Next Article in Journal
Stock Index Prediction Based on Time Series Decomposition and Hybrid Model
Next Article in Special Issue
Sublimation Study of Six 5-Substituted-1,10-Phenanthrolines by Knudsen Effusion Mass Loss and Solution Calorimetry
Previous Article in Journal
Enhancement of Cooperation and Reentrant Phase of Prisoner’s Dilemma Game on Signed Networks
Previous Article in Special Issue
Entropy Effects in Intermolecular Associations of Crown-Ethers and Cyclodextrins with Amino Acids in Aqueous and in Non-Aqueous Media
 
 
Font Type:
Arial Georgia Verdana
Font Size:
Aa Aa Aa
Line Spacing:
Column Width:
Background:
Article

Thermodynamic Study of Formamidinium Lead Iodide (CH5N2PbI3) from 5 to 357 K

1
Department of Chemistry, Sapienza University of Rome, P.le A. Moro 5, Building CU014, I-00185 Rome, Italy
2
Department of Chemistry, National Research Lobachevsky State University of Nizhny Novgorod, 23/5 Gagarin Av., 603950 Nizhny Novgorod, Russia
3
Department of Basic and Applied Science for Engineering (S.B.A.I.), Sapienza University of Rome, Via del Castro Laurenziano 7, Building RM017, I-00161 Rome, Italy
*
Authors to whom correspondence should be addressed.
Entropy 2022, 24(2), 145; https://doi.org/10.3390/e24020145
Submission received: 17 December 2021 / Revised: 13 January 2022 / Accepted: 14 January 2022 / Published: 18 January 2022

Abstract

:
In the present study, the molar heat capacity of solid formamidinium lead iodide (CH5N2PbI3) was measured over the temperature range from 5 to 357 K using a precise automated adiabatic calorimeter. In the above temperature interval, three distinct phase transitions were found in ranges from 49 to 56 K, from 110 to 178 K, and from 264 to 277 K. The standard thermodynamic functions of the studied perovskite, namely the heat capacity C°p(T), enthalpy [H0(T) − H0(0)], entropy S0(T), and [G°(T) − H°(0)]/T, were calculated for the temperature range from 0 to 345 K based on the experimental data. Herein, the results are discussed and compared with those available in the literature as measured by nonclassical methods.

1. Introduction

Since their first appearance in 2009, perovskite solar cells have attracted a great deal of attention, owing to their relatively simple technology and good performance. Nowadays, they constitute the photovoltaic technology with the fastest-growing conversion efficiency [1,2]. The first compound of the hybrid perovskite family to be extensively studied for photovoltaic devices was methylammonium lead iodide, CH3NH3PbI3 [3,4,5]. Its intriguing photophysical properties, such as its direct band gap, with a value very near optimal one for photovoltaic conversion of solar radiation, and its defect tolerance, were thoroughly studied following the discovery of its exceptional photovoltaic performance [6,7,8]. However, the limited chemical and thermal stability of CH3NH3PbI3 immediately emerged as a very serious problem. In spite of their impressive performances in photovoltaic devices, perovskite solar cells seem quite far from commercial debut.
The search for alternative compounds with enhanced stability led researchers to focus on cesium lead iodide (CsPbI3) and formamidinium lead iodide (CH5N2PbI3, FAPI) as the most promising options [9]. Both compounds have been extensively tested, either pure and in solid solutions (also with CH3NH3PbI3) [10,11,12,13]. Both CsPbI3 and CH5N2PbI3 occur as black phases (useful for photovoltaic purposes) at relatively high temperatures (T > 320 °C for CsPbI3 [14] and T > 185 °C for CH5N2PbI3 [15,16]) and yellow phases at lower temperatures.
In order to assess the stability under various operating conditions, a full thermodynamic characterization of the material and of its possible decomposition pathways is mandatory. To date, enthalpy and free-energy data have been published for CH3NH3PbI3 [17,18,19,20,21,22] and, to a lesser extent, for CsPbI3 [23,24,25,26]. Recently, data on the thermodynamic stability of CH5N2PbI3 were published by our group [27].
In this connection, the measurement of heat capacities from low temperature up to decomposition temperatures is of utmost importance to derive absolute entropy values and to calculate the values of thermodynamic quantities at temperatures different from those explored in the experiments. Furthermore, the study of heat capacities is of great help to investigate the low-temperature phase transitions that occur in the material, the dynamics of molecular motions, and the nature of the molecule–cage interaction [28], which is important to clarify the role of the organic cations in the photovoltaic performance. To the best of our knowledge, heat-capacity values measured by adiabatic calorimetry are available in literature only for CH3NH3PbI3 [5,29]. In regard to CH5N2PbI3, few papers are available wherein the heat capacity was reported [28,30,31]. In particular, Fabini and colleagues measured the heat capacities of powder samples in temperature ranges across the phase transitions by the pulse-relaxation method [28] and by differential scanning calorimetry [30], whereas Kawachi and colleagues [31] reported measurements of single crystal samples by the relaxation technique. The aim of the present paper is to present the first experimental determination of the heat capacities of CH5N2PbI3 in the temperature range from 5 to 357 K by classic adiabatic calorimetry and to provide the thermodynamic functions derived therefrom.

