Thermally Stable Perovskite Solar Cells by All-Vacuum Deposition

Abstract

Vacuum deposition is a solvent-free method suitable for growing thin films of metal halide perovskite (MHP) semiconductors. However, most reports of high-efficiency solar cells based on such vacuum-deposited MHP films incorporate solution-processed hole transport layers (HTLs), thereby complicating prospects of industrial upscaling and potentially affecting the overall device stability. In this work, we investigate organometallic copper phthalocyanine (CuPc) and zinc phthalocyanine (ZnPc) as alternative, low-cost, and durable HTLs in all-vacuum-deposited solvent-free formamidinium-cesium lead triodide [CH(NH 2 ) 2 ] 0.83 Cs 0.17 PbI 3 (FACsPbI 3 ) perovskite solar cells. We elucidate that the CuPc HTL, when employed in an "inverted" p−i−n solar cell configuration, attains a solar-to-electrical power conversion efficiency of up to 13.9%. Importantly, unencapsulated devices as large as 1 cm 2 exhibited excellent longterm stability, demonstrating no observable degradation in efficiency after more than 5000 h in storage and 3700 h under 85 °C thermal stressing in N 2 atmosphere.

A comprehensive review on the advancements and challenges in perovskite solar cell technology

“…Noteworthy research in this field includes the work by Henry J. Snaith's team, 242 who investigated inverted perovskite solar cells using a copper phthalocyanine (CuPc) hole transport layer. This study, notable for its insights into long-term stability, showed that these solar cells demonstrated remarkable endurance.…”

A review on conventional perovskite solar cells with organic dopant-free hole-transport materials: roles of chemical structures and interfacial materials in efficient devices

“…88–90 Besides, Pcs are characterized by excellent thermal and chemical stability, which are important for device stability. 91,92 Another feature of Pc derivatives is their strong absorption in the range of 600–700 nm, and it can be easily shifted into the near-infrared (NIR) region by extending the π-conjugation. 93 The charge carrier transport material with NIR absorption is attractive since it has the potential to extend the response of PSCs.…”

High-performance self-powered ultraviolet photodetector based on a ZnO/CuPc inorganic/organic heterojunction

“…9,10 Materials like phthalocyanines (Pcs) were proven to have low molecular weight and flat organic molecular characteristics, showing great potential in the application of optoelectronic devices. 11 A typical p-type organic semiconductor material, copper phthalocyanine (CuPc), has excellent π–π stacking characteristics and photoresponse, which is often used as the hole transport layer of optoelectronic devices, 12,13 such as solar cells, 14 field effect transistors 15,16 and light-emitting diodes. 17 In addition, a CuPc film fabricated by thermal evaporation technology exhibits positive stacking characteristics, high hole mobility, excellent chemical stability, thermal stability and hydrophobicity.…”