J. Nig. Soc. Phys. Sci. 1 (2019) 72–81

Journal of the
Nigerian Society

of Physical
Sciences

Original Research

Simulation and Optimization of Lead-Based Perovskite Solar
Cells with Cuprous Oxide as a P-type Inorganic Layer

D. Elia,d,∗, M. Y. Onimisia, S. Garbab, R. U. Ugbea, J. A. Owolabia, O. O. Igea, G. J. Ibeha, A. O.
Muhammedc

aDepartment of Physics, Nigerian Defence Academy, Kaduna, Nigeria
bDepartment of Chemistry, Nigerian Defence Academy, Kaduna, Nigeria

cDepartment of Physics, Bayero University, Kano, Nigeria
dDepartment of Physical Sciences, Greenfield University, Kaduna, Nigeria

Abstract

The hole transporting material (HTM) is responsible for selectively transporting holes and blocking electrons which also plays a crucial role in
the efficiency and stability of perovskite solar cells (PSCs). Spiro-MeOTAD is the most popular material, which is expensive and can be easily
affected by moisture contents. There is need to find an alternative HTM with sufficiently high resistance to moisture content. In this paper, the
influence of some parameters with cuprous oxide (Cu2O) as HTM was investigated using solar cell capacitance simulator (SCAPS). These include
the influence of doping concentration and thickness of absorber layer, the effect of thickness of ETM and HTM as well as electron affinities of
ETM and HTM on the performance of the PSCs. From the obtained results, it was found that concentration of dopant in absorber layer, thickness
of ETM and HTM and the electron affinity of HTM and ETM affect the performance of the solar cell. The cell performance improves greatly
with the reduction of ETM electron affinity and its thickness. Upon optimization of parameters, power conversion efficiency for this device was
found to be 20.42 % with current density of 22.26 mAcm−2, voltage of 1.12 V , and fill factor of 82.20 %. The optimized device demonstrates an
enhancement of 58.80 %, 2.25 %, 20.40 % and 30.23 % in PCE, Jsc, FF and Voc over the initial cell. The results show that Cu2O in lead-based
PSC as HTM is an efficient system and an alternative to spiro-MeOTAD.

Keywords: Perovskite solar cells, inorganic HTM, device simulation, cuprous oxide, defect density

Article History :
Received: 26 April 2019
Received in revised form: 16 May 2019
Accepted for publication: 18 May 2019
Published: 30 August 2019

c©2019 Journal of the Nigerian Society of Physical Sciences. All rights reserved.
Communicated by: B. J. Falaye

1. Introduction

The ecxiting properties, including tuned band gap, small
exciton energy, excellent bipolar carrier transport, long charge
diffusion, and amazingly high tolerance to defects [1-7], per-
ovskite halides have demonstrated promising abilities for a nu-
merous of optoelectronic applications, including photovolataics,

∗Corresponding author tel. no: +2348063307256
Email address: danladielibako@gmail.com (D. Eli )

light-emmision, photodetectors, x-rays imaging, lasers, gamma
ray detection etc [8-14].

Perovskite solar cells (PSCs) based on lead have demon-
strated remarkable breakthrough in almost a decade since after
its invention due to its advantages of low cost, high efficiency
and simple fabrication process. Its efficiency has grown from
3.9 % in 2009 to over 23 % in late 2018 [16, 17]. Despite
its remarkable attainment, these power conversion efficiencies
are still low as compared to inorganic solar cells such as crys-
talline silicon (c−S i, 25.7 %), gallium arsenide (GaAs, 28.8 %)

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D. Eli et al. / J. Nig. Soc. Phys. Sci. 1 (2019) 72–81 73

etc [18]. Methyl ammonium lead iodide (CH3NH3PbI3) with a
band gap of 1.50 eV that covers absorption within wide range
of visible spectrum was reported by various experimental and
theoretical studies [18, 19]. Generally, PSC is made up of hole
transporting layer, electron transporting layer and absorber layer.
The function demonstrated by each layer in PSC should be un-
derstood in order to enhance the performance of the device [20].

