The effects of heavy atoms on the exciton diffusion properties in photoactive thin films of tetrakis(4-carbomethoxyphenyl)porphyrins

2015 ◽  
Vol 3 (6) ◽  
pp. 1243-1249 ◽  
Author(s):  
Angy L. Ortiz ◽  
Graham S. Collier ◽  
Dawn M. Marin ◽  
Jennifer A. Kassel ◽  
Reynolds J. Ivins ◽  
...  
Keyword(s):  
Thin Films ◽  
Monte Carlo ◽  
Diffusion Coefficient ◽  
Diffusion Length ◽  
Heavy Atoms ◽  
Exciton Diffusion ◽  
Exciton Diffusion Length ◽  
Quenching Efficiency ◽  
Diffusion Properties

The exciton diffusion coefficient (D) and exciton diffusion length (LD) for three tetrakis(4-carbomethoxyphenyl)porphyrins were obtained by fitting the quenching efficiency and PL lifetime to a 3D exciton Monte Carlo ediffusion model.

Measurement of the triplet exciton diffusion length in organic semiconductors

2019 ◽  
Vol 7 (19) ◽  
pp. 5695-5701 ◽  
Author(s):  
Deepesh Rai ◽  
Russell J. Holmes
Keyword(s):  
Thin Films ◽  
Organic Semiconductors ◽  
Organic Semiconductor ◽  
Diffusion Length ◽  
Triplet Exciton ◽  
Exciton Diffusion ◽  
Exciton Diffusion Length ◽  
Semiconductor Thin Films ◽  
Quenching Efficiency ◽  
Triplet Excitons

We develop a methodology to measure the diffusion of dark triplet excitons in organic semiconductor thin films using a phosphorescent sensitizer-based approach that explicitly quantifies quenching efficiency by varying sensitizer concentration.

scholarly journals Self-Assembly-Directed Exciton Diffusion in Solution-Processable Metalloporphyrin Thin Films

Molecules ◽  
2021 ◽  
Vol 27 (1) ◽  
pp. 35
Author(s):  
Abhishek Shibu ◽  
Camilla Middleton ◽  
Carly O. Kwiatkowski ◽  
Meesha Kaushal ◽  
Jonathan H. Gillen ◽  
...  
Keyword(s):  
Thin Films ◽  
Diffusion Coefficient ◽  
Excited State ◽  
Self Assembly ◽  
State Energy ◽  
Excited State Energy ◽  
Exciton Diffusion ◽  
Energy Diffusion ◽  
Quenching Efficiency ◽  
Solution Processable

The study of excited-state energy diffusion has had an important impact in the development and optimization of organic electronics. For instance, optimizing excited-state energy migration in the photoactive layer in an organic solar cell device has been shown to yield efficient solar energy conversion. Despite the crucial role that energy migration plays in molecular electronic device physics, there is still a great deal to be explored to establish how molecular orientation impacts energy diffusion mechanisms. In this work, we have synthesized a new library of solution-processable, Zn (alkoxycarbonyl)phenylporphyrins containing butyl (ZnTCB4PP), hexyl (ZnTCH4PP), 2-ethylhexyl (ZnTCEH4PP), and octyl (ZnTCO4PP) alkoxycarbonyl groups. We establish that, by varying the length of the peripheral alkyl chains on the metalloporphyrin macrocycle, preferential orientation and molecular self-assembly is observed in solution-processed thin films. The resultant arrangement of molecules consequently affects the electronic and photophysical characteristics of the metalloporphyrin thin films. The various molecular arrangements in the porphyrin thin films and their resultant impact were determined using UV-Vis absorption spectroscopy, steady-state and time-resolved fluorescence emission lifetimes, and X-ray diffraction in thin films. The films were doped with C60 quencher molecules and the change in fluorescence was measured to derive a relative quenching efficiency. Using emission decay, relative quenching efficiency, and dopant volume fraction as input, insights on exciton diffusion coefficient and exciton diffusion lengths were obtained from a Monte Carlo simulation. The octyl derivative (ZnTCO4PP) showed the strongest relative fluorescence quenching and, therefore, the highest exciton diffusion coefficient (5.29 × 10−3 cm2 s−1) and longest exciton diffusion length (~81 nm). The octyl derivative also showed the strongest out-of-plane stacking among the metalloporphyrins studied. This work demonstrates how molecular self-assembly can be used to modulate and direct exciton diffusion in solution-processable metalloporphyrin thin films engineered for optoelectronic and photonic applications.

Morphology-dependent exciton diffusion length in PPE-PPVs thin films as revealed by a Forster mechanism based-study

2017 ◽  
Vol 226 ◽  
pp. 177-182 ◽  
Author(s):  
A. Saaidia ◽  
M.A. Saidani ◽  
S. Romdhane ◽  
A. Ben Fredj ◽  
D.A.M. Egbe ◽  
...  
Keyword(s):  
Thin Films ◽  
Diffusion Length ◽  
Exciton Diffusion ◽  
Exciton Diffusion Length

Triplet excitons: improving exciton diffusion length for enhanced organic photovoltaics

2019 ◽  
Vol 7 (6) ◽  
pp. 2445-2463 ◽  
Author(s):  
Bruno T. Luppi ◽  
Darren Majak ◽  
Manisha Gupta ◽  
Eric Rivard ◽  
Karthik Shankar
Keyword(s):  
Solar Cells ◽  
Organic Photovoltaics ◽  
Organic Materials ◽  
Diffusion Length ◽  
Future Research ◽  
Heavy Atoms ◽  
Exciton Diffusion ◽  
Exciton Diffusion Length ◽  
Fundamental Limitation ◽  
Triplet Excitons

Organic materials containing heavy atoms have been used in photovoltaics to overcome a fundamental limitation: short exciton diffusion length (LD). We highlight studies showing increased LD in solar cells using triplet-generating materials and tackle challenges that the field faces with possible avenues for future research.

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
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