High performance perovskite sub-module with sputtered SnO2 electron transport layer

Abstract

Hybrid perovskite solar cells (PSC) have gained stupendous achievement in single/tandem solar cell, semitransparent solar cell and flexible devices. Aiming for potential commercialization of perovskite photovoltaic technology, up scalable processing is crucial for all function layers in PSC. Herein we present a study on room temperature magnetron sputtering of tin oxide electron transporting layer (ETL) and apply it in a large area PSC for low cost and continues manufacturing. The SnO2 sputtering targets with varied oxygen and deposition models are used. Specifically, the working gas ratio of Ar/O2 during the radio frequency sputtering process plays a crucial role to obtain optimized SnO2 film. The sputtered SnO2 films demonstrate similar morphological and crystalline properties, but significant varied defect states and carrier transportation roles in the PSC devices. With further modification of thickness of SnO2, the PSCs based on sputtered SnO2 ETL shows a champion efficiency of 18.20% in small area and an efficiency of 14.71% in sub-module with an aperture area of 16.07 cm 2 , which is the highest efficiency of perovskite sub module with sputtered ETLs.

Tin Oxide Electron‐Selective Layers for Efficient, Stable, and Scalable Perovskite Solar Cells

“…Notably, m-TiO 2 , currently still the most employed ESL, usually needs high-temperature sintering at ≈500 °C, which is required to eliminate the organics/additives, resulting in the mesoporous structure. [115,116] SnO 2 can also be fabricated in a mesoporous structure through a similar high-temperature annealing step. [117] However, m-SnO 2 -based PSCs have remained less efficient compared to their m-TiO 2 counterparts, for two main reasons.…”

“…Following this, Bai et al recently reported sputtered SnO 2 ESLs at room temperature for mini-modules (again with an active area of 22.8 cm 2 ) with a champion PCE of 14.71%. [116] The main challenge for the sputtering method lies in control of oxygen vacancies in the SnO 2 film, which is usually accomplished by tuning the gas flows during processing or postannealing. Another concern is the amorphous or nanocrystalline nature of the films, causing tail states within the bandgap, which may result in V OC losses.…”

Toward efficient and stable operation of perovskite solar cells: Impact of sputtered metal oxide interlayers

“…Compared with DC sputtering that uses conductive SnO 2 target, RF sputtering of nonconductive SnO 2 produces ETL that leads to higher performance and is indeed commonly used in most works. [ 91 ] The electron configuration in the outermost occupied shell is the cause of two types of tin‐relate oxide: p‐type SnO with relatively high and tin vacancy–associated hole mobility, and n‐type SnO 2 whose conductivity originates from intrinsic defects like oxygen vacancies and tin interstitial. The latter one is obviously desired for the application as ETL.…”

“…Whereas over‐high content leads to undesired interstitial oxygen and rougher morphology. [ 91,93 ] Full coverage of the underlying layer requires thick‐enough SnO 2 film, but the Ar plasma damage and increased charge transport resistance coming with thicker films would cause a loss in FF . Balancing these effects leads to an optimum thickness.…”

Unravelling the theoretical window to fabricate high performance inorganic perovskite solar cells

“…The hybrid organic inorganic lead (Pb) based perovskite as an light absorber (APbI3) is the most investigated in PSCs due to their excellent electro-optical properties [1][2][3][4][5] and gave record performance. 6,7 However, hybrid organic-inorganic lead halide perovskite suffers from challenges such as, efficiency, 8 thermal instability at high temperature, originating due to volatile nature of organic cations (FA or MA). 9,10 Replacement of the organic cations by inorganic cations such as Cs found to be an effective approach to overcome such bottleneck.…”