With demonstrated power conversion efficiencies close to 23%, perovskite-based photovoltaics is already able to compete with established technologies like silicon, CdTe and CIGS. However, next to high efficiencies, the potential low-cost fabrication of devices with sufficient stability under real-world conditions is of key importance for the future economic prospects of the perovskite technology.
In this contribution, we report on a novel inexpensive architecture for efficient and highly reproducible, all-evaporated perovskite solar cells. Our evaporated CH3NH3PbI3 absorber is sandwiched between nickel oxide as hole transport material and C60 as electron transport material. By replacing the highly expensive hole transport layer Spiro-MeOTAD by electron-beam deposited nickel oxide and the gold back electrode by copper, we reduce the cost of materials on the lab-scale to one third of the price of the common stack based on Spiro-MeOTAD. At the same time, extraordinary stable devices even at operating temperatures of 80°C are achieved. Stabilized power conversion efficiencies under standard test conditions exceed values of 14%. Moreover, the vacuum deposition combines the ease of controlled deposition and a simple upscaling, making it a favorable process for industry. A homogenous and reproducible deposition on substrates with an area of up to 8x8 cm² is demonstrated by light beam induced current mapping, which is a fundamental requirement for the fabrication of larger prototype modules. Finally, as an inverted architecture with the anode deposited on top of the substrate the investigated layer stack is a promising candidate for two-terminal tandem devices on top of CIGS or p-type silicon.