The most routinely used electron transporting material (ETM)
is T iO2 because of its suitable energy level for electron injec-
tion, high electron mobility, good stability and environmental
friendliness [3, 4, 7, 18]. It is often a difficult task to make
good choice of hole transporting materials which are needed
for extracting holes effectively from the perovskite layer while
preventing electrons from recombination.

The most commonly used hole transport material is Spiro-
OMeTAD which is organic in nature [21]. It is made up of
basically two additives, 4-tert-butylpyridine (TBP) and bis (tri-
fluoromethane) sulfonamide lithium salt (Li-TFSI), which are
used to improve the conductivity and hole mobility of spiro-
MeOTAD. The most commonly used HTM demonstrate hygro-
scopic nature, tendency to crystalize, and vulnerability to both
moisture and heat, as such must be replaced with a cost effec-
tive and stable HTM having high hole mobility with ease of
synthesis [18, 22, 23, 24].

Robust metal oxide [25, 26], carbon [27, 28], and other in-
organic materials [18, 29] have shown outstanding behaviours
in stabilizing the device, but in the meantime, the optimization
of PCE in these devices is still necessary for accelerating the
commercialization. Inorganic p-type semi-conductor such as
Cu2O is considered to be an alternative to organic HTMs [30].

PCE has been greatly enhanced and reached up to 11.03 %
when Cu2O film was prepared via a facile process of Cu sput-
tering and controlled thermal oxidation [30, 31]. Except for ex-
perimental work, it is also equally important to investigate all
aspects of the device theoretically in order to fully understand
the device mechanism and optimize the device performance.

Considering Cu2O as HTM in lead based PSCs, very few
works have been demonstrated so far. For example, perovskite
(CH3NH3PbI3) solar cells with Cu2O as HTM was simulated
using SCAPS, while only the effect of thickness of the absorber
on the performance of PSCs was investigated [32, 33]. A de-
vice model that involve the simulation of various HTMs with
Cu2O inclusive, was done but with no sufficient investigation
on various parameters (only thickness of absorber) was carried
out [34].

In addition to the thickness of the absorber, there are also
many other important parameters which could affect the per-
formance of PSCs. These include doping concentration in the
absorber layer, thickness of the ETM and electron affinity of
ETM and HTM. For example, proper choice of suitable elec-
tron affinity of ETM and HTM can prevent exiton quenching at
the interface, thus can assist in enhancing device performance.
As such, a comprehensive study of these parameters needs to
be investigated in order to uncover further understanding and
thus improve device performance. In this paper, simulation of
lead based CH3NH3PbI3 PSCs with Cu2O as HTM and TiO2 as
ETM was done with SCAPS. The influence of all above men-

tioned parameters on the performance of PSCs were studied
systematically.

2. Device Simulation Parameters

The structure of our simulated PSC is considered with layer
configuration of glass substrate/TCO (transparent conducting
oxide)/TiO2 (ETM) absorber layer CH3 N H3 PbI3/Cu2O (HTM)/
metal back contact. The structure and the band diagram is
shown in figure 1 (a) and (b). From the band structure, the va-
lence band offset at the CH3NH3 PbI3/Cu2O interface is +0.08 eV ,
which can be considered beneficial for the flow of holes to the
back-metal contact in order to avoid their recombination with
the electrons in the perovskite layer.

The conduction band offset is +0.30 eV at the TiO2 /CH3NH3
PbI3 interface, which is also necessary for the flow of photo
excited electrons to the front electrode. Neutral Gaussian dis-
tribution defect is selected in the absorber layer and charac-
teristic energy is set to be 0.1 eV [18]. Two defect interfaces
are inserted for carrier recombination. One defect interface is
TiO2/CH3NH3PbI3 and the other one is CH3NH3PbI3/Cu2O.

