Floating Photovoltaic (PV) system is an emerging and rapidly developing solar PV application that utilizes water surfaces, such as reservoirs and lakes, as the installation grounds for the PV arrays and its balance of systems. In addition to becoming a solution to land scarcity issues of solar PV installation, floating PV systems also benefit from an improved thermal performance due to its proximity to water that results in a cooling effect for the PV modules. However, the extent of this cooling effect is not yet well-understood and established. Conventional thermal modelling tools and approaches, which are mostly validated for land-based PV systems, might not be directly applicable to floating PV systems without proper adaptation. This research aims to improve the accuracy of temperature and energy yield predictions for floating PV systems by evaluating and updating physics-based thermal models based on both analytical and computational methods. This study is driven by several research questions, which includes the analysis on how do existing thermal models perform in predicting floating PV module temperatures, how can Computational Fluid Dynamics (CFD) simulations be used to improve thermal models accuracy for floating PV applications, and how does the improvement in thermal model accuracy impact energy yield estimation in PV system energy yield simulation tools.

Chapter 2 conducts an evaluation of two analytical thermal modelling approaches for predicting floating PV module temperature, which are the Fuentes Model and the Resistive Thermal Model. Results show that while both models reasonably capture the PV module temperature trends, they tend to under-predict water-induced cooling effect that is present in floating PV environments, which results in a overestimation of PV module temperatures in general. Even though the Resistive Thermal Model results in a slightly higher accuracy compared to the Fuentes Model, a notable Root Mean Square Error (RMSE) is still observed with respect to measured values. This discrepancy highlights the need to improve the thermal dynamics representation, especially in capturing the effect of water proximity and the modified convective heat transfer interactions unique to floating PV systems. Chapter 3 implements CFD as a refinement tool for the analytical thermal modelling, with the goal of combining CFD's ability to capture detailed solid-fluid interactions and the computational cost effectiveness of the Resistive Thermal Model. The CFD-Updated Resistive Thermal Model is compared against measured data and shows a substantial RMSE reduction, with an RMSE of 0.72oC, significantly lower than the RMSE of the initial Resistive Thermal Model (1.70oC) and the Fuentes Model (2.30oC). Chapter 4 analyses how the improved thermal models affect energy yield prediction by using two simulation tools PVsyst and the PVMD Toolbox. The energy yield results show that the CFD-updated Resistive Thermal Model achieves the closest match to the measured specific energy yield, with an error of just 0.10%, compared to 1.75% and 1.27% error values for the Fuentes FD Model and the initial Resistive Thermal Model, respectively. These results clearly show that the increase in thermal model accuracy is directly related to a higher accuracy in energy yield simulation, where the energy yield simulation based on the improved thermal model results in a very close agreement with measured values. Chapter 5 focuses analysing how does practical installation scenario, specifically differing PV array row spacing, affect the thermal dynamics of floating PV systems. The results demonstrate that while close-proximity PV arrays with small row-spacing may offer higher power density per unit area, it comes at the cost of increased PV module temperatures and potentially reduced energy yield. On the contrary, large-proximity PV arrays with large row-spacing results in a lower overall PV module temperatures that potentially increase energy yield of the floating PV system.

In conclusion, this study demonstrates the important role of thermal modelling in improving floating PV performance prediction for floating PV systems. The integration of CFD-derived parameters into Resistive Thermal Model leads to significantly improved accuracy in temperature and energy yield predictions. However, the findings are based on limited real-world measurement data and a single floating PV archetype. A more extensive validation across more configurations and climates, as well as the development of generalized Nusselt number correlations for diverse floating PV archetypes are recommended for future works.

The first amorphous silicon solar cell using a p-i-n structure was developed in 1976 by Carlson and Wronski. In the following decades techniques such as hydrogenation and light trapping texturing were used to raise the efficiency of a-Si thin film solar cell from 2.4% to 9.3%. The research focus has since then shifted from single junction to multi junction solar cells. In a single junction solar cell much of the solar spectrum is underutilised. As photon energy that exceeds the bandgap is wasted as heat, and photons with energy below the bandgap can not be absorbed. In a multi junction structure this problem can be solved by tailoring each layer of the solar cell to a specific range of the solar spectrum, thereby increasing the efficiency.

