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Article

Effect of Methylammonium Iodide (MACl) on MAPbI3-Based Perovskite UV-C Photodetectors

by
Dong Jae Shin
1,
Sangmo Kim
2 and
Hyung Wook Choi
1,*
1
Department of Electrical Engineering, Gachon University, Seongnam 13120, Republic of Korea
2
Department of Artificial Intelligence Robotics, Sejong University, Seoul 05006, Republic of Korea
*
Author to whom correspondence should be addressed.
Appl. Sci. 2024, 14(14), 6223; https://doi.org/10.3390/app14146223
Submission received: 23 April 2024 / Revised: 15 July 2024 / Accepted: 15 July 2024 / Published: 17 July 2024
(This article belongs to the Special Issue Solar Energy and Photovoltaic Technologies, Materials and Their Applications)
Browse Figures
Versions Notes

Abstract

:
In this study, we fabricated deep ultraviolet (DUV) photodetectors based on perovskite thin films doped with halide materials using formamidinium bromide (FABr) and methylammonium iodide (MAI). The device was fabricated using a simple surface engineering technique by post-treating the MAPbI3 perovskite film with an FABr solution. This film acts as a light absorption layer, like a depletion layer with a p-i-n (PIN) structure, with n-type of SnO2-SDBS and p-type of spiro-OMeTAD. Adding 0.10 M MACl to the MAPbI3 precursor solution during the manufacturing process could effectively reduce the trap density compared with existing films. Films with MACl added in the two-step process can control a wide band gap and improve crystallinity. In addition, the Cl atom has a smaller atomic radius than iodine and a higher electronegativity of 3.16, which can improve phase stability, and the effect of the added Cl− increases the electron mobility of the perovskite, showing a fast response.

