Improved Efficiency and Stability of Perovskite Solar Cells Using a Difluorobenzothiadiazole-Based Interfacial Material

Abstract

The humidity stability of the perovskite solar cell (PSC) is an important issue, which limits its commercialization and practical application. To construct a waterproof interface upon a perovskite film is a valid strategy to improve the stability. In this article, a difluorobenzothiadiazole-based polymer, PffBT4T-C9C13, is employed as an interfacial material and a water barrier on the perovskite by a well-designed deposition method. A uniform perovskite film with a large crystal grain is obtained after the decoration of the polymer owing to its positive impact on the crystal growth. PffBT4T-C9C13 not only protects perovskite from water corrosion but also passivates the surface defects of perovskite. Charge accumulation at the interface is sufficiently suppressed, which is of benefit for the charge transport and extraction. As a result, PSCs with the structure of ITO/TiO2/MA1–x FA x PbI3/PffBT4T-C9C13/spiro-MeOTAD/Ag achieve the highest power conversion efficiency of 20.21%. More importantly, remarkable improvement of the humidity stability is achieved for both perovskite films and PSCs with PffBT4T-C9C13. The unencapsulated device retains more than 80% of its highest power conversion efficiency after 14 days’ aging in humidity of about 50%, and no apparent decomposition of the modified film is observed in 93 days. Therefore, this scheme provides a valuable approach to develop highly efficient and highly stable PSCs.

Polymers in High-Efficiency Solar Cells: The Latest Reports

“…Interface engineering has been shown to be an effective method for reducing defect density in organic–inorganic hybrid PSCs and is commonly utilized to improve their performance [ 181 , 182 , 183 , 184 , 185 , 186 , 187 , 188 ].…”

“…At the interface, the charge collection was adequately suppressed, which helped with charge extraction and transport. As a consequence, the ITO/TiO 2 /MA 1−x FA x PbI 3 /PffBT4T-C9C13/spiro-MeOTAD/Ag structure of the device had the best power conversion efficiency of 19.37% (0.50 mg mL −1 of PffBT4T-C9C13) [ 185 ].…”

Bifunctional Cellulose Interlayer Enabled Efficient Perovskite Solar Cells with Simultaneously Enhanced Efficiency and Stability

“…[17][18][19] Generally, organic small molecules and polymers with different functionalities can serve as effective modifiers for optimizing interfacial contact at perovskite grain boundaries or perovskite/hole-transporting material (HTM) interface. [13][14][15][20][21][22] Compared with small molecules, polymers are found to be beneficial for durable defect passivation under a moisture atmosphere owing to their long-chain molecular structure and abundant functional group sites. [15] For example, poly(vinyl acetate), [15] poly(ethylene glycol) diacrylate, [23] poly(methyl methacrylate), [24] poly(4vinylpyridine) [25] and hetero-cycle-based (thiophene, [20] quinoxaline, [14] benzothiadiazole [22] and bithiophene imide [26] ) conjugated polymers, have been reported as adequate interfacial layers for high-performance PSCs with good stability.…”

Broad-Band-Enhanced Plasmonic Perovskite Solar Cells with Irregular Silver Nanomaterials

“…Organic–inorganic perovskite solar cells (PSCs) have great potential to rival silicon-based solar cells with their rapidly developed power conversion efficiency (PCE) in the past decade. , Many attractive strategies are proposed to further enhance the performance of PSCs, such as interfacial modification − and compositional engineering. , The incorporation of noble metal nanomaterials (NMs) is a promising strategy to boost the PCE of PSCs closer to their theoretical limit. , The collective electron oscillations in metal NMs can be excited by the incident light of a matchable frequency/wavelength, and this phenomenon is known as localized surface plasmon resonance (LSPR). Under the resonance wavelength, a highly located near-field enhancement can be generated on the surface of metal NMs.…”