The focus of this project is to study the potential of germanium tin alloy as a low bandgap material for the bottom layer of a multi junction solar cell. This is done by depositing the a-GeSn:H layers through plasma enhanced chemical vapour deposition(PECVD) with germane and tetramethyltin(TMT) as precursor gas, and examining the optical and electrical properties of the samples made under various deposition conditions. This project will also study the effect of carbon inclusion in germanium, due to it being a side effect of using TMT as a precursor gas.

As the energy demand keeps rising and the need for clean, affordable energy increases, the switch to completely sustainable energy production comes closer and closer. Solar cells are expected to play a big role in this energy transition. However, the technology of the most used type of solar cell, crystalline silicon, is nearing its limit. This calls for other novel technologies that could surpass it. One of these promising technologies is the perovskite / c-Si tandem cell. This type of cell has shown promising results in recent years, but for it to be commercialized and challenge the current technologies that dominate the market, some steps need to be taken. This thesis focuses on hysteresis, a behaviour commonly shown in perovskite cells, resulting in an uncertainty when measuring the characteristics of these cells. The most common explanation for this behaviour has been due to ion migration under certain conditions. This report, however, looks at hysteresis from a different perspective. It investigates the effect of defects on the hysteresis behaviour, continuing on previous research on this mechanism. It is argued that the defects trap charge near the interfaces, affecting the charge extraction and with that the amount of recombination in the cell. This hypothesis is researched by modelling a state-of-the-art perovskite / c-Si tandem cell in TCAD Sentaurus. This research investigates multiple important parameters to these defects, such as defect density, distribution, energy level, and capture cross-section. With these variables, the hysteresis behaviour as a result of the defects is explored. These results are then used to compare the hysteresis behaviour of the tandem cell with a similar single-junction cell, after which the difference between the two is analysed. It is found the two types of cells have similar hysteresis behaviours, but not equal. With the main deviation finding its origin in the current-limiting that can be displayed by tandem cells.

Considering the rapidly growing energy demand in worldwide and climate deterioration caused by fossil fuel, the remarkable potential of solar energy has captured the attention of individuals and industries alike. Among different techniques, poly-Si based passivating contacts have shown great performance on solar cell application, which enabling a high efficiency of over 26%. Plasma-enhanced chemical vapor deposition (PECVD) as one of the promising technologies in a-Si contacting layer fabrication has gradually replaced the conventional LPCVD method in industry. However, the accompanied severe ion bombardment is not negligible, especially on its underlying fragile tunnelling oxide. In this work, the impact of PECVD a-Si:H contacting layer deposition on poly-Si/SiO_x passivating contact is investigated. 
PECVD radio-frequency (RF) power for the contacting a-Si layer on the underlying SiO_x is the only variable in this project, varying from 5 W to 55 W, and pinhole density acts as a bridge to help analyse the intrinsic principles. Firstly, the results of a-Si:H thin film characterization suggest that with an increasing RF power, the a-Si:H thin film is grown at a higher deposition rate and becomes porous. In addition, the pinholes in tunnel oxide are inspected by applying the concepts of “selective etching” and “pinhole magnification”. With a two-step five-point sampling method, it is shown that the effect of RF power on the pinhole density is not monotonically increasing. The highest value is found at 25 W. To explain this, a concept of “protective layer” is proposed, which is defined as a buffer layer (contacting layer) formed at the very beginning during a-Si:H deposition. It appears to be more effective when higher RF power (> 35 W) is applied. Another influence on tunnel oxide property is discussed according to the result from XPS measurement. The percentage of Si⁴⁺ species is found in the case of 25 W, corresponding to the highest pinhole density. This proves to some extent that the severe particle bombardment brought by strong power would weaken or directly break the Si-O bonds in the PECVD substrate, that is the tunnel oxide in our case.
As a result of thin film characterization, five factors contribute to pinhole formation: (i) Defects in tunnel oxide from imperfect oxidation leave potential for pinhole formation. (ii) Severe ion bombardments in PECVD deposition are allowed to weaken or break Si-O in SiO_x. (iii) Island growth of a-Si:H contacting layer makes the exposed region in tunnel oxide continue to be damaged. (iv) “Buffer layer” formation protects the substrate from ion bombardments. (v) The tensile stress applied by a-Si:H films during annealing intensifies the formation of pinholes. 
Subsequently, an unexpected result from passivation quality assessment is that higher passivation level is presented with higher pinhole density. The best passivation quality is found in the case of 25 W, with J₀ of 3.3 fA/cm² and iV_oc of 714 mV. Further, a large optimal process window for RF power adjustment is found from 25 W to 35 W, which leads to an iV_oc over 710 mV, with single side J₀ below 3.5 fA/cm². The results from specific contact resistivity indicate that it is positively correlated to the pinhole density. Eventually, the champion passivating contact with a selectivity of 14.37 in this project is expected to yield a maximum efficiency of 28.9% in an ideal c-Si solar cell.

