Chalcogenide As Inorganic Transport Layer in Perovskite Solar Cell

doi:10.21203/rs.3.rs-399307/v1

Download PDF

Research Article

Chalcogenide As Inorganic Transport Layer in Perovskite Solar Cell

https://doi.org/10.21203/rs.3.rs-399307/v1

This work is licensed under a CC BY 4.0 License

Journal Publication

published 14 Aug, 2021

Read the published version in Optical and Quantum Electronics →

You are reading this latest preprint version

Fill factor (FF) deficit and stability is a primary concern with the perovskite solar cell. Resistance values and band alignment at junction interface in perovskite are causing low fill factor. Moisture sensitivity of methylammonium lead halide perovskite is causing a stability issue. We tried to solve these issues by using inorganic hole transport layer (HTL). FF is sensitive to the band offset values. We study the band alignment/band offset effect at the Perovskite /HTL junction. Inorganic material replacing Spiro-MeOTAD can enhance the stability of the device by providing an insulation from ambient. Our simulation study shows that the earth abundant p-type chalcogenide materials of SnS as HTL in perovskite is comparable to Spiro-MeOTAD efficiency.

Electrical Engineering

Optical Materials and Devices

Atomic and Molecular Physics

Perovskite

Inorganic HTL

Chalcogenide

SCAPS Simulation

Terawatt scale Perennial supply of pollution-free energy at a competitive cost is a desirable for sustainable growth. Photovoltaic is potential solution subjected to availability of low cost, nontoxic material, and fabrication technology. Perovskite Methylammonium Lead Halide (CH₃NH₃PbI₃ or MAPbI₃) is the material with ideal properties of light absorption, defect-free bandgap, high mobility and diffusion length. In a short span of time perovskite has achieved high power conversion efficiency of 22.1% [1]. The organic component in the perovskite solar cell device structure has the challenge of stability due to moisture, thermal and photosensitivity [2, 3]. The sensitivity of the organic MA (methylammonium) toward polar solvent like water leads to their dissociation in presence of moisture. A moisture resistant perovskite material or suitable passivation from moisture is probable stability solution. Better insulation from thermal and ambient can be provided by encapsulation using inorganic layers. TiO₂ as electron transport layer (ETL) on one side and another inorganic material as hole transport layer (HTL) can better shield the perovskite layer. Low mobility of holes, unstable (thermal, Photo and moisture stability) issues in polymer HTL like Spiro-MeOTAD, PEDOT: PSS etc. could be overcome by using inorganic layers. Inorganic materials which are tried for HTL in literature are listed in Table. 1. On this line we explored inorganic Chalcogens materials (CIGS, CZTS, SnS, Cu₂S, PbS, Sb₂S₃, FeS₂) for HTL, where all the elements are nontoxic, abundant [4] and can be economically processed for solar cell application. The p-type nature of these chalcogens with high acceptor density and hole mobility can be exploited for HTL. Inorganic layer with low thermal conductivity and resilient to the ambient condition can enhance the lifetime of perovskite by encapsulating them from outside environment. In order to discuss and gain some insight into the feasibility of inorganic HTL here, we performed simulation study with inorganic hole transport layer in perovskite.

Chalcogens we selected here (CIGS, CZTS, SnS, Cu₂S, PbS, Sb₂S₃, FeS₂) are prominent p-type absorber material with high absorption coefficient (~10⁵cm^-1) and bandgap lying invisible region (0.5-1.5eV). Their material properties are listed in Table 2. These are all abundant material available enough for terawatt scale energy generation, nontoxic and cost-effective. Solution-processed fabrication techniques make them strong for the low-cost application. These are Multifunction material with application ranging from (i) prominent absorber layer in inorganic and hybrid solar cells, (ii) counter electrode in DSSC and batteries, (iii) as a photocatalyst, (iv) as a gas sensor (v) Counter electrode in quantum dot solar cell, (vi) Thermoelectric (vii) ultra-fast photo-detector and optoelectronic applications. All the selected chalcogens material binary (SnS, Cu₂S, PbS, Sb₂S₃, FeS₂) and quaternary (CIGS, CZTS) have higher hole mobility than Spiro-MeOTAD.

