Doping Free and Amorphous NiO_x Film via UV Irradiation for Efficient Inverted Perovskite Solar Cells

Abstract

High crystallization and conductivity are always required for inorganic carrier transport materials for cheap and high-performance inverted perovskite solar cells (PSCs). High temperature and external doping are inevitably introduced and thus greatly hamper the applications of inorganic materials for mass production of flexible and tandem devices. Here, an amorphous and dopant-free inorganic material, Ni 3+ -rich NiO x , is reported to be fabricated by a novel UV irradiation strategy, which is facile, easily scaled-up, and energy-saving because all the processing temperatures are below 82 °C. The as-prepared NiO x film shows highly improved conductivity and hole extraction ability. The rigid and flexible PSCs present the champion efficiencies of 22.45% and 19.7%, respectively. This work fills the gap of preparing metal oxide films at the temperature below 150 °C for inverted PSCs with the high efficiency of >22%. More importantly, this work upgrades the substantial understanding about inorganic materials to function well as efficient carrier transport layers without external doping and high crystallization.

High efficiency (>20%) and stable inverted perovskite solar cells: current progress and future challenges

“…Similarly, Lian et al 78 HT-NiO x HTLs are compared in Fig. 11f, where the former delivered a PCE of 22.45% compared to 19.79% for the latter.…”

“…Similarly, Lian et al 78 employed inorganic HTL NiO x synthesized by the process of UV irradiation (UV-NiO x ) and compared its performance with the NiO x HTL synthesized at high temperature (HT-NiO x ). A schematic illustration of the fabricated inverted PSC based on UV-NiO x is shown in Fig.…”

“…The stability test of the device based on FAPbI 3 (control and with 5 mol% excess PbI 2 ) was performed in the ambient environment with a relative humidity of 50% AE 5% at room temperature. Fig.11dshows that the device based on FAPbI 3 with an excess of 5 mol% PbI 2 maintained 92% of the initial PCE after 800 h, whereas the device based on pure FAPbI 3 lost 60% of its initial value after just 200 h.Similarly, Lian et al78 employed inorganic HTL NiO x synthesized by the process of UV irradiation (UV-NiO x ) and compared its performance with the NiO x HTL synthesized at high temperature (HT-NiO x ). A schematic illustration of the fabricated inverted PSC based on UV-NiO x is shown in Fig.11e.…”

Recent Progress of Hole Transport Layers of Inverted Perovskite Solar Cells

“…Besides, the co-doping of Li and Co also increased the fermi energy from 4.84 eV to 5.27 eV, building a more favorable energy alignment. Lian et al proposed a dopant-free Ni3+-rich NiOx film fabrication method using UV irradiation at below 82°C, which achieved a PCE of 22.45% [18]. As a high temperature is required for the prevalent fabrication of highly crystallized NiOx film, this approach significantly reduces the fabrication cost.…”

Electron‐Accepting PDI–Cb Interlayer for over 22% Inverted Perovskite Solar Cells with Photo‐ and Thermal Stability

“…Furthermore, the proper LUMO energy level may be beneficial to extracting electrons from the perovskite efficiently. [ 40 ] We noted that while stronger electron‐accepting capability contributes to enhanced charge extraction from perovskite layer, it can also debilitate charge transport across ETL, and therefore, when implemented as a single layer, increasing thickness results in a trade‐off relationship between high electron transfer and poor electron transport. In this regard, to extract synergy of facilitated electron transfer from PDI–Cb and efficient charge transport from C 60 ETL, we introduced PDI–Cb as an interlayer at perovskite and C 60 interface in the inverted PSCs and the device efficiency was increased from 19.98% to 22.31% at 1 sun condition.…”