To make silicon thin film solar cells attractive to the market, their efficiencies should reach the efficiencies of the dominant crystalline silicon solar cell. Therefore the search for ways to improve the efficiency of silicon thin film solar cells continues. TCO front contact layers and back reflector layers play a significant role in the increase of thin film solar cell efficiencies. For the optical characterization of these TCO layers, commonly used methods are found to differ significantly in results regarding the extinction coefficient which makes their accuracy questionable.

This research consists of two main parts. For the first part, the commonly used optical characterization methods spectroscopic ellipsometry and spectrophotometry + data analysis in SCOUT are analyzed in accuracy and compared to newly introduced methods using spectrophotometry + data analysis in GenPro4 and photothermal deflection spectroscopy + data analysis in GenPro4 to build a guide on optical characterization of TCO materials. For the second part, the optical response determined using the software GenPro4 of a double junction silicon thin film solar cell for a novel bi-layer front contact design consisting of IOH and i-ZnO will be compared to the optical response for standard used AZO, and ITO single layers to find the best front contact design. Furthermore, the optical response of a double junction silicon thin film solar cell for a back reflector containing an i-ZnO layer on top of the silver back contact will be compared to the optical response for a back reflector containing an AZO layer on top of the silver back contact to find the best back reflector design.

From the results of the optical characterization methods, it is concluded that photothermal deflection spectroscopy + data analysis in GenPro4 is the most accurate method for determining the extinction coefficient of a TCO material. The results of the optical simulations for front contact TCO and back reflector TCO designs showed that the bi-layer can enhance the optical response of a double junction silicon thin film solar cell significantly compared to the AZO and ITO single layers. The i-ZnO TCO back reflector layer was found to induce less parasitic absorption and therefore a better optical response of the double junction silicon thin film solar cell.

Perovskite solar cells (PSCs) are an emerging and promising photovoltaic technology that have demonstrated impressive power conversion efficiencies exceeding 25% after only fourteen years of development. This rapid progress can mostly be attributed to the development and optimisation of PSCs fabricated by solution-based methods, because of their easy processing and inexpensive equipment. However, to commercialise PSCs, alternative methods are required. Among these methods, the vacuum-based technique thermal evaporation is a suitable candidate. In thermal evaporation, solid precursors are evaporated and deposited onto a substrate in a high vacuum chamber. Thermal evaporation is a mature technique in the semiconductor industry to fabricate pinhole-free and highly uniform thin films at a large scale on different types of substrates. To date, the efficiency of PSCs by thermal evaporation is lagging behind their solution-based counterpart, partly due to limited research on vacuum deposited PVK films and several challenges unique to thermal evaporation.
In this MSc thesis project, organic-inorganic metal halide perovskite absorbers based on thermally evaporated FAxCs1-xPb(IyBr1-y)3 and spin-coated MAPbI3 have been developed together with the additional supporting layers for device fabrication. Several PSCs with different p-i-n architectures have been fabricated and characterised. The device comprises of: ITO as front electrode, spiro-TTB, spiro-OMeTAD and/or MoOx as hole transport layer, PVK absorber layer, C60 as electron transport layer, BCP as buffer layer, and silver and aluminium as metallic back electrode. The goal of this work is to develop and optimise the structural and opto-electronic properties of different device layers and demonstrate a working perovskite solar cell.
PVK engineering is carried out on both thermally evaporated and spin-coated PVK thin films with the aim at obtaining perovskite that possesses desirable opto-electronic properties. For FAxCs1-xPb(IyBr1-y )3 fabricated by sequential layer thermal evaporation, the uniformity and tooling factors were optimised to grow layers with a correct precursor ratio showing a high crystallinity and absorptance. No clear effect of post annealing could be detected for the temperatures and times tested in this work. Achieving the target thickness and obtaining a satisfactory reproducibility were not fully reached. For spin-coated MAPbI3, it was found that increasing the precursor solution concentration helped to achieve a desirable thickness for PSCs. Moreover, an adequate bandgap, diffractogram and absorptance were measured. However, based on the small crystal size determined with SEM, and poor device performance, further improvement is needed.
Transport, contact, and buffer layers were successfully fabricated by developing new deposition recipes for silver, BCP, and spiro-TTB. Furthermore, spectrophotometry measurements show that thermally evaporated HTLs (MoOx and spiro-TTB) exhibit much lower parasitical absorption losses compared to spin-coated spiro-OMeTAD. An optical model to fit spectroscopic ellipsometry data measured on spiro-TTB thin films is created to determine its thickness and optical properties. Moreover, time resolved microwave conductivity results indicate that C60 effectively extracts electrons from MAPbI3. In contrast, spiro-TTB films did not appear to possess any hole extracting abilities. Strong quenching of the steady-state PL signal is observed for bi-layers of MAPbI3 with either C60, spiro-OMeTAD and MoOx . This quenching is possibly caused by extraction of either electrons or holes and/or enhanced non-radiative recombination at the interface.
The optimised films were combined in complete PSCs with most layers fabricated by thermal evaporation through metal masks structuring cells with active areas of 0.16 and 0.36 cm2. Solar cells were characterised in the dark and under illumination using a solar simulator integrated with a glove box to prevent degradation. A wide range of J-V characteristics are identified and classified: (1) ohmic responses, possibly caused by poor quality PVK absorber layers with pinholes filled with thermally evaporated metal, (2) S-shaped curves under illumination, possibly caused by a mismatch in energy band alignment or increased non-radiative recombination at the MoOx/MAPbI3 interface, (3) diode behaviour in the dark, and (4) a high series resistance and low shunt resistance, possibly caused by low mobility, non-optimal thicknesses, internal currents, and a mismatches in band alignment. The most promising PSC featuring the ITO (200 nm)/Spiro-OMeTAD/MoOx (5 nm)/MAPbI3/C60 (20 nm)/BCP (4 nm)/Ag (150 nm) architecture, had a short circuit current of 10.0 mA/cm2 and an open circuit voltage of 0.67 V.
The experiments carried out in this MSc thesis project supported the development of several steps of PSC fabrication process. This work contributes towards understanding thermal evaporation processes of perovskite films and fabricating fully evaporated devices with high efficiency and a large area.

