QC468 : Investigation of relaxation and annihilation of triplet excitons in disordered organic semiconductors
Thesis > Central Library of Shahrood University > Physics > MSc > 2019
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Abstarct: Organic disordered semiconductor materials (ODSs) recently come popular because
they have optoelectronic properties of semiconductor with plastic mechanic properties
simultaneously. In this materials, light can cause excitation in its molecules that forms
a qausi-particle called Exciton. Oraginc solar cells and OLED’s are made of ODSs and
excitons plays essential role in them. To improve performance in this devices, there should
be a comprehension of processes that involved in exciton transport.
Most properties of semiconductors are described by Mobility Edge and Valence Edge,
but in OSCs because of Disorder, we have Transport level which is the same of Mobility
edge. In this materials, molecules made the transport foundations. To become transport
possible, energy levels of acceptor and donor molecules should be equivalent.In ODSs,
Phonos play a decisive role in compensation of close energy levels to become equivalent,
Now we can say transport level is a level which whenever an exciton comes to it, it is
delocalized and therefore can move easily. Transport level is depends on temperature,
localization length and disorder parameter.
Diffusion coefficient is the most important parameter in transport, in order to investigating
transport, we used Gaussian DOS and Miller-Abrahams energy transfer rate.
Diffusion coefficient is depend on temperature, disorder parameter and localization length
but it also reduces in course of time. In previous works, diffusion coefficient is considered
independent of time, but baxse on the model introduced in ”Theoretical study of
equilibrium and nonequilibrium exciton dynamics in disordered semiconductors” article,
we develope a model for triplet excitons to study annihilation and relaxation which can
explain transport in consits of Mont-Carlo simulation and experimental datas.
Keywords:
#relaxation and annihilation of exciton #triple exciton #triplet-triplet interaction #exciton transport #Organic Disordered Semiconductor Link
Keeping place: Central Library of Shahrood University
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Keeping place: Central Library of Shahrood University
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