Solar cell capacitance simulator SCAPS-1D version 3.3.0.2 is used for the theoretical study. SCAPS model semiconductor and electrostatic equation in 1D environment to simulate a thin film solar cell. Using Newton Raphson and Gummel iteration it solves 1D Poisson equation and continuity equation for heterostructures. To begin with, we have modeled a p-i-n structure FTO/TiO₂/MAPbI₃/Spiro-MeOTAD and simulated the performance of the solar cell. The reported material parameters of perovskite as thickness 350 nm, bandgap 1.55 eV, the dielectric constant of 10, a value of N_A of ~10¹³/cm³, the diffusion length of electrons in perovskite, L_p~1000 nm, we used similar values of L_n, the electron mobility of ~10 cm²/Vs, radiative recombination coefficient (cm³/s) 10^-13. Neutral defects density of 10¹⁴ at the center of the bandgap with a Gaussian distribution and characteristic energy of 0.1eV; and the capture cross-section of electrons and holes of 2×10⁻¹⁴ cm⁻². The absorption constant A (1/cm eV^(½)) was assumed to be 10⁵. The device is illuminated from FTO layer side with AM1.5 spectrum using relevant SCAPS option at temperature 300 K. Front contact is from the FTO layer and a back contact is taken from metal contact with work function taken to be 5.1eV. For the series resistance (R_s) and shunt resistance (R_sh), we have used typical values of 5Ω-cm² and 5k Ω-cm². The schematic of the device is shown in Fig. 1a.

The relevant material parameters used in the simulation were obtained from the literature and are listed in Table 3 [23-25]. Quantum efficiency (QE) curve shows maximum light absorption is within perovskite region. The simulated output parameter (V_OC=1.08V, J_SC=24.5mA/cm², FF=75.5%, Efficiency=20.02%) as shown in Fig. 1b are closely matching with the experimentally reported values of V_OC, J_SC, FF and efficiency [26]. The bandgap of perovskite is 1.55eV the corresponding SQ limiting parameter are (V_OC 1.287V, FF 90.32%, J_SC 26.37mA/cm², Efficiency 30.68%).

Design of the solar cell does affect the mechanism of the photovoltaic action and efficiency. The structure should be optimized for efficient separation and collection of photogenerated generated charge carrier. (a) Built-in Electric field, (b) effective force field (work function difference), (c) discontinuity at an energy level at the interface, are some of the design related options implemented for better performance of the photovoltaic device. The interface at heterojunction, control voltage generation and current flow, potential variation, the electric field at either side of the junction. Perovskite configuration of FTO/TiO₂/Perovskite/HTL is p-i-n type. p-i-n structures is suitable for large built-in potential across absorber layer. Built-in potential depends on the carrier density of p and n layer. The effective force field can be induced by the appropriate choice of the contacts work function. For design point of view, an HTL should be having a high hole to electron mobility ratio so that it acts as a selective contact. To gain large built-in voltage charge density should be higher in n and p region of a pin. Higher charge density will also shift the space charge layer into the intrinsic layer an advantageous situation for charge drift. Figure 2a shows the Higher builtin voltage resulting from higher density of carrier in p and n layer of pin structure. The slope of band energy level in i layer (absorber) also increases with the carrier density in p and n, as shown in figure 2a. A spike to be present at the valence band offset to lower the interfacing recombination between E_V,HTMand E_C,Perovskite[23,27]. The reason for the low recombination at slightly positive valence band offset is the low value of ∆. The ∆ is the energy difference E_{C Perovskites}-E_{V HTL} as shown in the Fig. 2. The cliff at the perovskite/HTL junction lowered the ∆ shown in figure 2b, enhancing the chances of recombination of an electron from perovskite to hole from HTL. The presence of spike at the junction increases the ∆ value shown in Fig. 2c and thus lower the chances of recombination of an electron from perovskite and hole from HTL. The high Spike value will impede hole transfer from perovskite to HTL. The slightly positive values of VBO are advantageous and their optimum value can be ascertained by simulation. Device optimization by simulation for an HTL (p layer) in p-i-n the optimizing conditions are

i) A positive VBO at the p-i junction.

ii) High hole density in p,n layer ( p⁺-i structure),

a) High built-in voltage

b) Lead to the higher field in absorber (i) layer.

