Optimized parameter extraction techniques for enhanced performance evaluation of organic solar cells

International Journal of Electrical and Computer Engineering (IJECE)
Vol. 14, No. 2, April 2024, pp. 1263~1273
ISSN: 2088-8708, DOI: 10.11591/ijece.v14i2.pp1263-1273  1263
Journal homepage: http://ijece.iaescore.com
Optimized parameter extraction techniques for enhanced
performance evaluation of organic solar cells
Mohd Uvais1
, Asif Jamil Ansari1
, Mohammed Asim1
, Mohammad Saood Manzar2
1
Department of Electrical Engineering, Faculty of Engineering and Information Technology, Integral University, Lucknow, India
2
Department of Environmental Engineering, Imam Abdurrahman Bin Faisal University, Dammam, Kingdom of Saudi Arabia
Article Info ABSTRACT
Article history:
Received Nov 1, 2023
Revised Nov 28, 2023
Accepted Dec 5, 2023
The global energy landscape is in the midst of a transformative shift,
compelled by the urgent need to reduce our reliance on fossil fuels and
embrace eco-friendly alternatives. Organic photovoltaics (OPVs) have
emerged as a promising alternative, offering the distinct advantage of
performing well in low-light conditions, including indoor environments.
Extensive research and development efforts are dedicated to realizing the
full potential of OPVs as adaptable, cost-effective, and environmentally
friendly solar energy solutions. This paper conducts a thorough examination
of the intricate characterization of organic solar cells, with a specific
emphasis on crucial parameters like power conversion efficiency, open-
circuit voltage, and fill factor. The study utilizes a single diode model to
simulate these cells' behavior, employing a meticulous process for parameter
extraction. This method leverages Origin software and Python programming,
incorporating open-source packages to ensure robust validation. This
systematic and rigorous approach significantly enhances our comprehension
of OPVs and plays a substantial role in optimizing their performance. In
essence, this research represents a significant step forward in advancing
sustainable energy technologies, laying a foundation for a greener and more
environmentally conscious future.
Keywords:
Five parameter model
I-V characteristics
Optimization technique
Organic photovoltaics
Parameter extraction
This is an open access article under the CC BY-SA license.
Corresponding Author:
Mohammed Asim
Department of Electrical Engineering, Faculty of Engineering and Information Technology, Integral
University
Kursi Road, Lucknow 226026, India
Email: asimamu@gmail.com
NOMECLATURE
𝐺 : Solar irradiance (W/m2
) 𝑃𝑚𝑎𝑥 : Maximum electrical power
𝐼 : Output current 𝑅𝐿 : Electrical load
𝐼𝐿 : Photocurrent 𝑅𝑆 : Series resistance
𝐼𝑀𝑃𝑃 : Current at maximum power point 𝑅𝑆𝐻 : Shunt current through 𝑅𝑆𝐻
𝐼𝑆𝐶 : Short circuit current 𝑇 : Temperature
𝐼0 : Reverse saturation current of diode 𝐼01 : Reverse saturation current of diode D1
𝑛 : Ideality factor of diode D1 𝐼02 : Reverse saturation current of diode D2
𝑛1 : Ideality factor of diode D2 𝑉 : Voltage generated
𝑛2 : Ideality factor of diode 𝑉𝑀𝑃𝑃 : Voltage at the maximum power point
𝑉𝑇T : Thermal voltage 𝑉𝑂𝐶 : Open circuit voltage

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Int J Elec & Comp Eng, Vol. 14, No. 2, April 2024: 1263-1273
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𝑁𝑆 : Number of cells 𝐷1 & 𝐷2 : Diode
𝑒 : Charge of electron 𝑞 : Charge
𝑉𝐷 : Diode voltage 𝑘 : Boltzmann constant
𝑉𝑃𝑉 : Output voltage 𝐼𝑠 : Reverse-bias saturation current
𝐶𝑆𝑉 : Comma separated values
1. INTRODUCTION
The global energy scenario is experiencing a significant transformation, driven by the need for
sustainable practices and environmental responsibility. While fossil fuels have historically dominated the
energy mix, there is a growing shift towards cleaner alternatives such as renewable energy sources. This
transition is supported by advancements in technology, declining costs, and favorable policies. Efforts to
improve energy efficiency, electrify various sectors, and promote decentralized energy systems are gaining
momentum. Furthermore, addressing energy access and equity remains a crucial aspect of global energy
initiatives. By embracing responsible energy practices, we can mitigate climate change, reduce greenhouse
gas emissions, and pave the way for a greener and more sustainable future [1]. Solar photovoltaics (PV) have
a crucial role in the global energy scenario, contributing to the transition towards cleaner and sustainable
energy sources. Solar PV systems harness sunlight to generate electricity, reducing dependence on fossil
fuels and mitigating greenhouse gas emissions. With falling prices and cost competitiveness, solar PV is
increasingly accessible and economically viable. Its scalability, diverse applications, and integration with
energy storage make it a versatile solution for decentralized energy generation, enhancing energy
independence and resilience. Moreover, solar PV stimulates job creation, supports local economic
development, and fosters a more sustainable and resilient energy future [2].