2. Materials and Methods

Synthesis and structural characterization of either methylammonium lead iodide (MAPI) or FAPI were carried out according to procedures reported in detail in previous studies [18,27].
The heat capacity of MAPI and FAPI was measured over the range of T = (5–357) K using an automatic BCT-3 low-temperature adiabatic calorimeter. The calorimeter was manufactured at ‘‘Termis” joint-stock company at the All-Russian Metrology Research Institute, Moscow, Russia. Its design and operation procedure are described in [32]. The iron and rhodium thermometer (resistance at T = 273.1 K is ~51 Ω) was calibrated on the basis of ITS-90 [33]. Liquid helium and nitrogen were used as cooling agents.
The ampoule with the fine crystalline substance was filled with dry helium as a heat-exchange gas to a pressure of 4 kPa at room temperature. The reliability of the calorimeter was checked by measuring C°p,m of standard samples of high-purity copper [34], standard synthetic corundum, n-heptane (chromatographically pure) [35], and K-3 benzoic acid [36,37] prepared at the Institute of Metrology of the State Standard Committee of the Russian Federation.
The test of the calorimeter revealed that average deviations of the experimental data from the precision literature data were 2% at T = (5–15) K, 0.5% at T = (15–40) K, and 0.2% at T = (40–357) K. The phase-transition temperatures were measured within a standard uncertainty of about u(T) = 0.01 K. The mass of the sample loaded in a 1.5 cm3 thin-walled cylindrical titanium ampoule of the BCT-3 device was 1.5551 g. The C°p,m measurements were carried out in the range of T = (5–357) K.
The experimental C°p,m values (Table 1) were obtained in six runs. The heat capacity of the sample varied from 54 to 92% of the total heat capacity of the (calorimetric ampoule + substance) in the range of T = (5–357) K.
The experimental C°p,m points were smoothed in all the temperature regions for which any transformations were absent, according to the following polynomials (Equations (1)–(3)):
C ° p , m = j = 1 n A j · ( T / 30 ) j         ( 177.35 264.5 )   K   and   ( 277.0 348.6 )   K
C ° p , m = j = 1 n A j · ln ( T / 30 ) j         ( 15.1 49 )   K   and   ( 55.3 169.25 )   K
ln C ° p , m = j = 1 n A j · ln ( T / 30 ) j         ( 5.1 15.59 )   K
where Aj represents the fitting polynomial coefficients, and n is the number of coefficients. The standard atomic masses recommended by the IUPAC Commission in 2013 [38] were used in the calculation of all molar quantities.
Table 1. The experimental values of the molar heat capacity of CH5N2PbI3 in J·K−1·mol−1, M(CH5N2PbI3) = 63,297,507 g·mol−1, p° = 0.1 MPa.
Table 1. The experimental values of the molar heat capacity of CH5N2PbI3 in J·K−1·mol−1, M(CH5N2PbI3) = 63,297,507 g·mol−1, p° = 0.1 MPa.
T/KC°p,m/
J·K−1·mol−1
T/KC°p,m/
J·K−1·mol−1
T/KC°p,m/
J·K−1·mol−1
Series 1
5.162.5617.0634.2451.44134.6
5.312.7517.5635.7452.62172.6
5.553.2018.0537.3553.87149.8
5.773.5218.5538.9255.27124.6
5.993.9619.0540.4356.61125.8
6.244.3019.5542.0957.89126.6
6.534.8420.0543.7659.16127.9
6.835.4320.8946.0860.44128.6
7.136.0422.0449.7161.72129.6
7.446.6123.2153.2662.99130.7
7.757.3224.3856.7964.27131.3
8.078.0025.5759.9865.54132.4
8.408.7226.7663.2166.82132.8
8.729.5127.9666.5168.10133.6
9.0510.329.1769.8569.38134.2
9.3811.130.3773.1471.10135.4
9.7212.031.5976.2873.26136.5
10.0612.932.8279.4175.42137.6
10.4513.934.0482.2077.57139.0
10.9015.235.2785.0079.74140.3
11.3516.536.5087.2981.90141.5
11.8117.937.7489.9084.06142.9
12.2719.238.9892.4786.23144.2
12.7320.840.2394.7688.40145.7
13.2022.241.4897.2890.57147.1
13.6723.742.73100.292.74147.9
14.1425.143.97103.394.91149.3
14.6226.645.22105.897.08150.4
15.1127.9746.47108.399.26151.9
15.5929.5847.73110.4101.63153.3
16.0831.0948.98115.6104.22154.2
16.5732.7550.21128.0
Series 2
44.57104.049.05114.752.90176.5
45.42105.849.93124.554.48127.4
46.33107.850.84129.855.51123.9
47.23110.151.74138.457.70126.9
48.13112.352.50171.759.21128.2
Series 3
84.76143.3156.2200.20224.31175.8
86.66144.8158.8204.09226.91175.9
88.35145.7161.4208.57229.51177.0
90.04146.5164.0213.7232.12177.2
91.72147.6166.6219.2234.75177.2
93.41147.8169.2226.3237.38178.6
95.08149.5171.9227.4240.00178.9
96.78150.2174.6173.0242.61180.0
99.54151.6177.4169.6245.22180.6
102.49153.5180.0169.6247.86180.9
105.07155.0182.6169.4250.48181.6
107.65156.5185.3169.3253.10182.1
110.23158.0187.9169.6255.72182.8
112.81159.9190.5169.9258.34183.5
115.40161.7193.1170.2260.97184.6
118.00163.2195.7170.5263.62185.4
120.57165.1198.3170.8266.26186.6
131.30174.1200.9171.6268.88188.4
134.33176.2203.5171.9271.50194.0
137.46179.6206.1172.3274.12194.3
140.49182.8208.7172.8276.77188.6
143.09185.9211.3173.3279.42186.6
145.70188.0213.9173.7282.06186.9
148.31190.4216.5174.2284.70187.2
150.93192.9219.1174.4287.34187.0
153.54196.7221.7175.3289.97188.3
Series 4
173.77183.3220.70174.9277.37186.6
177.43169.3223.74175.5280.60185.9
180.54169.2226.84176.3283.83186.1
183.62169.5229.92177.2287.06186.4
186.70169.6233.04177.5291.10187.2
189.78169.8236.18178.5293.54187.2
192.86169.7239.31179.2296.79187.6
195.93170.2242.43180.0300.04187.8
199.01170.8245.56180.2303.93187.9
202.08171.5248.72180.8308.43188.3
205.16172.0251.86181.6313.84189.4
208.24172.5255.01182.2318.91190.1
211.33172.8258.17183.2323.13190.9
214.42173.3261.33184.0327.41191.1
217.51174.2264.50185.3331.66191.7
220.60174.2267.68187.5335.91192.2
223.74175.5270.85194.3340.15191.8
217.51174.2274.14191.9344.39194.0
Series 5
119.77164.5185.93171.6265.82192.5
122.18166.2188.99172.2268.91196.1
124.25167.2192.06172.1272.00201.5
126.31169.6195.12172.8275.12195.2
128.36174.8198.18173.2278.26193.5
130.40179.3201.23174.0281.39194.3
132.45178.1204.31174.5284.53191.5
134.52178.8207.37174.9287.67191.1
136.57183.6210.43175.4290.83188.6
138.60186.4213.49176.1294.00188.3
140.59187.6216.55176.8297.17187.8
142.78182.6219.61177.3300.35188.4
145.02182.7222.67178.4304.13189.5
147.19184.0225.73179.3308.31189.2
149.36185.3228.79180.8312.49189.7
151.53187.3231.86181.2316.67190.1
154.68190.3234.94182.6320.87190.6
158.23193.7238.02183.1325.07190.7
161.27197.3241.09183.4329.26191.6
164.32201.5244.16183.8333.45191.8
167.36205.8247.25185.0337.63192.8
170.41211.8250.33186.0341.80194.8
173.53184.3253.45187.4345.97194.8
176.70171.0256.54187.7350.08194.5
179.80171.4259.63189.2
182.87171.4262.72190.7
Series 6
101.53151.9179.46171.5258.04190.5
104.98155.4183.83172.0262.44192.5
107.99157.1188.18172.7266.85194.5
110.99159.4192.54173.0271.24202.5
116.70164.2196.88174.0275.67196.4
121.66168.5201.23174.9280.14195.9
125.96172.1205.58175.7284.60192.8
130.22181.9209.93176.7289.17191.5
134.52182.5214.28177.2293.67189.0
138.82188.7218.66178.8298.18188.9
143.13190.3223.02179.8303.49190.1
148.24183.8227.37181.9309.40189.9
153.27186.7231.71183.1315.33190.1
157.59190.9236.09184.9321.27190.6
161.91195.5240.48185.3327.22190.9
166.22200.9244.86187.2333.16192.4
170.53207.8249.26187.2339.11194.5
174.98174.2253.65188.9345.01195.2

