Rapid Vapor-Phase Deposition of High-Mobility p-Type Buffer Layers on Perovskite Photovoltaics for Efficient Semitransparent Devices

Abstract

Perovskite solar cells (PSCs) with transparent electrodes can be integrated with existing solar panels in tandem configurations to increase the power conversion efficiency. A critical layer in semi-transparent PSCs is the inorganic buffer layer, which protects the PSC against damage when the transparent electrode is sputtered on top. The development of n-i-p structured semi-transparent PSCs has been hampered by the lack of suitable p-type buffer layers. In this work we develop a ptype CuO x buffer layer, which can be grown uniformly over the perovskite device without damaging the perovskite or organic hole transport layers. The CuO x layer has high hole mobility (4.3 ± 2 cm 2 V -1 s -1 ), high transmittance (>95%), and a suitable ionization potential for hole extraction (5.3 ± 0.2 eV). Semi-transparent PSCs with efficiencies up to 16.7% are achieved using the CuO x buffer layer. Our work demonstrates a new approach to integrate n-i-p structured PSCs into tandem configurations, as well as enable the development of other devices that need high quality, protective p-type layers.

Inorganic Materials by Atomic Layer Deposition for Perovskite Solar Cells

“…ALD copper oxide (CuO x ) and vanadium oxide (VO x ) have also been reported as buffer layers in semitransparent PSCs [ 72 , 73 ]. Growth methods by pulsed-chemical vapor deposition (pulsed-CVD) [ 60 ] or atmospheric-pressure chemical vapor deposition (AP-CVD) [ 64 ] have been reported for CuO x buffer layers in n - i - p structured semitransparent PSCs. CuO x films by AP-CVD resulted in high mobilities over 4 cm 2 /V·s, and semitransparent PSCs with these buffer layers resulted in PCEs over 16% ( Figure 7 c,d) [ 64 ].…”

“…Some common examples are pulsed-CVD [ 60 ], AP-CVD [ 64 ], and s-ALD [ 45 , 79 ]. Pulsed-CVD involves reducing the carrier purging step during the ALD sequence and pulsing the ALD precursors simultaneously, instead of separately, to reduce the deposition time [ 80 ].…”

“…Incorporation of atmospheric-pressure chemical vapor deposition (AP-CVD) of CuO x as a buffer layer in semitransparent PSC: ( c ) Schematic of band alignment of the device; ( d ) Cross-sectional SEM image of the device stack. Reproduced from [ 64 ], with permission from the American Chemical Society, 2020.…”

Recent Progress in the Semiconducting Oxide Overlayer for Halide Perovskite Solar Cells

“…Reproduced with permission. [ 40 ] Copyright 2020, American Chemical Society. h) 1‐R (R is reflectance) curve and corresponding EQE spectrum of Si/perovskite tandem using ALD‐SnO 2 /ZTO buffer layer.…”

Sputtered Indium‐Zinc Oxide for Buffer Layer Free Semitransparent Perovskite Photovoltaic Devices in Perovskite/Silicon 4T‐Tandem Solar Cells

“…However, the energetic bombardment in the sputtering process would damage the surface of the underlying carrier transport layer (CTL), and hence increase dangling bonds and trap density, resulting in interfacial recombinations in the device and finally deteriorate the device performance. [ 29 ] Among them, the introduction of buffer layer, including MoO x , [ 30–32 ] SnO x , [ 33–36 ] ZnO x , [ 37–40 ] and so on, [ 41–43 ] at the interface between IZO and CTL seems a reluctant choice to prevent the underlying CTL from the damage in the IZO deposition process. Undoubtedly, the additional buffer layer definitely increases the series resistance, resulting in some parasitic absorption and interfacial recombinations, which would deteriorate the device performance.…”