Organic photovoltaics (OPVs) present an alternative to conventional solar PV with distinct
advantages in the global energy landscape. Their flexibility and versatility enable integration into various
applications like flexible solar panels and wearable electronics. OPVs offer scalability and low-cost
production using solution-based techniques, making solar energy more accessible, especially in emerging
markets. They demonstrate improved performance under low light conditions, expanding their utility in
indoor environments. With lower environmental impact and potential recyclability, OPVs align with
sustainable practices. Although efficiency and stability are areas for ongoing improvement, OPVs hold
promise as they can be seamlessly integrated into building design and complement traditional PV
technologies. Ongoing research and development efforts continue to enhance OPVs' potential in the overall
energy scenario as a flexible, cost-effective, and environmentally friendly solution for solar energy
generation [3]. Organic solar cells, also known as OPVs, are a type of solar cell technology that utilizes
organic materials, typically polymers or small molecules, to convert sunlight into electricity. Unlike
traditional inorganic solar cells, which predominantly use silicon as the active material, organic solar cells
rely on organic semiconductors to absorb light and generate electrical current. These organic materials can be
deposited onto flexible substrates using low-cost manufacturing techniques such as printing or coating,
enabling the production of lightweight, flexible, and potentially transparent solar panels. Organic solar cells
offer the potential for low-cost and large-scale production, as well as unique applications in areas such as
wearable electronics, building-integrated photovoltaics (BIPV), and other emerging technologies. Ongoing
research and development efforts aim to improve organic solar cells' efficiency, stability, and commercial
viability to enhance their role in the renewable energy landscape [3].
Characteristics parameters of organic solar cells, also known as OPVs, include power conversion
efficiency (PCE), open-circuit voltage (𝑉𝑂𝐶), short-circuit current (𝐼𝑆𝐶), fill factor (FF), external quantum
efficiency (EQE), stability and degradation, material absorption range, and manufacturing cost. PCE
represents the ability to convert sunlight into electricity, while 𝑉
𝑜𝑐 and 𝐼𝑠𝑐 indicate the maximum voltage and
current output, respectively. FF quantifies charge extraction efficiency, and EQE measures the percentage of
incident photons converted to charge carriers. Stability, material absorption range, and manufacturing cost
are also essential considerations. Evaluating and optimizing these parameters enables the assessment of
organic solar cells' performance, efficiency, stability, and cost-effectiveness, promoting their potential as a
sustainable and economically viable solution for renewable energy generation [4], [5]. Efficiency is
determined by the PCE of the cell, which is expressed as a percentage. Higher PCE values indicate more
efficient energy conversion. The efficiency of organic solar cells has been steadily improving over the years,
with current state-of-the-art OPVs achieving PCE values exceeding 18%. This progress is attributed to
advancements in organic materials, device engineering, and fabrication techniques. Researchers are
continuously exploring novel materials and device architectures to enhance light absorption, charge transport,
and charge extraction within organic solar cells. Efforts are also focused on reducing energy losses due to

Int J Elec & Comp Eng ISSN: 2088-8708 
Optimized parameter extraction techniques for enhanced performance … (Mohd Uvais)
1265
non-radiative recombination and improving the stability of organic solar cells. Increasing efficiency is crucial
for making organic solar cells a competitive alternative to traditional inorganic solar cells and accelerating
their commercial adoption as a sustainable and efficient renewable energy technology [6].
Accurate characterization of OPV solar cells is indispensable for predicting their current-voltage
(I-V) traits and extracting essential intrinsic parameters. This process is pivotal for comprehending the
fundamental physics and optimizing the overall performance of these devices. Leveraging sophisticated
computational methodologies and mathematical models, researchers can effectively simulate the operational
behavior of OPVs across diverse conditions. This modelling framework facilitates the precise determination
of critical parameters, including open-circuit voltage, short-circuit current, fill factor, and power conversion
efficiency. The I-V attributes derived from modelling can be corroborated by empirical measurements,
thereby enhancing the credibility and precision of the models. Ultimately, the utilization of modelling
techniques for OPV solar cells constitutes an essential instrument, fostering insights into their operational
characteristics, steering advancements in design, and expediting their integration into real-world applications
within the renewable energy sector [7], [8]. Figure 1, the single diode model, as expounded in the preceding
response, stands as a valuable mathematical asset in emulating the current-voltage (I-V) traits of OPV solar
cells. This model portrays the OPV cell as an analogous electrical circuit comprising a solitary diode,
encompassing the pivotal charge transport and recombination mechanisms. By assimilating parameters
garnered from both modelling exercises and empirical data, the single diode model adeptly anticipates the
I-V curve of the OPV cell across varied operational scenarios. This model lays the groundwork for refining
crucial performance indicators such as open-circuit voltage, short-circuit current, fill factor, and power
conversion efficiency. While the single diode model streamlines the intricate physics inherent in OPV cells,
more advanced models are concurrently being refined to encompass supplementary phenomena.
Notwithstanding, the single diode model endures as an efficient and extensively employed instrument for
comprehending and enhancing the operational characteristics of OPV devices [9]–[12].
RSH
RS
D1
VPV
I
G
+
-
Figure 1. OPV model with one diode
𝐼 = 𝐼𝐿 − 𝐼𝑜 ⌊𝑒
𝑉+𝐼𝑅𝑆𝐻
𝑛𝑇 − 1 ⌋ −
𝑉+𝐼𝑅𝑆
𝑅𝑆𝐻
(1)
Figure 2, the dual diode model serves as an advanced mathematical framework employed to
simulate the I-V attributes inherent to OPV solar cells. This model integrates a pair of diodes to encapsulate
the intricate charge transport and recombination mechanisms within the device. One diode encapsulates bulk
charge transport and recombination, while the other diode delineates charge transfer and recombination
transpiring at interfaces. Through the consideration of diverse parameters and a precise portrayal of the
physical dynamics of the OPV cell, the dual diode model furnishes an accurate emulation of the I-V curve. In
doing so, it optimizes crucial performance metrics encompassing open-circuit voltage, short-circuit current,
fill factor, and power conversion efficiency. Despite introducing augmented intricacy, this model enriches the
comprehension and design of OPV devices [9]–[12].