3. Results and Discussion

3.1. Heat Capacity

A preliminary set of heat-capacity measurements under the identical operative conditions used for the tested compound were carried out on MAPI in order to check the internal consistency of either adiabatic measurements. The data of three experimental runs for MAPI are compared with the available literature data in Figure S1 [5]. A good agreement was found with relative deviations that do not exceed 0.9% up to—250 K and 3% in the range of 250–357 K, thus confirming that a reliable C°p,m may also be expected for FAPI.
The experimental values of the molar heat capacity of FAPI in the range of 5–357 K and the smoothing plot, C°p,m = f(T), are illustrated in Table 1 and Figure 1, respectively.
The C°p,m values were smoothed according to Equations (1)–(3) using a polynomial-regression least-square method, while the corresponding fitting coefficients are listed in Table 2.
The relative deviation of the experimental data from the fitting values related to the studied compound is illustrated in Figure 2.
Three distinct phase transitions were found in the ranges of 49–56 K, 110–178 K, and 264–277 K. The characteristics of these transitions are summarized in Table 3.
By means of thermal-expansion measurements, the hexagonal δ-FAPI phase was reported to undergo two phase transitions at 54.5 K and 173.0 K [39], in agreement with our findings. A transition at around 50 K was also reported in [28] (heat-capacity measurements of a powder sample by the pulse-relaxation technique) in the form of two closely-spaced peaks and assigned to the glassy freezing of molecular motions. The total entropy change reported in [28], ranging from 1.7 to 2.2 JK−1 mol−1, is similar to our result (see Table 3). However, this transition was not reported in [31], wherein a crystal sample was used. The anomaly at around 275 K could corresponds to the previously reported λ-shaped continuous tetragonal-to-cubic (β to α) phase transition [31] due to the formation of small amounts of tetragonal phase in our sample.

