Epitaxial CdTe Thin Films on Mica by Vapor Transport Deposition for Flexible Solar Cells

Abstract

Most high-quality CdTe thin films are epitaxially grown on single-crystalline substrates through chemical bondings by either molecular beam epitaxy or metalorganic chemical vapor deposition. The epitaxial CdTe films are rarely applied in electronic or optoelectronic devices because of the rigid single-crystalline substrate. We present high-quality CdTe films epitaxially grown on mica by vapor transport deposition process through weak interface interactions. The full width at half-maximum (fwhm) of the X-ray diffraction rocking curve of CdTe ( 111) and the fwhm of azimuthal in-plane angular dispersion of CdTe (111) were 0.23°and 0.36°, respectively. The weak interaction at the interface enables a transfer of the epitaxial film from mica onto other flexible substrates for applications. The epitaxial CdTe film was separated from the mica substrate by the surface tension of water during immersion and then transferred onto a flexible SU-8 photoresist substrate for the fabrication of CdTe solar cells. We successfully fabricated the flexible all-epitaxial, epi-CdS/epi-CdTe solar cells with a power conversion efficiency of 9.59%, which showed low interface defects and high diode quality compared to the poly-CdS/epi-CdTe solar cells.

Metal Chalcogenides (MxEy; E = S, Se, and Te) as Counter Electrodes for Dye–Sensitized Solar Cells: An Overview and Guidelines

“…The corresponding FDSSCs achieved the current highest record PCE of 10.28% for FDSSCs, and outstanding flexibility. The advantages observed for metal selenide-based CEs in FDSSCs were also observed for other metal chalcogenides such us metal sulfides [95,97] and metal tellurides [171][172][173][174][175][176][177][178][179][180] when incorporated in fibrous or flexible PV devices. Chen et al [97] prepared both a CoNi 2 S 4 nanoribbon on CFs (CoNi 2 S 4 nanoribbon-CFs), and a CoNi 2 S 4 nanorod on CFs (CoNi 2 S 4 nanorod-CFs) for use as CEs in FDSSCs.…”

“…As for metal tellurides, they were mostly used in nonfibrous flexible solar cells using polymer substrates (Figure 8b). [171][172][173][174][175][176][177][178][179][180] Some of the most remarkable research works conducted on this topic were from Rance et al [176] and Mahabaduge et al, [177]…”

Novel low-carbon energy solutions for powering emerging wearables, smart textiles, and medical devices

“…Protecting the PV components from environmental damage while permitting optimum absorption of the relevant wavelength on the top side of a module can be achieved in the superstrate configuration. 257 Wen et al designed CdS with epitaxially coated CdTe as an absorber for a thin film solar cell with 9.59% PCE. 249 The fabrication was done involving two different device structures.…”

“…257 Wen et al designed CdS with epitaxially coated CdTe as an absorber for a thin film solar cell with 9.59% PCE. 249 The fabrication was done involving two different device structures. CdTe was epitaxially grown on a mica substrate, and CdTe was grown on a buffer layer (CdS) positioned above the 250 (reproduced with permission 248 Copyright 2016, Elsevier) (reproduced with permission 249 Copyright 2020, ACS) (reproduced with permission 250 Copyright 2017, Elsevier).…”

Flexible and stretchable inorganic solar cells: Progress, challenges, and opportunities

“…4(b)]. 79 The transfer of the CdTe film from the mica substrate onto various flexible substrates was also possible due to the weak interfacial interactions. In fact, the epitaxial film was released from the substrate when dipped in water via surface tension, and an SU8 substrate was used as the flexible permanent substrate for the solar cell.…”