Impact of Blend Morphology on Interface State Recombination in Bulk Heterojunction Organic Solar Cells

Benjamin Bouthinon (1) , Raphaël Clerc (2) , Jérôme Vaillant (1) , J.-M Verilhac (1) , Jérôme Faure-Vincent (3) , David Djurado (3) , Irina Ionica (4) , Gabriel Man (5) , Antoine Gras (1) , Georges Pananakakis (4) , Romain Gwoziecki (1) , Antoine Kahn (5)

1 LITEN - Laboratoire d'Innovation pour les Technologies des Energies Nouvelles et les nanomatériaux
2 LHC - Laboratoire Hubert Curien
3 INAC - Institut Nanosciences et Cryogénie
4 IMEP-LAHC - Institut de Microélectronique, Electromagnétisme et Photonique - Laboratoire d'Hyperfréquences et Caractérisation
5 Princeton University

This work is a re-investigation of the impact of blend morphology and thermal annealing on the electrical performance of regioregular P3HT:PC 60 BM. The blend is first characterized by combining atomic force microscopy, X-rays diffraction and Time-of-Flight experiments. Then, current-voltage characteristics of photodiode devices are measured in the dark and under illumination. Finally, the existence of exponential tails of electronic gap states is experimentally confirmed by measuring the device spectral response in the sub-band gap regime. This method reveals the existence of a large density of gap states, which is partially reduced by successive annealing steps. The comparison between drift and diffusion 2 simulations and charge transport experiments show that, when band gap tails are properly taken into account, simulations can satisfactorily reproduce experimental currents under both dark and illumination conditions as a function of voltage and annealing time. This work further confirms the critical impact of tails states on the performance of solar cells.

Mots clés: morphology; annealing; bulk heterojunction; interface state; solar cell

Domaines: Micro et nanotechnologies/Microélectronique

Benjamin Bouthinon, Raphaël Clerc, Jérôme Vaillant, J.-M Verilhac, Jérôme Faure-Vincent, et al.. Impact of Blend Morphology on Interface State Recombination in Bulk Heterojunction Organic Solar Cells. Advanced Functional Materials, 2015, pp.10.1002/adfm.201401633. ⟨10.1002/adfm.201401633⟩. ⟨hal-01100102⟩