(19)

(11)

EP 3 807 213 A1

(12)

(43) Date of publication: 21.04.2021 Bulletin 2021/16 (21) Application number: 19736497.9 (22) Date of filing: 22.05.2019

(51) International Patent Classification (IPC):  C01B 19/00(2006.01) C25B 1/02(2006.01) H01L 29/51(2006.01) C25B 11/04(2021.01) (86) International application number: PCT/IB2019/054229 (87) International publication number: WO 2019/239235 (19.12.2019 Gazette 2019/51)

(84) Designated Contracting States: AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR Designated Extension States: BA ME Designated Validation States: KH MA MD TN (30) Priority: 15.06.2018 NL 2021131 (71) Applicant: North-West University 2531 Potchefstroom (ZA)	(72) Inventors: KRIEK, Roelof Jacobus 2531 Potchefstroom (ZA) IQBAL, Mohd, Zafar 2531 Potchefstroom (ZA) (74) Representative: Michalski Hüttermann & Partner Patentanwälte mbB  Speditionstraße 21 40221 Düsseldorf 40221 Düsseldorf (DE)