3.1.1 HTM layer parameter

For the simulation of inorganic HTL, we inserted an interface defect layer (IDL) at HTL perovskite junction. The width and defect density of IDL is taken to be 10nm and 10¹⁷cm^-3. High defect density in IDL is used to simulate the interfacial recombination caused by lattice mismatching and defect state. CZTS have bandgap tail state of multivalent defect near to conduction band and valence band. We have assumed multivalent defect of charge state {3+/2+, 2+/+, +/0} in CB at E_t =1.40eV with characteristic energy of 0.05eV. Acceptor defects of charge state {0/-, -/2-, 2-/3-} at VB. The defect density of 5×10¹⁴ cm^-3, capture cross section of 10^-13cm². To model SnS defects we have used a neutral defect of density 10¹⁷cm^-3. Energetic distribution of single level was .6eV above E_V and capture cross section of 10^-15cm². The parameter of the CZTS, CIGS, Cu2S, Sb2S3, PbS, FeS2, SnS are taken from literature and are listed in Table 2.

These inorganic material are p-type with 2-4 order high hole density than perovskite and have a similar bandgap. Simulation is run for these sulfide as HTL in Perovskite solar cell. HTL parameter of thickness, hole density are simulated. Fig. 3 shows the dependence of inorganic HTL device performance on hole density, thickness. The hole density in the HTL is varied from 10¹⁴to 10¹⁸cm^-3to simulate the effect on efficiency. Efficiency rises with hole density for all HTL. As doping concentration in HTL increases, the resistivity of HTL layer reduces. This increases the V_OC and FF whereas the current remains constant. Carrier (hole) concentration will affect the bend banding and potential distribution at the junction. Perovskite has a low doping thus higher doped HTL will induce banding in Perovskite absorber layer thus creating a potential distribution across perovskite layer. Higher carrier concentration will cause higher built-in voltage in the device and is favorable until limiting diffusion length at high carrier density, Auger and Radiative recombination effect supersedes. All the binary sulfides layers have shown 0.1µm optimum thickness after which efficiency becomes constant. Quaternary CZTS and CIGS have shown a 0.2µm as optimum thickness. With thickness, FF grows initially and then all the parameter becomes constant. Rau et. al. estimated critical mobility for achieving 90 % of efficiency in the solar cell [28]. The critical mobility values remain less than 1 cm²V^-1s^-1. The HTL material under consideration here are well know p-type material with mobilities higher than critical mobilities as required by Rau et al. The optimum value of thickness, hole density as obtained by simulations can be easily attainable in given HTL materials. These parameters are highly dependent on growth condition and stoichiometry. We have used the value of these parameter forms the experimental data reported in the literature and listed in Table 2.

3.1.2. Band diagram and IV

The band structure of all the HTL/Perovskite solar cell is simulated and shown in Fig. 4. The band alignment at the HTL/perovskite junction is observed in all structure. The CZTS, CIGS showed bending in HTL layer energy level as they have hole density of 10¹⁶cm^-3. SnS showed band bending at the back metal contact. Simulated IV curve of all the structure is shown in the Fig. 5. The junction of HTL/perovskite is changing. PbS, FeS₂ are showing low efficiency of 11.1% and 10.9% due to a large negative VBO at HTL/perovskite junction. CIGS and CZTS show a moderate value of efficiency 16.5% and 18.4% respectively. They have a positive VBO of 0.25 and 0.15 eV. SnS, Cu₂S, Sb₂S₃ are showing comparable efficiency to Spiro-MeOTAD perovskite solar cell at 20.88%, 20.6%, 20.2% respectively. The comparable efficiency of SnS could be further optimized and could replace Spiro organic HTL. The difference in electron affinity (X_HTL) of the HTL layer and perovskite (X_Abs) is causing the valence band offset (VBO) at the junction. For hole transport valence band offset (VBO) the alignment of the valence band level E_V of HTL and E_Vof perovskite is important. Also at this HTL junction, an interface defect density is assumed. A 10 nm thick layer is inserted at this junction to simulate any defect density arising from electrical or mechanical dissimilarity.