The nature of the defect is set as Gaussian and defect den-
sity is set as 1 × 1018 cm−3 [18, 32]. Table 1 shows the defect
parameters which are used in the simulation. Basic parameters
for each material used in the simulation are summarized in Ta-
ble 2. Thermal velocities of hole and electron are selected as
107 cms−1 [18, 32, 35, 36]. The optical reflectance is consid-
ered to be zero at the surface and at each interface [18]. Pa-
rameters are optimized in the study by using control variable
method. The initial total defect density of the absorber layer is
assumed to be 2.5 × 1013 cm−3.

The current density–voltage curve has been drawn with these
initial parameters as shown in Figure 2(A).

The short-circuit current density (Jsc) of 21.77 mAcm−2,
open-circuit voltage (Voc) of 0.865 V , Fill Factor (FF) of 68.27 %,
and PCE of 12.86 % are obtained. The simulated device perfor-
mance is consistent with the experimental results of lead-based
PSCs [30, 31]. This consistency shows that input parameters
are valid and close to the real device. In the incident photon-
to-current efficiency (IPCE) of the device shown in figure 2(B)
which is featured with a high platform between 300 nm and
850 nm with the maximum of 90 % at 570 nm. Optical ab-
sorption edge is red shifted to 800 nm which corresponds to
a band gap of 1.55 eV in CH3 N H3 PbI3. The IPCE covers
the whole visible spectrum which is closer to the experimen-
tal work [30, 31].

3. Results and Discussion

3.1. Influence of doping concentration (NA) of absorber layer

In order to enhance the performance of solar cells, doping is
a key process considered. Depending upon the type of dopants,
doping can either be n-type or p-type. Like the other crys-
talline semiconductors, the shallow point defects in absorber
could cause unintentional doping at room temperature. The per-
formance of PSC can be enhanced by introducing appropriate

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D. Eli et al. / J. Nig. Soc. Phys. Sci. 1 (2019) 72–81 74

Table 1: Defect parameters of interfaces and absorber [18, 32]

Parameters CH3 N H3 PbI3 T iO2/CH3 N H3 PbI3 interface CH3 N H3 PbI3/Cu2O interface
Defect type Neutral Neutral Neutral
Capture cross section for electrons (cm2) 2 × 10−15 2 × 10−16 2 × 10−15

Capture cross section for holes (cm2) 2 × 10−15 2 × 10−16 2 × 10−15

Energetic distribution Gaussian Single Single
Energetic level with respect to Ev(eV ) 0.500 0.650 0.650
Characteristic energy (eV ) 0.1 0.1 0.1
Total density (cm−3) 1 × 1015 − 1 × 1019 1 × 1018 1 × 1018

Table 2: Simulation parameters of PSCs devices

Parameters FTO ETM (T iO2) Absorber HTM (Cu2O)
Thickness (µm) 0.4 0.05 0.45 0.15
Band gap energy Eg (eV ) 3.5 3.26 [32] 1.55[32] 2.17[32]
Electron affinity χ(eV ) 4.0 4.2[32] 3.9[18] 3.2[32]
Relative permittivity �r 9 10 6.5 7.11[32]
Effective conduction band density Nc(cm−3) 2.2 × 1018 2.2 × 1018[32] 2.2 × 1018[32] 2.2 × 1018[32]
Effective valance band density Nv(cm−3) 2.2 × 1018 2.2 × 1018[32] 2.2 × 1018[32] 2.2 × 1018[32]
Electron mobility µn(cm2V−1 s−1) 20 20[18, 32] 2[32, 33] 80[32, 39]
Hole mobility µp(cm2V−1 s−1) 10 10[18, 32] 2[32, 33] 80[32, 39]
Donor concentration ND (cm−3) 1 × 1019 1 × 1017 0 0
Acceptor concentration NA (cm−3) 0 0 1 × 1013[7, 32] 1 × 1018[18, 32]
Defect density Nt (cm−3) 1 × 1015 1 × 1015[18, 32] 2.5 × 1013[18, 32] 1 × 1015[18, 32]

