The Application of Graphene Derivatives in Perovskite Solar Cells

Abstract

traditional power generation methods such as coal and natural gas due to the low-cost raw materials and relatively simple structures of PSCs. [14,15] Both the high efficiency and low cost make PSCs a promising candidate to realize commercialization. Currently, to further improve the performance of PSCs and accelerate the commercialization progress, there are still several challenges to be overcome. For example, the ion migration caused by weak Coulomb force in perovskite lattice is considered to be detrimental to the operational stability. [16-18] In addition, the energy loss originated from the nonradiative recombination limits the open-circuit voltage (V OC) of PSCs. [19,20] Graphene is a 2D and chemically stable material with a hexagonal honeycomb structure composed of carbon atoms, which make itself and their derivatives have multiple applications at interfaces or in functional layers of PSCs (Figure 1). [21,22] For example, the lattice parameter of graphene is 0.246 nm, which is smaller than the radius of I − (0.412 nm). [23] Therefore, it is an ideal material to block the ion migration in PSCs and improve the stability under working conditions. Furthermore, graphene derivatives have numerous derivatives with rich functional groups and adjustable band gaps, which can passivate the specific defect states by rational molecule design and therefore optimize the charge transport in PSCs and reduce the charge recombination. In addition, graphene materials have also been applied in flexible and translucent PSCs because of their semiconductor properties and foldable and transparent inherent natures. [24-26] In this paper, we introduce the history and preparation methods of graphene materials, such as the chemical vapor deposition (CVD) and oxidation-reduction methods. Then, the applications of graphene and its derivatives in PSCs are reviewed, including defect passivation, ion migration blocking, and charge transport optimization. We also summarize the progress of graphene as electrode materials in semitransparent and flexible devices. Finally, the challenges and prospects of the application of graphene materials in PSCs are proposed. 2. Graphene and Its Derivatives Carbon elements are rich in allotropes, [22] such as the 3D graphite and diamond, the 0D fullerenes (C 60) and 1D carbon Perovskite solar cells (PSCs) have attracted much attention due to their high efficiency and low manufacturing cost. However, the defects in perovskite films and the instability issue caused by ion migration limit the further improvement of its efficiency and stability. Graphene and its derivatives are potential materials to solve these problems due to their rich functional groups, environmental stability and compactness, which triggered extensive researches in recent years. In this paper, the development and preparation methods of graphene materials are summarized and then their applications in PSCs are reviewed, with particular emphasis on their function of blocking ion migration.

The Main Progress of Perovskite Solar Cells in 2020–2021

“…The chemical components of metal halide perovskite are bonded through weak interactions such as ionic interaction, hydrogen bonding, and van der Waals forces, which results in the soft-material nature of perovskite semiconductors. Irreversible decomposition of organic species and the ion migration occur easily in PSCs under moisture penetration, continuous light soaking, thermal stress, and external electric field [11,[40][41][42], which cause damage to both the perovskite and charge transport layers. On the other hand, the leakage of Pb during long-term operation of PSCs under bad weather conditions could further cause environmental and public health risk, which should also be considered as an important stability issue to be addressed for future commercialization.…”

“…Besides the efficiency progress, the long-term stability of PSCs against damp, light, and heat also improved significantly in recent years, which could be attributed to the construction of diffusion barrier against ion migration, additive engineering, design of chemically inert carbon-based electrodes, and development of cell encapsulation technique to reduce the lead leakage from a broken PSC module [11][12][13][14][15][16][17][18]. It was demonstrated that the printable PSCs had passed the most popular international standards of IEC61215:2016 for mature PV technology [19].…”

p‐Type Charge Transfer Doping of Graphene Oxide with (NiCo)1−yFeyOx for Air‐Stable, All‐Inorganic CsPbIBr2 Perovskite Solar Cells

“…As shown in Figure 4 b, the enlarged contact angle from 66° to 107° demonstrates the more hydrophobic surface of CsPbIBr 2 /NP‐GO. In addition, 2D graphene layer generally suppresses the diffusion of ions and therefore to enhance the environmental stability [5, 37, 38] . We have further aged the device under 150 °C for 16 hours to better understand the function of NP‐GO.…”

A Scalable Integrated Dopant‐Free Heterostructure to Stabilize Perovskite Solar Cell Modules

“…Moreover, although the use of a 2D network (such as graphene oxide, molybdenum disulfide, etc.) between perovskite and HTL is a considerable strategy for inhibiting ion migration from damaging the HTL, [ 28–32 ] it remains challenging to construct a robust and large‐area heterostructure without additional ionic dopants for efficient and stable PSC modules.…”