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𝐼 = 𝐼𝐿 − 𝐼01 (𝑒
𝑁𝑆
𝑛1𝑉𝑇
− 1 ) − 𝐼02 (𝑒
𝑁𝑆
𝑛2𝑉𝑇
− 1) −
𝑉+𝐼𝑅𝑆
𝑅𝑆𝐻
(2)
The parameter extraction process for organic solar cells is essential for accurately determining key
device parameters that characterize their performance. It involves a combination of experimental
measurements, electrical characterization techniques, and numerical modelling. Through I-V measurements
under various illumination conditions, parameters such as VOC, ISC, FF, and PCE are directly determined.
Numerical models, including the single diode or double diode models, complement experimental data by
extracting intrinsic parameters like series resistance, shunt resistance, and ideality factor. The accurate
extraction of these parameters aids in understanding device performance, guiding optimization efforts, and
facilitating the design of more efficient and reliable organic solar cells [13]. In this paper, a single diode
model of an organic solar cell has been utilized for the purpose of parameter extraction. The extraction
process consists of two main steps: initially, the solar I-V model was employed in the Origin software to
extract the parameters, followed by validation using the Brano et al.’s model [14], [15]. To implement
this model, Python programming language was employed, and open-source packages such as
scipy.optimize.least_square were utilized. The parameter extraction methodology involved the use of the
solar I-V model in the Origin software. This model allowed for the determination of various key parameters
of the organic solar cell. Once the parameters were obtained, this model was employed to validate the
extracted values. This model, implemented in Python, facilitated the verification of the extracted parameters
and ensured the reliability of the results. To accomplish the implementation of this model in Python, several
open-source packages were utilized. One such package, scipy.optimize.least_square, provided optimization
algorithms for minimizing the residuals between the experimental and simulated data. By employing these
algorithms, the accuracy of the parameter extraction process was enhanced. Further details and explanations
regarding the entire working process will be elaborated in the subsequent sections of the paper. These
sections will provide a comprehensive understanding of the methodology employed, the steps taken, and the
specific details related to the parameter extraction and validation process. Overall, this paper presents a
detailed and systematic approach to parameter extraction in organic solar cells, utilizing a single diode model
and validating the results through this model implemented in Python. The use of open-source packages and
software tools ensures the reproducibility and transparency of the methodology, thereby enhancing the
credibility of the obtained results.
RSH
D2
RS
D1
VPV
I
G
+
-
Figure 2. OPV model with double diode
The investigation pertaining to parameter derivation in organic solar cells through the utilization of
the single diode model has predominantly revolved around devising precise and streamlined techniques to
delineate the electrical attributes of these systems. The single diode model delineates an organic solar cell as
a diode interconnected in parallel with a resistor, with its parameters ascertained by synergizing empirical
measurements and mathematical simulation [16]. One commonly employed technique for parameter
extraction is the fitting of I-V curves. Researchers compare the experimental I-V characteristics of the solar

1267
cell with the predictions of the single diode model to determine the values of the model parameters. This
approach has been extensively utilized in numerous studies and provides valuable insights into the
performance and efficiency of the device [17]. The scholarly literature on parameter extraction of organic
solar cells using the single diode model highlights the diverse approaches employed to characterize the
electrical properties and optimize the performance of these devices. Experimental measurements,
mathematical modelling, and optimization techniques all play crucial roles in advancing the understanding
and development of organic solar cell technologies. The process of parameter extraction begins with the
acquisition of I-V curves, which describe the relationship between the current passing through the solar cell
and the voltage applied across it. These experimental measurements serve as the basis for comparing with the
predictions of the single diode model. The model represents the solar cell as a diode in parallel with a
resistor, capturing the essential electrical characteristics of the device [18]. In the pursuit of parameter
extraction within the context of the single diode model, investigators employ the utilization of curve fitting
methodologies. Empirical I-V curves are harmonized with theoretical I-V curves produced by the model, the
objective being to minimize disparities between the two datasets. This fitting procedure serves to unveil
pivotal parameters, encompassing the diode ideality factor, series resistance, shunt resistance, and
photocurrent. The diode ideality factor provides insight into the efficacy of charge carrier transportation
across the diode junction within the solar cell. The series resistance accommodates resistive losses transpiring
within the device, while the shunt resistance encapsulates inadvertent parallel pathways permitting current to
circumvent the active region of the solar cell. The photocurrent parameter quantifies the magnitude of current
generated by the solar cell under the influence of illumination [19]. While I-V curve fitting is a widely used
approach, researchers have also explored alternative methods such as impedance spectroscopy (IS) analysis.
IS analysis involves applying an alternating current (AC) signal with varying frequencies to the solar cell and
measuring the resulting impedance. The impedance response provides information about the device's
electrical properties, including the series resistance, shunt resistance, and capacitance. By analyzing the
impedance spectra obtained from IS measurements, researchers can extract additional parameters that
contribute to a more comprehensive understanding of the solar cell's behavior The series resistance represents
the resistive losses within the device and affects its overall performance. The shunt resistance accounts for
any parallel paths that allow current to bypass the active region, leading to reduced efficiency.