1. Introduction

Recenltly, ultraviolet-light (UV) or deep ultraviolet-light (DUV) photodetectors (PDs) have garnered significant interest from many scientists or experts due to their ob-jective in various optoelectronics devices, for example, solar UV monitoring, medical im-age analysis, covert communication (CC), lithography aligners, photodetector, secure space-to-space communications, and detection of missiles [1,2,3].
Generally, UV-light rays are divided into three parts depending on the wavelength range: UV-A (~400–320 nm), UV-B (~320–280 nm), and UV-C (~280–100 nm) [1]. From the Sun, UV radiation is directly irradiated to the Earth at all wavelengths but a little UV light is allowed to the Earth’s surface due to the ozone layer surrounding the Earth. Before most UV-B and UV-C rays reach the surface of Earth, the ozone layer absorbs all of them. However, some UV-A reaches the surface of Earth despite the ozone layer and other protective layers [4]. Sometimes UV-C can be observed from the corona discharge sur-rounding wire or insulator in the electric power poles, lightning strikes, or artificial light sources (lamp or laser) [5].
When short-wavelength ultraviolet rays of 300 nm or less reach human skin, they penetrate into the epidermis and have adverse effects on skin diseases, eye diseases, and the immune system, emerging as a hazardous substance to the human body [6,7]. Therefore, studies on PDs have detection functions for the UV-C region and need conversion process that changes from the irradiated UV-C light to an electrical signal.
In previous studies, methods using semiconductor materials with a high bandgap (>3.0 eV) including AlGaN, MgZnO, Ga2O3, ZnGa2O4, and MoS2 were attempted. However, these semiconductor materials should be synthesized at high temperatures in sophisti-cated equipment [8,9,10]. As an alternative, silicon (Si) photodiode that are equipped with a UV filter have been studied for UV-C sensor due its narrow bandgap, but excellent per-formance cannot be expected in UVC detection of Si diodes because light-generated carri-ers do not reach the depletion layer [11,12]. In contrast, low-temperature solution pro-cessing is increasingly applied using perovskite materials compared with other semi-conductors [13,14]. Perovskite has a notable absorption coefficient of nearly 105 cm−1 in the UVC spectral range and exhibits high mobility. This suggests that perovskite can exhibit higher sensitivity and faster response as a UV-C sensor than other sensors [15,16].
In recent research, the organic-inorganic hybrid perovskite used as a light absorber due to its excellent optical properties has a crystal structure of ABX3. Hybrid perovskite consists of organic and inorganic cations. Organic cations such as methylammonium (MA+, CH3NH3) and formamidinium (FA+, CH(NH2)2) are placed in A, and metal cations such as lead and tin are placed in B. At X, halogen anions such as I−, Br−, and Cl− are arranged to form a structure [17,18,19]. Organic-inorganic hybrid perovskites can control the band gap through halogen and anion substitution, and show its characteristics such as high absorption coefficient of light, long diffusion distance, and high electron mobility research on this has been conducted to determine the optimal perovskite composition. There has been a shift toward engineering [20,21]. MAPbX3, a representative organic-inorganic perovskite material, changes its valence band level by the 3p, 4p, and 5p orbitals of Cl−, Br−, and I− halogen ions respectively. When I− ions are arranged at the X position, it exhibits a band gap of approximately 1.5 eV, and when substituted with Br− ions, it increases to about 2.2 eV, when substituted with Cl− ions, it further increases to around 3.1 eV [22,23]. In this man-ner, MAPbX3 allows smooth band gap tuning by varying the material composition. This feature suggests that hybrid perovskites can be applied as light-absorbing layers in vari-ous fields and can enhance the device efficiency. Therefore, research is ongoing to enhance stability by utilizing combinations of monovalent cations like MA+, FA+, and CS+ or by incorporating halides such as Cl− and, Br− to improve the performance of optical components [24,25].
In this work, to improve the detection performance of the perovskite based UV-C photo-detector (PD), anions were mixed with MAPbI3—based hybrid perovskite film and played a role as a light absorption layer. In a fabrication process (2-step), a precursor solution was prepared by adding 0.10 M MACl to MAPbI3, and FABr was added as a post-treatment solution. MACl-doped perovskites have flexible bandgaps and exhibit improved crystal-linity. MACl-doped MAPbI3 thin films have high surface coverage, forming large perov-skite particles, which promotes electron transfer and improves device performance. Cl atoms have a smaller atomic radius compared to I and higher electronegativity of I (2.66) and Cl (3.16), which can improve phase stability, the effect of adding Cl− increases the electron mobility of perovskite, resulting in faster reaction. It looks like attempts to im-prove PD performance by post-treating the CH3NH3PbX3 precursor solution with anions have been reported in previous studies. This study presents a new direction by adding anions to the precursor solution. As a result, the fabricated perovskite-based PDs showed more sensitivity and higher detection performance for UV-C than the previously studied FABr-posttreated MAPbI3 precursor solution.

2. Materials and Methods

2.1. Experimental Materials

During this study, we purchased all experimental materials from commercial companies and used them without any additional purification process. Firslty, a quartz glass substrate (2 cm × 2 cm, Substrate thickness < 0.1 mm) coated with Indium Tin Oxide (ITO, Film thickness < 150 nm, Sheet resistance < 8 ohm/sq) was provided by the company TMA (Seoul, Republic of Korea). Tin(IV) oxide (SnO2, Alfa Aesar, Haverhill, MA, USA) was used as colloidal solution of 15 wt.% in water. We used methylammonium iodide (CH3NH3I, MAI), methylammonium hydrochloride (CH6ClN, MACl), and formamidinium bromide (CH5BrN2, FABr) that were produced from Greatcell Solar Materials. Ethyl alcohol (≥99.5%) was purchased from Duksan Pure Chemical Company. Pb(II) iodide (PbI2, 99.999%), 1-butyl alcohol (C4H9OH, ≥99%,), sodium dodecylbenzenesulfonate (SDBS, CH3(CH2)11C6H4SO3Na), acetonitrile (ACN, C2H3N, 99.93%), dimethyl sulfoxide (DMSO, (CH3)2SO; ≥99.9%), N,N-dimethylformamide (DMF, HCON(CH3)2; 99.8%), spiro-MeOTAD (C81H68N4O8; ≥99%), 2-propanol (IPA; 75 wt.%), lithium bistrifluoromethanesulfonimidate (CF3SO2NLiSO2CF3; ≥99.0%), toluene (99.9%), and 4-tert-Butylpyridine (C9H13N, 98%) were used and supplied from Sigma-Aldrich Chemical sciences company (St. Louis, MO, USA).

