Dependence of Exciton Diffusion Length on Crystalline Order in Conjugated Polymers

2014 ◽  
Vol 118 (2) ◽  
pp. 760-766 ◽  
Author(s):  
Myungsun Sim ◽  
Jisoo Shin ◽  
Chiyeoung Shim ◽  
Min Kim ◽  
Sae Byeok Jo ◽  
...  
Keyword(s):  
Conjugated Polymers ◽  
Diffusion Length ◽  
Crystalline Order ◽  
Exciton Diffusion ◽  
Exciton Diffusion Length

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.

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.

Method of determining the exciton diffusion length using optical interference effect in Schottky diode

2009 ◽  
Vol 94 (22) ◽  
pp. 223303 ◽  
Author(s):  
Suman Banerjee ◽  
Anukul Prasad Parhi ◽  
S. Sundar Kumar Iyer ◽  
Satyendra Kumar
Keyword(s):  
Schottky Diode ◽  
Interference Effect ◽  
Diffusion Length ◽  
Optical Interference ◽  
Exciton Diffusion ◽  
Exciton Diffusion Length

scholarly journals Enhancing Exciton Diffusion Length Provides New Opportunities for Organic Photovoltaics

Matter ◽  
2020 ◽  
Vol 3 (2) ◽  
pp. 341-354
Author(s):  
Muhammad T. Sajjad ◽  
Arvydas Ruseckas ◽  
Ifor D.W. Samuel
Keyword(s):  
Organic Photovoltaics ◽  
Diffusion Length ◽  
Exciton Diffusion ◽  
Exciton Diffusion Length

scholarly journals Long-range exciton diffusion in molecular non-fullerene acceptors

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Yuliar Firdaus ◽  
Vincent M. Le Corre ◽  
Safakath Karuthedath ◽  
Wenlan Liu ◽  
Anastasia Markina ◽  
...  
Keyword(s):  
Organic Semiconductors ◽  
Diffusion Length ◽  
Crystal Packing ◽  
Maximum Size ◽  
Exciton Diffusion ◽  
Exciton Diffusion Length ◽  
Donor And Acceptor ◽  
Wide Range ◽  
20 Nm ◽  
End Group

Abstract The short exciton diffusion length associated with most classical organic semiconductors used in organic photovoltaics (5-20 nm) imposes severe limits on the maximum size of the donor and acceptor domains within the photoactive layer of the cell. Identifying materials that are able to transport excitons over longer distances can help advancing our understanding and lead to solar cells with higher efficiency. Here, we measure the exciton diffusion length in a wide range of nonfullerene acceptor molecules using two different experimental techniques based on photocurrent and ultrafast spectroscopy measurements. The acceptors exhibit balanced ambipolar charge transport and surprisingly long exciton diffusion lengths in the range of 20 to 47 nm. With the aid of quantum-chemical calculations, we are able to rationalize the exciton dynamics and draw basic chemical design rules, particularly on the importance of the end-group substituent on the crystal packing of nonfullerene acceptors.

Connecting Molecular Structure and Exciton Diffusion Length in Rubrene Derivatives

2013 ◽  
Vol 25 (27) ◽  
pp. 3689-3693 ◽  
Author(s):  
Tyler K. Mullenbach ◽  
Kathryn A. McGarry ◽  
Wade A. Luhman ◽  
Christopher J. Douglas ◽  
Russell J. Holmes
Keyword(s):  
Molecular Structure ◽  
Diffusion Length ◽  
Exciton Diffusion ◽  
Exciton Diffusion Length

scholarly journals Excited state dynamics and exciton diffusion in triphenylamine/dicyanovinyl push–pull small molecule for organic optoelectronics

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Benedito A. L. Raul ◽  
Yuriy N. Luponosov ◽  
Wenyan Yang ◽  
Nikolay M. Surin ◽  
Olivier Douhéret ◽  
...  
Keyword(s):  
Excited State ◽  
Small Molecule ◽  
Potential Energy Surfaces ◽  
Density Functional ◽  
Diffusion Length ◽  
Bulk Heterojunction ◽  
Radiative Relaxation ◽  
Research Attention ◽  
Exciton Diffusion ◽  
Exciton Diffusion Length

AbstractTriphenylamine-based small push–pull molecules have recently attracted substantial research attention due to their unique optoelectronic properties. Here, we investigate the excited state de-excitation dynamics and exciton diffusion in TPA-T-DCV-Ph-F small molecule, having simple chemical structure with asymmetrical architecture and end-capped with electron-withdrawing p-fluorodicyanovinyl group. The excited state lifetime in diluted solutions (0.04 ns in toluene and 0.4 ns in chloroform) are found to be surprisingly shorter compared to the solid state (3 ns in PMMA matrix). Time-dependent density functional theory indicates that this behavior originates from non-radiative relaxation of the excited state through a conical intersection between the ground and singlet excited state potential energy surfaces. Exciton diffusion length of ~ 16 nm in solution processed films was retrieved by employing time-resolved photoluminescence volume quenching measurements with Monte Carlo simulations. As means of investigating the device performance of TPA-T-DCV-Ph-F, we manufactured solution and vacuum processed bulk heterojunction solar cells that yielded efficiencies of ~ 1.5% and ~ 3.7%, respectively. Our findings demonstrate that the short lifetime in solutions does not hinder per se long exciton diffusion length in films thereby granting applications of TPA-T-DCV-Ph-F and similar push–pull molecules in vacuum and solution processable devices.

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