3.2. Standard Thermodynamic Functions

The standard thermodynamic functions of FAPI reported in Table 4 were calculated from the C°p,m values in the temperature range of 0–345 K. To calculate the standard thermodynamic functions of FAPI, its C°p,m values were extrapolated from 5 to 0 K according to the Debye law and the multifractal theory of heat capacity in the extremely low-temperature limit [40,41,42]:
C°p,m = nDD/T)
where n is the number of degrees of freedom, D is the Debye function, and ΘD refers to the Debye characteristic temperature. The parameters selected for this study are n = 6 and ΘD = 60.5 K. They were selected so that the errors associated with the heat capacity in the region below 20 K did not exceed the experimental error of its determination.
The values of H°(T) − (0) and S°(T) were estimated in the temperature range of 0–345) K by the numerical integration of C°p,m = f(T) and C°p,m = f(lnT) values, respectively. The values of −[G°(T) − H°(0)]/T were determined according to Equation (5):
−[G°(T) − H°(0)]/T = −[H°(T) − (0)]/T + S°(T)
where all details related to the procedure adopted are available in [43].
As mentioned in the Introduction, the occurrence of gas-releasing decomposition reactions is one of the most severe obstacles on the road to the practical application of hybrid perovskites in photovoltaic technology. The absolute entropy of CH5N2PbI3 measured in this work, S°(298 K) = 385.5 J·K−1·mol−1, enables the calculation of the entropy change of the possible decomposition reactions undergone by the compound under real-use conditions.
Various decomposition processes have been identified and proposed in the literature for CH5N2PbI3 based on Knudsen effusion mass spectrometry, thermogravimetry/mass spectrometry, infrared spectroscopy, and gas chromatography/mass spectrometry [27,44,45,46], leading to the formation of volatile products, such as hydrogen iodide, formamidine, ammonia, hydrogen cyanide, and sym-triazine:
CH5N2PbI3 (s) → PbI2 (s) + HI (g) + CH4N2 (g)
CH5N2PbI3 (s) → PbI2 (s) + HI (g) + NH3 (g) + HCN (g)
CH5N2PbI3 (s) → PbI2 (s) + HI (g) + NH3 (g) + 1/3 H3C3N3 (g)
The following values of the absolute entropy at 298 K (expressed in J K−1 mol−1) were retrieved from the literature for the species involved in the above reactions: PbI2 (s), 174.85 [47]; HI (g), 206.60 [47]; NH3 (g), 192.77 [47]; HCN (g), 201.82 [47]; and H3C3N3 (g), 271.6 [48]. The value of S°(298) for formamidine, CH4N2 (g), is not apparently available, but an estimate can be obtained from the entropy change of the dissociation reaction of CH4N2 (g) → NH3 (g) + HCN (g), which was evaluated as 146.5 J K−1 mol−1 by ab initio calculations [49]. This leads to a S°(298) value of 248.1 J K−1 mol−1 for CH4N2 (g). Using the above values, the entropy changes of the above reported reactions are (in J K−1 mol−1): ΔS°(298) (6) = 244.1, ΔS°(298) (7) = 390.5, ΔS°(298) (8) =279.3. In conjunction with the corresponding enthalpy changes, these values can be of help for the prediction of the thermodynamic stability of CH5N2PbI3 as a function of temperature for the various decomposition channels.

4. Conclusions

This study reports original results regarding the calorimetric study on formamidinium lead iodide (FAPI). In particular, the heat capacity of FAPI was measured in the experimental temperature range of 5–357 K by precise vacuum adiabatic calorimetry. In the lower temperature range, two phase transitions were observed between 50 and 55 K and 110 and 178 K. A C°p,m anomaly was also found at around 274 K. A good agreement was found with data available in the literature (determined by unconventional methods). By numerical integration of the fitted C°p,m and C°p,m/T values, the standard enthalpy [H°(T) − H°(0)] the entropy S°(T), and −[G°(T) − H°(0)]/T values were determined over the temperature range of 0–345 K.

Supplementary Materials

The following are available online at https://www.mdpi.com/article/10.3390/e24020145/s1. Figure S1: Molar heat capacities of methylammonium lead iodide (MAPI) over the range from 5 to 357 K.

Author Contributions

Conceptualization, S.V.C. and A.V.M.; methodology, A.V.M. and N.N.S.; investigation. A.L. (Alessandro Latini), A.L. (Alessio Luongo) and A.V.M.; writing—original draft preparation, S.V.C., A.C.; writing—review and editing, S.V.C., A.C. and A.V.M.; funding acquisition, A.V.M. All authors have read and agreed to the published version of the manuscript.

Funding

This work was supported by the Ministry of Science and Higher Education of the Russian Federation (assignment 0729-2020-0053) using the equipment of the Collective Usage Center “New Materials and Resource-saving Technologies” (Lobachevsky State University of Nizhny Novgorod).

Data Availability Statement

Data are contained within the article.

Conflicts of Interest

The authors declare no conflict of interest.

