Tailored Cysteine‐Derived Molecular Structures toward Efficient and Stable Inorganic Perovskite Solar Cells

Abstract

Surface–defect‐triggered non‐radiative charge recombination and poor stability have become the main roadblock to continued improvement in inorganic perovskite solar cells (PSCs). Herein, the main culprits are identified on the inorganic perovskite surface by first‐principles calculations, and to purposefully design a brand‐new passivator, Boc‐S‐4‐methoxy‐benzyl‐l‐cysteine (BMBC), whose multiple Lewis‐based functional groups (NH, S and CO) to suppress halide vacancies and coordinate with undercoordinated Pb2+ through typical Lewis baseacid reactions. The tailored electron‐donating methoxyl group (CH3O–) can cause an increased electron density on the benzene ring, which strengthens the interaction with undercoordinated Pb2+ via electrostatic interactions. This BMBC passivation can reduce the surface trap density, enlarge grains, prolong the charge lifetime, and cause a more suitable energy‐level alignment. In addition, the hydrophobic tert‐butyl in butoxycarbonyl (Boc‐) group ensures that BMBC is uniformly covered and prevents harmful aggregation through steric repulsion at the perovskite/hole–transporting layer (HTL) interface, thus providing a hydrophobic umbrella to resist moisture invasion. Consequently, the combination of the above increases the efficiency of CsPbI3−xBrx PSC from 18.6% to 21.8%, the highest efficiency for this type of inorganic metal halide PSCs so far, as far as it is known. Moreover, the device exhibits higher environmental and thermal stability.

The stability of inorganic perovskite solar cells: from materials to devices

“…Much effort have been devoted to improve the performance of IHPSCs, and the efficiency of all these three types of IHPSCs has been rapidly improved in the past few years, as shown in figure 7(b). More recently, Meng et al promoted the certificated efficiency of n-i-p-type devices to 20.1% by interface engineering and perovskite passivation, and Liu et al fabricated CsPb(I, Br) 3 -based solar cells with 21.8% efficiency by employing Boc-S-4-methoxy-benzyl-L-cysteine as a passivator to suppress halide vacancies and coordinate with undercoordinated Pb 2+ [69,70]. It is worth noting that although the high performance of IHPSCSs so far is basically based on regular structures, some dopants in the HTL used in this structure are detrimental to the stability of the device, which will be discussed in section 4.…”

“…Regarding the fabrication methods of the IHPSCs, the preparation of IHPs with high crystalline quality is a prerequisite for high device performance (table 2) [70,77,[82][83][84][85][86][87][88]. Solution processing methods, such as spin coating, is the most widely used approach for IHPs.…”

Deciphering Reaction Products in Formamidine-Based Perovskites with Methylammonium Chloride Additive

“…These chemical agents may undergo intricate reactions with the perovskite or the solvent, both in bulk and at the interface, during phases such as solution aging, − high-temperature annealing, and photostability testing. − These reaction products may be vital in addressing the challenges of improving efficiency and ensuring the long-term stability of PSCs, yet they have received limited attention and research. Additionally, the impact of inorganic , and 2D perovskites , on this matter remains unexplored.…”

“…11−13 These reaction products may be vital in addressing the challenges of improving efficiency and ensuring the long-term stability of PSCs, yet they have received limited attention and research. Additionally, the impact of inorganic 14,15 and 2D perovskites 16,17 on this matter remains unexplored.…”

Optimization and Performance Analysis of a TiO2/i-CH3NH3SnBr3/CsPbI3/Al(BSF) Heterojunction Perovskite Solar Cell for Enhanced Efficiency

“…Additionally, the organic–inorganic halide perovskite solar cells (PSCs) have gained substantial attention in the past decade and are expected to compete with conventional silicon-based solar cells due to their outstanding device performance . Among the inorganic halide perovskites, CsPbI 3 has been reported to show higher thermal stability, especially in the cubic phase, which exhibits the most suitable band gap of 1.694 eV for photovoltaic applications. , From 2015 until now, the device efficiency for CsPbI 3 has increased from 2.9% , to 19.03% and to 21.75% by the group of Shengzhong (Frank) Liu indicating its great potential for high-efficiency inorganic PSCs. TiO 2 , a wide band gap ( E g = 3.2 eV) n-type semiconductor with high electron affinity, has been successfully used in perovskite and dye-sensitized solar cells. , It is commonly used as an electron transport layer (ETL) in various types of solar cells including perovskite solar cells and dye-sensitized solar cells (DSSCs).…”