Determining the exciton diffusion length of copper phthalocyanine in operating planar-heterojunction organic solar cells

2020 ◽  
Vol 89 (3) ◽  
pp. 30201 ◽  
Author(s):  
Xi Guan ◽  
Shiyu Wang ◽  
Wenxing Liu ◽  
Dashan Qin ◽  
Dayan Ban
Keyword(s):  
Solar Cells ◽  
Organic Solar Cells ◽  
Diffusion Length ◽  
Copper Phthalocyanine ◽  
Short Circuit ◽  
Thick Layer ◽  
Short Circuit Current ◽  
Short Circuit Current Density ◽  
Exciton Diffusion ◽  
Exciton Diffusion Length

Organic solar cells based on planar copper phthalocyanine (CuPc)/C60 heterojunction have been characterized, in which a 2 nm-thick layer of bathocuproine (BCP) is inserted into the CuPc layer. The thin layer of BCP allows hole current to tunnel it through but blocks the exciton diffusion, thereby altering the steady-state exciton profile in the CuPc zone (zone 1) sandwiched between BCP and C60. The short-circuit current density (JSC) of device is limited by the hole-exciton scattering effect at the BCP/CuPc (zone 1) interface. Based on the variation of JSC with the width of zone 1, the exciton diffusion length of CuPc is deduced to be 12.5–15 nm. The current research provides an easy and helpful method to determine the exciton diffusion lengths of organic electron donors.

scholarly journals Pseudo-bilayer architecture enables high-performance organic solar cells with enhanced exciton diffusion length

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Kui Jiang ◽  
Jie Zhang ◽  
Zhengxing Peng ◽  
Francis Lin ◽  
Shengfan Wu ◽  
...  
Keyword(s):  
Solar Cells ◽  
Active Layer ◽  
Organic Solar Cells ◽  
High Performance ◽  
Diffusion Length ◽  
Bulk Heterojunction ◽  
Short Circuit ◽  
Full Potential ◽  
Exciton Diffusion ◽  
Exciton Diffusion Length

AbstractSolution-processed organic solar cells (OSCs) are a promising candidate for next-generation photovoltaic technologies. However, the short exciton diffusion length of the bulk heterojunction active layer in OSCs strongly hampers the full potential to be realized in these bulk heterojunction OSCs. Herein, we report high-performance OSCs with a pseudo-bilayer architecture, which possesses longer exciton diffusion length benefited from higher film crystallinity. This feature ensures the synergistic advantages of efficient exciton dissociation and charge transport in OSCs with pseudo-bilayer architecture, enabling a higher power conversion efficiency (17.42%) to be achieved compared to those with bulk heterojunction architecture (16.44%) due to higher short-circuit current density and fill factor. A certified efficiency of 16.31% is also achieved for the ternary OSC with a pseudo-bilayer active layer. Our results demonstrate the excellent potential for pseudo-bilayer architecture to be used for future OSC applications.

Vertically Optimized Phase Separation with Improved Exciton Diffusion Enables High-Efficiency Organic Solar Cells with Thick Active Layers

2021 ◽  
Author(s):  
Yanming Sun ◽  
Yunhao Cai ◽  
Qian Li ◽  
Guanyu Lu ◽  
Hwa Sook Ryu ◽  
...  
Keyword(s):  
Solar Cells ◽  
Phase Separation ◽  
Active Layer ◽  
Organic Solar Cells ◽  
High Efficiency ◽  
Diffusion Length ◽  
Active Layer Thickness ◽  
Exciton Diffusion ◽  
Exciton Diffusion Length ◽  
Active Layers

Abstract The development of high-performance organic solar cells (OSCs) with thick active layers is of crucial importance for the roll-to-roll printing of large-area solar panels. Unfortunately, increasing the active layer thickness usually results in a significant reduction in efficiency. Herein, we fabricated efficient thick-film OSCs with an active layer consisting of one polymer donor and two non-fullerene acceptors. The two acceptors were found to possess enlarged exciton diffusion length in the mixed phase, which is beneficial to exciton generation and dissociation. Additionally, layer by layer approach was employed to optimize the vertical phase separation. Benefiting from the synergetic effects of enlarged exciton diffusion length and graded vertical phase separation, a record high efficiency of 17.31% (certified value of 16.9%) was obtained for the 300 nm-thick OSC, with an unprecedented short-circuit current density of 28.36 mA cm−2, and a high fill factor of 73.0%. Moreover, the device with an active layer thickness of 500 nm also shows a record efficiency of 15.21%. This work provides new insights into the fabrication of high-efficiency OSCs with thick active layers.

