In Situ Formation of NiO_x Interlayer for Efficient n–i–p Inorganic Perovskite Solar Cells

Abstract

Inorganic metal halide perovskites with intrinsically good thermal stability are potential candidates for stable perovskite solar cells (PSCs). However, band misalignment between perovskite absorber and hole-transport material (HTM) restricts the maximum attainable photovoltage and power conversion efficiency. In addition, widely used HTM 2,2′,7,7′-tetrakis[N,N-di(4methoxyphenyl)amino]-9,9′-spirobifluorene (Spiro) in the fabrication of highly efficient inorganic PSCs causes stability issue. Here, we report a facial way to deposit an in situ formed NiO x interlayer at low temperature between perovskite and Spiro in inorganic PSCs with an n−i−p configuration. Our results suggest that devices with the NiO x interlayer have better energy alignment and facilitate hole extraction and transfer more efficiently than those without NiO x . This leads to a 100 mV improvement in the opencircuit voltage (V OC ) and obtaining an excellent PCE of 13.6%, along with improved stability. This work provides a simple strategy to mitigate the V OC loss for efficient and stable inorganic perovskite devices.

Review of Interface Passivation of Perovskite Layer

“…Owing to their excellent chemical stability, high electron mobility, and an energy level structure that matches that of perovskites, oxide materials are considered to be an ideal option for ensuring the stability of perovskite surfaces [ 118 , 135 , 136 , 152 ]. The stability of the oxide was quite excellent.…”

“…Compared with inorganic PSCs prepared without a nickel oxide layer, the fabricated device demonstrated excellent efficiency. The open-circuit voltage of the device increased by 100 mV, and a PCE of 13.6% was obtained [ 135 ]. Li et al also successfully prepared a NiO x nanomicelle solution and applied it to n – i – p planar PSCs.…”

In‐Situ Hot Oxygen Cleansing and Passivation for All‐Inorganic Perovskite Solar Cells Deposited in Ambient to Breakthrough 19% Efficiency

“…In addition, it exhibits high temperature tolerance up to 400 °C, which is significantly improved compared to those organic-inorganic hybrid perovskites composed of volatile organic components that rapidly degrade over 150 °C. [13][14][15] However, the CsPbI 3 -based solar cells suffer from a large E loss (described by the equation: E loss = E g − qV OC ), [16][17][18][19] which leads to their device performance remaining inferior to that of the hybrid perovskites. [20][21][22][23] According to the statistical results of Wang et al, [24] the E loss of most CsPbX 3 (X = Br, I) solar cells varies from 0.60 to 1.00 eV, much higher than that of the hybrid ones (0.40-0.50 eV).…”

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

“…[ 62 ] Unfortunately, for high crystallinity, SOOMs require annealing above the degradation temperature of the perovskite layer. [ 63 ] Therefore, a low‐temperature deposition strategy is necessary that not only preserves the perovskite layer but also yields highly crystalline SOOMs. Third, for chemical deposition, a metal precursor and oxygen reactant are required to form the oxide film, but these could also decompose the underlying perovskite layer during the SOOMs deposition process, so the reactants must be compatible with the perovskite.…”