3.1.3. VBO and contact optimization of HTL layer

VBO is the discontinuity in the energy level at the junction shown by a vertical line in Fig. 3. VBO is given by (E_gHTM+X_HTL)- (E_gPerov.+ X_Perov), E_g is the bandgap, X is electron affinity. The simulated band diagram of the device Inorganic HTL/Perovskite shows valence band offset. The High negative offset introduces a cliff, favorable path way for hole transport from perovskite to HTL case shown in Fig. 2b for Perovskite /SpiroMeOTAD. High positive offset (X_HTL+E_gHTL>X_Abs+E_gAbs) introduces a spike forming a barrier for hole transfer from the absorber to HTL as the shown in Fig. 2c. At zero Valence band offset make continuity at the junction. The ∆ (as shown in the figure should be large to avoid interfacial recombination between E_{V HTL} and E_{C Perovskite}. The positive value of VBO will be suitable to increase ∆. However large VBO will inhibit the hole transfer from absorber to HTL. The height of spike should be less than the built-in voltage in absorber. SnS show comparable efficiency to Spiro, therefore, we optimized SnS for further efficiency enhancement. The electron affinity of the HTL layer is varied to vary the VBO and the band alignment. The band alignment is simulated for positive and the negative and zero valence band offset. SnS/perovskite has a E_VBO of 0.15eV shown in band diagram Fig. 4. The effect of Spike and Cliff on device performance is studied. The simulation is run for range of VBO from negative to positive value. The defect at the junction of perovskite/HTL is simulated by inserting a IDL (interface defect layer) with a defect density of 10¹⁷cm^-3.

The dependence of cell efficiency on valence Band offset at interface is shown in Fig. 6. For VBO values from -0.05 to .3eV the efficiency increases and peaks at a value of 0.15eV. Interface defect density at the junction highly affects the negative valence band. Recombination current dependence on valence band offset is shown in the inset of Fig. 4. Recombination current is minimum at the slightly positive band offset region. The efficiency maximizes at VBO where recombination current is minimum. Interface defect density is assumed to be high (10¹⁷cm^-3). Recombination current depends upon the defect density at the interface. High positive VBO is detrimental for performance as simulated results shows. Slightly positive band offset of 0.05eV to 0.1eV is yielding the highest efficiency irrespective of high defect density for SnS. The reason for the low recombination current at slightly positive valence band offset is the low value of ∆. Efficiency abruptly decreases for higher VBO values as seen in the simulation Fig. 6. Interfacial recombination within the HTL/Perovskite junction can be lowered by a positive band offset. The slightly positive values of VBO are advantageous and their optimum value can be ascertained by simulation. The prominent effect of VBO is on the fillfactor of the device. Table 4 summaries the VBO resulting by variation of the electron affinity of SnS. FF maximize at the slightly positive VBO (0.1eV) the similar trend followed by efficiency.

The band diagram of SnS/perovskite in the figure shows abrupt band bending at back contact. This suggests at Schottky at the back contact with the assumed metal contact of work function 5.1eV in the simulation. The barrier at the back contact can be sorted by optimizing back contact work function. The effect of work function (ϕ_m) of metal contact at HTL layer is simulated for contact optimization. Fig. 7 shows the efficiency improvement with the work function (ϕ_m) of back contact. Simulation results show that V_OC and efficiency rise initially with work function and then becomes constant for both the HTL shown in Fig. 7. This increase in V_OC is due to improved built-in voltage [29,30]. We have a metal/semiconductor back contact acting as Schottky barrier for majority carrier. The barrier is required to be low to make it near ohmic. The band diagram is simulated for increasing work function values. For higher work function there is rise in energy level of the HTL at the back contact. This rise in energy level at back contact improves built-in voltage in HTL and perovskite layer. The simulated band diagram is shown work function in the inset of Fig. 7. The bending in E_V and E_C level at rear contact is eliminated with metal contact of high work function as shown in the simulated diagram.

