Stability enhancement of lead‐free CsSnI₃ perovskite photodetector with reductive ascorbic acid additive

Abstract

Lead-free tin-based perovskites have attracted widespread research interest due to their nontoxicity and potential commercialization. However, their practical application is limited by high density of intrinsic defects and easy oxidation of Sn 2+ in ambient environment. To address these issues, we demonstrate an environment-friendly stable broadband photodetector based on CsSnI 3 perovskite with conventional SnF 2 and reducing agent ascorbic acid additive.Through optimizing the concentration of ascorbic acid, the optimal device reveals high responsivity (0.257 A W −1 ), fast response speed (0.35/1.6 ms), and excellent stability. The properties are comparable to most previously reported lead-free perovskite photodetectors. The enhanced performance is mainly due to the fact that ascorbic acid promotes the crystal growth, suppresses the formation of Sn 4+ , and makes it have good semiconductivity rather than metallicity.

Lead‐Free Perovskite Photodetectors: Progress, Challenges, and Opportunities

“…[ 38 ] To address issues mentioned above, Cao et al. demonstrate a stable broadband PD through adding SnF 2 and reducing agent ascorbic to CsSnI 3 perovskite precursor; [ 39 ] between them, SnF 2 has been demonstrated to effectively hinder Sn‐based perovskite from degradation. [ 40 ] Optimized device responses broadband ranging from 350 to 1000 nm, along with high responsivity of 0.257 A W −1 , short response time of 0.35/1.6 ms, and outstanding stability as displayed in Figure .…”

Investigation of non-Pb all-perovskite 4-T mechanically stacked and 2-T monolithic tandem solar devices utilizing SCAPS simulation

“…Input parameters have been carefully chosen from published literature [31,42,43] and experimental works [20,22,[44][45][46][47][48]. These parameters are listed in Table 2.…”

“…The inorganic perovskite CsSnX 3 (X = I, Br, Cl), additionally, has been considered to be a viable material to construct various optoelectronic devices, such as photodetectors, memories, solar cells, and light-emitting diodes [21]. CsSnI 3 showcases the smallest bandgap in CsSnX 3 perovskites family [22], together with a high thermal stability, making it an attractive material for a solar device [22]. By utilizing melt-synthesized cesium tin iodide (CsSnI 3 ) ingots that contains high-quality large single-crystal (SC) grains, CsSnI 3 devices have shown marked improvement in bulk carrier lifetimes, doping concentration, and minority-carrier diffusion lengths [23].…”

Progress of Lead‐Free Halide Perovskites: From Material Synthesis to Photodetector Application

“…In addition, our group used additives containing the reducing agent ascorbic acid in the CsSnI 3 perovskite precursor and prepared a CsSnI 3 film by using an antisolvent method ( Figure a). [ 64 ] The optimal sample can remain stable in ≈80% humidity air for one day. The main reduction process was the conversion of ascorbic acid to diketogulonic acid to reduce oxidized Sn 4+ to Sn 2+ , which was also confirmed by X‐ray photoelectron spectroscopy (XPS) (Figure 3b,c).…”

“…b,c) XPS curves of C 1s and Sn 3d of the CsSnI 3 /ascorbic acid sample with the sample exposed in air for 6 h. Reproduced under Creativ Commons Attribution 4.0 International License (CC BY 4.0). [ 64 ] Copyright 2020, The Authors, published by John Wiley Sons.…”