2.2. Device Fabrication Process of MAPbI3-Based Perovskite Photodetector

Before device fabrications, the ITO coated quartz glass substrates were purified to remove any impurities such as organic or inorganic particles. The ITO-coated substrates were then subsequently cleansed using an ultrasonic bath with a mild liquid soap, IPA, acetone, and purified water (D.I. Water < 18 MΩ) for about 15 min each. Then, any residue on the surface of the substrates was blown away by pure nitrogen gas. Subsequently, they were transferred to UV ozone treatment equipment and the contamination was removed from the surface of the substrate.
After the cleaning process, we dropped 1.2 mL of the SnO2 colloidal solution diluted in 5.2 mL of deionized water and mixed it with a magnetic stirrer. SDBS (1 mg) was added to the diluted solution to prepare the SnO2–SDBS mixed solution.
Next, to form the electron transport layer, the SnO2–SDBS mixed solution (500 μL) was dropped on the substrate and coated at 3000 rpm in a spin coater for 30 s. The samples were moved to hot plate and heated at 150 °C for 30 min. After that, the samples were cleaned in Ultraviolet (UV)-Ozone Cleaning Systems for 20 min to remove any impurities including moisture in the inside of coated films on the substrate before perovskite layer deposition.
To prepare MAPbI3 perovskite precursor solution, DMF and DMSO were mixed in 10:1 v/v and PbI2 (1.4 mol), MAI (1.4 mol), and MACl (0.10 M) were solved in the DMF and DMSO mixture with magnetic strring. The mixture process was conducted under the condition that it was stored completely unexposed from any light for 3 h (200 rpm) to form uniform particles in the perovskite layer of photo-detector devices.
FABr chemicals were solved in various contents (0, 5, 10, 15, 20, and 25 mg) with IPA solution. The FABr solutions were transferred to a Teflon container and stirred for 1 h (200 rpm) for FABr post-processing. Subsequently, toluene (250 μL) was added dropwise for 15 s on the surface of the substrate during the spin coating process to form an antisolvent.
The perovskite (MAPbI3) layer was formed on the SnO2–SDBS/ITO-coated quartz substrate with a spin-coating process at 4000 rpm for 25 s. After spin coating, the samples were treated at a temperature of 140 °C for 15 min on a hotplate and naturally cooled down. A spiro-OMeTAD solution was prepared as the following process; chlorobenzene solution (1 mL) contained 72.3 mg of Spiro-OMeTAD, 28.8 μL of 4-tert-Butyl pyridine, and 17.5 μL of Lithium bistrifluoromethanesulfonimidate solution (ACN in 1 mL of Lithium bistrifluoromethanesulfonimidate 520 mg). The Spiro-OMeTAD solution was dopped on the perovskite layer grown on the substrate and was coated at 2000 rpm for 35 s. Finally, we employed a thermal evaporator for Au deposition. An Au top electrode was thermally evaporated in a vacuum of 2 × 106 Torr. The vertical structure of the photo detector device and the more detailed photo detector device fabrication process are shown in Figure 1a,b.

2.3. Device Characterization

High resolution X-ray Diffractometer (XRD; SmartLab, Rigaku, Tokyo, Japan) analysis was performed using Cu-Kα radiation (3 KW, λ = 1.542 Å) to investigate the crystal structure of the film. Field-emission scanning electron microscopy (FE-SEM; Hitachi, S-4700, Tokyo, Japan) was used to observe the surface morphology of as-prepared films. The light absorption properties of the samples were measured using an ultraviolet-visible (UV-vis) spectrophotometer (Agilent 8453, Santa Clara, CA, USA). The photon energy (energy band gap, Eg) of samples was calculated from the absorption data by plotting the graph between (αhν)2 on the y-axis versus photon energy (eV) on the x-axis. A combined source and measurement meter (Source Measure Unit, Keithley 2400, Cleveland, OH, USA) was used to measure the electrical responses of the perovskite PDs. A UV lamp (6 W, 254 nm) (VL-6. LC; Vilber Lourmat, Collégien, France) irradiated the cells at 254 nm.

