2D drift-diffusion study of interfacial effects in thin-film solar cells
Christian Ahläng a, Oskar Sandberg a, Ronald Österbacka a
a Åbo Akademi University, Finland, Porthaninkatu, 3, Turku, Finland
International Conference on Hybrid and Organic Photovoltaics
Proceedings of International Conference on Hybrid and Organic Photovoltaics (HOPV18)
Benidorm, Spain, 2018 May 28th - 31st
Organizers: Emilio Palomares and Rene Janssen
Poster, Christian Ahläng, 259
Publication date: 21st February 2018

In order to study phenomena occurring at interfaces in thin-film solar cells, we have developed a two-dimensional drift-diffusion simulation. The simulation makes it possible to include the morphology of the active layer and thereby to study how effects occurring at interfaces between materials affect the overall performance of the device.

In organic bulk-heterojunction, the active layer consists of a blend of a donor and acceptor, ensuring that interfaces required for efficient charge separation are found throughout the layer. Recently, several UPS studies have found shifts in the vacuum level at both metal/organic and organic/organic interfaces in bilayer structures. Utilizing the simulation, we have studied the effect of such vacuum level shifts at interfaces, arising due to the presence of mid-gap states, on charge transport in bulk-heterojunction devices. We determined when mid-gap states would give rise to vacuum level shifts, the shape of the potential landscape in the active layer and described how this would affect the charge transport in the device[1].

We also want to clarify how single crystal parameters of perovskites are related to the overall properties of the perovskite layers in photovoltaic devices. The simulation makes it possible to divide the active layer into crystallites, within which the transport is governed by single-crystal parameters, and grain boundaries separating the crystallites. By comparing the device performance to experimental results, it is possible to create a model for transport across grain boundaries and relate parameters such as crystallite size to device performance. The simulation will also let us study trap-assisted recombination at grain boundaries, as well as recombination at interfaces between the perovskite and selective layers, and relate it to the overall recombination in the device

 

[1] C. Ahläng, O. Sandberg, R Österbacka, Investigating the role of interface dipoles in bulk-heterojunction solar cells with a 2D drift-diffusion simulation. Manuscript in preparation

© FUNDACIO DE LA COMUNITAT VALENCIANA SCITO
We use our own and third party cookies for analysing and measuring usage of our website to improve our services. If you continue browsing, we consider accepting its use. You can check our Cookies Policy in which you will also find how to configure your web browser for the use of cookies. More info