[institut] Podsecanje, danas je SCL seminar (povodom izbora u zvanje), Marko Mladenovic, petak 6. septembar u 14:00

[Nenad Vukmirović]

Поштоване колегинице и колеге,

Подсећам вас да ће се доле најављени семинар одржати данас.

Срдачан поздрав,

-- 
Др Ненад Вукмировић,
Виши научни сарадник,
Лабораторија за примену рачунара у науци,
Институт за физику Београд,
Србија.
URL: http://www.scl.rs/nenad

On 09/03/2013 01:19 PM, Nenad Vukmirović wrote:
> Поштоване колегинице и колеге,
>
> Позивам вас на СЦЛ семинар који ће у петак 6. септембра 2013. године у
> 14:00 у читаоници Института за физику одржати Марко Младеновић (СЦЛ,
> Институт за физику у Београду) поводом предстојећег избора у звање
> истраживач сарадник. Наслов семинара је:
>
> Electronic States at Low-Angle Grain Boundaries in Polycrystalline
> Naphthalene
>
> Abstract:
>
> Organic semiconductors are materials of great promise for electronic
> devices, such as organic field-effect transistors (FETs), organic
> light-emitting diodes (LEDs), and organic solar cells (OSCs). Their
> advantage over inorganic counterparts is that they are flexible and have
> a low processing cost. However, devices made of organic semiconductors
> still have relatively low charge mobility and low efficiency. Thin films
> of crystalline organic semiconductors have a polycrystalline form, which
> is composed of many different crystalline grains.  Previous works
> indicate that grain boundaries are the most limiting intrinsic factor
> for efficient charge transport in small molecule based polycrystalline
> organic semiconductors.
>
> We have investigated the influence of grain boundaries on electronic
> properties of polycrystalline organic semiconductor naphthalene. Atomic
> structure of grain boundaries was found using a Monte Carlo method,
> while electronic structure calculations were performed using the density
> functional theory based charge patching method. We found that grain
> boundaries introduce trap states within the band gap of the material.
> Wave functions of these states are localized on closely spaced pairs of
> molecules from opposite sides of the boundary. The energies of trap
> states are strongly correlated with the distances between the molecules
> in the pair. These findings were used to calculate the electronic
> density of trap states, which was found to exhibit a qualitatively
> different behavior for grain boundaries perpendicular to the a and b
> direction of the naphthalene unit cell [1].
>
> [1] M. Mladenovic, N. Vukmirovic and I. E. Stankovic, J. Phys. Chem. C
> 117, 15741 (2013).