Dual Passivation of SnO₂ by Tetramethylammonium Chloride for High-Performance CsPbI₂Br-Based Inorganic Perovskite Solar Cells

Abstract

Here, the modification of the SnO2 electron transport layer (ETL) by tetramethylammonium chloride (TMACl) is described. The theoretical and experimental studies in this work demonstrate that TMA and Cl ions complementarily passivate the oxygen vacancies on the surface of SnO2 ETL, while TMACl passivation also contributes to increase the conduction band edge of SnO2 by reducing the work function. As a result, the charge carrier recombination and electron transfer/extraction behaviors at the interface of CsPbI2Br and SnO2 ETL are significantly improved, leading to inorganic perovskite solar cells with efficiencies of up to 13.84% and 28.68% under 1-sun illumination and indoor lighting, respectively. TMACl-passivated SnO2 also boosts the operative stability of the device under humidity and thermal stress, which reveals the potential of TMACl as a promising passivation agent of SnO2 for high-performance perovskite optoelectronics.

A cascade bilayer electron transport layer toward efficient and stable Ruddlesden‐Popper perovskite solar cells

“…Three peaks at 528.2, 528.8, and 529.8 eV represent the lattice oxygen (O L ), the vacancy oxygen (O V ), and the chemisorbed oxygen (O C ), respectively. In specific, the peak at the lowest binding energy (O L ) is associated with the lattice oxygen atoms (O 2− ) in a fully coordinated SnO 2 with the Sn 4+ ions while the highest binding energy peak is the loosely adsorbed dissociated oxygen or hydroxyl group at the surface (O C ) 28 . The binding energy peak at the middle range (O V ) can thus be interpreted to the oxygen attributed to vacancies in the lattice matrix of SnO 2 (O − , O 2− ).…”

“…Apart from the materials engineering of the perovskite absorber layer, modification of interfacial charge transport layers also plays an important role in determining the charge extraction and recombination kinetics of PSCs 24‐28 . In particular, the moisture/oxygen permeability of the interfaces of the device can cause serious degradation of PSCs, so suitable selection of the optimal interfacial layers is critical to increasing PCE and stability of PSCs, simultaneously.…”

Perovskite Photovoltaics for Artificial Light Harvesting

“…To passivate the oxygen vacancies on the SnO 2 ETL for n‐i‐p PALCs, Parida et al [61] . used tetramethylammonium chloride (TMACl).…”

“…To passivate the oxygen vacancies on the SnO 2 ETL for n-i-p PALCs, Parida et al [61] used tetramethylammonium chloride (TMACl). They found that interfacial charge transfer and extraction in PALCs was enhanced by minimizing losses through charge carrier recombination after SnO 2 was treated with TAMCl.…”

“…Even though PALCs might be exposed to milder environmental conditions compared to outdoor solar cell devices, efficient encapsulation methods are expected to be developed for long-lasting devices and prevention of heavy metal leakages in the case of Pb-and Sn-perovskite-based devices. [91,92] From the perspective of perovskite materials, the suppression of phase segregation by controlling the composition of mixed cations [42][43][44] and the development of all-inorganic perovskites by removing the organic cations [58,61,93] are noticeable approaches for highly stable PALCs. Engineering in charge transport layers, such as bilayer and alloy ETL [63,64,67] and dopant-free HTL, [70,71] should be also addressed for enhanced stability of PALCs.…”