Figure 1: (a) The structure of perovskite solar cell in the simulation and
(b) Energy level diagram of Cu2O in the device

dopant in absorber layer [18, 37]. The self-doping process can
be adopted for n- or p-type doping in absorber layer. It has been
demonstrated experimentally that n-type or p-type self-doping
in CH3 N H3 PbI3 lead towards the manipulation of carrier den-
sity, majority carrier type and charge transport by changing the

thermal annealing or precursor ratios in the solutions [37, 38].
Formation of CH3 N H3 PbI3 involves organic and inorganic

precursors named methyl ammonium iodide (MAI) and lead io-
dide (PbI2). The ratio between precursors (PbI2/MAI) decides
the doping of the absorber. Upon thermal annealing, PbI2 rich
absorber layer is n-doped and PbI2 deficit absorber layer is p-
doped [39]. Furthermore, CH3 N H3 PbI3 is unstable in air and
humidity.

When moist air comes in contact with device then PbI2 is
generated and oxidation state of lead is changed. This process
is the cause of introducing impurities in absorber layer. The
effect of doping concentration on the performance of perovskite
solar cell is studied by choosing the values of NA in the range
of 1014–1017cm−3. Table 3 gives the PCE of PSC with various
values of doping concentration. It is worth noting that PCE
is maximum when the value of NA is 1 × 1015 cm−3. Jsc also
has the same behaviour. The results above demonstrate that
charge carriers are transported and collected more efficiently at
the same irradiance when NA of the absorber is 1 × 1015 cm−3.

Therefore, proper selection of NA is necessary for the im-
provement of performance of PSCs. On the other hand, Jsc and
Voc decrease when values of NA increases beyond 1×1015 cm−3.
The variation in the cell performance with the doping concen-
tration can be explained in terms of built-in electric field which
is enhanced with the increase of doping concentration. The
charge carriers are separated and increased by the increase of
electric field resulting in the enhanced performance of PSCs
[18, 40].

The decrease in Jsc with increasing doping concentration
could be explained from the perspective of Auger recombina-

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D. Eli et al. / J. Nig. Soc. Phys. Sci. 1 (2019) 72–81 75

Figure 2: (A) J–V curve of PSC with initial parameters, (B) IPCE spec-
tra of the device with initial parameters

tion. Auger recombination rate increases with further increase
of doping density beyond 1 × 1015 cm−3. It is also clear that
total recombination rate also increases when doping density in-
creases beyond 1 × 1015 cm−3. The scattering and recombina-
tion increases due to increasing doping density thus suppressing
hole transportation [18, 41]. Therefore, optimum doping den-
sity enhances the Voc and Jsc which in turn increases the PCE.
While further increase in doping density is not favourable due
to high recombination and scattering.

There should be lower carrier concentration in lead per-
ovskite so that carrier mobility can increase within the absorber.
The optimum performance with Jsc of 22.10 mAcm−2, Voc of
0.85 V , FF of 73.97 % and PCE of 13.82 % is obtained under
the doping density of 1 × 1015 cm−3. The comparison is shown
between J–V curves with different value of NA in Figure 3(B).
With the optimization, PCE was enhanced by 7.38 %, and Jsc
increases 1.52 %, as compared with the device having initial

value of NA = 1 × 1013cm−3. Figure 3(A) shows the simula-
tion results by changing the value of doping concentration from
1×1015 to 1×1017cm−3 with respect to photovoltaic parameters
(PCE, Voc, Jsc, and FF).

Figure 3: (A) Variation in performance parameters of PSC with doping
concentration of absorber, (B) J–V curves of PSC with different values
of doping concentration.

