ORCID Profile
0000-0002-8632-780X
Current Organisation
RMIT University
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Publisher: Wiley
Date: 17-05-2022
Abstract: Herein, an in‐depth experimental investigation into the effect of employing different high resistance metal oxide (HRMO) layers on the quality of the front contact in solar cells with an fluorine‐doped tin oxide (FTO)/(HRMO)/CdS/Sb 2 Se 3 /Au device architecture is presented. The application of ZnO or TiO 2 HRMO layers between FTO substrates and CdS improves the overall device performance. Short‐circuit current gains of ≈20%, orders of magnitude higher shunt resistances (≈10 4 Ω cm 2 ), and greatly improved device stabilities—maintaining over 95% of their initial efficiency over 137 days are observed. A suppression of the unfavorable (120) orientation of the photoactive Sb 2 Se 3 layer is observed in devices with HRMO interlayers. The application of HRMO layers is crucial to prevent both ohmic and non‐ohmic current leaks and maintain device stability over time. Cross‐over in the current‐voltage ( JV ) curves observed in the case of TiO 2 indicates the presence of a high barrier for the diode current in these devices. Wavelength‐dependent JV curves coupled with capacitance measurements and simulations show that this barrier can be attributed to a high density of interfacial acceptor states. In contrast, ZnO deposition is found to reduce interface defects and enhance the quality of the front contact, while boosting performance and increasing device longevity.
Publisher: Wiley
Date: 30-05-2023
Abstract: Antimony chalcogenide, Sb 2 X 3 (X = S, Se), applications greatly benefit from efficient charge transport along covalently bonded (001) oriented (Sb 4 X 6 ) n ribbons, making thin film orientation control highly desirable – although particularly hard to achieve experimentally. Here, it is shown for the first time that substrate nanostructure plays a key role in driving the growth of (001) oriented antimony chalcogenide thin films. Vapor Transport Deposition of Sb 2 Se 3 thin films is conducted on ZnO substrates whose morphology is tuned between highly nanostructured and flat. The extent of Sb 2 Se 3 (001) orientation is directly correlated to the degree of substrate nanostructure. These data showcase that nanostructuring a substrate is an effective tool to control the orientation and morphology of Sb 2 Se 3 films. The optimized s les demonstrate high (001) crystallographic orientation. A growth mechanism for these films is proposed, wherein the substrate physically restricts the development of undesirable crystallographic orientations. It is shown that the surface chemistry of the nanostructured substrates can be altered and still drive the growth of (001) Sb 2 Se 3 thin films – not limiting this phenomenon to a particular substrate type. Insights from this work are expected to guide the rational design of Sb 2 X 3 thin film devices and other low‐dimensional crystal‐structured materials wherein performance is intrinsically linked to morphology and orientation.
Publisher: IOP Publishing
Date: 12-05-2023
Abstract: Post transition metal chalcohalides are an emerging class of semiconductor materials for optoelectronic applications. Within this class, bismuth oxyiodide (BiOI) is of particular interest due to its high environmental stability, low toxicity, and defect tolerance considered typical of ‘ns 2 ’ materials. Here we fabricate BiOI thin films using a solution-processed method that affords pin-hole free highly pure films without any residual carbon or other contaminant species. Based on these films, solution processed all-inorganic solar cells with an architecture ITO/NiO x /BiOI/ZnO/Al are fabricated for the first time. Additional device improvements are realised by templating BiOI thin film growth to attain efficiencies that rival some of the best vacuum deposited devices. The BiOI thin films and devices outlined here are an excellent platform for the further development of solution processed bismuth chalcohalide optoelectronic devices.
No related grants have been discovered for Joao Mendes.