scholarly journals SCAPS Simulation on P3HT:Graphene Nanocomposites Based Bulk-Heterojunction Organic Solar Cells

2019 ◽  
Vol 9 (1) ◽  
pp. 28
Author(s):  
Nur Shakina Mohd Shariff ◽  
Puteri Sarah Mohamad Saad ◽  
Mohamad Rusop Mahmood
Keyword(s):  
Solar Cells ◽  
Organic Solar Cells ◽  
Fill Factor ◽  
Bulk Heterojunction ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Short Circuit Current Density ◽  
Open Circuit ◽  
Simulation Software ◽  
Capacitance Voltage

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.

An asymmetric small molecule acceptor for organic solar cells with a short circuit current density over 24 mA cm−2

2020 ◽  
Vol 8 (31) ◽  
pp. 15984-15991 ◽  
Author(s):  
Fangfang Cai ◽  
Hongjian Peng ◽  
Honggang Chen ◽  
Jun Yuan ◽  
Jiefeng Hai ◽  
...  
Keyword(s):  
Solar Cells ◽  
Small Molecule ◽  
Current Density ◽  
Organic Solar Cells ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Short Circuit Current Density

Acceptor Y22 with an asymmetric hexacyclic A–DA′D–A structure achieved a high PCE of 15.4% and a high Jsc of 24.37 mA cm−2, which are among the best values reported for asymmetric acceptor based binary organic solar cells.

scholarly journals Benzothiadiazole Based Cascade Material to Boost the Performance of Inverted Ternary Organic Solar Cells

Energies ◽  
2020 ◽  
Vol 13 (2) ◽  
pp. 450 ◽  
Author(s):  
Miron Krassas ◽  
Christos Polyzoidis ◽  
Pavlos Tzourmpakis ◽  
Dimitriοs M. Kosmidis ◽  
George Viskadouros ◽  
...  
Keyword(s):  
Solar Cells ◽  
Organic Solar Cells ◽  
Short Circuit ◽  
Photovoltaic Performance ◽  
Short Circuit Current ◽  
Short Circuit Current Density ◽  
Open Circuit ◽  
Fused Ring ◽  
Electron Cascade ◽  
First Time

A conjugated, ladder-type multi-fused ring 4,7-dithienbenzothiadiazole:thiophene derivative, named as compound ‘T’, was for the first time incorporated, within the PTB7:PC71BM photoactive layer for inverted ternary organic solar cells (TOSCs) realization. The effective energy level offset caused by compound T between the polymeric donor and fullerene acceptor materials, as well as its resulting potential as electron cascade material contribute to an enhanced exciton dissociation, electron transfer facilitator and thus improved overall photovoltaic performance. The engineering optimization of the inverted TOSC, ITO/PFN/PTB7:Compound T(5% v/v):PC71BM/MoO3/Al, resulted in an overall power conversion efficiency (PCE) of 8.34%, with a short-circuit current density (Jsc) of 16.75 mA cm−2, open-circuit voltage (Voc) of 0.74 V and a fill factor (FF) of 68.1%, under AM1.5G illumination. This photovoltaic performance was improved by approximately 12% with respect to the control binary device.

RELIABILITY STUDIES OF P3HT: PCBM ORGANIC SOLAR CELLS FABRICATED WITH CALCIUM–ALUMINUM AND LITHIUM FLUORIDE–ALUMINIUM CATHODES

2011 ◽  
Vol 10 (04n05) ◽  
pp. 803-807
Author(s):  
T. S. KRISHNAN ◽  
S. SUNDAR KUMAR IYER
Keyword(s):  
Solar Cells ◽  
Organic Solar Cells ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Short Circuit Current Density ◽  
Open Circuit ◽  
Continuous Illumination ◽  
Stress Tests ◽  
Ambient Conditions ◽  
Over Time

