The present work is focused on the synthesis of hybrid composite of reduced graphene oxide and metal oxides, especially rGO/SnO2 and rGO/CuO, in order to produce gas sensing printable inks. The reduction of GO was obtained by exploiting the reduction ability of metal’s cations such as Sn(II)/Sn(IV) couple. CuO and SnO2 are a known and commonly used materials for gas detection. In the present study, different complexing and synthesis methods were conducted in order to produce rGO/CuO nanostructured composites, but at the end, the production of this composite was not reproducible enough to produce an ink. However, in the case of rGO/SnO2 composite, after trying different synthesis methods, a successful rGO/SnO2 composite was synthesized in order to improve tin oxide sensitivity and its ability to sense gases at room temperature. The aforementioned composite was used in order to produce a printable ink based on rGO/SnO2 composite. The working principle of the synthesis method of the composites in this study was the mutual interaction between graphene oxide and the metallic precursor such as SnCl2. Different methods were analyzed and compared during the optimization of the synthesis process, in order to improve the quality of the final materials. The use of laboratory synthesized GO was compared with commercial GO in terms of particles dimension and dispersibility. After selecting the laboratory synthesized GO, various complexing and synthesis methods were tried in order to obtain a better final result and being able to more precisely control the overall reaction, especially degree of reduction of GO. Characteristics and properties of the obtained rGO/SnO2 composite were studied and compared with other composites through different laboratory tests including electrochemical analysis, XRD, SEM, Raman spectroscopy, and XPS. Best rGO/SnO2 nanocomposite was later utilized for the formulation of a printable ink. Different compositions of the ink were studied in order to find the best ink in term of stability and dispersibility. The best produced ink was used in inkjet printer in order to print the functional ink on the paper. After printing 10 layers of the final ink on the paper by inkjet printer, a SEM test was conducted in order to characterize the printed functional ink. The final aim of this study is to produce a metal oxide-based functional ink for application in inkjet printing of gas sensors.
Il presente lavoro si concentra sulla sintesi di composito ibrido di ossido di grafene ridotto e ossidi di metallo, in particolare rGO / SnO 2 e rGO / CuO, al fine di produrre inchiostri stampabili sensibili al gas. La riduzione di GO è stata ottenuta sfruttando la capacità di riduzione dei metalli cationi come coppia SN (II) / Sn (IV). CuO e SnO 2 sono materiali noti e comunemente usati per il rilevamento di gas. Nel presente studio, sono stati condotti diversi complessanti e metodi di sintesi per produrre compositi nanostrutturati GO / CuO, ma alla fine la produzione di questo composito non era sufficientemente riproducibile per produrre un inchiostro. Tuttavia, nel caso del composito rGO / SnO 2, dopo aver provato diversi metodi di sintesi, è stato sintetizzato un composito rGO / SnO 2 di successo al fine di migliorare la sensibilità dell'ossido di stagno e la sua capacità di rilevare i gas a temperatura ambiente. Il suddetto composito è stato utilizzato per produrre un inchiostro stampabile basato sul composito rGO / SnO 2. Il principio di funzionamento del metodo di sintesi interazione reciproca tra ossido di grafene e precursore metallico come SnCl 2. Metodi diversi sono stati analizzati e confrontati durante l'ottimizzazione del processo di sintesi, al fine di migliorare la qualità dei materiali finali. L'uso del GO sintetizzato in laboratorio è stato confrontato con il GO commerciale in termini di dimensione delle particelle e dispersibilità. Dopo aver selezionato il GO sintetizzato in laboratorio, sono stati provati vari complessanti e metodi di sintesi al fine di ottenere un risultato finale migliore ed essere in grado di controllare più precisamente la reazione generale, in particolare il grado di riduzione del GO. Le caratteristiche e le proprietà del composito rGO / SnO 2 ottenuto sono state studiate e confrontate con altri compositi attraverso diversi test di laboratorio tra cui analisi elettrochimiche, XRD, SEM spettroscopia Raman e XPS. Il miglior nanocomposito rGO / SnO 2 è stato successivamente utilizzato per la formulazione di un inchiostro stampabile. Sono state studiate diverse composizioni dell'inchiostro al fine di trovare l'inchiostro migliore in termini di stabilità e dispersibilità. L'inchiostro prodotto meglio è stato utilizzato nella stampante a getto d'inchiostro al fine di stampare 10 strati dell'inchiostro finale sulla carta dalla stampante a getto d'inchiostro, è stato condotto un test SEM per caratterizzare l'inchiostro funzionale stampato. Lo scopo finale di questo studio è quello di produrre un inchiostro funzionale a base di metaloossido per l'applicazione nella stampa a getto d'inchiostro dei sensori di gas.
Redox synthesis of rGO-based composites for inkjet printable sensors
KHOSRAVI-HASHEMI, SHAYAN
2018/2019
Abstract
The present work is focused on the synthesis of hybrid composite of reduced graphene oxide and metal oxides, especially rGO/SnO2 and rGO/CuO, in order to produce gas sensing printable inks. The reduction of GO was obtained by exploiting the reduction ability of metal’s cations such as Sn(II)/Sn(IV) couple. CuO and SnO2 are a known and commonly used materials for gas detection. In the present study, different complexing and synthesis methods were conducted in order to produce rGO/CuO nanostructured composites, but at the end, the production of this composite was not reproducible enough to produce an ink. However, in the case of rGO/SnO2 composite, after trying different synthesis methods, a successful rGO/SnO2 composite was synthesized in order to improve tin oxide sensitivity and its ability to sense gases at room temperature. The aforementioned composite was used in order to produce a printable ink based on rGO/SnO2 composite. The working principle of the synthesis method of the composites in this study was the mutual interaction between graphene oxide and the metallic precursor such as SnCl2. Different methods were analyzed and compared during the optimization of the synthesis process, in order to improve the quality of the final materials. The use of laboratory synthesized GO was compared with commercial GO in terms of particles dimension and dispersibility. After selecting the laboratory synthesized GO, various complexing and synthesis methods were tried in order to obtain a better final result and being able to more precisely control the overall reaction, especially degree of reduction of GO. Characteristics and properties of the obtained rGO/SnO2 composite were studied and compared with other composites through different laboratory tests including electrochemical analysis, XRD, SEM, Raman spectroscopy, and XPS. Best rGO/SnO2 nanocomposite was later utilized for the formulation of a printable ink. Different compositions of the ink were studied in order to find the best ink in term of stability and dispersibility. The best produced ink was used in inkjet printer in order to print the functional ink on the paper. After printing 10 layers of the final ink on the paper by inkjet printer, a SEM test was conducted in order to characterize the printed functional ink. The final aim of this study is to produce a metal oxide-based functional ink for application in inkjet printing of gas sensors.| File | Dimensione | Formato | |
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https://hdl.handle.net/10589/152063