The capacitance parameter reflects the energy storage capability of the solar cell [20]. Furthermore,
researchers have turned to advanced optimization algorithms to improve the efficiency and accuracy of
parameter extraction. Genetic algorithms and particle swarm optimization are two examples of optimization
techniques employed in this context. These algorithms search for the best-fit values of the parameters by
iteratively modifying them and evaluating the resulting simulated I-V curves or impedance spectra against
the experimental data [21], [22]. In [23] genetic algorithms mimic the process of natural selection, where a
population of potential solutions evolves over generations. The fittest solutions, which exhibit the closest
match to the experimental data, are more likely to be selected for subsequent iterations [24]. Particle swarm
optimization, on the other hand, simulates the movement of particles within a multidimensional parameter
space. Each particle represents a potential solution, and their collective behavior leads to the identification of
optimal parameter values. By employing these optimization algorithms, researchers aim to overcome the
challenges associated with manual or exhaustive search methods. These techniques facilitate a more efficient
exploration of the parameter space and help identify optimal solutions that may not be immediately apparent
through traditional approaches.
In the realm of parameter extraction for organic solar cells through the utilization of the single diode
model, a diverse array of techniques is embraced with the intention of achieving precise and streamlined
characterization of the electrical attributes of these devices. The amalgamation of strategies such as I-V curve
fitting, impedance spectroscopy analysis, and optimization algorithms collectively propels the progression of
our comprehension and the evolution of technologies relating to organic solar cells. These methodologies
collectively empower researchers to deduce critical model parameters' values, enhance the efficacy of organic
solar cells, and ultimately catalyze the widespread integration of this sustainable energy technology.
2. METHOD
Numerical techniques, also known as numerical methods, refer to mathematical algorithms and
procedures used to solve problems and perform calculations using numerical approximations. These
techniques are employed when analytical solutions are difficult or impossible to obtain, or when dealing with
complex systems or large amounts of data. Numerical techniques involve translating mathematical models or
problems into a computational form, where numerical approximations and algorithms are applied to obtain
solutions or results. These methods rely on iterative processes, where calculations are repeated and refined to
converge towards an accurate solution. Numerical techniques play a crucial role in the study and optimization
of organic solar cells. These techniques are employed to model, simulate, and analyze the behavior of organic

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solar cells, as well as to optimize their performance. Here are some ways in which numerical techniques are
used for organic solar cells.
Device modelling and simulation: Numerical techniques allow researchers to develop mathematical
models that describe the behavior of organic solar cells. These models take into account various physical and
electrical phenomena, such as charge generation, transport, recombination, and light absorption. By solving
the mathematical equations representing these phenomena using numerical methods, researchers can simulate
the performance of organic solar cells under different operating conditions, material properties, and device
architectures. This helps in understanding the underlying physics and optimizing the design of organic solar
cells.
Parameter extraction: Numerical techniques are utilized to extract the parameters of the
mathematical models used to describe organic solar cells. Experimental data, such as I-V characteristics, are
fitted to the mathematical models using optimization algorithms. Numerical methods, such as least squares
fitting, are employed to minimize the differences between the experimental data and the simulated results,
thereby determining the values of key parameters that characterize the organic solar cell.
2.1. Shockley diode equation using curve fit module
In study [25], the Shockley diode equation is a mathematical model that describes the behavior of a
diode under forward bias. It relates the current flowing through a diode (𝐼) to the voltage across the diode
(𝑉). The equation is given as (3), (4):
𝐼 = 𝐼𝑠 (𝑒
𝑉
𝑛𝑉𝑇 − 1) (3)
𝐼 = 𝐼𝐿 − 𝐼0 [𝑒 (
𝑞𝑉𝐷
𝑛𝑘𝑇
) − 1] −
𝑉𝐷
𝑅𝑆𝐻
(4)
where 𝑉𝐷 = 𝑉𝑃𝑉 + 𝑅𝑠𝐼. The Shockley diode equation helps us understand how the I-V characteristics of a
diode change with varying voltage and other factors.
2.2. Curve fit module in python
The curve fit module is a part of the scipy.optimize library in Python. It provides a method for fitting
a mathematical model to a set of data points using a least-squares optimization algorithm. In simpler terms, it
allows us to find the best-fitting parameters for a given equation to match a given set of data.
2.3. Fitting the I-V data of a diode
Certainly, when fitting current-voltage (I-V) data of a diode using a curve fit module, several steps
are involved to ensure accurate modeling. Initially, the data is prepared, often involving normalization and
cleaning to remove any outliers or inconsistencies. Then, selecting an appropriate mathematical model such
as the Shockley diode equation is crucial. Finally, the curve fitting process involves adjusting parameters
within the chosen model to best align with the experimental data points, typically through iterative
optimization techniques, resulting in a fitted curve that represents the behavior of the diode.
