The Essence and Efficiency Limits of Bulk-Heterostructure Organic Solar Cells

2012 ◽  
Vol 1390 ◽  
Author(s):  
M. Alam ◽  
B. Ray ◽  
M. Khan ◽  
S. Dongaonkar

Abstract:Since its introduction in early 1990s, bulk-heterojunction organic photovoltaic solar cell (BHJ-OPV) has promised high-efficiency at ultra-low cost and weight, with potential for non-traditional applications such as building-integrated PV. There is a widespread presumption, however, that the complexity of morphology makes carrier transport in OPV irreducibly complicated, and possibly, beyond predictive modeling. In this paper, we use elementary and intuitive arguments to derive the fundamental thermodynamic as well as morphology-specific practical limits of BHJ-OPV efficiency. We find that constraints of the percolation threshold and trade-off among short-circuit current, open circuit voltage, and fill factor make substantial improvement in OPV efficiency difficult. We posit that future improvement in OPV will rely not on morphology engineering, or reducing the polymer bandgap, but on increasing both the effective μ × τ product and the cross-gap between donor/acceptors. Even if the OPV fails to achieve the highest efficiency anticipated by the thermodynamic limit, its novel form factor, lightweight, and transparency can make it a commercially viable option for many applications.

Author(s):  
Nur Shakina Mohd Shariff ◽  
Puteri Sarah Mohamad Saad ◽  
Mohamad Rusop Mahmood

There has been an increasing interest towards organic solar cells after the discovery of conjugated polymer and bulk-heterojunction concept. Eventhough organic solar cells are less expensive than inorganic solar cells but the power conversion energy is still considered low. The main objective of this research is to investigate the effect of the P3HT’s thickness and concentration towards the efficiency of the P3HT:Graphene solar cells. A simulation software that is specialize for photovoltaic called SCAPS is used in this research to simulate the effect on the solar cells. The solar cell’s structure will be drawn inside the simulation and the parameters for each layers is inserted. The result such as the open circuit voltage (Voc), short circuit current density (Jsc), fill factor (FF), efficiency (η), capacitance-voltage (C-V) and capacitance-frequency (C-f) characteristic will be calculated by the software and all the results will be put into one graph.


2011 ◽  
Vol 1359 ◽  
Author(s):  
A.J. Trindade ◽  
M.G. Santos ◽  
J. Gomes ◽  
L. Pereira

ABSTRACTThis work shows the relationship between the morphology (studied by AFM) of an active bulk-heterojunction (BHJ) layer composed by MEH-PPV (poly(2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene) and PCBM ([6,6]-phenyl-C61-butyric acid methyl ester) and the respective photovoltaic figures of merit. It is observed that the most relevant parameter (influencing the efficiency) is the fill-factor (FF), as both the open circuit voltage and short circuit current are not significantly affected by the microscopic morphology. Different local conformation of the active films can change the FF from near 25% to more than 65%, having a strong impact in the efficiency. These results were modulated by an equivalent circuit. Serial and parallel resistances were related with the physical behavior of the organic cells. These were observed to have a direct relationship with the achieved morphology.


2013 ◽  
Vol 311 ◽  
pp. 419-423
Author(s):  
Kan Lin Chen ◽  
D.W. Chou ◽  
Chien Jung Huang ◽  
Jhong Ciao Ke ◽  
Wen Ray Chen ◽  
...  

Small molecule organic solar cell with an optimized structure of indium tin oxide (ITO)/copper phthalocyanine (CuPc) (10nm)/CuPc: C60mixed (20nm)/fullerene (C60) (20nm)/bathocuproine (BCP) (10nm)/Al) was fabricated. With optimizing the hybrid planar-mixed molecular heterojunction (PM-HJ) from the double layer heterojunction (HJ) and the bulk heterojunction (BHJ), the short-circuit current density (Jsc) increased from 3.09 to 5.11mA/cm2, the open-circuit voltage (Voc) increased from 0.40 to 0.47V, and the power conversion efficiency (ηp) increased from 0.66 to 1.28% under 100mW/cm2 AM1.5G illumination. These improvements were attributed to reach the optimal balance among the light absorption efficiency, the exciton dissociation efficiency and the carrier collection efficiency of the device, resulting in enhancement of Jscwithout affecting the value of fill factor (FF) and the reduction of the dark current. Furthermore a decrease of dark current is caused to the higher Voc.


