis of Sn-Pb perovskite film arrays on the TFT arrays by a spinonpatterned deposition with a perfluoro(1butenyl vinyl ether) polymer (CYTOP)assisted hydrophilic-hydrophobic surfaceinduced growth (Figure 12g). A NIR image sensor based on a Sn-Pb perovskite film array was fabricated (Figure 12f), which showed a broad photore sponse range of 300-1000 nm, a high specific detectivity of 10 11 Jones at 850 nm, as well as the rise and decay times of 19 and 13 ms, respectively.…”

“…i) Output photocurrent mapping of the NIR light image of the number "11" by a 10 × 10 photodiode array. g-i) Reproduced with permission [102]. Copyright 2019, Wiley-VCH.…”

A Review of Phototransistors Using Metal Oxide Semiconductors: Research Progress and Future Directions

“…[ 10 ] Therefore, since metal oxide semiconductors do not require an additional crystallization process, the fabrication process of oxide TFTs is less complicated than that of Si‐based TFTs. [ 34 ]…”

“…Recently, phototransistors with a hybrid structure in which such perovskite is stacked together with an oxide semiconductor have been reported. [ 114–119 ]…”