3.2. Influence of electron affinity of ETM and HTM

One of the important factor considered in T iO2/ perovskite/
Cu2O is band offset which becomes a determining factor as
to the carrier recombination at the interface and is the mea-
sure of Voc. By varying the values of electron affinities of
T iO2(3.7–4.3 eV ) and Cu2O(3.1–3.7 eV ), the band offset can
be adjusted. Figures 4(A) and 5(A) show variation of PCE, Voc,
Jsc and FF with electron affinity of ETM and HTM respectively.
The values of 3.7 eV and 3.3 eV give the best PCE for T iO2 and
Cu2O respectively. When the electron affinity of ETM is high
(greater than 3.7 eV ), then Voc and Jsc decrease slightly. PCE
of 20.29 %, Jsc of 22.55 mAcm−2, Voc of 1.10 V and FF of
81.72 % were obtained upon optimizing value of electron affin-
ity of ETM, as shown in Table 4 and PCE of 13.11 %, Jsc of
21.87 mAcm−2, Voc of 0.87 V and FF of 69.31 % were obtained
upon optimizing value of electron affinity of HTM, as shown in
Table 5. It is evident that proper ETM and HTM selection with
suitable electron affinity can reduce the recombination of car-

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D. Eli et al. / J. Nig. Soc. Phys. Sci. 1 (2019) 72–81 76

Table 3: Dependence of solar cell performance on the doping concentration of Absorber layer

Parameters NA(cm−3) Jsc(mAcm−2) Voc (V ) FF PCE (%)
1014 21.80 0.86 69.02 12.99
1015 22.80 0.85 73.97 13.82
1016 21.96 0.79 76.43 13.21
1017 19.20 0.60 73.45 8.40

riers and performance of PSCs can further be optimised [42].

Figure 4: (A) Variation in performance parameters of PSC with elec-
tron affinity of ETM, (B) J–V curves of PSC with different values of
electron affinity of ETM.

3.3. Influence of thickness of ETM and HTM
Figure 6(A) is the plot of solar cell parameters; VOC , JS C ,

FF and PCE versus thickness of the ETM; T iO2. In both cases
VOC , JS C , FF and PCE are gradually decreasing due to frac-
tional absorption of incident light by the T iO2 layer, the bulk
recombination and surface recombination at the interface [15].
Thickness of ETMs has been varied from 0.001 to 0.160 µm
which shows a decrease in photovoltaic parameters with in-
crease in ETM thickness, as shown in Table 6. Similarly, Fig-

Figure 5: (A) Variation in performance parameters of PSC with elec-
tron affinity of HTM, (B) J–V curves of PSC with different values of
electron affinity of HTM.

ure 6(B) shows reverse case as VOC , JS C , FF and PCE increase
with increase in HTM up to 0.02 µm. Above 0.02 µm we no-
ticed a constant value for VOC , JS C , FF and PCE, which means
the thickness that gives optimum performance is from 0.04 to
0.16 µm. The slightly increase with increase in thickness up to
0.02 µm suggests the higher conductivity of the T iO2 and partial
absorption of the light. PCE of 15.52 %, Jsc of 22.10 mAcm−2,
VOC of 1.01 V and FF of 69.81 % are obtained at a thickness of
0.001 µm which is the optimized value of HTM thickness and
PCE of 12.87 %, JS C of 21.77 mAcm−2, VOC of 0.87 V and FF
of 68.27 % are obtained, as shown in Table 7.

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D. Eli et al. / J. Nig. Soc. Phys. Sci. 1 (2019) 72–81 77

Table 4: Dependence of solar cell performance on the electron affinity of ETM

Parameters EA(eV ) Jsc(mAcm−2) Voc (V ) FF PCE (%)
3.7 22.50 1.10 81.72 20.29
3.8 22.49 1.10 81.20 20.10
3.9 22.25 1.09 77.50 18.78
4.0 22.07 1.05 71.14 16.49
4.1 21.93 0.97 69.21 14.64
4.2 21.77 0.87 68.27 12.87
4.3 21.58 0.77 67.36 11.13