2.4. Model of Brano, based on single diode model
In the domain of solar cell research, a noteworthy contribution emerges from Brano in reference
[14]. Brano introduces a pioneering technique designed to meticulously ascertain solar cell parameters. What
distinguishes Brano's methodology is its resolute dedication to circumventing any oversimplifications or
presumptions during the course of extracting the quintet of parameters delineated in (2). This innovative
approach marks a departure by exclusively leaning upon routine technical data amassed under standard test
conditions (STC), aligned with the constructs of a single-diode model. The crux of Brano's method lies in the
formulation of five distinct mathematical equations. These equations have been carefully designed to
calculate the correct values of the five parameters required for the single-diode model. Through the
concurrent solution of these equations, Brano's method enables the extraction of the previously unknown
parameters, providing a robust and accurate characterization of the solar cell's behavior. The formulation of
these mathematical equations within Brano's method underscores the meticulousness and attention to detail
of this innovative approach. Each equation takes into account specific aspects of the solar cell's electrical
behavior, including current-voltage relationships, resistive losses, and the impact of temperature and
irradiance variations. By simultaneously considering these multiple factors, Brano's method offers a
comprehensive understanding of the solar cell's behavior and facilitates the determination of precise
parameter values. The precise parameter values obtained through Brano's method allow for a deeper

1269
understanding of the underlying mechanisms governing solar cell operation. Consequently, researchers and
engineers can optimize solar cell designs, develop more efficient manufacturing processes, and enhance the
overall performance and integration of solar energy conversion technologies. In conclusion, Brano's method
represents a significant advancement in solar cell research. By eliminating simplifications and assumptions,
this innovative approach enables the extraction of the five critical parameters required for the single-diode
model, based solely on the normal technical data collected under STC. Concurrently solving the formulated
mathematical equations ensures the accuracy and reliability of the extracted parameter values. This
breakthrough not only enhances our understanding of solar cell behavior but also holds immense potential for
optimizing solar energy conversion technologies [15].
The foundational equation can be derived by utilizing the ISC values. The premise rests on the
assumption that the voltage equates to zero at the juncture of short-circuit current. Through the act of
substituting these designated values into (1), the intended result shall be realized:
𝑓𝑛1 : 𝐼𝐿 + [1 − 𝑒
(
𝐼𝑆𝐶𝑅𝑆
𝑛𝑇
)
] 𝐼0 −
𝐼𝑆𝐶𝑅𝑆
𝑅𝑆𝐻
− 𝐼𝑆𝐶 = 0 (5)
The subsequent equation can be derived by employing the 𝑉𝑂𝐶 values. This derivation similarly rests on the
presumption that the current corresponds to zero at the juncture of open-circuit voltage. Through the process
of substituting these specified values into (1), the intended outcome will be achieved:
𝑓𝑛2 : 𝐼𝐿 + [1 − 𝑒
(
𝑉𝑂𝐶
𝑛𝑇
)
] 𝐼0 −
𝑉𝑂𝐶
𝑅𝑆𝐻
= 0 (6)
The third equation can be derived using the data from the maximum power point (MPP), where 𝑉 represents
𝑉𝑀𝑃𝑃 and I represent 𝐼𝑀𝑃𝑃. By substituting these values into (1), the desired outcome will be obtained:
𝑓𝑛3 : 𝐼𝐿 + [1 − 𝑒
(
𝐼𝑀𝑃𝑃𝑅𝑆+ 𝑉𝑀𝑃𝑃
𝑛𝑇
)
] 𝐼0 −
𝐼𝑆𝐶𝑅𝑆+𝑉𝑀𝑃𝑃
𝑅𝑆𝐻
− 𝐼𝑀𝑃𝑃 = 0 (7)
Subsequently, the fourth equation can be obtained by expressing equation in terms of V, where V represents
𝑉𝑀𝑃𝑃 and I represents 𝐼𝑀𝑃𝑃:
𝑓𝑛4 :
−𝑛𝑇−[𝑒
(
𝑛𝑇
)
]𝐼0𝑅𝑆𝐻
𝑛𝑇(𝑅𝑆+𝑅𝑆𝐻)+[𝑒
(
𝑛𝑇
)
]𝐼0𝑅𝑆𝐻𝑅𝑆
+
𝐼𝑀𝑃𝑃
𝑉𝑀𝑃𝑃
= 0 (8)
Lastly, the fifth equation of the model can be obtained by expressing. In this case, 𝑉 represents 𝑉𝑀𝑃𝑃 and 𝐼
represents 𝐼𝑀𝑃𝑃:
𝑓𝑛5 ∶
𝑉𝑀𝑃𝑃𝑛𝑇[𝐼0𝑅𝑆𝐻+𝐼𝐿𝑅𝑆𝐻−2𝑉𝑀𝑃𝑃+[𝑒
(
𝐼𝑀𝑃𝑃𝑉𝑀𝑃𝑃𝑅𝑆+ 𝑉2
𝑀𝑃𝑃
𝑉𝑀𝑃𝑃𝑛𝑇
)𝐼0𝑅𝑆𝐻
]𝐼𝑀𝑃𝑃𝑉𝑀𝑃𝑃𝑅𝑆−𝑉𝑀𝑃𝑃(𝑛𝑇+𝑉𝑀𝑃𝑃)]
𝑉𝑀𝑃𝑃{𝐼0𝑅𝑆𝑅𝑆𝐻[𝑒
(
𝐼𝑀𝑃𝑃𝑉𝑀𝑃𝑃𝑅𝑆+ 𝑉2
𝑀𝑃𝑃
𝑉𝑀𝑃𝑃𝑛𝑇
)
]+𝑛𝑇(𝑅𝑆𝐻+𝑅𝑆)}
= 0 (9)
3. RESULTS AND DISCUSSION
3.1. Extraction of data points from the graph
The graph image was prepared for analysis by removing irrelevant elements, such as labels or
annotations that obstructed the curve. The pre-processed image was typically converted into a jpeg format to
simplify the analysis. Then algorithm identifies the curve within the image by detecting its edges or contours.
Edge detection algorithms, Canny edge detection, was employed to locate the boundaries of the curve
accurately. Once the curve was detected, a tracing algorithm was used to follow its path and extract its points.