3. Results and Discussion

3.1. Crystallinity and Surface Morphological Properties of the Samples

The thin films produced in this method are labeled with FABr 0, 5, 10, 15, 20, and 25 (mg) depending on the Br− mixture. Figure 2 shows the XRD patterns. This pattern indicated the formation of crystals in the thin film. Figure 2a shows the XRD patterns of bare MAPbI3 coated at 4000 rpm, MAPbI3 with the antisolvent process, and the MAPbI3 thin film with 0.10 M MACl. As shown in Figure 2a, sharp diffraction peaks are observed at 2θ = 14.12° and 28.46°, which are assigned to the planes (110) and (220), respectively. For the bare coating at 4000 rpm, the 12.5° (001) peak of PbI2 was very large. This can be attributed to the formation of PbI2 crystals owing to the thermal decomposition of CH3NH3I [26,27,28]. In the case of MAPbI3, with the addition of an antisolvent process, the PbI2 peak decreased rapidly compared with the bare MAPbI3, and when 0.10 M of MACl was added, the PbI2 peak became negligibly small. The sizes of the MAPbI3-coated crystal for each variable calculated using the Debye–Scherrer equation were approximately 38.02, 36.37, and 34.85 nm. The XRD peak attributed to the (110) crystal plane of the MAPbI3 film with the addition of 0.10 M MACl shifted to a larger diffraction angle of 14.18°. The lattice constant calculated using Bragg’s law was 3.156 Å at a diffraction angle of 14.12°, and decreased to 3.1432 Å at 14.18°. The lattice constant is believed to decrease because of the addition of Cl, which has a smaller atomic radius. This suggests that, in this study, a UV PD with improved performance was fabricated by adding MACl to the precursor solution. Figure 2b illustrates that the crystallinity of the film steadily enhances with increasing FABr content in the MAPbI3 precursor solution with the addition of 0.10 M MACl. The reduced peak intensity of FABr 25 indicates that the high density of FABr causes particle shrinkage, which negatively affects the crystalline film formation. The optimal crystallinity is observed for FABr 20. The optical properties are improved through the anion addition process, which means that the performance of PD is improved [29].
Figure 3 shows the results of observing the surface morphology of each perovskite film using SEM. By adding MACl to the precursor solution, overall, a more stable surface formation was observed compared with that of the MAPbI3 thin film without the addition of MACl. As the post-treatment solution was added, the surface of the film was stabilized and particle formation was improved. This indicates improved photoelectric behavior, characterized by extended carrier lifetime and enhanced light absorption [30,31]. Figure 3a shows that in the case of the bare MAPbI3 film, the particle size is not uniform, pinholes are observed, and surface formation is unstable. Additionally, PbI2 residues are observed, which may be due to the dewetting phenomenon [32]. Therefore, the thickness of the thin film in the vertically structured device becomes unstable and deteriorates in quality. The thin film of MAPbI3 with the added anti-solvent process in Figure 3b shows a more uniform surface than Figure 3a. The MAPbI3 thin film with 0.10 M MACl added in Figure 3c forms large perovskite particles due to its high surface coverage, facilitating the movement of electrons and improving device performance. Consequently, Figure 3 shows that adding an anti-solvent process or adding Cl anions to MAPbI3 affects the structural change in the perovskite, resulting in a change in its properties [33].