References

  1. Chart of Best Research-Cell Efficiencies Provided by NREL. Available online: https://www.nrel.gov/pv/cell-efficiency.html (accessed on 16 December 2021).
  2. Kojima, A.; Teshima, K.; Shirai, Y.; Miyasaka, T. Organometal Halide Perovskites as Visible-Light Sensitizers for Photovoltaic C ells. J. Am. Chem. Soc. 2009, 131, 6050–6051. [Google Scholar] [CrossRef]
  3. Weber, D. CH3NH3PbX3. a Pb(II)-System with Cubic Perovskite Structure. Z. Naturforsch. 1978, 33b, 1443–1445. [Google Scholar] [CrossRef]
  4. Poglitsch, A.; Weber, D. Dynamic disorder in Methylammoniumtrihalogenoplumbates (II) observed by millimeter-wave spectroscopy. J. Chem. Phys. 1987, 87, 6373–6378. [Google Scholar] [CrossRef]
  5. Onoda-Yamamuro, N.; Matsuo, T.; Suga, H. Calorimetric and IR Spectroscopic Studies of Phase Transitions in Methylammonium Trihalogenoplumbates (II). J. Phys. Chem. Solids 1990, 51, 1383–1395. [Google Scholar] [CrossRef]
  6. Lee, M.M.; Teuscher, J.; Miyasaka, T.; Murakami, T.N.; Snaith, H.J. Efficient Hybrid Solar Cells Based on Meso-Superstructured Organometal Halide Perovskites. Science 2012, 338, 643–647. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  7. Stoumpos, C.C.; Malliakas, C.D.; Kanatzidis, M.G. Semiconducting Tin and Lead Iodide Perovskites with Organic Cations: Phase Transitions. High Mobilities. and Near-Infrared Photoluminescent Properties. Inorg. Chem. 2013, 52, 9019–9038. [Google Scholar] [CrossRef] [PubMed]
  8. Correa-Baena, J.-P.; Abate, A.; Saliba, M.; Tress, W.; Jacobsson, T.J.; Grátzel, M.; Hagfeldt, A. The Rapid Evolution of Highly Efficient Perovskite Solar Cells. Energy Environ. Sci. 2017, 10, 710–727. [Google Scholar] [CrossRef]
  9. Li, Z.; Yang, M.; Park, J.S.; Wei, S.H.; Berry, J.J.; Zhu, K. Stabilizing Perovskite Structures by Tuning Tolerance Factor: Formation of Formamidinium and Cesium Lead Iodide Solid-State Alloys. Chem. Mater. 2016, 28, 284–292. [Google Scholar] [CrossRef]
  10. Saidaminov, M.I.; Abdelhady, A.L.; Maculana, G.; Bakr, O.M. Retrograde Solubility of Formamidinium and Methylammonium Lead Halide Perovskites enabling Rapid Single Crystal Growth. Chem. Commun. 2015, 51, 17658–17661. [Google Scholar] [CrossRef] [Green Version]
  11. Di Girolamo, D.; Phung, N.; Kosasih, F.U.; Di Giacomo, F.; Matteocci, F.; Smith, J.A.; Flatken, M.A.; Köbler, H.; Cruz, S.H.T.; Mattoni, A. Ion Migration-Induced Amorphization and Phase Segregation as a Degradation Mechanism in Planar Perovskite Solar Cells. Adv. Energy Mater. 2020, 10, 2000310. [Google Scholar] [CrossRef]
  12. Dai, J.; Fu, Y.; Manger, L.H.; Rea, M.T.; Hwang, L.; Goldsmith, R.H.; Jin, S. Carrier Decay Properties of Mixed Cation Formamidinium-Methylammonium Lead Iodide Perovskite [HC(NH2)2]1–x[CH3NH3]xPbI3 Nanorods. J. Phys. Chem. Lett. 2016, 5036–5043. [Google Scholar] [CrossRef]
  13. Charles, B.; Dillon, J.; Weber, O.J.; Islam, M.S.; Weller, M.T. Understanding the Stability of Mixed A-Cation Lead Iodide Perovskites. J. Mater. Chem. A 2017, 5, 22495–22499. [Google Scholar] [CrossRef] [Green Version]
  14. Kim, Y.G.; Kim, T.Y.; Oh, J.H.; Choi, K.S.; Kim, Y.J.; Kim, S.Y. Cesium Lead Iodide Solar Cells Controlled by Annealing Temperature. Phys. Chem. Chem. Phys. 2017, 19, 6257–6263. [Google Scholar] [CrossRef]
  15. Han, Q.; Bae, S.H.; Sun, P.; Hsieh, Y.T.; Yang, Y.; Rim, Y.S.; Zhao, H.; Chen, Q.; Shi, W.; Li, G.; et al. Single Crystal Formamidinium Lead Iodide (FAPbI3): Insight into the Structural. Optical. and Electrical Properties. Adv. Mater. 2016, 28, 2253–2258. [Google Scholar] [CrossRef] [PubMed]
  16. Yang, W.S.; Noh, J.H.; Jeon, N.J.; Kim, Y.C.; Ryu, S.; Seo, J.; Seok, S.I. High-performance Photovoltaic Perovskite Layers Fabricated Through Intramolecular Exchange. Science 2015, 348, 1234–1237. [Google Scholar] [CrossRef]