The final parameters of the Perovskite with inorganic HTL layer are summarized in the Fig. 8. The inorganic HTL (CZTS, Sb₂S₃, Cu₂S, SnS) have higher FF and SnS have higher efficiency than the standard perovskite cell with organic Spiro HTL. The V_OC, FF, J_SC and Efficiency are compared with Spiro-MeOTAD and the SQ limit. The SQ limit gap in V_OC, J_SC, FF for Spiro-MeOTAD is shown. Among them FF has the largest deficit this may be due to suboptimal band alignment at the perovskite/HTL, perovskite/ETL and the high value of series resistance and low shunt resistance values in perovskite solar cell. The efficiency of the SnS is higher than Spiro-MeOTAD. The stability of SnS and low thermal conductivity is advantageous over organic HTL like PEDOT: PSS, Spiro-MeOTAD etc. Apart from high efficiency they can provide stable encapsulation to organic-inorganic perovskite from outer moisture and temperature gradient.

Earth-abundant inorganic HTL are used to provide insulation to perovskite layer for enhanced stability and replacing costly, unstable organic HTM (Spiro-MeOTAD, PTAA etc). Simulation points out HTL property (a) small positive VBO at the HTL/perovskite junction and (b) high doping density. The inorganic chalcogenides are well-known p-type material exploiting them for hole transport applications. These materials are well suited for their availability, material stability and processability. Perovskite with inorganic HTL (Cu₂S, Sb₂S₃, SnS, CZTS, CIGS, FeS₂, PbS) are simulated shows high efficiency. A slightly positive VBO matching is showing to give efficiency to 20% which can be further improved with the flat band at the back contact. SnS can replace organic Spiro-MeOTAD HTL effectively with improved performance and stable perovskite cell.

Decleration of interest

Author declare that he has no conflict of interest

Acknowledgment

We gratefully acknowledgment Dr Marc Burgelman, Honorary Professor, University of Gent for providing SCAPS-1D software and allowing its use.