This involved boundary following techniques to track the curve's trajectory. The traced curve was sampled at
regular intervals or based on certain criteria to obtain a set of discrete points. The points represent the curve's
coordinates in the digital space and can be stored as (x, y) pairs. The extracted points underwent additional
processing steps, such as filtering or smoothing, to remove noise or irregularities introduced during the
extraction process [26]–[28].

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3.2. Fitting of I-V data using origin lab software
Data was imported the data into Origin Lab software by loading a file. After that a fitting function
‘SolarIV’ represented the mathematical model. After that, adjusting fitting parameters: Once the fitting
function is selected, you need to adjust the initial values of the parameters. These parameters control the
shape, position, and other characteristics of the curve. You can manually set initial values or let the software
estimate them automatically. Origin Lab software was used for optimization algorithms to minimize the
difference between the fitted curve and the actual data. It adjusts the parameters of the fitting function to find
the best fit. You can choose different algorithms and customize fitting options based on your requirements.
After that a fitting process, Origin Lab provides statistical measures to evaluate the quality of the fit, such as
the coefficient of determination (R-squared), and root-mean-square error (RMSE) statistic. These measures
help assess how well the fitted curve represents the data. Origin Lab generates a plot showing the original
data points and the fitted curve. This allows you to visually assess the fit and make any necessary
adjustments to the model or parameters. You can extract the fitted parameters, their uncertainties, and other
relevant information for further analysis shown in Figures 3, 4 and 5.
3.3. Extraction of 𝑽𝑴𝑷𝑷 and 𝑱𝑴𝑷𝑷 from python
First, you need to import the I-V curve data into Python. This can be done using various libraries,
such as NumPy or Pandas, from CSV files, Excel sheets, or directly through data arrays. Plot the I-V curve
using a suitable plotting library like Matplotlib. This helps to visualize the characteristics of the PV device
and locate the MPP on the graph. Identify the MPP on the I-V curve. The MPP corresponds to the point
where the power output is maximized. You can use various peak detection algorithms available in Python to
find this point. Once the MPP was detected, you can extract the corresponding voltage (𝑉𝑀𝑃𝑃) and current
(𝐽𝑀𝑃𝑃) values from the I-V curve data. In Figures 6, 7 and 8, can present the extracted 𝑉𝑀𝑃𝑃 and 𝐽𝑀𝑃𝑃 values.
Figure 3. I-V characteristic of OSC [26] Figure 4. I-V characteristic of OSC [27]
Figure 5. I-V characteristic of OSC [28] Figure 6. 𝑉
𝑚𝑝𝑝 and 𝐽𝑚𝑝𝑝 of OSC [26]

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Figure 7. 𝑉
𝑚𝑝𝑝 and 𝐽𝑚𝑝𝑝 of OSC [27] Figure 8. 𝑉
𝑚𝑝𝑝 and 𝐽𝑚𝑝𝑝 of OSC [28]
3.4. Analysis of I-V data: fitting with Origin Lab, 𝑽𝑴𝑷𝑷 and 𝑱𝑴𝑷𝑷 extraction in python using least
squares method
The least squares method is a mathematical technique utilized to determine the optimal solution for
an over-determined linear equation system. In cases where the number of equations surpasses the count of
unknown variables, an exact solution is often unattainable. The method's objective is to minimize the discord
between the left-hand side (LHS) and right-hand side (RHS) of the equations. The LHS amalgamates
variables and their coefficients, while the RHS accounts for constant terms. The distinction between LHS and
RHS is termed the residual, gauging the error within each equation. Residual computation involves
measuring the gap between the actual LHS value and the corresponding RHS value. Functioning through the
minimization of the sum of squared residuals across all equations, the least squares method identifies variable
values. This is accomplished by squaring the residuals and summing them, prioritizing substantial errors
while penalizing smaller ones, culminating in an overall optimal fit. The mathematical pursuit revolves
around minimizing the sum of squared differences (LHS-RHS) for all equations. Calculus techniques are
harnessed to determine partial derivatives of the sum of squares concerning each variable, subsequently
setting these derivatives to zero. Solving the resultant equation system generally involves matrix algebra,
yielding the best-fit solution, as detailed in Table 1.
Table 1. Tabulation of the results
Parameters Method I
(Origin Lab Software)
Method II
(Bruno et al.’s Model [14], [15])
Cell 1 Cell 2 Cell 3 Cell 1 Cell 2 Cell 3
𝐼𝑆 1.7551*10-14
2.1205*10-15
4.8099*10-11
1.6541*10-14
2.1004*10-15
4.6089*10-11
𝑅𝑆 0.0103 0.00841 0.0094 0.0113 0.0082 0.0095
𝑛 1 1 1 1 1 1
𝑅𝑆𝐻 0.9055 0.6024 0.2675 0.9433 0.6039 0.2547
𝐼𝐿 12.4383 22.7347 21.6366 12.4692 22.5065 21.5933
3.5. Discussion
We have employed a methodology encompassing the single diode model to deduce circuit
parameters for organic solar cells, leveraging measurements of short-circuit current relative to thin active
layers and an optical model. The resultant dataset is systematically organized in the table provided below.
Employing this dataset, our coupled optoelectronic simulation yields an established lower threshold for
efficiency, valuing at 12%. Our numerical analysis, upon integration of the measured current-voltage curve,
effectively confirms circuit parameters aligning with the previously estimated 12% efficiency.
Our study delves into the electrical transport dynamics within an organic bulk-heterojunction solar
cell, encompassing diverse experiments utilizing the single diode model and a consistent set of parameters.
