The Stratakis Lab

The Stratakis Lab

Ultrafast Laser Micro and Nano Processing Laboratory

Applications of Lasers in Perovskite Solar Cells and Organic Photovoltaics

The objective of the activity is the application of laser-based processing and diagnostics in the field of organic photovoltaics (OPVs) and perovskite solar cells (PSCs).

Organic (plastic) photovoltaic devices (OPVs) and a new generation of organo-metal and inorganic halide perovskite absorbers thin-film photovoltaic cells (PSCs) have recently emerged displaying exceptional properties. OPVs and PSCs have attracted significant attention because they facilitate low-cost solution processing, and are simple to fabricate. Furthermore, OPVS and PSCs can be tuned chemically in order to adjust separately band gap, and energy levels. Finally, all-plastic devices can potentially be recyclable, minimizing their impact on the environment at the end of their life cycle. Our research aim is to exploit laser-based processing and diagnostics techniques in the area of Solar Cells. Over the years, we have focused on the pulsed laser assisted synthesis and functionalization of new types of nanostructures that can be exploited for the OPV cells performance improvement. In particular, enhancement of both the efficiency and stability of bulk heterojunction polymer-fullerene OPV devices is demonstrated by the addition of laser-fabricated Au or Al NPs in either the active layer or the interface between the buffer and the active layers. On a similar manner, we recently start working on the development of novel PSCs following laser assisted crystallization techniques, as well as, wet chemistry protocols. Among others techniques, Transient Absorption Spectroscopy (TAS) is employed for studying the fundamental photo-physics and decay dynamics in OPVs, low band-gap polymers and PSCs on a temporal scale. TAS provides useful information on fundamental photovoltaic processes and charge transfer in both OPVs and PSCs, i.e. photon absorption, exciton diffusion into donor/acceptor interfaces, charge transfer mobilities, dissociation of free charge carriers and recombination processes. In addition, TAS allows us to correlate the morphology of active layer with decay components and recombination processes. All these factors are strongly correlated with the efficiency of the OPVs and PSCs, and thus, their study assists the design of photovoltaic devices with enhanced performance. The research activity is implemented by a joint effort between the Ultrafast Laser Micro- and Nano- Processing (ULMNP) group of the Institute of Electronic Structure and Laser (IESL) of the foundation for Research and Technology Hellas (FORTH) and the Nanomaterials and Organic Electronics group of the Center of Materials Technology and Photonics (CEMATEP) of the Technical Educational Institute (TEI) of Crete, headed by Prof. Emmanuel Kymakis. Our mission is to provide research facilities for state of the art research in the multidisciplinary field of nanotechnology and advanced electronics. Further information:

Figure: (left) J-V characteristics of OPV devices with laser-synthesized Au NPs, embedded into the active layer, (right) Transient absorption spectra of a methylammonium lead iodide perovskite film.

Prof. Emmanuel Kymakis, and Prof. Emmanuel Koudoumas, Dept. of Electrical Engineering, Technical Educational Institute (T.E.I) of Crete.

Dr. Barbara Paci, ISM-CNR Roma, Italy.

Dr. Antonios G. Kanaras, Physics & Astronomy, University of Southampton.

Dr. Christos Chochos, University of Ioannina & Advent Technologies SA


Selected publications:

1) Serpetzoglou, E., Konidakis, I., Kakavelakis, G., Maksudov, T., Kymakis, E., Stratakis, E.
Improved Carrier Transport in Perovskite Solar Cells Probed by Femtosecond Transient Absorption Spectroscopy. ACS Appl. Mater. Interfaces, 2017, 9, 43910-43919.

2) Chochos, C., Singh, R., Gregoriou, V., Kim, M., Katsouras, A., Serpetzoglou, E., Konidakis, I., Stratakis, E., Cho, K., Avgeropoulos, A.
Enhancement the Power Conversion Efficiency of Organic Solar Cells via Unveiling the Appropriate Rational Design Strategy in Indacenodithiophene-alt-Quinoxaline π-Conjugated Polymers. ACS Appl. Mater. Interface, DOI: 10.1021/acsami.7b18381

3) Squeo, B., Gregoriou, V. G., Han, Y., Palma-Cando, A., Allard, S., Serpetzoglou, E., Konidakis, I., Stratakis, E., Avgeropoulos, A., Anthopoulos, T. D., Heeney, M., Scherf, U., Chochos, C. L.
α,β-Unsubstituted meso-Positioning Thienyl BODIPY: A Promising Electron Deficient Building Block for the Development of Near Infrared (NIR) p-type Donor-Acceptor (D-A) Conjugated Polymers.
J. Mater. Chem C., 2018, DOI: 10.1039/C7TC05900K.

4) Chochos, C. L., Leclerc, N., Gasparini, N., Zimmerman, N., Tatsi, E., Katsouras, A., Moschovas, D., Serpetzoglou, E., Konidakis, I., Fall, S., Lévêque, P., Heiser, T., Spanos, M., Gregoriou, V. G., Stratakis, E., Ameri, T., Brabec, C. J., Avgeropoulos, A.
The role of chemical structure in indacenodithienothiophene-alt-benzothiadiazole copolymers for high performance organic solar cells with improved photo-stability through minimization of burn-in loss. J. Mater. Chem. A, 2017, 5, 25064-25076.



Project Members
Prof. Costas Fotakis
Dr. Emmanuel Stratakis
Dr. Panagiotis Loukakos
Dr. Ioannis Konidakis
Dr. Maria Sygletou
Ms. KyriakiSavva
Mr. Efthymios Serpetzoglou
Dr. Myron Krassas
Mr. George Kakavelakis