This work addresses the shelf life characteristics of P3HT: PCBM blend based organic solar cells (OSC) fabricated with Ca–Al and LiF–Al cathodes. Some of these devices are encapsulated in nitrogen ambient and some in room ambient. Device electrical characteristics are studied under both dark and light. In the analysis under dark ambient conditions, the degradation in peak dark current is monitored over time (in days) and an empirical model is postulated for the degradation based on statistical curve fitting techniques. In the analysis under light, degradation of parameters such as fill factor (FF), open circuit voltage (V oc ) and short circuit current density (J sc ) is monitored over time in these devices (for different cathodes and different ambients) and the results are analyzed and compared. Also, accelerated stress tests are conducted wherein the devices are subjected to continuous illumination for a period of 1.5 h under two different intensities (0.76 sun and 1 sun) and again, the results are analyzed and compared. A model is fitted to the observed degradation in normalized J sc and the degradation constants (k deg ) are obtained. It is seen that the devices fabricated with cathode as LiF–Al and being encapsulated in nitrogen ambient provide the best performance over time.

Phosphor-doping enhanced efficiency in bilayer organic solar cells due to longer exciton diffusion length

2014 ◽  
Vol 151 ◽  
pp. 193-196 ◽  
Author(s):  
Kang Xiong ◽  
Lintao Hou ◽  
Ping Wang ◽  
Yuxin Xia ◽  
Dongcheng Chen ◽  
...  
Keyword(s):  
Solar Cells ◽  
Organic Solar Cells ◽  
Diffusion Length ◽  
Exciton Diffusion ◽  
Exciton Diffusion Length

HYBRID ORGANIC SOLAR CELLS BLENDED WITH CNTs

2015 ◽  
Vol 22 (06) ◽  
pp. 1550072
Author(s):  
SUDIP ADHIKARI ◽  
HIDEO UCHIDA ◽  
MASAYOSHI UMENO
Keyword(s):  
Solar Cells ◽  
Organic Solar Cells ◽  
Short Circuit ◽  
Photovoltaic Performance ◽  
Short Circuit Current ◽  
Short Circuit Current Density ◽  
Open Circuit ◽  
Photovoltaic Device ◽  
Device Fabrication ◽  
Walled Cnts

In this paper, composite carbon nanotubes (C-CNTs); single-walled CNTs (SWCNTs) and multi-walled CNTs (MWCNTs) are synthesized using an ultrasonic nebulizer in a large quartz tube for photovoltaic device fabrication in poly-3-octyl-thiophene (P3OT)/ n - Si heterojunction solar cells. We found that the device fabricated with C-CNTs shows much better photovoltaic performance than that of a device without C-CNTs. The device with C-CNTs shows open-circuit voltage (Voc) of 0.454 V, a short circuit current density (Jsc) of 12.792 mA/cm2, fill factor (FF) of 0.361 and power conversion efficiency of 2.098 %. Here, we proposed that SWCNTs and MWCNTs provide efficient percolation paths for both electron and hole transportation to opposite electrodes and leading to the suppression of charge carrier recombination, thereby increasing the photovoltaic device performance.

scholarly journals Optical Property and Photoelectrical Performance of a Low-bandgap Conducting Polymer Incorporated with Quantum Dots Used for Organic Solar Cells

2015 ◽  
Vol 25 (2) ◽  
pp. 139
Author(s):  
Tran Thi Thao ◽  
Vu Thi Hai ◽  
Nguyen Nang Dinh ◽  
Le Dinh Trong
Keyword(s):  
Quantum Dots ◽  
Solar Cells ◽  
Organic Solar Cells ◽  
Fill Factor ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Short Circuit Current Density ◽  
Open Circuit ◽  
Low Bandgap ◽  
A Value

By using spin-coating technique, a low bandgap conjugated polymer, poly[2,6-(4,4-bis-(2-ethylhexyl)-4H-cyclopen-ta[2,1-b;3,4-b′]dithiophene)-alt-4,7-(2,1,3-benzothiadiazole)] (PCPDTBT)  and its composite thin films have been prepared. The optical absorption and photoconductive properties with over a wide spectral range, from 350 to 950  nm, were characterized. The obtained results showed that PCPDTBT:10 wt% CdSe  composite is the most suitable for efficient light-harvesting in polymer-based photovoltaic cells. The photoelectrical conversion efficiency (PCE) of the device with  a multilayer structure of ITO/PEDOT/ PCPDTBT:CdSe /LiF/Al  reached a value as large as 1.34% with an open-circuit voltage (Voc) = 0.57 V, a short-circuit current density (Jsc) = 4.29 mA/cm2, and a fill factor (FF) = 0.27. This suggests a useful application in further fabrication of quantum dots/polymers based solar cells.

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