Notably, we observe accurate reproduction of steady-state effects within the current-voltage characteristics,
alongside precise emulation of the transient photo-current response time dynamics. This accuracy is achieved
through a simplified drift-diffusion model employing constant mobilities. We emphasize that intricate
phenomena such as charge trapping, electric field-dependent mobilities, or CT-excitons are deemed non-

 ISSN: 2088-8708
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essential to describe the solar cell scrutinized in this study. To optimize parameter extraction while
minimizing the number of unknown variables, we advocate employing the simplest model, resorting to more
complex models only if the initial approach proves inadequate. Advanced models, when warranted, can
supplement the analysis by revealing additional parameters accessible through complementary experiments.
4. CONCLUSION
The future scope of the presented research involves several promising directions. The methodology
for deriving model parameters, which reduces parameter correlation through a correlation matrix, opens
avenues for monitoring aging trends in organic solar cells. Additionally, the research aims to explore the
influence of layer attributes, morphology, and material variances on model parameters, contributing to the
optimization of designs. To enhance the reliability of the technique, the plan is to include additional
experiments in the analysis repertoire. Overall, the commitment is to advance precision and applicability in
organic solar cell research, with a focus on sustainable and efficient energy solutions.
ACKNOWLEDGEMENTS
The authors would like to acknowledge Integral University for providing the necessary support
(Article MCN no IU/R&D/2023-MCN0002264).
REFERENCES
[1] K. Fukuda, K. Yu, and T. Someya, “The future of flexible organic solar cells,” Advanced Energy Materials, vol. 10, no. 25, Jul.
2020, doi: 10.1002/aenm.202000765.
[2] W. Hou, Y. Xiao, G. Han, and J.-Y. Lin, “The applications of polymers in solar cells: A review,” Polymers, vol. 11, no. 1, Jan.
2019, doi: 10.3390/polym11010143.
[3] J. Qin et al., “Recent progress in flexible and stretchable organic solar cells,” Advanced Functional Materials, vol. 30, no. 36,
Sep. 2020, doi: 10.1002/adfm.202002529.
[4] A. Wagenpfahl, D. Rauh, M. Binder, C. Deibel, and V. Dyakonov, “S-shaped current-voltage characteristics of organic solar
devices,” Physical Review B, vol. 82, no. 11, Sep. 2010, doi: 10.1103/PhysRevB.82.115306.
[5] D. S. H. Chan and J. C. H. Phang, “Analytical methods for the extraction of solar-cell single- and double-diode model parameters
from I-V characteristics,” IEEE Transactions on Electron Devices, vol. 34, no. 2, pp. 286–293, Feb. 1987, doi: 10.1109/T-
ED.1987.22920.
[6] C. Li et al., “Non-fullerene acceptors with branched side chains and improved molecular packing to exceed 18% efficiency in
organic solar cells,” Nature Energy, vol. 6, no. 6, pp. 605–613, May 2021, doi: 10.1038/s41560-021-00820-x.
[7] M. N. Zidan, N. Everitt, T. Ismail, and I. S. Fahim, “Organic solar cells parameters extraction and characterization techniques,”
Polymers, vol. 13, no. 19, Sep. 2021, doi: 10.3390/polym13193224.
[8] B. Mazhari, “An improved solar cell circuit model for organic solar cells,” Solar Energy Materials and Solar Cells, vol. 90,
no. 7–8, pp. 1021–1033, May 2006, doi: 10.1016/j.solmat.2005.05.017.
[9] M. Hejri, H. Mokhtari, M. R. Azizian, and L. Söder, “An analytical-numerical approach for parameter determination of a five-
parameter single-diode model of photovoltaic cells and modules,” International Journal of Sustainable Energy, vol. 35, no. 4,
pp. 396–410, Apr. 2016, doi: 10.1080/14786451.2013.863886.
[10] F. Ghani, G. Rosengarten, M. Duke, and J. K. Carson, “The numerical calculation of single-diode solar-cell modelling
parameters,” Renewable Energy, vol. 72, pp. 105–112, Dec. 2014, doi: 10.1016/j.renene.2014.06.035.
[11] S. B. Dongue, D. Njomo, and L. Ebengai, “An improved nonlinear five-point model for photovoltaic modules,” International
Journal of Photoenergy, vol. 2013, pp. 1–11, 2013, doi: 10.1155/2013/680213.
[12] M. Uvais, A. J. Ansari, and M. Asim, “Modeling and analysis of organic solar cells using multiple diodes,” in 2022 2nd
International Conference on Emerging Frontiers in Electrical and Electronic Technologies (ICEFEET), Jun. 2022, pp. 1–5, doi:
10.1109/ICEFEET51821.2022.9848028.
[13] K. Chennoufi, M. Ferfra, and M. Mokhlis, “An accurate modelling of photovoltaic modules based on two-diode model,”
Renewable Energy, vol. 167, pp. 294–305, Apr. 2021, doi: 10.1016/j.renene.2020.11.085.
[14] V. Lo Brano and G. Ciulla, “An efficient analytical approach for obtaining a five parameters model of photovoltaic modules using
only reference data,” Applied Energy, vol. 111, pp. 894–903, Nov. 2013, doi: 10.1016/j.apenergy.2013.06.046.
[15] V. Lo Brano, A. Orioli, G. Ciulla, and A. Di Gangi, “An improved five-parameter model for photovoltaic modules,” Solar Energy
Materials and Solar Cells, vol. 94, no. 8, pp. 1358–1370, Aug. 2010, doi: 10.1016/j.solmat.2010.04.003.
