Modeling and Simulation of Low-Cost and High-Efficiency Perovskite Solar Cells

Modeling and Simulation of Low-Cost and High-Efficiency Perovskite Solar Cells

Project Description[A1]

Solar photovoltaic (PV) energy conversion is an important technology for generating low-cost electricity to replace coal-generated power. A hybrid organic-inorganic perovskite-based solar cell is a photovoltaic (PV) technology based on applying low-cost materials in a series of ultrathin layers encapsulated by protective sealants which have attracted the attention of researchers and scientists over the world. From 2009 when active research work began on perovskite photovoltaic (PV) applications, efficiencies above 24 percent have been achieved compared to silicon-based solar cells with a current efficiency of around 25.1 percent figure1 since research work on the silicon-based device started in 1954. To bring the cost of the solar energy down comparing to the existing technologies.  A typical planar heterojunction perovskite-based solar cell consists of 6 main layers of different materials figure2 can be constructed in the lab; these are glass transport electrode, an electron transport layer, a perovskite material, hole transport layer, and the gold electrode. This technology can be directly integrated into the building components to achieve highly competitive building integrated photovoltaics (BIPV). This proposal focuses centers on the appropriate choice of the perovskite-based solar cell’s composite materials such as the hole transport materials, the type of perovskite material, the electron transport layer. The light illuminating the absorber (Perovskite material) promotes an electron into the excited state, followed by a rapid electron transfer and collection by the titanium oxide layer. On the other hand, the remaining positive charge is transferred to the opposite electrode, in this case, HTM, thereby generating an electrical current. A photovoltaic device is then constructed using the chosen materials. The intent is to establish research lab and conduct research for the purpose of improving this new Perovskite material solar cell efficiency. The proposal will present mathematical modeling of the new solar cell and develop electrical circuit representation of the solar cell durability to do simulation and validate it with implementation. The proposal is focused on designing and fabricating: 1) a monolithic single junction perovskite solar cell .2) a monolithic tandem cell structure with a high gap perovskite cell deposited on top of a high efficiency c-Si and CIGS cell. The two cells are connected using novel tunnel junctions. Several new materials, processes and device structures need to be developed for the concept to work. Among these are:

1)-A perovskite material with a bandgap of 1.35-1.9 eV range as opposed to the current 1.56 eV material. The higher bandgap is needed to make efficient tandem cells with a c-Si and CIGS bottom cell. We will develop a new deposition method which is the open-air PLD in collaboration with Dr. Darwish from Dillard University to make an efficient Pb (I, Br, Cl) perovskites film to tune the bandgap accordingly.

2)-A perovskite material which is physically stable at higher temperatures so that transparent contacts can be deposited on the device to allow light to be incident form the top of the cell. We will use novel organic precursors such as formamidinium iodide and urea hydroiodide to achieve thermally stable perovskites.

3)-A new vacuum process PLD for depositing perovskites at higher temperatures which avoids the instability of the solution growth process.

4)-The use of inorganic heterojunction layers for electron and hole extraction, thus avoiding unstable organic heterojunction layers.

5)-FTO/ITO/ZnO tunnel junctions to connect the two cells.  The project includes comprehensive material and device analysis tasks to understand the physics of the device.

Figure 1 Comparison of the lab efficiencies of Silicon, thin film and Perovskite over the years. Source: International Tin Research Institute

Preliminary Work related to Hybrid Organic-inorganic perovskite solar cell

The team did preliminary work to evaluate the use of numerical simulation methods for determining the optimal configuration of perovskite-based solar cells and analyzing their optoelectronic behavior. The outcome of the simulation study on the Hybrid Organic-inorganic perovskite solar cell focusing on the role of the different components of the solar cell using SCAPS 1D (Solar Cell Capacitance Simulator) as a simulation tool are discussed. Preliminary simulation results show a photoconversion efficiency of 14.07 %, 19.85% and 20.34% using Al, Ag, and Au contacts respectively have been found after optimizing the different parameters involved. The Team has obtained encouraging results and reported a better efficiency using different layers of the perovskite solar cell. The proposed project will provide the optical and electrical modeling of Hybrid organic-inorganic Perovskite Solar Cells (PSCs).

The  team did secondary work in which they designed a new fabrication method to the PSC layers Figure 2 called PLD (plus laser deposition) that produces less pinholes or defects in the absorber layer. As shown in figure 1 the solar device is  a lead -based PSC model with a cell structure of Glass/FTO/TiO2/CH3NH3PBI3/Spiro-OMeTAD/(Au, Ag, Al, Cu, Cr, C and Pt) and analyzed the structure with different contact materials using Solar Cell Capacitance Simulator (SCAPS-1D) which is well adopted by many researchers to study and analyze the hybrid solar cell. Using the software allow researchers to inexpensively and promptly the effect of the absorber and the contacts materials on the performance of the proposed solar cell model. We also studied the bandgap of the active layer, defect density, thickness and operating temperature of the model. A promising result was achieved table 1. Efficiencies of 27.25%, 26.52%, 18.90%, 25.66%, 22.77%, 27.25%, and 27.25% were obtained for the devices with Au, Ag, Al, Cu, Cr, Pt and C, respectively. The effect of the work function on the back contact has a major influence over the FF and efficiency.  Research work will continue to improve the efficiency in term of simulation and implementation.

Figure 2 Perovskite solar cell normal setup

Table 1 simulation results

Sample at 500nm
Voc (V)
Jsc(mA/cm²)
FF
PCE %
Au
1.51
19.841
90.96
27.25
Ag
1.505
19.841
88.77
26.52
Al
1.396
19.838
68.23
18.9
Cu
1.504
19.841
85.97
25.66
Cr
1.503
19.840
76.33
22.77
Pt
1.51
19.841
90.96
27.25
Cu-graphite alloy
1.51
19.841
90.96
27.25

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