Internal Photoeffect and Exciton Diffusion in Cadmium and Zinc Sulfides

1958 ◽  
Vol 112 (1) ◽  
pp. 123-135 ◽  
Author(s):  
M. Balkanski ◽  
R. D. Waldron
Keyword(s):  
Exciton Diffusion ◽  
Internal Photoeffect

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.

Device-Based Probe of Triplet Exciton Diffusion in Singlet Fission Materials

2021 ◽  
Vol 12 (3) ◽  
pp. 966-972
Author(s):  
Tao Zhang ◽  
Deepesh Rai ◽  
Russell J. Holmes
Keyword(s):  
Triplet Exciton ◽  
Singlet Fission ◽  
Exciton Diffusion

scholarly journals Picosecond time-resolved photon antibunching measures nanoscale exciton motion and the true number of chromophores

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Gordon J. Hedley ◽  
Tim Schröder ◽  
Florian Steiner ◽  
Theresa Eder ◽  
Felix J. Hofmann ◽  
...  
Keyword(s):  
Rational Design ◽  
Three Dimensional ◽  
Dna Origami ◽  
Fluorescent Nanoparticles ◽  
Time Resolved ◽  
Exciton Diffusion ◽  
Polymer Aggregates ◽  
True Number ◽  
Particle Level ◽  
Photon Antibunching

AbstractThe particle-like nature of light becomes evident in the photon statistics of fluorescence from single quantum systems as photon antibunching. In multichromophoric systems, exciton diffusion and subsequent annihilation occurs. These processes also yield photon antibunching but cannot be interpreted reliably. Here we develop picosecond time-resolved antibunching to identify and decode such processes. We use this method to measure the true number of chromophores on well-defined multichromophoric DNA-origami structures, and precisely determine the distance-dependent rates of annihilation between excitons. Further, this allows us to measure exciton diffusion in mesoscopic H- and J-type conjugated-polymer aggregates. We distinguish between one-dimensional intra-chain and three-dimensional inter-chain exciton diffusion at different times after excitation and determine the disorder-dependent diffusion lengths. Our method provides a powerful lens through which excitons can be studied at the single-particle level, enabling the rational design of improved excitonic probes such as ultra-bright fluorescent nanoparticles and materials for optoelectronic devices.

Decay of excitonic gratings: Effect of exciton diffusion and reabsorption of exciton fluorescence

1987 ◽  
Vol 63 (4) ◽  
pp. 329-334 ◽  
Author(s):  
V.M. Agranovich ◽  
A.M. Ratner ◽  
M. Salieva
Keyword(s):  
Exciton Diffusion

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.

Quenching of luminescence and exciton diffusion in KI at low temperature

1977 ◽  
Vol 21 (8) ◽  
pp. 725-727 ◽  
Author(s):  
A. Nouailhat ◽  
G. Guillot ◽  
E. Mercier
Keyword(s):  
Low Temperature ◽  
Exciton Diffusion ◽  
Quenching Of Luminescence

Exciton diffusion and dissociation in a poly(p‐phenylenevinylene)/C60 heterojunction photovoltaic cell

1996 ◽  
Vol 68 (22) ◽  
pp. 3120-3122 ◽  
Author(s):  
J. J. M. Halls ◽  
K. Pichler ◽  
R. H. Friend ◽  
S. C. Moratti ◽  
A. B. Holmes
Keyword(s):  
Photovoltaic Cell ◽  
Exciton Diffusion

scholarly journals Ultrafast Exciton Dynamics in Two Dimensional Covalent Organic Frameworks Reveals Size Dependence to Exciton Diffusion

2020 ◽  
Author(s):  
Nathan C. Flanders ◽  
Matthew S. Kirschner ◽  
Pyosang Kim ◽  
Thomas Fauvell ◽  
Austin Evans ◽  
...  
Keyword(s):  
High Performance ◽  
Transient Absorption ◽  
Domain Size ◽  
Spectroscopic Techniques ◽  
Two Dimensional ◽  
Exciton Dynamics ◽  
Singlet Exciton ◽  
Exciton Diffusion ◽  
Absorption Studies ◽  
Exciton Annihilation

<p>Large singlet exciton diffusion lengths are a hallmark of high performance in organic based devices such as photovoltaics, chemical sensors, and photodetectors. In this study, exciton dynamics of a two-dimensional covalent organic framework, COF- 5, is investigated using ultrafast spectroscopic techniques. Following photoexcitation, the COF-5 exciton decays via three pathways: 1) excimer formation (4 ± 2 ps), 2) excimer relaxation (160 ± 40 ps), and 3) excimer decay (>3 ns). Excitation fluence-dependent transient absorption studies suggest that COF-5 has a relatively large diffusion coefficient (0.08 cm2/s). Furthermore, exciton-exciton annihilation processes are characterized as a function of COF-5 crystallite domain size in four different samples, which reveal domain- size dependent exciton diffusion kinetics. These results reveal that exciton diffusion in COF-5 is constrained by its crystalline domain size. These insights indicate the outstanding promise of delocalized excitonic processes available in 2D COFs, which motivate their continued design and implementation into optoelectronic devices. </p>

Sign in / Sign up

Export Citation Format

Share Document