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Organic light-emitting transistors with an efficiency that outperforms the equivalent light-emitting diodes

Nature Materials volume 9, pages 496–503 (2010)Cite this article

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Abstract

The potential of organic semiconductor-based devices for light generation is demonstrated by the commercialization of display technologies based on organic light-emitting diodes (OLEDs). Nonetheless, exciton quenching and photon loss processes still limit OLED efficiency and brightness. Organic light-emitting transistors (OLETs) are alternative light sources combining, in the same architecture, the switching mechanism of a thin-film transistor and an electroluminescent device. Thus, OLETs could open a new era in organic optoelectronics and serve as testbeds to address general fundamental optoelectronic and photonic issues. Here, we introduce the concept of using a p-channel/emitter/n-channel trilayer semiconducting heterostructure in OLETs, providing a new approach to markedly improve OLET performance and address these open questions. In this architecture, exciton–charge annihilation and electrode photon losses are prevented. Our devices are >100 times more efficient than the equivalent OLED, >2× more efficient than the optimized OLED with the same emitting layer and >10 times more efficient than any other reported OLETs.

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Figure 1: Trilayer OLET device structure and active materials forming the heterostructure.
Figure 2: Optical micrographs of the lit trilayer OLET and its emission spectra.
Figure 3: Optoelectronic characteristics of the trilayer OLET and topographical images of the individual layers forming the heterostructure.
Figure 4: Images of the light-emitting area within the OLET device channel.
Figure 5: EQE as a function of the applied gate voltage for the two trilayer heterostructure OLET configurations.
Figure 6: Device structure and optoelectronic characteristics of the trilayer OLED in direct and reverse configurations.

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Acknowledgements

Authors kindly acknowledge R. Zamboni, G. Ruani and T. J. Marks for useful discussions, as well as the valuable technical support of M. Murgia. Financial support from Italian MIUR projects FIRBRBIP06YWBH (NODIS), and FIRB-RBIP0642YL (LUCI), Italian MSE project Industria 2015 (ALADIN), and EU projects PF6 035859-2 (BIMORE) and FP7-ICT- 248052 (PHOTO-FET) is acknowledged.

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Authors and Affiliations

  1. Consiglio Nazionale delle Ricerche (CNR), Istituto per lo Studio dei Materiali Nanostrutturati (ISMN), via P. Gobetti 101, I-40129 Bologna, Italy

    Raffaella Capelli, Stefano Toffanin, Gianluca Generali & Michele Muccini

  2. Polyera Corporation, 8045 Lamon Avenue, Skokie, Illinois 60077, USA

    Hakan Usta & Antonio Facchetti

  3. E.T.C. srl, via P. Gobetti 101, I-40129 Bologna, Italy

    Michele Muccini

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  1. Raffaella Capelli
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Contributions

R.C. defined the concept of the trilayer heterostructure, fabricated devices, executed optoelectronic experiments, analysed and interpreted results. S.T. defined the concept of the trilayer heterostructure, executed spectroscopic and photonic experiments, analysed and interpreted results. G.G. carried out AFM measurements, contributed to fabricate devices and to execute optoelectronic experiments. H.U. synthesized DH-4T and DFH-4T. A.F. supervised the synthesis and discussed the results. M.M. defined the concept of the trilayer heterostructure, took part to the key experiments, interpreted results and supervised the entire work. A.F. and M.M. wrote the manuscript.

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Correspondence to Raffaella Capelli or Michele Muccini.

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Capelli, R., Toffanin, S., Generali, G. et al. Organic light-emitting transistors with an efficiency that outperforms the equivalent light-emitting diodes. Nature Mater 9, 496–503 (2010). https://doi.org/10.1038/nmat2751

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