  17. Brunetti, B.; Cavallo, C.; Ciccioli, A.; Gigli, G.; Latini, A. On the Thermal and Thermodynamic (In)Stability of Methylammonium Lead Halide Perovskites. Sci. Rep. 2016, 6, 31896. [Google Scholar] [CrossRef] [PubMed]
  18. Ciccioli, A.; Latini, A. Thermodynamics and the Intrinsic Stability of Lead Halide Perovskites CH3NH3PbX3. J. Phys. Chem. Lett. 2018, 9, 3756–3765. [Google Scholar] [CrossRef] [PubMed]
  19. Latini, A.; Gigli, G.; Ciccioli, A. A Study on the Nature of the Thermal Decomposition of Methylammonium Lead Iodide Perovskite. CH3NH3PbI3: An Attempt to Rationalise Contradictory Experimental Results. Sustain. Energy Fuels 2017, 1, 1351–1357. [Google Scholar] [CrossRef]
  20. Juarez-Perez, E.J.; Hawash, Z.; Raga, S.R.; Ono, L.K.; Qi, Y. Thermal degradation of CH3NH3PbI3 perovskite into NH3 and CH3I gases observed by coupled thermogravimetry-mass spectrometry analysis. Energy Environ. Sci. 2016, 9, 3406–3410. [Google Scholar] [CrossRef] [Green Version]
  21. García-Fernández, A.; Juarez-Perez, E.J.; Castro-García, S.; Sánchez-Andújar, M.; Ono, L.K.; Jiang, Y.; Qi, Y. Benchmarking Chemical Stability of Arbitrarily Mixed 3D Hybrid Halide Perovskites for Solar Cell Applications. Small Methods 2018, 2, 1800242. [Google Scholar] [CrossRef] [Green Version]
  22. Juarez-Perez, E.J.; Ono, L.K.; Uriarte, I.; Cocinero, E.J.; Qi, Y. Degradation Mechanism and Relative Stability of Methylammonium Halide Based Perovskites Analyzed on the Basis of Acid-Base Theory. ACS Appl. Mater. Interfaces 2019, 11, 12586–12593. [Google Scholar] [CrossRef] [Green Version]
  23. Wang, B.; Novendra, N.; Navrotsky, A. Energetics. Structures. and Phase Transitions of Cubic and Orthorhombic Cesium Lead Iodide (CsPbI3) Polymorphs. J. Am. Chem. Soc. 2019, 141, 14501–14504. [Google Scholar] [CrossRef]
  24. Tsvetkov, D.S.; Mazurin, M.O.; Sereda, V.V.; Ivanov, I.L.; Malyshkin, D.A.; Zuev, A.Y. Formation Thermodynamics. Stability. and Decomposition Pathways of CsPbX3 (X = Cl. Br. I) Photovoltaic Materials. J. Phys. Chem. C 2020, 124, 4252–4260. [Google Scholar] [CrossRef]
  25. Wang, B.; Navrotsky, A. Thermodynamics of cesium lead halide (CsPbX3. x = I. Br. Cl) perovskites. Thermochim. Acta 2021, 695, 178813. [Google Scholar] [CrossRef]
  26. Dastidar, S.; Hawley, C.J.; Dillon, A.D.; Gutierrez-Perez, A.D.; Spanier, J.E.; Fafarman, A.T. Quantitative Phase-Change Thermodynamics and Metastability of Perovskite-Phase Cesium Lead Iodide. J. Phys. Chem. Lett. 2017, 8, 1278–1282. [Google Scholar] [CrossRef] [PubMed]
  27. Luongo, A.; Brunetti, B.; Vecchio Ciprioti, S.; Ciccioli, A.; Latini, A. Thermodynamic and Kinetic Aspects of Formamidinium Lead Iodide Thermal Decomposition. J. Phys. Chem. C 2021, 125, 21851–21861. [Google Scholar] [CrossRef]
  28. Fabini, D.H.; Siaw, T.A.; Stoumpos, C.C.; Laurita, G.; Olds, D.; Page, K.; Hu, J.G.; Kanatzidis, M.G.; Han, S.; Seshadri, R. Universal Dynamics of Molecular Reorientation in Hybrid Lead Iodide Perovskites. J. Am. Chem. Soc. 2017, 139, 16875–16884. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  29. Knop, O.; Wasylishen, R.E.; White, M.A.; Cameron, T.S.; Van Oort, M.J.M. Alkylammonium Lead Halides. Part 2. CH3NH3PbX3 (X = Cl. Br. I) Perovskites: Cuboctahedral Halide Cages with Isotropic Cation Reorientation. Can. J. Chem. 1990, 68, 412–422. [Google Scholar] [CrossRef] [Green Version]
  30. Fabini, D.H.; Hogan, T.; Evans, H.A.; Stoumpos, C.C.; Kanatzidis, M.G.; Seshadri, R. Dielectric and Thermodynamic Signatures of Low-Temperature Glassy Dynamics in the Hybrid Perovskites CH3NH3PbI3 and HC(NH2)2PbI3. J. Phys. Chem. Lett. 2016, 7, 376–381. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  31. Kawachi, S.; Atsumi, M.; Saito, N.; Ohashi, N.; Murakami, Y.; Yamaura, J.-I. Structural and Thermal Properties in Formamidinium and Cs-Mixed Lead Halides. J. Phys. Chem. Lett. 2019, 10, 6967–6972. [Google Scholar] [CrossRef]
