Vol.:(0123456789) 1 3 Journal of Materials Science: Materials in Electronics https://doi.org/10.1007/s10854-019-00979-w Transparent bacterial cellulose nanocomposites used as substrate for organic light-emitting diodes Cristiano Legnani 1,2  · Hernane S. Barud 3  · José M. A. Caiut 4  · Vanessa L. Calil 2,6  · Indhira O. Maciel 1,2  · Welber G. Quirino 1,2  · Sidney J. L. Ribeiro 5  · Marco Cremona 2,6 Received: 15 January 2019 / Accepted: 19 February 2019 © Springer Science+Business Media, LLC, part of Springer Nature 2019 Abstract In this work, high transparent bacterial cellulose (HTBC) biocompatible membranes were produced to be used as substrates in organic light-emitting diodes (OLEDs). These multifunctional membranes are based on bacterial cellulose (BC) and an organic–inorganic sol, composed of boehmite (Boe) nanoparticles and epoxi modified siloxane (GTPS). In order to be used as substrates, BC/Boe-GPTS membranes were covered with silicon dioxide (SiO 2 ) and indium tin oxide (ITO) thin films deposited at room temperature using radio frequency (RF) magnetron sputtering. Visible light transmission improves to 88%, instead of 40% previously achieved. The electrical properties for HTBC/SiO 2 /ITO substrate shows that the ITO deposited films are n-type doped semiconductors with resistivity of 2.7 × 10 −4  Ω cm, carrier concentration of − 1.48 × 10 21  cm −3 , and mobility of 15.2 cm 2  V −1  s −1 . These values are comparable to those of commercial ITO deposited onto glass substrates. After the characterization of the HTBC film, we used it as a substrate for the fabrication of a small molecule organic light-emitting diode OLED. The maximum efficiencies obtained were 1.95 cd/A and 1.68 cd/A for the reference OLED and the HTBC OLED, respectively. The HTBC OLED efficiency is then around 86% of the standard ITO-based OLED. This is clearly a good improvement, since previous BC-based simple architecture devices without Boe-GPTS have an efficiency 50% smaller than that of the standard OLED. 1 Introduction The development of new optoelectronics in photonic organic devices, like organic light-emitting diodes (OLEDs), is strongly based in the unique properties of their compound materials [1, 2]. Generally, OLEDs are assembled using a heterojunction architecture between three or more organic molecular materials: an electron injection layer, the emit- ting layer and finally the hole injection layer. As the OLEDs are mainly small molecule vacuum-deposited or solution processed layers with no crystalline structure, they can be fabricated onto plastic film substrates, such as polyethylene terephthalate (PET) and polycarbonate (PC). The flexibility of these substrates, due to the relatively weak nature of the Van der Waals forces responsible for intermolecular bonding in these substrates, is then preserved. This unique fabrica- tion, combining both flexible OLED and substrate, allows the development of flexible organic light-emitting diodes (FOLEDs), that can be shaped for specific needs—from electronic paper (e-paper) to medical sensors and even art design lighting. In memory of Marcos Costa e Silva. * Cristiano Legnani legnani@fisica.uf.br 1 Laboratório de Eletrônica Orgânica, Departamento de Física, Universidade Federal de Juiz de Fora, UFJF, Juiz de Fora, MG 36036-330, Brazil 2 Divisão de Metrologia de Materiais (DIMAT), Inmetro, Xerém-Duque de Caxias, RJ 25250-020, Brazil 3 Laboratório de Biopolímeros e Biomateriais – BioPolMat, Universidade de Araraquara (Uniara), Araraquara, SP 14801-340, Brazil 4 Departamento de Química, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP 14040-901, Brazil 5 Instituto de Química, Universidade Estadual Paulista, UNESP, Araraquara, SP 14800-901, Brazil 6 Laboratório de Optoeletrônica Molecular, Departamento de Física, Pontifícia Universidade Católica do Rio de Janeiro, PUC-Rio, Rio de Janeiro, RJ 22453-970, Brazil