[16] C. Zhang, J. Zhang, Y. Hao, Z. Lin, and C. Zhu, “A simple and efficient solar cell parameter extraction method from a single
current-voltage curve,” Journal of Applied Physics, vol. 110, no. 6, Sep. 2011, doi: 10.1063/1.3632971.
[17] H. K. Mehta, H. Warke, K. Kukadiya, and A. K. Panchal, “Accurate expressions for single-diode-model solar cell
parameterization,” IEEE Journal of Photovoltaics, vol. 9, no. 3, pp. 803–810, May 2019, doi: 10.1109/JPHOTOV.2019.2896264.
[18] M. Asim, A. Sarwar, M. Shahabuddin, and M. S. Manzar, “Development of solar photovoltaic model for wide range of operating
conditions,” International Journal of Power Electronics and Drive Systems (IJPEDS), vol. 12, no. 4, Dec. 2021, doi:
10.11591/ijpeds.v12.i4.pp2483-2491.
[19] L. Sandrolini, M. Artioli, and U. Reggiani, “Numerical method for the extraction of photovoltaic module double-diode model
parameters through cluster analysis,” Applied Energy, vol. 87, no. 2, pp. 442–451, Feb. 2010, doi: 10.1016/j.apenergy.2009.07.022.
[20] G. Sulyok and J. Summhammer, “Extraction of a photovoltaic cell’s double‐diode model parameters from data sheet values,”
Energy Science & Engineering, vol. 6, no. 5, pp. 424–436, Oct. 2018, doi: 10.1002/ese3.216.
[21] D. Wei, M. Wei, H. Cai, X. Zhang, and L. Chen, “Parameters extraction method of PV model based on key points of I-V curve,”
Energy Conversion and Management, vol. 209, Apr. 2020, doi: 10.1016/j.enconman.2020.112656.

1273
[22] T. R. Ayodele, A. S. O. Ogunjuyigbe, and E. E. Ekoh, “Evaluation of numerical algorithms used in extracting the parameters of a
single-diode photovoltaic model,” Sustainable Energy Technologies and Assessments, vol. 13, pp. 51–59, Feb. 2016, doi:
10.1016/j.seta.2015.11.003.
[23] Y. Chen, Y. Sun, and Z. Meng, “An improved explicit double-diode model of solar cells: Fitness verification and parameter
extraction,” Energy Conversion and Management, vol. 169, pp. 345–358, Aug. 2018, doi: 10.1016/j.enconman.2018.05.035.
[24] J. A. Jervase, H. Bourdoucen, and A. Al-Lawati, “Solar cell parameter extraction using genetic algorithms,” Measurement Science
and Technology, vol. 12, no. 11, pp. 1922–1925, Nov. 2001, doi: 10.1088/0957-0233/12/11/322.
[25] M. Diantoro, T. Suprayogi, A. Hidayat, A. Taufiq, A. Fuad, and R. Suryana, “Shockley’s equation fit analyses for solar cell
parameters from I-V curves,” International Journal of Photoenergy, vol. 2018, pp. 1–7, 2018, doi: 10.1155/2018/9214820.
[26] W. Zhao et al., “Fullerene‐free polymer solar cells with over 11% efficiency and excellent thermal stabilit,” Advanced Materials,
vol. 28, no. 23, pp. 4734–4739, Jun. 2016, doi: 10.1002/adma.201600281.
[27] Y. Ma et al., “Efficient organic solar cells from molecular orientation control of M-series acceptors,” Joule, vol. 5, no. 1,
pp. 197–209, Jan. 2021, doi: 10.1016/j.joule.2020.11.006.
[28] X. Shi et al., “An electron acceptor with broad visible–NIR absorption and unique solid state packing for as‐cast high
performance binary organic solar cells,” Advanced Functional Materials, vol. 28, no. 33, Aug. 2018, doi:
10.1002/adfm.201802324.
BIOGRAPHIES OF AUTHORS
Mohd Uvais is a research scholar in Electrical Engineering Department at the
Integral University, Lucknow, India. He received his B.Tech, M.Tech, degree in electrical
engineering from Integral University India, in 2011 and 2016, respectively His research interests
include the field of instrumentation and control, process control, power electronics, renewable
energy, and artificial intelligence. He can be contacted at email: uvaisk@gmail.com.
Asif Jamil Ansari received the M.Tech. degree in instrumentation and control
from Aligarh Muslim University, Aligarh, India, in 2007 and PhD degree in electrical
engineering from Integral University, Lucknow, India, in 2014. He has been working as an
associate professor with the Department of Electrical Engineering, Integral University,
Lucknow, India, since 2014. He can be contacted at email: ajansari@iul.ac.in.
Mohammed Asim is currently working as an assistant professor at Integral
University, Lucknow since 2013. His research area includes power electronics and renewable
energy. He has got several patents and number of research paper. He has completed a project
sponsored by National Project Implementation Unit, Govt of India. He can be contacted at
email: asimamu@gmail.com.
Mohammad Saood Manzar is a lecturer in Environmental Engineering
Department of Imam Abdurrahman Bin Faisal, Dammam, Kingdom of Saudi Arabia since 2014.
Previously, he served as an assistant professor for about 3-years in SRM University, Ghaziabad
(India). He has over 19 research publications, and more than 5 presentations and invited talks in
conferences and seminars. He can be contacted at email: msmanzar@iau.edu.sa.

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