Atomic layer deposition processed interlayers in photovoltaics: applications, challenges and perspectives

Abstract

Atomic layer deposition (ALD) has driven significant advancements in photovoltaic technologies by enabling the development of interlayers that improve both the efficiency and stability of devices. This review traces the evolution of ALD interlayers across various photovoltaic technologies, starting with early silicon solar cells and progressing into a variety of thin-film solar cells. We then delve into the role of ALD in state-of-the-art single-junction perovskite solar cells, particularly in optimizing the critical interfaces of perovskites/charge-transporting layers/electrodes. Apart from that, we screen the functionality of ALD processing, which consists of reducing surface/interfacial defects and thus mitigating energy loss. Particularly, it enables efficient stacking of multiple thin layers, making a variety of tandem solar cells possible (silicon/perovskite, etc.) for higher efficiency. Moreover, the ALD-processed interlayer prevents the ion migration between metals and perovskites, inhibiting the inter-diffusion-induced degradation of devices. Despite ALD technology extensively elevating the performance of above conventional/emerging solar cells, key challenges such as precursor flammability, cross-contamination during processing, and low deposition pace persist. We go over these challenges and expect our comprehensive overview of ALD techniques could shed light on pushing the envelope of photovoltaic efficiency.