Perovskite materials gain a huge interest in the photovoltaic (PV) community due to its unique characteristics, including long carrier diffusion length, widely tunable bandgap, light absorption potential, and low processing cost. Nowadays, most perovskite fabrication methods employ a solution-based process due to its simplicity and production speed. However, this deposition method provides a non-uniform structure and uses highly toxic solvents, posing the risk of contamination and adverse effects on the environment. On the other hand, a solvent-free method like thermal evaporation can produce a uniform and conformal layer. This method can be used to produce not only the perovskite absorber layer but also the contact layers and transport layers. Depending on the deposition parameters, the resulting morphological properties also change. Therefore, it becomes interesting to understand the detailed knowledge of the film growth and the effects of the deposition parameters on the exact kinetics and the optical properties. Hence, the first objective of this study focuses on developing C60 electron transport layers (ETL) for application in all-evaporated perovskite solar cells (PSCs). The C60 thin film was deposited with different thicknesses of 20, 30, 40 nm and deposition rates 0.3, 0.5, and 1 Å/s on top of the silicon wafer substrate. The resulting surface morphology is obtained from scanning electron microscopy (SEM) and atomic force microscopy (AFM). It indicates that C60 with 40 nm thickness and 0.3 Å/s deposition rate shows a pinhole-free layer with an average surface roughness of 1.05 nm and thickness uniformity of more than 94%. The X-ray diffraction (XRD) measurement shows that decrease of peak intensity as the thickness is reduced from 40 to 20 nm. Moreover, with different deposition rates, 1 Å/s of deposition rate exhibits an asymmetric broadening peak which attributes to the small grain size and the presence of a planar defect in the structure of C60.
The optical analysis has also been performed to get the complex refractive index C60 and identify the effect of deposition rates and layer thicknesses on optical constants. A procedure to extract optical constant for the perovskite absorber layer has been developed during this thesis project using a combination approach of b-spline and Tauc-Lorentz dispersion model. The obtained results were found to be in excellent agreement with experimental work and literature data.
Furthermore, the complete solar cells with p-i-n configuration and semi-transparent perovskite solar cells (ST-PSCs) were optically simulated using GenPro4 software. This simulation aims to identify both the photocurrent density of the perovskite absorber layer and the optical losses caused by parasitic absorption in the supporting layers. In the p-i-n structure, ITO and MoOx layer located on the illuminated side contribute to the main portion of optical loss. Simulations suggest that 40-nm-thick ITO and 10-nm-thick MoOx is an ideal layer stack to deliver high implied photocurrent (22.14 mA/cm2). On the other hand, the optical loss in semi-transparent perovskite solar cells is investigated in two different wavelength regions (i) 300 – 800 nm and (ii) 800 – 1200 nm. In this investigation, the metal back contact is replaced with ITO and cells illuminated from the ETL side. The results show that, in the first wavelength range, the main optical losses are due to reflection, parasitic absorption in the C60 and top ITO layer. These losses are reduced by applying 120-nm-thick anti-reflective coating MgF2 and decreasing the thickness of C60 to 10 nm. Moreover, in the wavelength region of 800 – 1200 nm, the optical losses are mainly affected by the top and bottom ITO, MoOx layer, and reflected light. After optimizing top ITO and MgF2 thickness to 50 and 120 nm, respectively, a 17.07 mA/cm2 of photocurrent transmitted through the cells can be achieved. The light transmittance is ~88%, indicating the potential of semi-transparent perovskite solar cells to be applied in perovskite/silicon tandem devices.