3.2. Optical and Electrical Properties of Samples

The UV–vis absorption spectrum in Figure 4a shows the absorbance of the fabricated film. The absorption spectrum was relatively improved as the Br− increased. Various results were obtained depending on the mixture of FABr in the 2-step process to the previously prepared MAPbI3 precursor solution containing Cl anions, with FABr 20 showing the best absorbance. These results appeared as the composition ratio of the X site in MAPbX3 changed. The addition of an optimal amount of Br− is expected to improve the binding density of particles and membrane properties, as shown in the absorbance measurement results [34]. The dependence of (F(R∞)hv)2 on photon energy using the Kubelka–Munk function is shown in Figure 4b. Sharp band edges were observed for MAPbI3, indicating a direct bandgap of MAPbI3. This indicates that the bandgap can be adjusted by controlling the amount of FABr added.
Resistivity, mobility, and carrier concentration shown in Figure 5 are important indicators in evaluating the optical properties of the produced film and were analyzed by the Hall measurement meter [35]. By varying the composition ratio of anions during the post-processing process, changes in the properties of the film can be observed. The resistivity of FABr 0 was 0.7604 Ω∙cm, whereas the FABr-doped perovskite films, FABr 5 to FABr 25, and exhibited resistivities of 0.2415, 0.2847, 0.2198, 0.1977, and 0.8211 Ω∙cm, respectively. The pure film (FABr 0) exhibited a mobility of 5.23 cm2/V∙s, whereas FABr 20 exhibited a mobility of 26.57 cm2/V∙s, the optimum value among the tested samples. Mobility is correlated with structural changes in the film. Electronegativity is Cl (3.16) and Br (2.96), which are higher than I (2.66), and the lattice constant and interatomic distance decrease due to changes in relative bond length. At the point where the mobility decreases, it can be seen that excessive anion has been added [36]. Therefore, it can be seen that the addition of appropriate anions can generate more photocurrent and improve the quality of PD [37]. The characteristic values covered in Figure 5 are shown in Table 1.

3.3. Ultraviolet (UV) Detection Performance Evaluation of the Fabricated Photodetection Device

The properties of MAPbI3 PD doped with 0.10 M MACl can be investigated by irradiating the light of wavelength 254 nm with a light intensity of 0.774 mW/cm2 in the dark experimental condition and analyzing the current-voltage (I-V) characteristics from −2 to +2 V. Figure 6 indicates the generated photocurrent depending on the mixture of Br−. The generation of the photocurrent is affected by the intensity of the irradiated light and the bias voltage. The photocurrents generated at a voltage of 2 V were 36.8, 56.2, 76.2, 91.5, 115.2, and 80.9 μA, respectively, for the addition of FABr 0, FABr 5, FABr 10, FABr 15, FABr 20, and FABr 25. As the ratio of Br− increases, the amount of photocurrent generated increases. As can be seen in the previous pictures, this is because the extinction coefficient increased as the film gained structural stability. At the point where the photocurrent decreases again, it can be seen that excessive addition of anions has occurred. This suggests that an appropriate composition ratio is necessary for improved properties of the film.
Figure 7a shows the responsivity (R) and detectivity (D) of as-prepared films. R represents the response efficiency of the fabricated PDs to the irradiated UV light. As the FABr content increased from FABr 0 to FABr 20, the R values increased to 24.5, 37.4, 50.7, 60.9, and 76.7 mA/W, respectively. However, for FABr 25, the R-value decreased to 53.9 mA/W. In addition, the D value is an important characterisic that indicates whether the PD area can be detected. Detectivity (D) is related to the R-value and noise of the device and can be validated by these characteristics. The R- and D-values are proportional. As R values are increasing, the D values are also increased. The D values of the produced films increased to 1.82 × 1012, 5.12 × 1012, 2.61 × 1013, 3.07 × 1013, and 4.89 × 1013 Jones for FABR 0 to FABr 20. However, for FABr 25, it decreased to 2.67 × 1013 Jones. The corresponding values are shown in Table 2.
Figure 7b illustrates the external quantum efficiency (EQE) of the PD as a function of the amount of FABr added. The EQE refers to how much photon is produced compared to injected electrons in the device (PDs) and the value shows the ratio of the number of photons versus electrons. A high EQE indicates a good PD conversion efficiency. With increasing FABr content, the EQE values at 2 V increased to 19%, 28%, 39%, 47%, and 60% for FABr 0 to FABr 20, respectively. However, for FABr 25, the EQE decreased to 42%. Overall, the MAPbI3 perovskite film mixed with MACl shows more improved performance parameters than the previous study. This means that the mixed anionic film has superior photoelectric properties than the single film.
Figure 8a shows the ultraviolet (UV) detection performance evaluation of PDs without and with MACl. The response properties of MAPbI3 were measured at a bias voltage of 1 V and a 254 nm light source with a light intensity of 0.774 mW/cm2. If the signal input to the manufactured photodetector changes with time, a delay occurs until it reaches the output of the device, and this is the response time. There is an inverse correlation between response speed and response time and these are important factors in evaluating PD performance. Rise/decay times show rise/decay times of 46.1 ms/44.3 ms, 39.2 ms/45.9 ms and 36 ms/32 ms. Figure 8b shows the ON/OFF repeatability of the MAPbI3 sensor with 0.10 M MACl added at a 254 nm light source with a light intensity of 0.774 mW/cm2. For the first time, the photocurrent was 2.19 μA, and after 100 repetitions, the photocurrent was 2.53 μA. It can be seen that reproducibility is continuously maintained compared to the initial photocurrent. It demonstrates the stability of the PD.