2021 ◽  
Vol 26 (4) ◽  
Author(s):  
Cristian Moisés Díaz-Acosta ◽  
Antonia Martínez-Luévanos ◽  
Sofía Estrada-Flores ◽  
Lucia Fabiola Cano-Salazar ◽  
Elsa Nadia Aguilera-González ◽  
...  

ABSTRACT Solar energy is one of the most promising and developed technologies in recent years, due to its high efficiency and low cost. Perovskite-type solar cells have been the focus of attention by the world scientific community. The main objective of this article is to present an (PSCs) analysis of the various investigations reported on the development of ABX3 inorganic halide perovskite-based solar cells, with emphasis in the effect that temperature and humidity have on their chemical and crystal structure stability. The main methods that are used to obtain ABX3 inorganic halide perovskites are also presented and analyzed. An analysis about the structure of these photovoltaic cells and how to improve their efficiency (PCS), fill factor (FF), short circuit current density (Jsc) and open circuit voltage (Voc) of these devices is presented. As a conclusion, a relationship of the methods, synthesis variables, and type of inorganic halide perovskite used for the development of devices with the best efficiencies is presented; the trends towards which this area of science is heading are also highlighted.


2011 ◽  
Vol 2011 ◽  
pp. 1-5 ◽  
Author(s):  
Ziyang Hu ◽  
Baochen Jiao ◽  
Jianjun Zhang ◽  
Xiaodan Zhang ◽  
Ying Zhao

Indium-doped zinc oxide (IZO) thin films were prepared by low-cost ultrasonic spray pyrolysis (USP). Both a low resistivity (3.13×10−3 Ω cm) and an average direct transmittance (400∼1500 nm) about 80% of the IZO films were achieved. The IZO films were investigated as anodes in bulk-heterojunction organic photovoltaic (OPV) devices based on poly(3-hexylthiophene) and [6,6]-phenyl C61-butyric acid methyl ester. The device fabricated on IZO film-coated glass substrate showed an open circuit voltage of 0.56 V, a short circuit current of 8.49 mA cm-2, a fill factor of 0.40, and a power conversion efficiency of 1.91%, demonstrating that the IZO films prepared by USP technique are promising low In content and transparent electrode candidates of low-cost OPV devices.


2019 ◽  
Vol 966 ◽  
pp. 501-506
Author(s):  
Ahmad Sholih ◽  
Dadan Hamdani ◽  
Sigit Tri Wicaksono ◽  
Mas Irfan P. Hidayat ◽  
Yoyok Cahyono ◽  
...  

In this paper, we have investigated the effect of the work function of transparent conducting oxides (TCO) on the performance of a-Si:H p-i-n solar cells, including open circuit voltage (VOC), short circuit current (JSC), fill factor (FF) and conversion efficiency, using AFORS-HET software. The simulation has focused on two layers: front contact work function (ΦTCO-front) and back contact work function (ΦTCO-back) with various band from 4.7 eV to 5.3 eV and 4.2 eV to 4.9 eV respectively. From the simulation results, we know that the work function of TCO greatly affects the performance of solar cells such as Voc, Jsc, FF and conversion efficiency. By optimization, we arrive at results for Voc, Jsc, FF and conversion efficiencies of 0.88 V, 8.95 mA / cm2, 65% and 5.1% respectively. This result is obtained on ΦTCO-front 5.2 eV. When ΦTCO-front 5.2 eV, the value of VOC, FF and conversion efficiency has been saturated, while the value of the J sc actually begins to decrease. Furthermore, when the ΦTCO - back is 4.3 eV, we get the best results for VOC, Jsc, FF and conversion Efficiency of 0.9 V, 8.96 mA / cm2, 73 % and 5.9 % respectively. When ΦTCO-back 4.3 eV, the value of VOC, FF and conversion efficiency begins to decrease, while the value of the Jsc does’t change significantly. These optimizations may help in producing low cost high efficiency p-i-n solar cells experimentally.