Green, M.A., Emery, K., Hishikawa, Y., Warta, W., Dunlop, E.D., Levi, D.H.: and A.W. Y. Ho-Baillie, Solar cell efficiency tables (version 49), Prog. Photovolt: Res. Appl. 25, 3–13 (2017)
Wang, D., Wright, M., Elumalai, N.K., Uddin, A.: Stability of perovskite solar cells. Solar Energy Materials & Solar Cells 147, 255–275 (2016)
Hwang, I., Jeong, I., Lee, J., Ko, M.J., Yong, K.: Enhancing Stability of Perovskite Solar Cells to Moisture by the Facile Hydrophobic Passivation. ACS Appl. Mater. Interfaces 7, 17330 (2015)
Mitzi, D.B., Gunawan, O., Todorov, T.K., Barkhouse, D.A.R.: Philosophical transsactions of Royal Society A 371, 20110432 (2013)
Yu, W., Li, F., Wang, H., Alarousu, E., Chen, Y., Lin, B., Wang, L., Hedhili, M.N., Li, Y., Wu, K., Wang, X., Mohammed, O.F., Wu, T.: Ultrathin Cu₂O as an efficient inorganic hole transporting material for perovskite solar cells. Nanoscale 8, 6173 (2016)
You, J., Meng, L., Song, T., Guo, T., Y. (Michael) Yang, Chang, W., Hong, Z., Chen, H., Zhou, H., Chen, Q., Liu, Y., Marco, N.D., Yang, Y., Improved air stability of perovskite solar cells via solution-processed metal oxide transport layers, Nature Nanotechnology 11 (2016) 75
Dhingra, P., Singh, P., Rana, P.J.S., Garg, A., Kar, P.: Hole-Transporting Materials for Perovskite-Sensitized Solar Cells, Energy Technol., 4 (2016) 1
Lv, M., Zhu, J., Huang, Y., Li, Y., Shao, Z., Xu, Y., Dai, S.: Colloidal CuInS₂ Quantum Dots as Inorganic Hole-Transporting Material in Perovskite Solar Cells. ACS Appl. Mater. Interfaces 7, 17482 (2015)
Qin, P., Tanaka, S., Ito, S., Tetreault, N., Manabe, K., Nishino, H., Nazeeruddin, M.K., Gratzel, M.: Inorganic hole conductor-based lead halide perovskite solar cells with 12.4% conversion efficiency. Nat. Commun. 5, 3834 (2014)
Xu, L., Deng, L., Cao, J., Wang, X., Chen, W., Jiang, Z.: Solution-Processed Cu(In,Ga)(S,Se)₂, Nanocrystal as Inorganic Hole-Transporting Material for Efficient and Stable Perovskite Solar Cells. Nanoscale Res. Lett. 12, 159 (2017)
Wu, Q., Xue, C., Li, Y., Zhou, P., Liu, W., Zhu, J., Dai, S., Zhu, C., Yang, S.: Kesterite Cu₂ZnSnS₄ as a Low-Cost Inorganic Hole-Transporting Material for High-Efficiency Perovskite Solar Cells. ACS Appl. Mater. Interfaces 7, 28466 (2015)
Gokmen, T., Gunawan, O., Mitzi, D.B.: Minority carrier diffusion length extraction in Cu₂ZnSn(Se,S)₄ solar cells. J. Appl. Phys. 114, 114511 (2013)
Shin, B., Gunawan, O., Zhu, Y., Bojarczuk, N.A., Chey, S.J., Guha, S.: Thin film solar cell with 8.4% power conversion efficiency using an earth-abundant Cu₂ZnSnS₄ absorber, Prog. Photovolt: Res. Appl. 21, 72 (2013)
Burton, A., Colombara, D., Abellon, R.D., Grozema, F.C., Peter, L.M., Savenije, T.J., Dennler, G., Walsh, A.: Synthesis, Characterization, and Electronic Structure of Single Crystal SnS, Sn₂S₃, and SnS₂ L. Chem. Mater. 25, 4908 (2013)
Skelton, J.M., Jackson, A.J., Dimitrievska, M., Wallace, S.K., Walsh, A.: Vibrational spectra and lattice thermal conductivity of kesterite-structured Cu₂ZnSnS₄ and Cu₂ZnSnSe₄. APL Materials 3, 041102 (2015)
Lim, Y., Ok, Y.-W., Tark, S.-J., Kang, Y., Kim, D.: Electrical contact properties of Cu₂S nanowires grown vertically on Cu foil by gas–solid reaction. Curr. Appl. Phys. 9, 890 (2009)
Tang, Y.-Q., Ge, Z.-H., Feng, J.: Synthesis and Thermoelectric Properties of Copper Sulfides via Solution Phase Methods and Spark. Plasma Sintering Crystals 7, 141 (2017)
Yeon, D.H., Mohanty, B.C., Lee, S.M., Cho, Y.S.: Effect of band-aligned double absorber layers on photovoltaic characteristics of chemical bath deposited PbS/CdS thin film solar cells Scientific Reports 5 (2015) 14353
Wei, L., Chen, J., He, Q.: W. Teng,Study of lattice thermal conductivity of PbS. J. Alloy. Compd. 584, 381 (2014)
De Angelis, A.D., Christian Kemp, K., Gaillard, N., Kim, K.S.: Antimony (III) Sulfide Thin Films as a Photoanode Material in Photocatalytic Water Splitting. ACS Appl. Mater. Interfaces 8, 445 (2016)
Pietro, P., Altermatt, T., Kiesewetter, K., Ellmer, H., Tributsch: Specifying targets of future research in photovoltaic devices containing pyrite ðFeS₂ Þ by numerical modeling. Solar Energy Materials & Solar Cells 71, 181 (2002)
Popov, P.A., Fedorov, P.P., Kuznetsov, S.V.: Thermal conductivity of FeS2 pyrite crystals in the temperature range 50–300 K. Crystallogr. Rep. 58, 319 (2013)
Minemoto, T., Murata, M.: Theoretical analysis on effect of band offsets in perovskite solar cells. Solar Energy Materials & Solar Cells 133, 8 (2015)
Hossain, M.I., Alharbi, F.H., Tabet, N.: Copper oxide as inorganic hole transport material for lead halide perovskite based solar cells. Sol. Energy 120, 370 (2015)
Casas, G.A., Cappelletti, M.A., Cedola, A.P., Soucase, B.M., E.L. P. y Blanca, Analysis of the power conversion efficiency of perovskite solar cells with different materials as Hole-Transport Layer by numerical simulations, Superlattices and Microstructures 107: (2017) 136
Yang, W.S., Noh, J.H., Jeon, N.J., Kim, Y.C., Ryu, S., Seo, J., Seok, S.I.I.: High performance photovoltaic perovskite layers fabricated through intramolecular exchange. Science 348, 1234 (2015)
Rau, U., Schock, H.W.: Electronic properties of Cu(In,Ga)Se₂ heterojunction solar cells–recent achievements, current understanding, and future challenges. Appl. Phys. A 69, 131 (1999)
Mattheis, J., Werner, J.H., Rau, U.: Finite mobility effects on the radiative efficiency limit of pn-junction solar cells. Phys. Rev. B 77, 085203 (2008)
Rached, D., Mostefaoui, R.: Influence of the front contact barrier height on the Indium Tin Oxide/hydrogenated p-doped amorphous silicon heterojunction solar cells. Thin Solid Films 516, 5087 (2008)
Minemoto, T., Murata, M.: Impact of work function of back contact of perovskite solar cells without hole transport material analyzed by device simulation. Curr. Appl. Phys. 14, 1428 (2014)