Table 5: Dependence of solar cell performance on the HTM

Parameters EA(eV ) Jsc(mAcm−2) Voc (V ) FF PCE (%)
3.1 21.59 0.87 64.10 12.01
3.2 21.77 0.87 68.27 12.87
3.3 21.87 0.87 69.31 13.11
3.4 21.88 0.87 68.48 12.96
3.5 21.74 0.86 61.94 11.64
3.6 21.54 0.83 55.03 9.90
3.7 21.28 0.75 51.43 8.16

Table 6: Dependence of solar cell performance on the ETM

Parameters T (µm) Jsc(mAcm−2) Voc (V ) FF PCE (%)
0.0010 22.10 1.01 69.81 15.52
0.0025 22.05 0.97 69.37 14.89
0.0050 22.00 0.95 69.12 14.37
0.0100 21.93 0.91 69.84 13.81
0.0200 21.86 0.89 68.50 13.27
0.0400 21.79 0.87 68.33 12.93
0.0800 21.73 0.86 68.27 12.81
0.1600 21.64 0.86 68.30 12.76

Table 7: Dependence of solar cell performance on the HTM

Parameters T (µm) Jsc(mAcm−2) Voc (V ) FF PCE (%)
0.0010 21.23 0.82 55.61 9.66
0.0025 21.24 0.82 55.73 9.76
0.0050 21.29 0.84 56.41 10.12
0.0100 21.51 0.87 62.00 11.58
0.0200 21.76 0.87 68.15 12.84
0.0400 21.77 0.87 68.27 12.87
0.0800 21.77 0.87 68.27 12.87
0.1600 21.77 0.87 68.27 12.87

Table 8: Dependence of solar cell performance on the Absorber

Parameters T (µm) Jsc(mAcm−2) Voc (V ) FF PCE (%)
0.2 17.57 0.83 74.16 10.78
0.3 20.32 0.85 71.75 12.32
0.4 21.43 0.86 69.51 12.83
0.5 21.99 0.87 67.05 12.82
0.6 22.20 0.87 64.72 12.52
0.7 22.21 0.88 62.50 12.22
0.8 22.10 0.88 60.48 11.82
0.9 21.93 0.87 58.67 11.41

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D. Eli et al. / J. Nig. Soc. Phys. Sci. 1 (2019) 72–81 78

Table 9: Optimized Parameters of the device

Optimized parameters ETM(T iO2) Absorber (CH3 N H3 PbI3) HTM(Cu2O)
Doping density (cm−3) – 1 × 1015 –
Electron affinity (eV ) 3.7 – 3.3
Thickness (µm) 0.0010 0.4000 0.1600

Table 10: Photovoltaic parameters of Cu2O based perovskite solar cells reported in the experimental work in the literature and simulated results using SCAPS.

Simulation Jsc(mAcm−2) Voc (V ) FF PCE (%)
Initial 21.76 0.86 68.26 12.86
Optimized NA of absorber 22.09 0.85 73.97 13.82
Optimized thickness of absorber 21.43 0.86 69.51 12.83
Optimized EA of ETM 22.55 1.10 81.72 20.29
Optimized EA of HTM 21.87 0.87 69.31 13.11
Optimized thickness of ETM 22.10 1.00 69.81 15.52
Optimized thickness of HTM 21.77 0.87 68.27 12.87
Final optimization 22.26 1.12 82.20 20.42
[30] 17.50 0.95 66.20 11.03
[31] 19.02 0.99 73.63 13.97

Figure 6: (A) Variation in performance parameters of PSC with thicknss
of ETM, (B) J–V curves of PSC with different values of thickness of
ETM.

Figure 7: (A) Variation in performance parameters of PSC with thick-
ness of HTM, (B) J–V curves of PSC with different values of thickness
of HTM.

3.4. Influence of thickness of absorber layer
There is another parameter, thickness of absorber layer, which

affects the performance of solar cell. The influence of thickness78



D. Eli et al. / J. Nig. Soc. Phys. Sci. 1 (2019) 72–81 79

Figure 8: (A) Variation in performance parameters of PSC with thick-
ness of Absorber, (B) J–V curves of PSC with different values of Ab-
sorber thickness.

