Perovskite solar cells (PSCs), the third generation photovoltage technology, are obtaining more and more attention.
The power conversion efficiency of small area PSCs can reach over 25.5% by solution method. However, it is difficult to achieve uniform preparation in large area and high-throughput production by solution preparation technology, and the solvent residues also affect the stability of the devices.
Recently, a research team led by Prof. LIU Shengzhong from the Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences, in collaboration with Prof. FENG Jiangshan from Shaanxi Normal University, developed high-throughput large-area vacuum deposition for high-performance formamidine-based PSCs.
Their findings were published in Energy & Environmental Science on March 26.
(a) Schematic illustration of multisource vacuum deposition with an in-vacuum annealing process for large-area perovskite films. Photographs of FA-based perovskite films deposited on (b) glass and (c) PET substrates (Image by DUAN Lianjie and WANG Hui)
The researchers prepared CsxFA1-xPbI3 thin films with large size, high density and high quality on 400cm2 rigid and 300cm2 flexible substrates by layer-to-layer deposition technology. By combing with low vacuum and low temperature annealing strategy, they effectively regulated the nucleation and grain growth of perovskite thin films.
"The photoelectric conversion efficiency (PCE) of the PSC fabricated by combining the Spiro-OMeTAD hole transport layer (HTL) is 21.32%, which is the highest PCE of the PSC fabricated by vacuum method ever reported," said Prof. LIU.
In addition, the researchers resolved the HTLs prepared by vacuum method, and obtained PCE of 18.89% by full vacuum deposition method. The efficiency of a PSC prepared by the all-vacuum process increases by 1% from its initial value after storage in ambient in the dark for 189 days, demonstration the high stability of devices prepared by full vacuum method.
This study shows that the all-vacuum method can realize the large-area and high-throughput preparation of PSCs with high efficiency and high stability. (Text by DUAN Lianjie and WANG Hui)