Table 1: The reported inorganic HTL in perovskite solar cell in literature.

	V_OC(V)	J_SC (mA/cm²)	FF (%)	Eff. (%)
Cu₂O[5]	0.952	17.5	66.2	11.03
NiO[6]	1.01	21	76	16.1
CuI[7]	0.55	17.8	62	6
CuInS₂[8]	0.878	16.6	45.1	6.57
CuSCN[9]	1.020	19.2	58	11.4
CIGS[10]	0.94	17.66	54.88	9.15
CZTS[11]	1.06	20.54	58.7	12.75
PbS[7]	0.86	12.1	72	7.5

Table 2: Some of the material property of selected Chalcogenide for the inorganic hole transport layer.

Parameters	CIGS[12]	CZTS[12-13]	SnS[14]	Cu₂S[16-17]	PbS[18,19]	Sb₂S₃[20]	FeS₂[21,22]
Hall mobility (cm²/Vs)	~35	6-30	100	25	80	10	10
Thermal conductivity (Wm^-1K^-1)	4.44[15]	1.69 [15]	1.25	.3-.5	2.19	-	45
Band gap (eV)	1.13	1.5	1.5	1.2	0.92	1.7	0.95
Hole density (cm^-3)	~10¹⁶	~10¹⁴-10¹⁷	~10¹⁷	~10¹⁹	10¹⁵10¹⁷	~10¹⁶	~10¹⁸
Conductivity type	p	p	p	p	p	p	p
Electron Affinity (eV)	4.58	4.2	3.9-4.2	4.25	3.95	3.95	3.9

Table 3: List of material parameters used in the simulation.

Parameters	TiO₂	SpiroMeOTAD	Perovskite
Thickness(nm)	100	190	350
Bandgap(eV)	1.5	3	1.55
Electron affinity(eV)	3.6	2.2	3.9
Dielectric permittivity	10	3	10
CB effective density of state N_C(cm^-3)	2.2x10¹⁸	2.8x10¹⁹	2.2x10¹⁸
VB effective density of state N_V(cm^-3)	1.8x10¹⁹	1.x10¹⁹	1.8x10¹⁹
Electron thermal velocity(cm/s)	10⁷	10⁷	10⁷
Hole thermal velocity(cm/s)	10⁷	10⁷	10⁷
Electron/hole mobility(cm²/Vs)	10	.0001/.0039	10/10
Donor/ Acceptor density, N_D/N_A (cm^-3)	10¹⁷	10¹⁸	10¹³

Table 4: FF variation with band alignment (VBO) at the SnS/perovskite junction.

Electron affinity (eV)	VBO (eV)	FF (%)
3.8	-0.01	75.33
3.9	0.0	76.98
4	0.1	77.67
4.1	0.2	77.24
4.15	0.25	76.14

Download PDF

Journal Publication

published 14 Aug, 2021

Read the published version in Optical and Quantum Electronics →

Editorial decision: Major revisions
01 Jun, 2021
Reviewers invited by journal
13 Apr, 2021
Reviews received at journal
13 Apr, 2021
First submitted to journal
05 Apr, 2021

You are reading this latest preprint version

Chalcogenide As Inorganic Transport Layer in Perovskite Solar Cell

Status:

Journal Publication

Version 1

Abstract

Figures

Introduction

Chalcogens

Simulation Detail

Results And Discussion

Conclusion

Declarations

References

Tables

Status:

Journal Publication

Version 1