Figure 9: J–V curves of PSC with Optimized parameters.

of absorber on the solar cell parameters; VOC , JS C , FF and PCE
is shown in Figure 8(B). PCE is lower when thickness of the
layer is too small (0.2 µm) due to the poor light absorption.
PCE of PSCs increases with the increase of the thickness of the
absorber 0.20 to 0.40 µm before it starts decreasing. For thick-
ness beyond 0.4 µm, the collection of photo generated carriers
decreased because of charge recombination.

The PCE of the device increases when thickness of the ab-
sorber layer increases. PCE decreases when thickness is larger
than 0.40 µm. Considering, the effect of thickness of the ab-
sorber, the optimized parameters are PCE of 12.83 %. JS C of
21.43 mA/cm2, VOC of 0.86 V , and FF of 69.51 %, as shown in
Table 8. It is evident from literature that pin hole free structure
of methyl ammonium lead iodide perovskite can be obtained by
using dimethyl sulfoxide (DMSO) and using polyethylene gly-
col (PEG) also gives a better effects on the surface morphology
[18, 43, 44]. By using solvent retarding method (SR), optimal
thick and uniform perovskite film can be deposited [45].

3.5. Performance of Optimized parameters

At the end, considering all the factors as doping concen-
tration, electron affinity and thickness, we obtained PCE to be
20.42 % with current density of 22.26 mAcm−2, voltage of 1.12 V ,
and fill factor of 82.20 %, which shows an improvement of
58.80 %, 2.25 %, 20.40 % and 30.23 % in PCE, Jsc, FF and
Voc over the initial cell. The final optimized parameters and
optimised J–V curve are shown in Table 9 and Figure 9 respec-
tively. We compared our simulated results with the experiment
work published by other researchers and the related data is sum-
marized in Table 10.

In the literature, the best efficiency of 11.03 % has been
achieved for PSCs with Cu2O as HTM. The VOC , FF and JS C
still need to be increased to achieve 20.42 % efficiency. This
could be achieved by further improving the film morphology
and crystalline quality of both the absorber and Cu2O layer.
Doping of Cu2O by replacing either part of Cu or part of O
by other element might/can further modify the charge carrier
concentration and mobility of HTM.

4. Conclusion

In this work, the lead-based perovskite solar cells with Cu2O
as HTM are studied by one dimensional simulation programme.
The results show that optimum doping concentration in the ab-
sorber layer gives improved PCE. High values of doping con-
centration leads to decrease of PCE due to higher recombina-
tion rates. To reduce the recombination rates at the interfaces,
proper selection is made for the electron affinity of ETM and
HTM. By choosing the electron affinity of ETM as 3.7 eV , PCE
of PSCs increases from 12.86 % to 20.29 %, and by choos-
ing the electron affinity of HTM as 3.3 eV , PCE of PSCs in-
creases from 12.86 % to 13.11 %. With the optimised thickness
of 0.001 µm, for ETM layer, the PCE of the device increases
from 12.86 % to 15.52 %. With the optimised HTM thickness
of 0.16 µm, thus, PCE increases up to 12.87 %. The overall
PCE, FF, JS C , and VOC , of 20.42 %, 82.20 %, 22.26 mAcm−2,

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D. Eli et al. / J. Nig. Soc. Phys. Sci. 1 (2019) 72–81 80

and 1.12 V respectively were obtained by using all optimised
parameters. The results show that Cu2O as alternate HTM has
the potential to be used with CH3 N H3 PbI3 and can replace the
spiro-MeOTAD which is costly HTM for perovskite solar cell.

Acknowledgments

We thank the referees for the positive enlightening com-
ments and suggestions, which have greatly helped us in mak-
ing improvements to this paper. The authors would also like
to thank Professor Marc Burgelman, Department of Electronics
and Information Systems, University of Gent for the develop-
ment of the SCAPS software package and for allowing its use.

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