2015 ◽  
Vol 112 (36) ◽  
pp. 11193-11198 ◽  
Author(s):  
Biswajit Ray ◽  
Aditya G. Baradwaj ◽  
Mohammad Ryyan Khan ◽  
Bryan W. Boudouris ◽  
Muhammad Ashraful Alam

The bulk heterojunction (BHJ) organic photovoltaic (OPV) architecture has dominated the literature due to its ability to be implemented in devices with relatively high efficiency values. However, a simpler device architecture based on a single organic semiconductor (SS-OPV) offers several advantages: it obviates the need to control the highly system-dependent nanoscale BHJ morphology, and therefore, would allow the use of broader range of organic semiconductors. Unfortunately, the photocurrent in standard SS-OPV devices is typically very low, which generally is attributed to inefficient charge separation of the photogenerated excitons. Here we show that the short-circuit current density from SS-OPV devices can be enhanced significantly (∼100-fold) through the use of inverted device configurations, relative to a standard OPV device architecture. This result suggests that charge generation may not be the performance bottleneck in OPV device operation. Instead, poor charge collection, caused by defect-induced electric field screening, is most likely the primary performance bottleneck in regular-geometry SS-OPV cells. We justify this hypothesis by: (i) detailed numerical simulations, (ii) electrical characterization experiments of functional SS-OPV devices using multiple polymers as active layer materials, and (iii) impedance spectroscopy measurements. Furthermore, we show that the collection-limited photocurrent theory consistently interprets typical characteristics of regular SS-OPV devices. These insights should encourage the design and OPV implementation of high-purity, high-mobility polymers, and other soft materials that have shown promise in organic field-effect transistor applications, but have not performed well in BHJ OPV devices, wherein they adopt less-than-ideal nanostructures when blended with electron-accepting materials.


Inventions ◽  
2019 ◽  
Vol 4 (3) ◽  
pp. 45 ◽  
Author(s):  
Waleed I. Hameed ◽  
Baha A. Sawadi ◽  
Safa J. Al-Kamil ◽  
Mohammed S. Al-Radhi ◽  
Yasir I. A. Al-Yasir ◽  
...  

Prediction of solar irradiance plays an essential role in many energy systems. The objective of this paper is to present a low-cost solar irradiance meter based on artificial neural networks (ANN). A photovoltaic (PV) mathematical model of 50 watts and 36 cells was used to extract the short-circuit current and the open-circuit voltage of the PV module. The obtained data was used to train the ANN to predict solar irradiance for horizontal surfaces. The strategy was to measure the open-circuit voltage and the short-circuit current of the PV module and then feed it to the ANN as inputs to get the irradiance. The experimental and simulation results showed that the proposed method could be utilized to achieve the value of solar irradiance with acceptable approximation. As a result, this method presents a low-cost instrument that can be used instead of an expensive pyranometer.


2009 ◽  
Vol 1212 ◽  
Author(s):  
Dewei Zhao ◽  
Xiao Wei Sun ◽  
Lin Ke ◽  
Swee Tiam Tan

AbstractWe present an efficient polymer-small molecule triple-tandem organic solar cell (OSC), consisting of poly(3-hexylthiophene) (P3HT) and 1-(3-methoxycarbonyl)-propyl-1-phenyl-(6,6)C61 (PCBM) bulk heterojunction as the first and second cells, and small molecules copper phthalocyanine (CuPc) and fullerene (C60) as the third cell on top. These sub-cells are connected by an intermediate layer of Al(1 nm)/MoO3(15 nm), which appears to be highly transparent, structurally smooth, and electrically functional. Compared to our previous all polymer triple-tandem organic solar cells (2.03%), this polymer-small molecule triple-tandem organic solar cell achieves an improved power conversion efficiency of 2.18% with a short-circuit current density (Jsc) = 3.02 mA/cm2, open-circuit voltage (Voc) = 1.51 V, and fill factor (FF) = 47.7% under simulated solar irradiation of 100 mW/cm2 (AM1.5G), which can be attributed to the increased photocurrent generation in the third cell since the third cell has the complementary absorption with two bottom cells despite a slightly reduced Voc.


2012 ◽  
Vol 550-553 ◽  
pp. 476-479
Author(s):  
Ai Fen Wang

The three photovoltaic cells with two different anode buffer layer on the basis of Pentacene/C60 as active layer was fabicated, the effect and mechanism of anode buffer layer on performance of organic photovoltaic cell are explored. The experimental result shows transition metal oxide inserted between organic active layer and ITO could increase short circuit current and open-circuit voltage,power conversion efficiency is increased to 107%,so it is effective anode buffer material.


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