4. Conclusions

An anion mixed perovskite UVC PD was produced by adding FABr to a precursor solution of 0.10 M MACl stirred in MAPbI3. The fabricated UV PD exhibited superior performance compared to the previously studied MAPbI3-based perovskite PDs. A more stable perovskite PD was also obtained by adding a halide (Cl−) to the antisolvent. The bare film, the film that went through the anti-solvent process, and the film with MACl added showed sequentially better photoelectric properties under a 254 nm far-ultraviolet light source. This appears to be because the MACl-doped MAPbI3 thin film forms large perovskite particles due to its high surface coverage, facilitating the movement of electrons and improving device performance. Therefore, the proposed PDs are expected to be useful for various fields.

Author Contributions

Device fabrication and sample measurement and original draft preparation: D.J.S.; Analysis and editing: S.K.; Supervision and editing: H.W.C. All authors have read and agreed to the published version of the manuscript.

Funding

Basic Science Research Capacity Enhancement Project through a Korea Basic Science Institute (National Research Facilities and Equipment Center) grant funded by the Ministry of Education (2019R1A6C1010016) and 2023 Gachon University Research Grant (GCU-202300810001).

Institutional Review Board Statement

Not applicable.

Informed Consent Statement

Not applicable.

Data Availability Statement

Data are contained within the article.

Acknowledgments

This research was supported by the Basic Science Research Capacity Enhancement Project through a Korea Basic Science Institute (National Research Facilities and Equipment Center) grant funded by the Ministry of Education (2019R1A6C1010016) and by the 2023 Gachon University Research Grant (GCU-202300810001).

Conflicts of Interest

The authors declare no conflict of interest.