Solar cells can play a key role in the transition towards a sustainable future. This transition is one of the major challenges our society faces during the coming decades. Development of high-efficiency photovoltaic solutions at reasonable costs will help accelerating the transformation of our energy system. In this respect, perovskite solar cells are very promising due to their outstanding opto-electronical properties and low-cost fabrication. Obtaining a complete understanding of the device physics and charge transfer mechanisms inside perovskites is crucial for further device improvements. This thesis focuses on the notorious hysteresis in the current-voltage characteristics of perovskite solar cells. So far, this remarkable phenomenon has usually been explained using ion migration, despite the lack of clear experimental evidence. We implement a simulation platform of perovskite solar cells to analyse the charge transfer mechanisms among energy states including those with energy within the forbidden bandgap. We evaluate transient behaviour and identify the limiting physical mechanisms. To explain anomalous hysteresis in perovskite solar cells we use a novel approach in which charge accumulates near the material interfaces due to defects with relatively low capture cross-sections. Defects in lead halide perovskites create shallow sub-gap energy states, that act as charge carrier traps. Near the interfaces, this leads to accumulation of trapped charge carriers, effectively screening the electric field inside the perovskite layer. This reduces the device performance. A slow release of trapped charge due to low capture cross-sections results in hysteresis in the current-voltage curve at commonly used scan rates. TCAD Sentaurus is used as a platform to simulate J-V scans of a planar non-inverted architecture based on the archetypal perovskite MAPbI3, with TiO2 as electron transport layer and spiro-OMeTAD as hole transport layer. This thesis presents a systematic study of different trap distributions, both in the spatial and energetic domain. The capture cross-sections, densities, energy levels and locations of traps are varied and also the effect of scan rate is analysed. This work analyses both tail state defects and deep defects, based on reported values in literature. It is found that defects near the ETL/perovskite interface potentially cause anomalous hysteresis in the current-voltage curve. These defects have their transition energy around 0.25 eV and are possibly attributed to iodine interstitials.

Since the discovery of the photovoltaic properties of metal halide perovskites in 2009, the material has rapidly gained interest in the scientific community. In less than 10 years, the power conversion efficiency of perovskite solar cells (PSC) has increased from 3.9% to over 25%, reaching levels of conventional silicon cells. PSCs have multiple favorable properties, such as low manufacturing costs, thin film flexibility, and a tunable bandgap, which is promising for tandem solar cells that can surpass the Shockley-Queisser efficiency limit of conventional (single-junction) solar cells. Other applications are color-tunable LEDs and super sensitive (x-ray) photodetectors. However, there are still mysteries surrounding perovskites that need to be solved in order to fully understand the extraordinary properties of the material. For a specific perovskite, CH3NH3PbI3 (MAPI), it is debated whether it has a direct or indirect bandgap. In this work, a new Photothermal Deflection Spectroscopy (PDS) setup is designed and build that can perform sensitive below-bandgap absorption measurements under hydrostatic pressure (up to 400 MPa). Measurements performed with this setup resulted in absorption spectra of MAPI at different pressures, showing a transition from a primarily indirect bandgap at ambient pressure to a more direct bandgap at 375MPa. The data provides new empirical evidence indicating an indirect-to-direct bandgap transition at 325MPa, which opens a novel perspective on unraveling the nature of the bandgap of metal halide perovskites.

