Boosting the Conversion Efficiency Over 20% in MAPbI3 Perovskite Planar Solar Cells by Employing a Solution-Processed Aluminum-Doped Nickel Oxide Hole Collector

Interfacial Layer Materials with a Truxene Core for Dopant-Free NiOx-Based Inverted Perovskite Solar Cells

Nickel oxide (NiOx) is commonly used as a holetransporting material (HTM) in p-i-n perovskite solar cells. However, the weak chemical interaction between the NiOx and CH3NH3PbI3 (MAPbI3) interface results in poor crystallinity, ineffective hole extraction, and enhanced carrier recombination, which are the leading causes for the limited stability and power conversion efficiency (PCE). Herein, two HTMs, TRUX-D1 (N2,N7,N12-tris(9,9-dimethyl-9H-fluoren-2-yl)-5,5,10,10,15,15-hexaheptyl-N2,N7,N12-tris(4-methoxyphenyl)-10,15-dihydro-5H-diindeno[1,2-a:1',2'-c]fluorene-2,7,12-triamine) and TRUX-D2 (5,5,10,10,15,15-hexaheptyl-N2,N7,N12-tris(4-methoxyphenyl)-N2,N7,N12-tris(10-methyl-10H-phenothiazin-3-yl)-10,15-dihydro-5H-diindeno[1,2-a:1',2'-c]fluorene-2,7,12-triamine), are designed with a rigid planar C3 symmetry truxene core integrated with electron-donating amino groups at peripheral positions. The TRUX-D molecules are employed as effective interfacial layer (IFL) materials between the NiOx and MAPbI3 interface. The incorporation of truxene-based IFLs improves the quality of perovskite crystallinity, minimizes nonradiative recombination, and accelerates charge extraction which has been confirmed by various characterization techniques. As a result, the TRUX-D1 exhibits a maximum PCE of up to 20.8% with an impressive long-term stability. The unencapsulated device retains 98% of their initial performance following 210 days of aging in a glove box and 75.5% for the device after 80 days under ambient air condition with humidity over 40% at 25 °C.

Development on inverted perovskite solar cells: A review

Recently, inverted perovskite solar cells (IPSCs) have received note-worthy consideration in the photovoltaic domain because of its dependable operating stability, minimal hysteresis, and low-temperature manufacture technique in the quest to satisfy global energy demand through renewable means. In a decade transition, perovskite solar cells in general have exceeded 25 % efficiency as a result of superior perovskite nanocrystalline films obtained via low temperature synthesis methods along with good interface and electrode materials management. This review paper presents detail processes of refining the stability and power conversion efficiencies in IPSCs. The latest development in the power conversion efficiency, including structural configurations, prospect of tandem solar cells, mixed cations and halides, films' fabrication methods, charge transport material alterations, effects of contact electrode materials, additive and interface engineering materials used in IPSCs are extensively discussed. Additionally, insights on the state of the art and IPSCs' continued development towards commercialization are provided.

Recent Developments in Upscalable Printing Techniques for Perovskite Solar Cells

Just over a decade, perovskite solar cells (PSCs) have been emerged as a next-generation photovoltaic technology due to their skyrocketing power conversion efficiency (PCE), low cost, and easy manufacturing techniques compared to Si solar cells. Several methods and procedures have been developed to fabricate high-quality perovskite films to improve the scalability and commercialize PSCs. Recently, several printing technologies such as blade-coating, slot-die coating, spray coating, flexographic printing, gravure printing, screen printing, and inkjet printing have been found to be very effective in controlling film formation and improving the PCE of over 21%. This review summarizes the intensive research efforts given for these printing techniques to scale up the perovskite films as well as the hole transport layer (HTL), the electron transport layer (ETL), and electrodes for PSCs. In the end, this review presents a description of the future research scope to overcome the challenges being faced in the printing techniques for the commercialization of PSCs.

Amorphous NiCoB-coupled MAPbI3 for efficient photocatalytic hydrogen evolution

It was thought that the organic-inorganic hybrid perovskite MAPbI₃ could be used to collect visible light for the photocatalytic hydrogen evolution reaction (HER). However, its ability to generate H₂ is limited. Herein, we synthesized amorphous NiCoB through a redox method and coupled it with MAPbI₃ to form the NiCoB/MAPbI₃ composite photocatalyst by electrostatic self-assembly. 30% NiCoB/MAPbI₃ exhibited the maximum H₂ generation yield of 2625.57 μmol g^-1 h^-1, which was approximately 114 fold that of pristine MAPbI₃ and much better than that of Pt/MAPbI₃. In addition to the excellent photocatalytic HER capability, NiCoB/MAPbI₃ maintained good stability in the 24 h cycling hydrogen evolution experiment. The photoelectric analysis showed that NiCoB as a cocatalyst could realize rapid charge separation. This work can offer a reference for the construction of efficient photocatalysts based on lead halide perovskites.

High-Efficiency and Stable Inverted Planar Perovskite Solar Cells with Pulsed Laser Deposited Cu-Doped NiOx Hole-Transport Layers

High-quality hole-transport layers (HTLs) with excellent optical and electrical properties play a significant role in achieving high-efficient and stable inverted planar perovskite solar cells (PSCs). In this work, the optoelectronic properties of Cu-doped NiO_x (Cu:NiO_x) films and the photovoltaic performance of PSCs with Cu:NiO_x HTLs were systematically studied. The Cu-doped NiO_x with different doping concentrations was achieved by a high-temperature solid-state reaction, and Cu:NiO_x films were prepared by pulsed laser deposition (PLD). Cu⁺ ion dopants not only occupy the Ni vacancy sites to improve the crystallization quality and increase the hole mobility, but also substitute lattice Ni²⁺ sites and act as acceptors to enhance the hole concentration. As compared to the undoped NiO_x films, the Cu:NiO_x films exhibit a higher electrical conductivity with a faster charge transportation and extraction for PSCs. By employing the prepared Cu:NiO_x films as HTLs for the PSCs, a high photocurrent density of 23.17 mA/cm² and a high power conversion efficiency of 20.41% are obtained, which are superior to those with physical vapor deposited NiO_x HTLs. Meanwhile, the PSC devices show a negligible hysteresis behavior and a long-term air-stability, even without any encapsulation. The results demonstrate that pulsed laser deposited Cu-doped NiO_x film is a promising HTL for realizing high-performance and air-stable PSCs.