Growth Temperature Influence on Atomic-Layer-Deposited In2O3 Thin Films and Their Application in Inorganic Perovskite Solar Cells

Abstract

Recently, indium oxide (In2O3) thin films have emerged as a promising electron transport layer (ETL) for perovskite solar cells; however, solution-processed In2O3 ETL suffered from poor morphology, pinholes, and required annealing at high temperatures. This research aims to carry out and prepare pinhole-free, transparent, and highly conductive In2O3 thin films via atomic layer deposition (ALD) seizing efficiently as an ETL. In order to explore the growth-temperature-dependent properties of In2O3 thin film, it was fabricated by ALD using the triethyl indium (Et3In) precursor. The detail of the ALD process at 115–250 °C was studied through the film growth rate, crystal structure, morphology, composition, and optical and electrical properties. The film growth rate increased from 0.009 nm/cycle to 0.088 nm/cycle as the growth temperature rose from 115 °C to 250 °C. The film thickness was highly uniform, and the surface roughness was below 1.6 nm. Our results confirmed that film’s structural, optical and electrical properties directly depend on film growth temperature. Film grown at ≥ 200 °C exhibited a polycrystalline cubic structure with almost negligible carbon impurities. Finally, the device ALD-In2O3 film deposited at 250 °C exhibited a power conversion efficiency of 10.97% superior to other conditions and general SnO2 ETL.

Inorganic CsPbI2Br halide perovskites: from fundamentals to solar cell optimizations

“…A PCE of 10.97% (a J SC of 13.64 mA cm −2 , a V OC of 1.13 V and a FF of 0.710) was achieved for the device under investigation derived from the In 2 O 3 ETL deposited at 250 °C. 59 To replace the commonly used ETL ( i.e. [6,6]-phenyl C61 butyric acid methyl ester, PCBM and the derivatives of C60) in the inverted p–i–n CsPbI 2 Br PSC structure, a low-temperature solution-processed metal sulphide ETL was developed by a simple ligand exchange process in the anhydrous ether solution containing 1, 2-ethanedithiol (EDT).…”

Metal oxide charge transporting layers for stable high-performance perovskite solar cells

“…Bulk In 2 O 3 exhibits high carrier mobility (140-170 cm 2 V −1 s −1 ), low resistivity, and excellent chemical and thermal stabilities. 169 In 2 O 3 has been used as a good alternative electron selective layer in PSCs, achieving a PCE of 13.01%. 170 The In 2 O 3 film surface was passivated by PCBM to produce pinhole and crack-free films, achieving an enhanced PCE of 14.83% with reduced hysteresis.…”

Monolithic bilayered In2O3 as an efficient interfacial material for high‐performance perovskite solar cells

“…[ 16 ] To improve the quality of the SnO 2 /perovskite interface, researchers have explored many interfacial materials, such as inorganic salts (KCl, [ 17 ] KOH, [ 18 ] NH 4 Cl, [ 19,20 ] and NH 4 F [ 21 ] ), organic small molecules (ethylenediaminetetraacetic acid [EDTA], [ 22 ] triphenylphosphine oxide [TPPO] [ 23 ] ), and polymers (polyethylene glycol [PEG], [ 24 ] poly(ethylene glycol) diacrylate ([PEGDA] [ 25 ] ). Particularly, previous literature report that In 2 O 3 can be utilized as ETL, [ 26–30 ] interlayer between transparent conducting oxide and ETL [ 26,31,32 ] or interlayer between ETL and perovskite layer [ 33–35 ] due to the high electron mobility (~25 cm 2 V −1 s −1 ), [ 36 ] high light transmission properties, [ 37 ] and low‐temperature processing (~200°C). [ 31 ] These interfacial materials facilitate the electron transfer at the SnO 2 /perovskite interface by aligning the conduction band maximum and passivating the interfacial defects.…”

“…[PEG], [24] poly(ethylene glycol) diacrylate ([PEGDA] [25] ). Particularly, previous literature report that In 2 O 3 can be utilized as ETL, [26][27][28][29][30] interlayer between transparent conducting oxide and ETL [26,31,32] or interlayer between ETL and perovskite layer [33][34][35] due to the high electron mobility (~25 cm 2 V −1 s −1 ), [36] high light transmission properties, [37] and low-temperature processing (~200°C). [31] These interfacial materials facilitate the electron transfer at the SnO 2 /perovskite interface by aligning the conduction band maximum and passivating the interfacial defects.…”