New techniques are urgently demanded to remove organic micropollutants (OMPs) such as endocrine disrupting compounds, pharmaceuticals and pesticides from our drinking water sources. With increasing salinity of surface waters in coastal regions, salt removal has also become an issue in the production of drinking water. When advanced oxidation processes are combined they are capable to remove OMPs to a large extent, but without the removal of salts. Dense membranes like reverse osmosis (RO) or flat-sheet nanofiltration (NF) membranes – which require an extensive pretreatment – can sufficiently remove OMPs and salts, but only at low permeabilities and by producing a saline waste stream. Hollow fiber NF membranes seem very promising in this respect as they have higher permeabilities, lower energy consumptions and can be applied directly. In this study, the removal of salts and OMPs from synthetic surface water and real lake water from the Valkenburgse Meer (VM) by the polyelectrolyte multilayer (PEM) coated dNF40 membrane was studied in order to make it suitable for dune infiltration water. This type of membrane is fabricated by depositing polycations and polyanions alternately on a porous support medium, also known as the layer by layer (LbL) technique, which enables control of the membrane’s surface charge and permeability. Hollow fiber NF membranes have the ability to separate ions or solutes with smaller sizes and hydraulic radii than the pore size of the membrane due to electrostatic repulsion. The membrane is negatively charged at neutral pH.

The dNF40 membrane showed ion retentions of up to 27% for Cl-, 98% for SO42-, 87% for Mg2+, 76% for Ca2+ and 17% for Na+ in once-through configuration with a hydraulic permeability of 5.8 Lm-2h-1 and molecular weight cut-off (MWCO) of ~200 Da. However, lower ion retention values were observed for filtration of real lake water, except for SO42-. Retentions were unaffected by cross-flow velocity, but increased with increasing permeate flux. Moreover, the ion retentions reduced considerably when the system recovery increased to 75%. In addition to the salt retentions, the retention of a mix of 20 distinctively different pharmaceuticals, both positively charged, negatively charged and neutral OMPs with molecular weights between 119 and 748 gmol−1, was investigated. An average retention as high as 79% and 89% was reached for SW (no natural organic matter (NOM)) and VM water (11.6 mgL-1 of NOM), respectively. As expected, the negatively charged pharmaceuticals were retained best as a result of electrostatic interactions with the negatively charged membrane, followed by the positively charged compounds, of which repulsion is probably promoted by underlying polycation layers in the membrane structure. Neutral compounds were retained less.

The dNF40 membrane showed to be resistant to fouling, while no extensive pretreatment was applied, making it suitable for direct treatment of surface water. Furthermore, OMPs were largely removed, hardness was partially reduced and NOM was almost completely removed, but insufficient NaCl was retained to meet dune infiltration water standards. Therefore, an additional step becomes necessary in the pretreatment of surface water. Four suggestions were provided.

High-performance perovskite solar cells (PSCs) have attracted great attention from researchers around the world. Rapid researches and developments of PSCs are shown by the increase of its efficiency from 3.8% in 2009 to a new world record of 22.4% in 2017. Hysteresis phenomenon in current density voltage (J-V) is one of the challenges occurring in some specific PSCs that should be overcome to continue the improvement of PSCs. This phenomenon occurs when a voltage is swept with different scan directions from negative to positive value (forward) and positive to negative value (backward). Hysteresis effect results in a different maximum power point on the J-V characteristic leading to under- or overestimation of PSCs efficiency.

Furthermore, when the applied voltage is abruptly changed, a transient current density response is introduced implying a capacitive behaviour. Due to this behaviour, there is an indication that PSCs cannot be represented by the conventional equivalent circuit. Thus, the purpose of this project is to investigate hysteresis phenomenon in PSC by electrical modelling. In this project, a PSC sample was fabricated by Solliance Solar Research. Time-resolved J-V measurement was done to obtain more insight of J(t) as a function of applied voltage. The hysteresis phenomenon was analyzed in different voltage scan direction and various scan rates. Simulation of band diagram in dark condition was done to understand working principle of PSC device. Two predicted equivalent circuit of the cell were derived from the simulated band diagram. These equivalent circuit models considered the charge accumulation at the bulk of perovskite and at the interface between charge transport layers and perovskite. Furthermore, two additional equivalent circuit models were proposed to represent the hysteresis effect. J(t) curve fitting of measurement results and simulation was employed to verify the equivalent circuit. This insight might help to get a better understanding of hysteresis effect in PSCs.