  32. Varushchenko, R.M.; Druzhinina, A.I.; Sorkin, E.L. Low-temperature Heat Capacity of 1-bromoperfluorooctane. J. Chem. Thermodyn. 1997, 29, 623–637. [Google Scholar] [CrossRef]
  33. Preston-Thomas, H. The international temperature scale of 1990 (ITS-90). Metrologia 1990, 27, 3–10. [Google Scholar] [CrossRef]
  34. Stevens, R.; Boerio-Goates, J. Heat Capacity of Copper on the ITS-90 Temperature Scale using Adiabatic Calorimetry. J. Chem. Thermodyn. 2004, 36, 857–863. [Google Scholar] [CrossRef]
  35. Douglas, T.B.; Furukawa, G.T.; McCoskey, R.E.; Ball, A.F. Calorimetric Properties of Normal Heptane from 0 to 520 K. J. Res. Natl. Bur. Stand. 1954, 53, 139–153. [Google Scholar] [CrossRef]
  36. Gatta, G.D.; Richardson, M.J.; Sarge, S.M.; Stølen, S. Standards, Calibration, and Guidelines in Microcalorimetry. Part 2. Calibration Standards for Differential Scanning Calorimetry (IUPAC Technical Report). Pure Appl. Chem. 2006, 78, 1455–1476. [Google Scholar] [CrossRef] [Green Version]
  37. Furukawa, G.T.; McCoskey, R.E.; King, G.J. Calorimetric Properties of Benzoic Acid from 0 ° to 410 ° K. J. Res. Natl. Bur. Stand. 1951, 47, 256–261. [Google Scholar] [CrossRef]
  38. Meija, J.; Coplen, T.B.; Berglund, M.; Brand, W.A.; Bièvre, P.; De Gröning, M.; Holden, N.E.; Irrgeher, J.; Loss, R.D.; Walczyk, T.; et al. Atomic weights of the Elements 2013 (IUPAC Technical Report). Pure Appl. Chem. 2016, 88, 265–291. [Google Scholar] [CrossRef]
  39. Keshavarz, M.; Ottesen, M.; Wiedmann, S.; Wharmby, M.; Küchler, R.; Yuan, H.; Debroye, E.; Steele, J.A.; Martens, J.; Hussey, N.E.; et al. Tracking Structural Phase Transitions in Lead-Halide Perovskites by Means of Thermal Expansion. Adv. Mater. 2019, 31, 1900521. [Google Scholar] [CrossRef] [PubMed]
  40. Lazarev, V.B.; Izotov, A.D.; Gavrichev, K.S.; Shebershneva, O.V. Fractal model of heat capacity for substances with diamond-like structures. Thermochim. Acta 1995, 269–270, 109–116. [Google Scholar] [CrossRef]
  41. Tarasov, V.V. Theory of heat capacity of chain and layer structures. J. Fiz. Him. 1950, 24, 111–128. [Google Scholar]
  42. Rabinovich, I.B.; Nistratov, V.P.; Telnoy, V.I.; Sheiman, M.S. Thermochemical and Thermodynamic Properties of Organometallic Compounds; Begell House, Inc.: New York, NY, USA, 1999. [Google Scholar]
  43. McCullough, J.P.; Scott, D.W. Calorimetry of Non-Reacting Systems; Pergamon Press: London, UK, 1968. [Google Scholar]
  44. Juarez-Perez, E.J.; Ono, L.K.; Qi, Y. Thermal degradation of formamidinium based lead halide perovskites into sym-triazine and hydrogen cyanide observed by coupled thermogravimetry-mass spectrometry analysis. J. Mater. Chem. A 2019, 7, 16912–16919. [Google Scholar] [CrossRef]
  45. Ma, L.; Guo, D.; Li, M.; Wang, C.; Zhou, Z.; Zhao, X.; Zhang, F.; Ao, Z.; Nie, Z. Temperature-Dependent Thermal Decomposition Pathway of organic-Inorganic Halide Perovskite Materials. Chem. Mater. 2019, 31, 8515–8522. [Google Scholar] [CrossRef]
  46. Shi, L.; Bucknall, M.P.; Young, T.L.; Zhang, M.; Hu, L.; Bing, J.; Lee, D.S.; Kim, J.; Wu, T.; Takamure, N.; et al. Gas Chromatography-Mass Spectrometry Analyses of Encapsulated Stable Perovskite Solar Cells. Science 2020, 368, eaba2412. [Google Scholar] [CrossRef]
  47. Iorish, V.S.; Belov, G.V. Thermocenter of the Russian Academy of Sciences; IVTAN Association: Moscow, Russia, 1994. [Google Scholar]
  48. Dorofeeva, O.V.; Tolmach, P.I. Estimation of the thermodynamic properties of nitroguanidine. hexahydro-1.3.5-trinitro-1.3.5-triazine and octahydro-1.3.5.7-tetranitro-45. 1.3.5.7-tetrazocine in the gas phase. Thermochim. Acta 1994, 240, 47–66. [Google Scholar] [CrossRef]
  49. Almatarneh, M.H.; Flinn, C.G.; Poirier, R.A. Ab initio study of the decomposition of formamidine. Can. J. Chem. 2005, 83, 2082–2090. [Google Scholar] [CrossRef]
Figure 1. Molar heat capacities of formamidinium lead iodide (FAPI) in the range of 5–357 K.