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Figure 1. (a) Schematic and (b) manufacturing process of MAPbI3-based deep-UV PD.
Figure 1. (a) Schematic and (b) manufacturing process of MAPbI3-based deep-UV PD.
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Figure 2. XRD patterns of (a) MAPbI3 and (b) films with different amounts of FABr added.
Figure 2. XRD patterns of (a) MAPbI3 and (b) films with different amounts of FABr added.
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Figure 3. SEM images of MAPbI3-based perovskite films: (a) Bare, (b) Anti-solvent, (c) 0.10 M MACl.
Figure 3. SEM images of MAPbI3-based perovskite films: (a) Bare, (b) Anti-solvent, (c) 0.10 M MACl.
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Figure 4. (a) UV–vis absorbance spectra and (b) bandgaps of films with different amounts of FABr added.
Figure 4. (a) UV–vis absorbance spectra and (b) bandgaps of films with different amounts of FABr added.
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Figure 5. Electrical properties (Resistivity, Mobility, and Carrier concentration) of samples as a function of FABr 0−25.
Figure 5. Electrical properties (Resistivity, Mobility, and Carrier concentration) of samples as a function of FABr 0−25.
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Figure 6. I-V characteristics of the (MAPbI3)0.96(MACl)0.04-based PD (a) FABr 0, (b) FABr 5, (c) FABr 10, (d) FABr 15, (e) FABr 20, and (f) FABr 25.
Figure 6. I-V characteristics of the (MAPbI3)0.96(MACl)0.04-based PD (a) FABr 0, (b) FABr 5, (c) FABr 10, (d) FABr 15, (e) FABr 20, and (f) FABr 25.
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Figure 7. (a) Calculated R as a function of voltage and D*, and (b) EQE.
Figure 7. (a) Calculated R as a function of voltage and D*, and (b) EQE.
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Figure 8. (a) Current−time characteristics of the UV photodetectors, (b) Photostability.
Figure 8. (a) Current−time characteristics of the UV photodetectors, (b) Photostability.
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Table 1. Resistivity, mobility, and carrier concentration of all the films.
Table 1. Resistivity, mobility, and carrier concentration of all the films.
Sample NameResistivity (ρ)
(Ω-cm)		Mobility (μ)
(cm2/V∙s)		Carrier Concentration (n)
(×1013 cm−3)
FABr 00.7604 (0.7704)5.23 (5.01)2.607 (2.506)
FABr 50.2415 (0.2519)11.67 (11.47)3.012 (2.821)
FABr 100.2847 (0.2975)12.89 (12.64)3.841 (3.564)
FABr 150.2198 (0.2249)14.61 (14.29)5.619 (5.358)
FABr 200.1977 (0.2077)26.57 (25.48)5.864 (5.469)
FABr 250.8211 (0.8474)18.02 (17.48)4.782 (4.242)
( ) is the value after going through the anti-solvent process without adding MACl.
Table 2. Performance parameters of the PD according to the amount of FABr added before and after.
Table 2. Performance parameters of the PD according to the amount of FABr added before and after.
Sample NameResponsivity (R)
(mA/W)		Detectivity (D)
(Jones)		EQE
(%)
FABr 024.5 (21.1)1.82 × 1012 (1.74 × 1012)19 (16)
FABr 537.4 (34.4)5.12 × 1012 (4.98 × 1012)28 (27)
FABr 1050.7 (46.7)2.61 × 1013 (2.38 × 1013)39 (36)
FABr 1560.9 (56.8)3.07 × 1013 (2.89 × 1013)47 (44)
FABr 2076.7 (72.2)4.89 × 1013 (4.67 × 1013)60 (56)
FABr 2553.9 (50.2)2.67 × 1013 (2.44 × 1013)42 (39)
( ) is the value after going through the anti-solvent process without adding MACl.
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MDPI and ACS Style

Shin, D.J.; Kim, S.; Choi, H.W. Effect of Methylammonium Iodide (MACl) on MAPbI3-Based Perovskite UV-C Photodetectors. Appl. Sci. 2024, 14, 6223. https://doi.org/10.3390/app14146223

AMA Style

Shin DJ, Kim S, Choi HW. Effect of Methylammonium Iodide (MACl) on MAPbI3-Based Perovskite UV-C Photodetectors. Applied Sciences. 2024; 14(14):6223. https://doi.org/10.3390/app14146223

Chicago/Turabian Style

Shin, Dong Jae, Sangmo Kim, and Hyung Wook Choi. 2024. "Effect of Methylammonium Iodide (MACl) on MAPbI3-Based Perovskite UV-C Photodetectors" Applied Sciences 14, no. 14: 6223. https://doi.org/10.3390/app14146223

APA Style

Shin, D. J., Kim, S., & Choi, H. W. (2024). Effect of Methylammonium Iodide (MACl) on MAPbI3-Based Perovskite UV-C Photodetectors. Applied Sciences, 14(14), 6223. https://doi.org/10.3390/app14146223

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