Printed zinc tin oxide diodes: From combustion synthesis to large-scale manufacturing

Emanuel Carlos (Corresponding Author), Rita Branquinho, Elina Jansson, Jaakko Leppäniemi (Corresponding Author), Jose Menezes, Rita Pereira, Jonas Deuermeier, Ari Alastalo, Kim Eiroma, Liisa Hakola, Elvira Fortunato, Rodrigo Martins (Corresponding Author)

Research output: Contribution to journalArticleScientificpeer-review

5 Citations (Scopus)


Printed metal oxide devices have been widely desired in flexible electronic applications to allow direct integration on foils and to reduce electronic waste and associated costs. Especially, semiconductor devices made from non-critical raw materials, such as Zn, Sn (and not, for example, In), have gained significant interest. Despite considerable progress in the field, the upscale requirements from lab to fab scale to produce these materials and devices remain a challenge. In this work, we report the importance of solution combustion synthesis (SCS) when compared with sol-gel in the production of zinc tin oxide (ZTO) thin films using a solvent (1-methoxypropanol) that has lower environmental impact than the widely used and toxic 2-methoxyethanol. To assure the compatibility with low-cost flexible substrates in high-throughput printing techniques, a low annealing temperature of 140 °C was achieved for these thin films by combining SCS and infrared annealing in a short processing time. These conditions allowed the transition from spin-coating (lab scale) to flexographic printing (fab scale) at a printing speed of 10 m min-1 in a roll-to-roll pilot line. The ZTO (1:1 Zn:Sn-ratio) diodes show a rectification ratio of 103, a low operation voltage (≤ 3 V), promising reproducibility and low variability. The results provide the basis for further optimisation (device size, encapsulation) to meet the requirements of diodes in flexible electronics applications such as passive-matrix addressing, energy harvesting and rectification.

Original languageEnglish
Article number014005
Number of pages11
JournalFlexible and Printed Electronics
Issue number1
Publication statusPublished - 31 Jan 2022
MoE publication typeA1 Journal article-refereed


This work is funded in part by National Funds through FCT—Fundação para a Ciência e Tecnologia, I P, under the scope of the project UIDB/50025/2020. E Carlos acknowledges the postdoctoral grant (Grant No. 951774) from the project FOXES. VTT’s and FCT’s work was funded in part by European Institute of Innovation and Technology (EIT RawMaterials, Horizon 2020) Supersmart, Scale-Up of Printed Electronics, Grant Agreement 17161. Part of the facilities used at VTT were provided by the Academy of Finland Research Infrastructure Printed Intelligence Infrastructure (PII‐FIRI, Grant No. 32020). E Fortunato acknowledges the ERC AdG Grant 787410 from the project DIGISMART. We acknowledge to the project SYNERGY H2020-WIDESPREAD-2020-5, CSA, proposal No. 952169.


  • low temperature
  • metal oxides
  • printed Schottky diodes
  • roll-to-roll (R2R)
  • solution combustion synthesis


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