Figure 1. Molar heat capacities of formamidinium lead iodide (FAPI) in the range of 5–357 K.
Entropy 24 00145 g001
Figure 2. Percentages of deviation of the experimental heat capacity of FAPI from the fitting values.
Figure 2. Percentages of deviation of the experimental heat capacity of FAPI from the fitting values.
Entropy 24 00145 g002
Table 2. The polynomial-fitting coefficients of the temperature dependence of the molar heat capacity of CH5N2PbI3.
Table 2. The polynomial-fitting coefficients of the temperature dependence of the molar heat capacity of CH5N2PbI3.
ΔT/K5.1–15.5915.1–4955.3–169.25177.35–264.5277–348.6
Polynomial EquationEquation (3)Equation (2)Equation (2)Equation (1)Equation (1)
Polynomial coefficients Aj/J·K−1·mol−1
A16.9806324556972.1805440502665.25563697145681.42805838877.64561611
A223.795592019977.9940374434−3441.21621166−37665.2837805−4276.71076903
A374.75727368024.923977881538727.2295782512968.2759007846.025046732
A4129.714906491−42.6554451220−11401.7231003−2377.65802029−84.1041302983
A5127.77585679514.28642142988200.53002955244.7910406644.19903809680
A672.6841227853168.566960506−3085.56203393−13.4148724548−0.0841152839781
A722.2866932511179.845822583476.9850498210.305655340534
A82.8586046450842.4593828923
Table 3. The characteristics of transitions for CH5N2PbI3.
Table 3. The characteristics of transitions for CH5N2PbI3.
TransitionΔT/K Tmax/KC°p,m/J·K−1·mol−1Enthalpy/J·mol−1Entropy/J·K−1·mol−1
I49.5–55.552.9176.5132.52.5
II110.0–177.5171.85227.4156910.3
III 264.5–277.4273.72195.356.60.21
Table 4. Thermodynamic functions of CH5N2PbI3. M(CH5N2PbI3) = 632.97507 g·mol−1. p° = 0.1 MPa.
Table 4. Thermodynamic functions of CH5N2PbI3. M(CH5N2PbI3) = 632.97507 g·mol−1. p° = 0.1 MPa.
T/KC°p,m/
J·K−1·mol−1
[H°(T) − H°(0)]/
kJ·mol−1
S°(T)/
J·K−1·mol−1
−[G°(T) − H°(0)]/T J·K−1·mol−1
Crystal III
52.290.002890.7720.193
1012.70.03805.231.430
1527.80.13813.23.933
2043.470.316523.307.475
2558.370.571434.6211.76
3072.180.898446.5016.55
3584.191.29058.5621.69
4094.551.73770.4927.05
45104.92.23682.2132.53
50117.62.79193.8938.08
52.9122.63.139100.741.32
Crystal II
52.9122.63.271103.241.32
60128.14.165119.049.60
70135.05.481139.360.99
80140.76.860157.771.94
90146.28.294174.682.42
100152.19.785190.392.43
110158.411.34205.1102.0
120165.212.96219.1111.2
130172.614.64232.6120.0
140181.316.41245.7128.5
150192.318.28258.6136.8
160206.920.27271.5144.8
170226.722.43284.6152.6
Crystal I
180169.324.34295.5160.3
190169.826.04304.7167.6
200171.127.74313.4174.7
210172.829.46321.8181.5
220174.831.20329.9188.1
230177.032.96337.7194.4
240179.234.74345.3200.5
250181.336.54352.6206.5
260183.938.37359.8212.2
270190.440.23366.8217.9
280186.442.14373.8223.3
290186.944.01380.3228.6
298.15187.645.53385.5232.8
300187.845.88386.7233.8
310188.947.76392.9238.8
320190.249.66398.9243.7
330191.551.56404.7248.5
340192.853.49410.5253.2
345193.354.45413.3255.5
Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Share and Cite

MDPI and ACS Style

Ciccioli, A.; Latini, A.; Luongo, A.; Smirnova, N.N.; Markin, A.V.; Vecchio Ciprioti, S. Thermodynamic Study of Formamidinium Lead Iodide (CH5N2PbI3) from 5 to 357 K. Entropy 2022, 24, 145. https://doi.org/10.3390/e24020145

AMA Style

Ciccioli A, Latini A, Luongo A, Smirnova NN, Markin AV, Vecchio Ciprioti S. Thermodynamic Study of Formamidinium Lead Iodide (CH5N2PbI3) from 5 to 357 K. Entropy. 2022; 24(2):145. https://doi.org/10.3390/e24020145

Chicago/Turabian Style

Ciccioli, Andrea, Alessandro Latini, Alessio Luongo, Natalia N. Smirnova, Alexey V. Markin, and Stefano Vecchio Ciprioti. 2022. "Thermodynamic Study of Formamidinium Lead Iodide (CH5N2PbI3) from 5 to 357 K" Entropy 24, no. 2: 145. https://doi.org/10.3390/e24020145

Note that from the first issue of 2016, this journal uses article numbers instead of page numbers. See further details here.

Article Metrics

Back to TopTop